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[v7,0/3] media: ov8856: Add devicetree support

Message ID 20200505100129.104673-1-robert.foss@linaro.org
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Series media: ov8856: Add devicetree support | expand

Message

Robert Foss May 5, 2020, 10:01 a.m. UTC
This adds devicetree support to the ov8856 driver.
In order to to aid debugging and enable future sensor
modes to be supported, module revision detection is also added.


Dongchun Zhu (1):
  media: dt-bindings: ov8856: Document YAML bindings

Robert Foss (2):
  media: ov8856: Add devicetree support
  media: ov8856: Implement sensor module revision identification

 .../devicetree/bindings/media/i2c/ov8856.yaml | 142 +++++++++++++
 MAINTAINERS                                   |   1 +
 drivers/media/i2c/ov8856.c                    | 190 ++++++++++++++++--
 3 files changed, 319 insertions(+), 14 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/media/i2c/ov8856.yaml

Comments

Marco Felsch May 5, 2020, 10:16 a.m. UTC | #1
Hi Robert,

On 20-05-05 12:01, Robert Foss wrote:
> Add match table, enable ov8856_probe() to support
> both ACPI and DT modes.
> 
> ACPI and DT modes are primarily distinguished from
> by checking for ACPI mode and by having resource like
> be NULL.
> 
> Signed-off-by: Robert Foss <robert.foss@linaro.org>
> ---
> 
> - Changes since v6:
>   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> 
> - Changes since v5:
>   * Maxime & Sakari: Replaced clock tolerance check with warning
> 
> - Changes since v4:
>   * Maxime & Sakari: Switch to clock-frequency
> 
> - Changes since v3:
>   * Remove redundant {}-brackets
>   * Compare xvclk_rate to 5% tolerance
>   * Andy: Use dev_fwnode()
>   * Andy: Use %pe instead of %ld + PTR_ERR()
>   * Andy: Invert reset_gpio logic
>   * Andy: Remove dev_dbg() from failing reset_gpio setup
>   * Andy: Use dev_err for logging for failures
>   * Andy: Remove dev_warn from EDEFER/regulator error path
>   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
>   * Maxime & Sakari: Verify clock frequency from DT
>   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
>   * Sakari: Remove duplicate ov8856->dev assignment
> 
> - Changes since v2:
>   * Added "struct device *dev" member to struct ov8856
>   * Andy: Switch to optional version of devm_gpiod_get
>   * Andy: Switch to optional version of devm_clk_get
>   * Fabio: Add reset sleep period
>   * Sakari: Unify defines for 19.2Mhz
>   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
>   * Sakari: Replace dev_info() with dev_dbg()
>   * Sakari: Switch induction variable type to unsigned
>   * Sakari: Don't wait for reset_gpio when in ACPI mode
>   * Sakari: Pull reset GPIO high on power on failure
>   * Sakari: Add power on/off to resume/suspend
>   * Sakari: Fix indentation
>   * Sakari: Power off during ov8856_remove()
>   * Sakari: Don't sleep during power-on in ACPI mode
>   * Sakari: Switch to getting xvclk from clk_get_rate
> 
> - Changes since v1:
>   * Andy & Sakari: Make XVCLK optional since to not break ACPI
>   * Fabio: Change n_shutdown_gpio name to reset_gpio
>   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change
>   * Fabio: Remove empty line
>   * Fabio: Remove real error from devm_gpiod_get() failures
>   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
>   * Sakari: Use XVCLK rate as provided by DT
> 
>  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
>  1 file changed, 123 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> index 8655842af275..e6418a79801e 100644
> --- a/drivers/media/i2c/ov8856.c
> +++ b/drivers/media/i2c/ov8856.c
> @@ -3,10 +3,13 @@
>  
>  #include <asm/unaligned.h>
>  #include <linux/acpi.h>
> +#include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
>  #include <linux/module.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-fwnode.h>
> @@ -18,7 +21,7 @@
>  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
>  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
>  #define OV8856_SCLK			144000000ULL
> -#define OV8856_MCLK			19200000
> +#define OV8856_XVCLK_19_2		19200000
>  #define OV8856_DATA_LANES		4
>  #define OV8856_RGB_DEPTH		10
>  
> @@ -64,6 +67,12 @@
>  
>  #define to_ov8856(_sd)			container_of(_sd, struct ov8856, sd)
>  
> +static const char * const ov8856_supply_names[] = {
> +	"dovdd",	/* Digital I/O power */
> +	"avdd",		/* Analog power */
> +	"dvdd",		/* Digital core power */
> +};
> +
>  enum {
>  	OV8856_LINK_FREQ_720MBPS,
>  	OV8856_LINK_FREQ_360MBPS,
> @@ -566,6 +575,11 @@ struct ov8856 {
>  	struct media_pad pad;
>  	struct v4l2_ctrl_handler ctrl_handler;
>  
> +	struct device		*dev;

Why do we need this reference here? We already have all information we
need to retrieve the device.

> +	struct clk		*xvclk;
> +	struct gpio_desc	*reset_gpio;
> +	struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)];
> +
>  	/* V4L2 Controls */
>  	struct v4l2_ctrl *link_freq;
>  	struct v4l2_ctrl *pixel_rate;
> @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable)
>  	return ret;
>  }
>  
> +static int __ov8856_power_on(struct ov8856 *ov8856)
> +{
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> +	int ret;
> +
> +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> +		return 0;
> +
> +	ret = clk_prepare_enable(ov8856->xvclk);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to enable xvclk\n");
> +		return ret;
> +	}
> +
> +	if (ov8856->reset_gpio) {
> +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +		usleep_range(1000, 2000);
> +	}
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> +				    ov8856->supplies);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to enable regulators\n");
> +		goto disable_clk;
> +	}
> +
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> +	usleep_range(1500, 1800);
> +
> +	return 0;
> +
> +disable_clk:
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +	clk_disable_unprepare(ov8856->xvclk);
> +
> +	return ret;
> +}
> +
> +static void __ov8856_power_off(struct ov8856 *ov8856)
> +{
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> +			       ov8856->supplies);

In case of ACPI this will still be a unbalanced regulator. Albeit it is a
dummy_regulator it will produce warnings in the ACPI case. Therefore I
said to add the check:

if (is_acpi_node(dev_fwnode(ov8856->dev)))
	return 0;

here to at the begin of this function.


> +	clk_disable_unprepare(ov8856->xvclk);
> +}
> +
>  static int __maybe_unused ov8856_suspend(struct device *dev)
>  {
>  	struct i2c_client *client = to_i2c_client(dev);
> @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
>  	if (ov8856->streaming)
>  		ov8856_stop_streaming(ov8856);
>  
> +	__ov8856_power_off(ov8856);
>  	mutex_unlock(&ov8856->mutex);
>  
>  	return 0;
> @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
>  	int ret;
>  
>  	mutex_lock(&ov8856->mutex);
> +
> +	__ov8856_power_on(ov8856);
>  	if (ov8856->streaming) {
>  		ret = ov8856_start_streaming(ov8856);
>  		if (ret) {
> @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
>  	return 0;
>  }
>  
> -static int ov8856_check_hwcfg(struct device *dev)
> +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
>  {
> +	struct device *dev = ov8856->dev;
>  	struct fwnode_handle *ep;
>  	struct fwnode_handle *fwnode = dev_fwnode(dev);
>  	struct v4l2_fwnode_endpoint bus_cfg = {
>  		.bus_type = V4L2_MBUS_CSI2_DPHY
>  	};
> -	u32 mclk;
> +	u32 xvclk_rate;
>  	int ret;
>  	unsigned int i, j;
>  
>  	if (!fwnode)
>  		return -ENXIO;
>  
> -	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> +		&xvclk_rate);
>  	if (ret)
>  		return ret;
>  
> -	if (mclk != OV8856_MCLK) {
> -		dev_err(dev, "external clock %d is not supported", mclk);
> -		return -EINVAL;
> +	if (!is_acpi_node(fwnode)) {
> +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> +		if (IS_ERR(ov8856->xvclk)) {
> +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> +					ov8856->xvclk);

I tought I commented this to. Pls align it :)

Regards,
  Marco

> +			return PTR_ERR(ov8856->xvclk);
> +		}
> +
> +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> +		xvclk_rate = clk_get_rate(ov8856->xvclk);
>  	}
>  
> +	if (xvclk_rate != OV8856_XVCLK_19_2)
> +		dev_warn(dev, "external clock rate %d is unsupported", xvclk_rate);
> +
> +	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> +		GPIOD_OUT_LOW);
> +	if (IS_ERR(ov8856->reset_gpio))
> +		return PTR_ERR(ov8856->reset_gpio);
> +
> +	for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> +		ov8856->supplies[i].supply = ov8856_supply_names[i];
> +
> +	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(ov8856_supply_names),
> +				      ov8856->supplies);
> +	if (ret)
> +		return ret;
> +
>  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
>  	if (!ep)
>  		return -ENXIO;
> @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
>  	pm_runtime_disable(&client->dev);
>  	mutex_destroy(&ov8856->mutex);
>  
> +	__ov8856_power_off(ov8856);
> +
>  	return 0;
>  }
>  
> @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
>  	struct ov8856 *ov8856;
>  	int ret;
>  
> -	ret = ov8856_check_hwcfg(&client->dev);
> +	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> +	if (!ov8856)
> +		return -ENOMEM;
> +
> +	ov8856->dev = &client->dev;
> +
> +	ret = ov8856_get_hwcfg(ov8856);
>  	if (ret) {
> -		dev_err(&client->dev, "failed to check HW configuration: %d",
> +		dev_err(&client->dev, "failed to get HW configuration: %d",
>  			ret);
>  		return ret;
>  	}
>  
> -	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> -	if (!ov8856)
> -		return -ENOMEM;
> -
>  	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> +
> +	ret = __ov8856_power_on(ov8856);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to power on\n");
> +		return ret;
> +	}
> +
>  	ret = ov8856_identify_module(ov8856);
>  	if (ret) {
>  		dev_err(&client->dev, "failed to find sensor: %d", ret);
> -		return ret;
> +		goto probe_power_off;
>  	}
>  
>  	mutex_init(&ov8856->mutex);
> @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
>  	v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
>  	mutex_destroy(&ov8856->mutex);
>  
> +probe_power_off:
> +	__ov8856_power_off(ov8856);
> +
>  	return ret;
>  }
>  
> @@ -1254,11 +1356,18 @@ static const struct acpi_device_id ov8856_acpi_ids[] = {
>  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);
>  #endif
>  
> +static const struct of_device_id ov8856_of_match[] = {
> +	{ .compatible = "ovti,ov8856" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> +
>  static struct i2c_driver ov8856_i2c_driver = {
>  	.driver = {
>  		.name = "ov8856",
>  		.pm = &ov8856_pm_ops,
>  		.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> +		.of_match_table = ov8856_of_match,
>  	},
>  	.probe_new = ov8856_probe,
>  	.remove = ov8856_remove,
> -- 
> 2.25.1
> 
>
Marco Felsch May 5, 2020, 10:17 a.m. UTC | #2
Hi Robert,

On 20-05-05 12:01, Robert Foss wrote:
> Query the sensor for its module revision, and compare it
> to known revisions.
> 
> Currently 2A and 1B revision indentification is supported.
> 
> Signed-off-by: Robert Foss <robert.foss@linaro.org>
> ---
> 
> - Changes since v3:
>   * Actually add module revision 2A
> 
> - Changes since v2:
>   * Add module revision 2A
>   * Sakari: Remove ov8856_check_revision()
>   * Sakari: Stop EEPROM streaming mode
> 
>  drivers/media/i2c/ov8856.c | 53 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 53 insertions(+)
> 
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> index e6418a79801e..3c82c3e588d7 100644
> --- a/drivers/media/i2c/ov8856.c
> +++ b/drivers/media/i2c/ov8856.c
> @@ -32,6 +32,19 @@
>  #define OV8856_MODE_STANDBY		0x00
>  #define OV8856_MODE_STREAMING		0x01
>  
> +/* module revisions */
> +#define OV8856_2A_MODULE		0x01
> +#define OV8856_1B_MODULE		0x02
> +
> +/* the OTP read-out buffer is at 0x7000 and 0xf is the offset
> + * of the byte in the OTP that means the module revision
> + */
> +#define OV8856_MODULE_REVISION		0x700f
> +#define OV8856_OTP_MODE_CTRL		0x3d84
> +#define OV8856_OTP_LOAD_CTRL		0x3d81
> +#define OV8856_OTP_MODE_AUTO		0x00
> +#define OV8856_OTP_LOAD_CTRL_ENABLE	BIT(0)
> +
>  /* vertical-timings from sensor */
>  #define OV8856_REG_VTS			0x380e
>  #define OV8856_VTS_MAX			0x7fff
> @@ -1152,6 +1165,46 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
>  		return -ENXIO;
>  	}
>  
> +	ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> +			       OV8856_REG_VALUE_08BIT, OV8856_MODE_STREAMING);
> +	if (ret)
> +		return ret;
> +
> +	ret = ov8856_write_reg(ov8856, OV8856_OTP_MODE_CTRL,
> +			       OV8856_REG_VALUE_08BIT, OV8856_OTP_MODE_AUTO);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to set otp mode");
> +		return ret;
> +	}
> +
> +	ret = ov8856_write_reg(ov8856, OV8856_OTP_LOAD_CTRL,
> +			       OV8856_REG_VALUE_08BIT,
> +			       OV8856_OTP_LOAD_CTRL_ENABLE);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to enable load control");
> +		return ret;
> +	}
> +
> +	ret = ov8856_read_reg(ov8856, OV8856_MODULE_REVISION,
> +			      OV8856_REG_VALUE_08BIT, &val);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to read module revision");
> +		return ret;
> +	}
> +
> +	dev_info(&client->dev, "OV8856 revision %x (%s) at address 0x%02x\n",
> +		val,
> +		val == OV8856_2A_MODULE ? "2A" :
> +		val == OV8856_1B_MODULE ? "1B" : "unknown revision",
> +		client->addr);

Pls check the alignment here too.

Regards,
  Marco

> +
> +	ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> +			       OV8856_REG_VALUE_08BIT, OV8856_MODE_STANDBY);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to exit streaming mode");
> +		return ret;
> +	}
> +
>  	return 0;
>  }
>  
> -- 
> 2.25.1
Robert Foss May 6, 2020, 2:43 p.m. UTC | #3
On Tue, 5 May 2020 at 12:16, Marco Felsch <m.felsch@pengutronix.de> wrote:
>
> Hi Robert,
>
> On 20-05-05 12:01, Robert Foss wrote:
> > Add match table, enable ov8856_probe() to support
> > both ACPI and DT modes.
> >
> > ACPI and DT modes are primarily distinguished from
> > by checking for ACPI mode and by having resource like
> > be NULL.
> >
> > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > ---
> >
> > - Changes since v6:
> >   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> >
> > - Changes since v5:
> >   * Maxime & Sakari: Replaced clock tolerance check with warning
> >
> > - Changes since v4:
> >   * Maxime & Sakari: Switch to clock-frequency
> >
> > - Changes since v3:
> >   * Remove redundant {}-brackets
> >   * Compare xvclk_rate to 5% tolerance
> >   * Andy: Use dev_fwnode()
> >   * Andy: Use %pe instead of %ld + PTR_ERR()
> >   * Andy: Invert reset_gpio logic
> >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> >   * Andy: Use dev_err for logging for failures
> >   * Andy: Remove dev_warn from EDEFER/regulator error path
> >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> >   * Maxime & Sakari: Verify clock frequency from DT
> >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> >   * Sakari: Remove duplicate ov8856->dev assignment
> >
> > - Changes since v2:
> >   * Added "struct device *dev" member to struct ov8856
> >   * Andy: Switch to optional version of devm_gpiod_get
> >   * Andy: Switch to optional version of devm_clk_get
> >   * Fabio: Add reset sleep period
> >   * Sakari: Unify defines for 19.2Mhz
> >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> >   * Sakari: Replace dev_info() with dev_dbg()
> >   * Sakari: Switch induction variable type to unsigned
> >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> >   * Sakari: Pull reset GPIO high on power on failure
> >   * Sakari: Add power on/off to resume/suspend
> >   * Sakari: Fix indentation
> >   * Sakari: Power off during ov8856_remove()
> >   * Sakari: Don't sleep during power-on in ACPI mode
> >   * Sakari: Switch to getting xvclk from clk_get_rate
> >
> > - Changes since v1:
> >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> >   * Fabio: Change n_shutdown_gpio name to reset_gpio
> >   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW change
> >   * Fabio: Remove empty line
> >   * Fabio: Remove real error from devm_gpiod_get() failures
> >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> >   * Sakari: Use XVCLK rate as provided by DT
> >
> >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> >  1 file changed, 123 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > index 8655842af275..e6418a79801e 100644
> > --- a/drivers/media/i2c/ov8856.c
> > +++ b/drivers/media/i2c/ov8856.c
> > @@ -3,10 +3,13 @@
> >
> >  #include <asm/unaligned.h>
> >  #include <linux/acpi.h>
> > +#include <linux/clk.h>
> >  #include <linux/delay.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/i2c.h>
> >  #include <linux/module.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regulator/consumer.h>
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-device.h>
> >  #include <media/v4l2-fwnode.h>
> > @@ -18,7 +21,7 @@
> >  #define OV8856_LINK_FREQ_360MHZ              360000000ULL
> >  #define OV8856_LINK_FREQ_180MHZ              180000000ULL
> >  #define OV8856_SCLK                  144000000ULL
> > -#define OV8856_MCLK                  19200000
> > +#define OV8856_XVCLK_19_2            19200000
> >  #define OV8856_DATA_LANES            4
> >  #define OV8856_RGB_DEPTH             10
> >
> > @@ -64,6 +67,12 @@
> >
> >  #define to_ov8856(_sd)                       container_of(_sd, struct ov8856, sd)
> >
> > +static const char * const ov8856_supply_names[] = {
> > +     "dovdd",        /* Digital I/O power */
> > +     "avdd",         /* Analog power */
> > +     "dvdd",         /* Digital core power */
> > +};
> > +
> >  enum {
> >       OV8856_LINK_FREQ_720MBPS,
> >       OV8856_LINK_FREQ_360MBPS,
> > @@ -566,6 +575,11 @@ struct ov8856 {
> >       struct media_pad pad;
> >       struct v4l2_ctrl_handler ctrl_handler;
> >
> > +     struct device           *dev;
>
> Why do we need this reference here? We already have all information we
> need to retrieve the device.

Ack, I'll remove it in the next revision.

>
> > +     struct clk              *xvclk;
> > +     struct gpio_desc        *reset_gpio;
> > +     struct regulator_bulk_data supplies[ARRAY_SIZE(ov8856_supply_names)];
> > +
> >       /* V4L2 Controls */
> >       struct v4l2_ctrl *link_freq;
> >       struct v4l2_ctrl *pixel_rate;
> > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd, int enable)
> >       return ret;
> >  }
> >
> > +static int __ov8856_power_on(struct ov8856 *ov8856)
> > +{
> > +     struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > +     int ret;
> > +
> > +     if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > +             return 0;
> > +
> > +     ret = clk_prepare_enable(ov8856->xvclk);
> > +     if (ret < 0) {
> > +             dev_err(&client->dev, "failed to enable xvclk\n");
> > +             return ret;
> > +     }
> > +
> > +     if (ov8856->reset_gpio) {
> > +             gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +             usleep_range(1000, 2000);
> > +     }
> > +
> > +     ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> > +                                 ov8856->supplies);
> > +     if (ret < 0) {
> > +             dev_err(&client->dev, "failed to enable regulators\n");
> > +             goto disable_clk;
> > +     }
> > +
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> > +     usleep_range(1500, 1800);
> > +
> > +     return 0;
> > +
> > +disable_clk:
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +     clk_disable_unprepare(ov8856->xvclk);
> > +
> > +     return ret;
> > +}
> > +
> > +static void __ov8856_power_off(struct ov8856 *ov8856)
> > +{
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +     regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > +                            ov8856->supplies);
>
> In case of ACPI this will still be a unbalanced regulator. Albeit it is a
> dummy_regulator it will produce warnings in the ACPI case. Therefore I
> said to add the check:
>
> if (is_acpi_node(dev_fwnode(ov8856->dev)))
>         return 0;
>
> here to at the begin of this function.

Ah, I thought the dummy regulators wouldn't generate an error. I'll
add the early escape for ACPI.

>
>
> > +     clk_disable_unprepare(ov8856->xvclk);
> > +}
> > +
> >  static int __maybe_unused ov8856_suspend(struct device *dev)
> >  {
> >       struct i2c_client *client = to_i2c_client(dev);
> > @@ -918,6 +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> >       if (ov8856->streaming)
> >               ov8856_stop_streaming(ov8856);
> >
> > +     __ov8856_power_off(ov8856);
> >       mutex_unlock(&ov8856->mutex);
> >
> >       return 0;
> > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct device *dev)
> >       int ret;
> >
> >       mutex_lock(&ov8856->mutex);
> > +
> > +     __ov8856_power_on(ov8856);
> >       if (ov8856->streaming) {
> >               ret = ov8856_start_streaming(ov8856);
> >               if (ret) {
> > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> >       return 0;
> >  }
> >
> > -static int ov8856_check_hwcfg(struct device *dev)
> > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> >  {
> > +     struct device *dev = ov8856->dev;
> >       struct fwnode_handle *ep;
> >       struct fwnode_handle *fwnode = dev_fwnode(dev);
> >       struct v4l2_fwnode_endpoint bus_cfg = {
> >               .bus_type = V4L2_MBUS_CSI2_DPHY
> >       };
> > -     u32 mclk;
> > +     u32 xvclk_rate;
> >       int ret;
> >       unsigned int i, j;
> >
> >       if (!fwnode)
> >               return -ENXIO;
> >
> > -     ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> > +     ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > +             &xvclk_rate);
> >       if (ret)
> >               return ret;
> >
> > -     if (mclk != OV8856_MCLK) {
> > -             dev_err(dev, "external clock %d is not supported", mclk);
> > -             return -EINVAL;
> > +     if (!is_acpi_node(fwnode)) {
> > +             ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > +             if (IS_ERR(ov8856->xvclk)) {
> > +                     dev_err(dev, "could not get xvclk clock (%pe)\n",
> > +                                     ov8856->xvclk);
>
> I tought I commented this to. Pls align it :)

Done!

>
> Regards,
>   Marco
>
Robert Foss May 6, 2020, 2:48 p.m. UTC | #4
Hey Marco,

On Tue, 5 May 2020 at 12:17, Marco Felsch <m.felsch@pengutronix.de> wrote:
>
> Hi Robert,
>
> On 20-05-05 12:01, Robert Foss wrote:
> > Query the sensor for its module revision, and compare it
> > to known revisions.
> >
> > Currently 2A and 1B revision indentification is supported.
> >
> > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > ---
> >
> > - Changes since v3:
> >   * Actually add module revision 2A
> >
> > - Changes since v2:
> >   * Add module revision 2A
> >   * Sakari: Remove ov8856_check_revision()
> >   * Sakari: Stop EEPROM streaming mode
> >
> >  drivers/media/i2c/ov8856.c | 53 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > index e6418a79801e..3c82c3e588d7 100644
> > --- a/drivers/media/i2c/ov8856.c
> > +++ b/drivers/media/i2c/ov8856.c
> > @@ -32,6 +32,19 @@
> >  #define OV8856_MODE_STANDBY          0x00
> >  #define OV8856_MODE_STREAMING                0x01
> >
> > +/* module revisions */
> > +#define OV8856_2A_MODULE             0x01
> > +#define OV8856_1B_MODULE             0x02
> > +
> > +/* the OTP read-out buffer is at 0x7000 and 0xf is the offset
> > + * of the byte in the OTP that means the module revision
> > + */
> > +#define OV8856_MODULE_REVISION               0x700f
> > +#define OV8856_OTP_MODE_CTRL         0x3d84
> > +#define OV8856_OTP_LOAD_CTRL         0x3d81
> > +#define OV8856_OTP_MODE_AUTO         0x00
> > +#define OV8856_OTP_LOAD_CTRL_ENABLE  BIT(0)
> > +
> >  /* vertical-timings from sensor */
> >  #define OV8856_REG_VTS                       0x380e
> >  #define OV8856_VTS_MAX                       0x7fff
> > @@ -1152,6 +1165,46 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> >               return -ENXIO;
> >       }
> >
> > +     ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_MODE_STREAMING);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_OTP_MODE_CTRL,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_OTP_MODE_AUTO);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to set otp mode");
> > +             return ret;
> > +     }
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_OTP_LOAD_CTRL,
> > +                            OV8856_REG_VALUE_08BIT,
> > +                            OV8856_OTP_LOAD_CTRL_ENABLE);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to enable load control");
> > +             return ret;
> > +     }
> > +
> > +     ret = ov8856_read_reg(ov8856, OV8856_MODULE_REVISION,
> > +                           OV8856_REG_VALUE_08BIT, &val);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to read module revision");
> > +             return ret;
> > +     }
> > +
> > +     dev_info(&client->dev, "OV8856 revision %x (%s) at address 0x%02x\n",
> > +             val,
> > +             val == OV8856_2A_MODULE ? "2A" :
> > +             val == OV8856_1B_MODULE ? "1B" : "unknown revision",
> > +             client->addr);
>
> Pls check the alignment here too.

Ack.

>
> Regards,
>   Marco
>
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_MODE_STANDBY);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to exit streaming mode");
> > +             return ret;
> > +     }
> > +
> >       return 0;
> >  }
> >
> > --
> > 2.25.1
Kao, Ben May 7, 2020, 8:06 a.m. UTC | #5
Hi Robert,

On 20-05-05 12:01, Robert Foss wrote:
> Add match table, enable ov8856_probe() to support both ACPI and DT modes.
> 
> ACPI and DT modes are primarily distinguished from by checking for ACPI mode
> and by having resource like be NULL.
> 
> Signed-off-by: Robert Foss <robert.foss@linaro.org>
> ---
> 
> - Changes since v6:
>   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> 
> - Changes since v5:
>   * Maxime & Sakari: Replaced clock tolerance check with warning
> 
> - Changes since v4:
>   * Maxime & Sakari: Switch to clock-frequency
> 
> - Changes since v3:
>   * Remove redundant {}-brackets
>   * Compare xvclk_rate to 5% tolerance
>   * Andy: Use dev_fwnode()
>   * Andy: Use %pe instead of %ld + PTR_ERR()
>   * Andy: Invert reset_gpio logic
>   * Andy: Remove dev_dbg() from failing reset_gpio setup
>   * Andy: Use dev_err for logging for failures
>   * Andy: Remove dev_warn from EDEFER/regulator error path
>   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
>   * Maxime & Sakari: Verify clock frequency from DT
>   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
>   * Sakari: Remove duplicate ov8856->dev assignment
> 
> - Changes since v2:
>   * Added "struct device *dev" member to struct ov8856
>   * Andy: Switch to optional version of devm_gpiod_get
>   * Andy: Switch to optional version of devm_clk_get
>   * Fabio: Add reset sleep period
>   * Sakari: Unify defines for 19.2Mhz
>   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
>   * Sakari: Replace dev_info() with dev_dbg()
>   * Sakari: Switch induction variable type to unsigned
>   * Sakari: Don't wait for reset_gpio when in ACPI mode
>   * Sakari: Pull reset GPIO high on power on failure
>   * Sakari: Add power on/off to resume/suspend
>   * Sakari: Fix indentation
>   * Sakari: Power off during ov8856_remove()
>   * Sakari: Don't sleep during power-on in ACPI mode
>   * Sakari: Switch to getting xvclk from clk_get_rate
> 
> - Changes since v1:
>   * Andy & Sakari: Make XVCLK optional since to not break ACPI
>   * Fabio: Change n_shutdown_gpio name to reset_gpio
>   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW
> change
>   * Fabio: Remove empty line
>   * Fabio: Remove real error from devm_gpiod_get() failures
>   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
>   * Sakari: Use XVCLK rate as provided by DT
> 
>  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
>  1 file changed, 123 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c index
> 8655842af275..e6418a79801e 100644
> --- a/drivers/media/i2c/ov8856.c
> +++ b/drivers/media/i2c/ov8856.c
> @@ -3,10 +3,13 @@
> 
>  #include <asm/unaligned.h>
>  #include <linux/acpi.h>
> +#include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
>  #include <linux/module.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regulator/consumer.h>
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-device.h>
>  #include <media/v4l2-fwnode.h>
> @@ -18,7 +21,7 @@
>  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
>  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
>  #define OV8856_SCLK			144000000ULL
> -#define OV8856_MCLK			19200000
> +#define OV8856_XVCLK_19_2		19200000
>  #define OV8856_DATA_LANES		4
>  #define OV8856_RGB_DEPTH		10
> 
> @@ -64,6 +67,12 @@
> 
>  #define to_ov8856(_sd)			container_of(_sd, struct ov8856, sd)
> 
> +static const char * const ov8856_supply_names[] = {
> +	"dovdd",	/* Digital I/O power */
> +	"avdd",		/* Analog power */
> +	"dvdd",		/* Digital core power */
> +};
> +
>  enum {
>  	OV8856_LINK_FREQ_720MBPS,
>  	OV8856_LINK_FREQ_360MBPS,
> @@ -566,6 +575,11 @@ struct ov8856 {
>  	struct media_pad pad;
>  	struct v4l2_ctrl_handler ctrl_handler;
> 
> +	struct device		*dev;
> +	struct clk		*xvclk;
> +	struct gpio_desc	*reset_gpio;
> +	struct regulator_bulk_data
> supplies[ARRAY_SIZE(ov8856_supply_names)];
> +
>  	/* V4L2 Controls */
>  	struct v4l2_ctrl *link_freq;
>  	struct v4l2_ctrl *pixel_rate;
> @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd,
> int enable)
>  	return ret;
>  }
> 
> +static int __ov8856_power_on(struct ov8856 *ov8856) {
> +	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> +	int ret;
> +
> +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> +		return 0;
> +
> +	ret = clk_prepare_enable(ov8856->xvclk);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to enable xvclk\n");
> +		return ret;
> +	}
> +
> +	if (ov8856->reset_gpio) {
> +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +		usleep_range(1000, 2000);
> +	}
> +
> +	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> +				    ov8856->supplies);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "failed to enable regulators\n");
> +		goto disable_clk;
> +	}
> +
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> +	usleep_range(1500, 1800);
> +
> +	return 0;
> +
> +disable_clk:
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +	clk_disable_unprepare(ov8856->xvclk);
> +
> +	return ret;
> +}
> +
> +static void __ov8856_power_off(struct ov8856 *ov8856) {
> +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> +			       ov8856->supplies);
> +	clk_disable_unprepare(ov8856->xvclk);
> +}
> +
>  static int __maybe_unused ov8856_suspend(struct device *dev)  {
>  	struct i2c_client *client = to_i2c_client(dev); @@ -918,6 +978,7 @@
> static int __maybe_unused ov8856_suspend(struct device *dev)
>  	if (ov8856->streaming)
>  		ov8856_stop_streaming(ov8856);
> 
> +	__ov8856_power_off(ov8856);
>  	mutex_unlock(&ov8856->mutex);
> 
>  	return 0;
> @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct
> device *dev)
>  	int ret;
> 
>  	mutex_lock(&ov8856->mutex);
> +
> +	__ov8856_power_on(ov8856);
>  	if (ov8856->streaming) {
>  		ret = ov8856_start_streaming(ov8856);
>  		if (ret) {
> @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856
> *ov8856)
>  	return 0;
>  }
> 
> -static int ov8856_check_hwcfg(struct device *dev)
> +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
>  {
> +	struct device *dev = ov8856->dev;
>  	struct fwnode_handle *ep;
>  	struct fwnode_handle *fwnode = dev_fwnode(dev);
>  	struct v4l2_fwnode_endpoint bus_cfg = {
>  		.bus_type = V4L2_MBUS_CSI2_DPHY
>  	};
> -	u32 mclk;
> +	u32 xvclk_rate;
>  	int ret;
>  	unsigned int i, j;
> 
>  	if (!fwnode)
>  		return -ENXIO;
> 
> -	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> +		&xvclk_rate);
>  	if (ret)
>  		return ret;
> 
> -	if (mclk != OV8856_MCLK) {
> -		dev_err(dev, "external clock %d is not supported", mclk);
> -		return -EINVAL;
> +	if (!is_acpi_node(fwnode)) {
> +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> +		if (IS_ERR(ov8856->xvclk)) {
> +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> +					ov8856->xvclk);
> +			return PTR_ERR(ov8856->xvclk);
> +		}
> +
> +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> +		xvclk_rate = clk_get_rate(ov8856->xvclk);
>  	}
> 
> +	if (xvclk_rate != OV8856_XVCLK_19_2)
> +		dev_warn(dev, "external clock rate %d is unsupported",
> xvclk_rate);
> +
> +	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> +		GPIOD_OUT_LOW);
> +	if (IS_ERR(ov8856->reset_gpio))
> +		return PTR_ERR(ov8856->reset_gpio);
> +
> +	for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> +		ov8856->supplies[i].supply = ov8856_supply_names[i];
> +
> +	ret = devm_regulator_bulk_get(dev,
> ARRAY_SIZE(ov8856_supply_names),
> +				      ov8856->supplies);
> +	if (ret)
> +		return ret;
> +

In case of ACPI this cannot get ov8856->reset_gpio  and ov8856->supplies, please add the check for ACPI case:
if (!is_acpi_node(fwnode)) { }

Thanks.
Ben

>  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
>  	if (!ep)
>  		return -ENXIO;
> @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
>  	pm_runtime_disable(&client->dev);
>  	mutex_destroy(&ov8856->mutex);
> 
> +	__ov8856_power_off(ov8856);
> +
>  	return 0;
>  }
> 
> @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
>  	struct ov8856 *ov8856;
>  	int ret;
> 
> -	ret = ov8856_check_hwcfg(&client->dev);
> +	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> +	if (!ov8856)
> +		return -ENOMEM;
> +
> +	ov8856->dev = &client->dev;
> +
> +	ret = ov8856_get_hwcfg(ov8856);
>  	if (ret) {
> -		dev_err(&client->dev, "failed to check HW configuration: %d",
> +		dev_err(&client->dev, "failed to get HW configuration: %d",
>  			ret);
>  		return ret;
>  	}
> 
> -	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> -	if (!ov8856)
> -		return -ENOMEM;
> -
>  	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> +
> +	ret = __ov8856_power_on(ov8856);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to power on\n");
> +		return ret;
> +	}
> +
>  	ret = ov8856_identify_module(ov8856);
>  	if (ret) {
>  		dev_err(&client->dev, "failed to find sensor: %d", ret);
> -		return ret;
> +		goto probe_power_off;
>  	}
> 
>  	mutex_init(&ov8856->mutex);
> @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
>  	v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
>  	mutex_destroy(&ov8856->mutex);
> 
> +probe_power_off:
> +	__ov8856_power_off(ov8856);
> +
>  	return ret;
>  }
> 
> @@ -1254,11 +1356,18 @@ static const struct acpi_device_id ov8856_acpi_ids[]
> = {  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);  #endif
> 
> +static const struct of_device_id ov8856_of_match[] = {
> +	{ .compatible = "ovti,ov8856" },
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> +
>  static struct i2c_driver ov8856_i2c_driver = {
>  	.driver = {
>  		.name = "ov8856",
>  		.pm = &ov8856_pm_ops,
>  		.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> +		.of_match_table = ov8856_of_match,
>  	},
>  	.probe_new = ov8856_probe,
>  	.remove = ov8856_remove,
> --
> 2.25.1
Marco Felsch May 7, 2020, 8:21 a.m. UTC | #6
Hi Ben,

On 20-05-07 08:06, Kao, Ben wrote:
> Hi Robert,
> 
> On 20-05-05 12:01, Robert Foss wrote:
> > Add match table, enable ov8856_probe() to support both ACPI and DT modes.
> > 
> > ACPI and DT modes are primarily distinguished from by checking for ACPI mode
> > and by having resource like be NULL.
> > 
> > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > ---
> > 
> > - Changes since v6:
> >   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> > 
> > - Changes since v5:
> >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > 
> > - Changes since v4:
> >   * Maxime & Sakari: Switch to clock-frequency
> > 
> > - Changes since v3:
> >   * Remove redundant {}-brackets
> >   * Compare xvclk_rate to 5% tolerance
> >   * Andy: Use dev_fwnode()
> >   * Andy: Use %pe instead of %ld + PTR_ERR()
> >   * Andy: Invert reset_gpio logic
> >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> >   * Andy: Use dev_err for logging for failures
> >   * Andy: Remove dev_warn from EDEFER/regulator error path
> >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> >   * Maxime & Sakari: Verify clock frequency from DT
> >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> >   * Sakari: Remove duplicate ov8856->dev assignment
> > 
> > - Changes since v2:
> >   * Added "struct device *dev" member to struct ov8856
> >   * Andy: Switch to optional version of devm_gpiod_get
> >   * Andy: Switch to optional version of devm_clk_get
> >   * Fabio: Add reset sleep period
> >   * Sakari: Unify defines for 19.2Mhz
> >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> >   * Sakari: Replace dev_info() with dev_dbg()
> >   * Sakari: Switch induction variable type to unsigned
> >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> >   * Sakari: Pull reset GPIO high on power on failure
> >   * Sakari: Add power on/off to resume/suspend
> >   * Sakari: Fix indentation
> >   * Sakari: Power off during ov8856_remove()
> >   * Sakari: Don't sleep during power-on in ACPI mode
> >   * Sakari: Switch to getting xvclk from clk_get_rate
> > 
> > - Changes since v1:
> >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> >   * Fabio: Change n_shutdown_gpio name to reset_gpio
> >   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW
> > change
> >   * Fabio: Remove empty line
> >   * Fabio: Remove real error from devm_gpiod_get() failures
> >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> >   * Sakari: Use XVCLK rate as provided by DT
> > 
> >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> >  1 file changed, 123 insertions(+), 14 deletions(-)
> > 
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c index
> > 8655842af275..e6418a79801e 100644
> > --- a/drivers/media/i2c/ov8856.c
> > +++ b/drivers/media/i2c/ov8856.c
> > @@ -3,10 +3,13 @@
> > 
> >  #include <asm/unaligned.h>
> >  #include <linux/acpi.h>
> > +#include <linux/clk.h>
> >  #include <linux/delay.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/i2c.h>
> >  #include <linux/module.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regulator/consumer.h>
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-device.h>
> >  #include <media/v4l2-fwnode.h>
> > @@ -18,7 +21,7 @@
> >  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
> >  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
> >  #define OV8856_SCLK			144000000ULL
> > -#define OV8856_MCLK			19200000
> > +#define OV8856_XVCLK_19_2		19200000
> >  #define OV8856_DATA_LANES		4
> >  #define OV8856_RGB_DEPTH		10
> > 
> > @@ -64,6 +67,12 @@
> > 
> >  #define to_ov8856(_sd)			container_of(_sd, struct ov8856, sd)
> > 
> > +static const char * const ov8856_supply_names[] = {
> > +	"dovdd",	/* Digital I/O power */
> > +	"avdd",		/* Analog power */
> > +	"dvdd",		/* Digital core power */
> > +};
> > +
> >  enum {
> >  	OV8856_LINK_FREQ_720MBPS,
> >  	OV8856_LINK_FREQ_360MBPS,
> > @@ -566,6 +575,11 @@ struct ov8856 {
> >  	struct media_pad pad;
> >  	struct v4l2_ctrl_handler ctrl_handler;
> > 
> > +	struct device		*dev;
> > +	struct clk		*xvclk;
> > +	struct gpio_desc	*reset_gpio;
> > +	struct regulator_bulk_data
> > supplies[ARRAY_SIZE(ov8856_supply_names)];
> > +
> >  	/* V4L2 Controls */
> >  	struct v4l2_ctrl *link_freq;
> >  	struct v4l2_ctrl *pixel_rate;
> > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd,
> > int enable)
> >  	return ret;
> >  }
> > 
> > +static int __ov8856_power_on(struct ov8856 *ov8856) {
> > +	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > +	int ret;
> > +
> > +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > +		return 0;
> > +
> > +	ret = clk_prepare_enable(ov8856->xvclk);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > +		return ret;
> > +	}
> > +
> > +	if (ov8856->reset_gpio) {
> > +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +		usleep_range(1000, 2000);
> > +	}
> > +
> > +	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> > +				    ov8856->supplies);
> > +	if (ret < 0) {
> > +		dev_err(&client->dev, "failed to enable regulators\n");
> > +		goto disable_clk;
> > +	}
> > +
> > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> > +	usleep_range(1500, 1800);
> > +
> > +	return 0;
> > +
> > +disable_clk:
> > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +	clk_disable_unprepare(ov8856->xvclk);
> > +
> > +	return ret;
> > +}
> > +
> > +static void __ov8856_power_off(struct ov8856 *ov8856) {
> > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > +			       ov8856->supplies);
> > +	clk_disable_unprepare(ov8856->xvclk);
> > +}
> > +
> >  static int __maybe_unused ov8856_suspend(struct device *dev)  {
> >  	struct i2c_client *client = to_i2c_client(dev); @@ -918,6 +978,7 @@
> > static int __maybe_unused ov8856_suspend(struct device *dev)
> >  	if (ov8856->streaming)
> >  		ov8856_stop_streaming(ov8856);
> > 
> > +	__ov8856_power_off(ov8856);
> >  	mutex_unlock(&ov8856->mutex);
> > 
> >  	return 0;
> > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct
> > device *dev)
> >  	int ret;
> > 
> >  	mutex_lock(&ov8856->mutex);
> > +
> > +	__ov8856_power_on(ov8856);
> >  	if (ov8856->streaming) {
> >  		ret = ov8856_start_streaming(ov8856);
> >  		if (ret) {
> > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856
> > *ov8856)
> >  	return 0;
> >  }
> > 
> > -static int ov8856_check_hwcfg(struct device *dev)
> > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> >  {
> > +	struct device *dev = ov8856->dev;
> >  	struct fwnode_handle *ep;
> >  	struct fwnode_handle *fwnode = dev_fwnode(dev);
> >  	struct v4l2_fwnode_endpoint bus_cfg = {
> >  		.bus_type = V4L2_MBUS_CSI2_DPHY
> >  	};
> > -	u32 mclk;
> > +	u32 xvclk_rate;
> >  	int ret;
> >  	unsigned int i, j;
> > 
> >  	if (!fwnode)
> >  		return -ENXIO;
> > 
> > -	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> > +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > +		&xvclk_rate);
> >  	if (ret)
> >  		return ret;
> > 
> > -	if (mclk != OV8856_MCLK) {
> > -		dev_err(dev, "external clock %d is not supported", mclk);
> > -		return -EINVAL;
> > +	if (!is_acpi_node(fwnode)) {
> > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > +		if (IS_ERR(ov8856->xvclk)) {
> > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > +					ov8856->xvclk);
> > +			return PTR_ERR(ov8856->xvclk);
> > +		}
> > +
> > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> >  	}
> > 
> > +	if (xvclk_rate != OV8856_XVCLK_19_2)
> > +		dev_warn(dev, "external clock rate %d is unsupported",
> > xvclk_rate);
> > +
> > +	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > +		GPIOD_OUT_LOW);
> > +	if (IS_ERR(ov8856->reset_gpio))
> > +		return PTR_ERR(ov8856->reset_gpio);
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> > +		ov8856->supplies[i].supply = ov8856_supply_names[i];
> > +
> > +	ret = devm_regulator_bulk_get(dev,
> > ARRAY_SIZE(ov8856_supply_names),
> > +				      ov8856->supplies);
> > +	if (ret)
> > +		return ret;
> > +
> 
> In case of ACPI this cannot get ov8856->reset_gpio  and ov8856->supplies, please add the check for ACPI case:
> if (!is_acpi_node(fwnode)) { }

I tought that dummy-regulators will be created in case of ACPI?

Regards,
  Marco

> Thanks.
> Ben
> 
> >  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> >  	if (!ep)
> >  		return -ENXIO;
> > @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
> >  	pm_runtime_disable(&client->dev);
> >  	mutex_destroy(&ov8856->mutex);
> > 
> > +	__ov8856_power_off(ov8856);
> > +
> >  	return 0;
> >  }
> > 
> > @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
> >  	struct ov8856 *ov8856;
> >  	int ret;
> > 
> > -	ret = ov8856_check_hwcfg(&client->dev);
> > +	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > +	if (!ov8856)
> > +		return -ENOMEM;
> > +
> > +	ov8856->dev = &client->dev;
> > +
> > +	ret = ov8856_get_hwcfg(ov8856);
> >  	if (ret) {
> > -		dev_err(&client->dev, "failed to check HW configuration: %d",
> > +		dev_err(&client->dev, "failed to get HW configuration: %d",
> >  			ret);
> >  		return ret;
> >  	}
> > 
> > -	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > -	if (!ov8856)
> > -		return -ENOMEM;
> > -
> >  	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> > +
> > +	ret = __ov8856_power_on(ov8856);
> > +	if (ret) {
> > +		dev_err(&client->dev, "failed to power on\n");
> > +		return ret;
> > +	}
> > +
> >  	ret = ov8856_identify_module(ov8856);
> >  	if (ret) {
> >  		dev_err(&client->dev, "failed to find sensor: %d", ret);
> > -		return ret;
> > +		goto probe_power_off;
> >  	}
> > 
> >  	mutex_init(&ov8856->mutex);
> > @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
> >  	v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
> >  	mutex_destroy(&ov8856->mutex);
> > 
> > +probe_power_off:
> > +	__ov8856_power_off(ov8856);
> > +
> >  	return ret;
> >  }
> > 
> > @@ -1254,11 +1356,18 @@ static const struct acpi_device_id ov8856_acpi_ids[]
> > = {  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);  #endif
> > 
> > +static const struct of_device_id ov8856_of_match[] = {
> > +	{ .compatible = "ovti,ov8856" },
> > +	{ /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> > +
> >  static struct i2c_driver ov8856_i2c_driver = {
> >  	.driver = {
> >  		.name = "ov8856",
> >  		.pm = &ov8856_pm_ops,
> >  		.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> > +		.of_match_table = ov8856_of_match,
> >  	},
> >  	.probe_new = ov8856_probe,
> >  	.remove = ov8856_remove,
> > --
> > 2.25.1
> 
>
Robert Foss May 7, 2020, 8:39 a.m. UTC | #7
On Thu, 7 May 2020 at 10:06, Kao, Ben <ben.kao@intel.com> wrote:
>
> Hi Robert,
>
> On 20-05-05 12:01, Robert Foss wrote:
> > Add match table, enable ov8856_probe() to support both ACPI and DT modes.
> >
> > ACPI and DT modes are primarily distinguished from by checking for ACPI mode
> > and by having resource like be NULL.
> >
> > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > ---
> >
> > - Changes since v6:
> >   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> >
> > - Changes since v5:
> >   * Maxime & Sakari: Replaced clock tolerance check with warning
> >
> > - Changes since v4:
> >   * Maxime & Sakari: Switch to clock-frequency
> >
> > - Changes since v3:
> >   * Remove redundant {}-brackets
> >   * Compare xvclk_rate to 5% tolerance
> >   * Andy: Use dev_fwnode()
> >   * Andy: Use %pe instead of %ld + PTR_ERR()
> >   * Andy: Invert reset_gpio logic
> >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> >   * Andy: Use dev_err for logging for failures
> >   * Andy: Remove dev_warn from EDEFER/regulator error path
> >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> >   * Maxime & Sakari: Verify clock frequency from DT
> >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> >   * Sakari: Remove duplicate ov8856->dev assignment
> >
> > - Changes since v2:
> >   * Added "struct device *dev" member to struct ov8856
> >   * Andy: Switch to optional version of devm_gpiod_get
> >   * Andy: Switch to optional version of devm_clk_get
> >   * Fabio: Add reset sleep period
> >   * Sakari: Unify defines for 19.2Mhz
> >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> >   * Sakari: Replace dev_info() with dev_dbg()
> >   * Sakari: Switch induction variable type to unsigned
> >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> >   * Sakari: Pull reset GPIO high on power on failure
> >   * Sakari: Add power on/off to resume/suspend
> >   * Sakari: Fix indentation
> >   * Sakari: Power off during ov8856_remove()
> >   * Sakari: Don't sleep during power-on in ACPI mode
> >   * Sakari: Switch to getting xvclk from clk_get_rate
> >
> > - Changes since v1:
> >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> >   * Fabio: Change n_shutdown_gpio name to reset_gpio
> >   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH -> GPIO_ACTIVE_LOW
> > change
> >   * Fabio: Remove empty line
> >   * Fabio: Remove real error from devm_gpiod_get() failures
> >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> >   * Sakari: Use XVCLK rate as provided by DT
> >
> >  drivers/media/i2c/ov8856.c | 137 +++++++++++++++++++++++++++++++++----
> >  1 file changed, 123 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c index
> > 8655842af275..e6418a79801e 100644
> > --- a/drivers/media/i2c/ov8856.c
> > +++ b/drivers/media/i2c/ov8856.c
> > @@ -3,10 +3,13 @@
> >
> >  #include <asm/unaligned.h>
> >  #include <linux/acpi.h>
> > +#include <linux/clk.h>
> >  #include <linux/delay.h>
> > +#include <linux/gpio/consumer.h>
> >  #include <linux/i2c.h>
> >  #include <linux/module.h>
> >  #include <linux/pm_runtime.h>
> > +#include <linux/regulator/consumer.h>
> >  #include <media/v4l2-ctrls.h>
> >  #include <media/v4l2-device.h>
> >  #include <media/v4l2-fwnode.h>
> > @@ -18,7 +21,7 @@
> >  #define OV8856_LINK_FREQ_360MHZ              360000000ULL
> >  #define OV8856_LINK_FREQ_180MHZ              180000000ULL
> >  #define OV8856_SCLK                  144000000ULL
> > -#define OV8856_MCLK                  19200000
> > +#define OV8856_XVCLK_19_2            19200000
> >  #define OV8856_DATA_LANES            4
> >  #define OV8856_RGB_DEPTH             10
> >
> > @@ -64,6 +67,12 @@
> >
> >  #define to_ov8856(_sd)                       container_of(_sd, struct ov8856, sd)
> >
> > +static const char * const ov8856_supply_names[] = {
> > +     "dovdd",        /* Digital I/O power */
> > +     "avdd",         /* Analog power */
> > +     "dvdd",         /* Digital core power */
> > +};
> > +
> >  enum {
> >       OV8856_LINK_FREQ_720MBPS,
> >       OV8856_LINK_FREQ_360MBPS,
> > @@ -566,6 +575,11 @@ struct ov8856 {
> >       struct media_pad pad;
> >       struct v4l2_ctrl_handler ctrl_handler;
> >
> > +     struct device           *dev;
> > +     struct clk              *xvclk;
> > +     struct gpio_desc        *reset_gpio;
> > +     struct regulator_bulk_data
> > supplies[ARRAY_SIZE(ov8856_supply_names)];
> > +
> >       /* V4L2 Controls */
> >       struct v4l2_ctrl *link_freq;
> >       struct v4l2_ctrl *pixel_rate;
> > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev *sd,
> > int enable)
> >       return ret;
> >  }
> >
> > +static int __ov8856_power_on(struct ov8856 *ov8856) {
> > +     struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > +     int ret;
> > +
> > +     if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > +             return 0;
> > +
> > +     ret = clk_prepare_enable(ov8856->xvclk);
> > +     if (ret < 0) {
> > +             dev_err(&client->dev, "failed to enable xvclk\n");
> > +             return ret;
> > +     }
> > +
> > +     if (ov8856->reset_gpio) {
> > +             gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +             usleep_range(1000, 2000);
> > +     }
> > +
> > +     ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> > +                                 ov8856->supplies);
> > +     if (ret < 0) {
> > +             dev_err(&client->dev, "failed to enable regulators\n");
> > +             goto disable_clk;
> > +     }
> > +
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> > +     usleep_range(1500, 1800);
> > +
> > +     return 0;
> > +
> > +disable_clk:
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +     clk_disable_unprepare(ov8856->xvclk);
> > +
> > +     return ret;
> > +}
> > +
> > +static void __ov8856_power_off(struct ov8856 *ov8856) {
> > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > +     regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > +                            ov8856->supplies);
> > +     clk_disable_unprepare(ov8856->xvclk);
> > +}
> > +
> >  static int __maybe_unused ov8856_suspend(struct device *dev)  {
> >       struct i2c_client *client = to_i2c_client(dev); @@ -918,6 +978,7 @@
> > static int __maybe_unused ov8856_suspend(struct device *dev)
> >       if (ov8856->streaming)
> >               ov8856_stop_streaming(ov8856);
> >
> > +     __ov8856_power_off(ov8856);
> >       mutex_unlock(&ov8856->mutex);
> >
> >       return 0;
> > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct
> > device *dev)
> >       int ret;
> >
> >       mutex_lock(&ov8856->mutex);
> > +
> > +     __ov8856_power_on(ov8856);
> >       if (ov8856->streaming) {
> >               ret = ov8856_start_streaming(ov8856);
> >               if (ret) {
> > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct ov8856
> > *ov8856)
> >       return 0;
> >  }
> >
> > -static int ov8856_check_hwcfg(struct device *dev)
> > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> >  {
> > +     struct device *dev = ov8856->dev;
> >       struct fwnode_handle *ep;
> >       struct fwnode_handle *fwnode = dev_fwnode(dev);
> >       struct v4l2_fwnode_endpoint bus_cfg = {
> >               .bus_type = V4L2_MBUS_CSI2_DPHY
> >       };
> > -     u32 mclk;
> > +     u32 xvclk_rate;
> >       int ret;
> >       unsigned int i, j;
> >
> >       if (!fwnode)
> >               return -ENXIO;
> >
> > -     ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> > +     ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > +             &xvclk_rate);
> >       if (ret)
> >               return ret;
> >
> > -     if (mclk != OV8856_MCLK) {
> > -             dev_err(dev, "external clock %d is not supported", mclk);
> > -             return -EINVAL;
> > +     if (!is_acpi_node(fwnode)) {
> > +             ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > +             if (IS_ERR(ov8856->xvclk)) {
> > +                     dev_err(dev, "could not get xvclk clock (%pe)\n",
> > +                                     ov8856->xvclk);
> > +                     return PTR_ERR(ov8856->xvclk);
> > +             }
> > +
> > +             clk_set_rate(ov8856->xvclk, xvclk_rate);
> > +             xvclk_rate = clk_get_rate(ov8856->xvclk);
> >       }
> >
> > +     if (xvclk_rate != OV8856_XVCLK_19_2)
> > +             dev_warn(dev, "external clock rate %d is unsupported",
> > xvclk_rate);
> > +
> > +     ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > +             GPIOD_OUT_LOW);
> > +     if (IS_ERR(ov8856->reset_gpio))
> > +             return PTR_ERR(ov8856->reset_gpio);
> > +
> > +     for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> > +             ov8856->supplies[i].supply = ov8856_supply_names[i];
> > +
> > +     ret = devm_regulator_bulk_get(dev,
> > ARRAY_SIZE(ov8856_supply_names),
> > +                                   ov8856->supplies);
> > +     if (ret)
> > +             return ret;
> > +
>
> In case of ACPI this cannot get ov8856->reset_gpio  and ov8856->supplies, please add the check for ACPI case:
> if (!is_acpi_node(fwnode)) { }

Do you prefer the explicit check for clarity reasons or for functional reasons?

As far as I understand it, reset_gpio will be NULL and supplies will
be populated with dummy supplies in the ACPI case.
Both can be treated as if they were initialized fully during later
calls to their respective APIs.

>
> Thanks.
> Ben
>
> >       ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> >       if (!ep)
> >               return -ENXIO;
> > @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
> >       pm_runtime_disable(&client->dev);
> >       mutex_destroy(&ov8856->mutex);
> >
> > +     __ov8856_power_off(ov8856);
> > +
> >       return 0;
> >  }
> >
> > @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
> >       struct ov8856 *ov8856;
> >       int ret;
> >
> > -     ret = ov8856_check_hwcfg(&client->dev);
> > +     ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > +     if (!ov8856)
> > +             return -ENOMEM;
> > +
> > +     ov8856->dev = &client->dev;
> > +
> > +     ret = ov8856_get_hwcfg(ov8856);
> >       if (ret) {
> > -             dev_err(&client->dev, "failed to check HW configuration: %d",
> > +             dev_err(&client->dev, "failed to get HW configuration: %d",
> >                       ret);
> >               return ret;
> >       }
> >
> > -     ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > -     if (!ov8856)
> > -             return -ENOMEM;
> > -
> >       v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> > +
> > +     ret = __ov8856_power_on(ov8856);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to power on\n");
> > +             return ret;
> > +     }
> > +
> >       ret = ov8856_identify_module(ov8856);
> >       if (ret) {
> >               dev_err(&client->dev, "failed to find sensor: %d", ret);
> > -             return ret;
> > +             goto probe_power_off;
> >       }
> >
> >       mutex_init(&ov8856->mutex);
> > @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
> >       v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
> >       mutex_destroy(&ov8856->mutex);
> >
> > +probe_power_off:
> > +     __ov8856_power_off(ov8856);
> > +
> >       return ret;
> >  }
> >
> > @@ -1254,11 +1356,18 @@ static const struct acpi_device_id ov8856_acpi_ids[]
> > = {  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);  #endif
> >
> > +static const struct of_device_id ov8856_of_match[] = {
> > +     { .compatible = "ovti,ov8856" },
> > +     { /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> > +
> >  static struct i2c_driver ov8856_i2c_driver = {
> >       .driver = {
> >               .name = "ov8856",
> >               .pm = &ov8856_pm_ops,
> >               .acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> > +             .of_match_table = ov8856_of_match,
> >       },
> >       .probe_new = ov8856_probe,
> >       .remove = ov8856_remove,
> > --
> > 2.25.1
>
Kao, Ben May 8, 2020, 9:45 a.m. UTC | #8
Hi Marco Felsch,

> 20-05-08 04:22, Marco Felsch wrote:  
> Hi Ben,
> 
> On 20-05-07 08:06, Kao, Ben wrote:
> > Hi Robert,
> >
> > On 20-05-05 12:01, Robert Foss wrote:
> > > Add match table, enable ov8856_probe() to support both ACPI and DT modes.
> > >
> > > ACPI and DT modes are primarily distinguished from by checking for
> > > ACPI mode and by having resource like be NULL.
> > >
> > > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > > ---
> > >
> > > - Changes since v6:
> > >   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> > >
> > > - Changes since v5:
> > >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > >
> > > - Changes since v4:
> > >   * Maxime & Sakari: Switch to clock-frequency
> > >
> > > - Changes since v3:
> > >   * Remove redundant {}-brackets
> > >   * Compare xvclk_rate to 5% tolerance
> > >   * Andy: Use dev_fwnode()
> > >   * Andy: Use %pe instead of %ld + PTR_ERR()
> > >   * Andy: Invert reset_gpio logic
> > >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> > >   * Andy: Use dev_err for logging for failures
> > >   * Andy: Remove dev_warn from EDEFER/regulator error path
> > >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> > >   * Maxime & Sakari: Verify clock frequency from DT
> > >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> > >   * Sakari: Remove duplicate ov8856->dev assignment
> > >
> > > - Changes since v2:
> > >   * Added "struct device *dev" member to struct ov8856
> > >   * Andy: Switch to optional version of devm_gpiod_get
> > >   * Andy: Switch to optional version of devm_clk_get
> > >   * Fabio: Add reset sleep period
> > >   * Sakari: Unify defines for 19.2Mhz
> > >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> > >   * Sakari: Replace dev_info() with dev_dbg()
> > >   * Sakari: Switch induction variable type to unsigned
> > >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> > >   * Sakari: Pull reset GPIO high on power on failure
> > >   * Sakari: Add power on/off to resume/suspend
> > >   * Sakari: Fix indentation
> > >   * Sakari: Power off during ov8856_remove()
> > >   * Sakari: Don't sleep during power-on in ACPI mode
> > >   * Sakari: Switch to getting xvclk from clk_get_rate
> > >
> > > - Changes since v1:
> > >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> > >   * Fabio: Change n_shutdown_gpio name to reset_gpio
> > >   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH ->
> > > GPIO_ACTIVE_LOW change
> > >   * Fabio: Remove empty line
> > >   * Fabio: Remove real error from devm_gpiod_get() failures
> > >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> > >   * Sakari: Use XVCLK rate as provided by DT
> > >
> > >  drivers/media/i2c/ov8856.c | 137
> > > +++++++++++++++++++++++++++++++++----
> > >  1 file changed, 123 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > > index 8655842af275..e6418a79801e 100644
> > > --- a/drivers/media/i2c/ov8856.c
> > > +++ b/drivers/media/i2c/ov8856.c
> > > @@ -3,10 +3,13 @@
> > >
> > >  #include <asm/unaligned.h>
> > >  #include <linux/acpi.h>
> > > +#include <linux/clk.h>
> > >  #include <linux/delay.h>
> > > +#include <linux/gpio/consumer.h>
> > >  #include <linux/i2c.h>
> > >  #include <linux/module.h>
> > >  #include <linux/pm_runtime.h>
> > > +#include <linux/regulator/consumer.h>
> > >  #include <media/v4l2-ctrls.h>
> > >  #include <media/v4l2-device.h>
> > >  #include <media/v4l2-fwnode.h>
> > > @@ -18,7 +21,7 @@
> > >  #define OV8856_LINK_FREQ_360MHZ		360000000ULL
> > >  #define OV8856_LINK_FREQ_180MHZ		180000000ULL
> > >  #define OV8856_SCLK			144000000ULL
> > > -#define OV8856_MCLK			19200000
> > > +#define OV8856_XVCLK_19_2		19200000
> > >  #define OV8856_DATA_LANES		4
> > >  #define OV8856_RGB_DEPTH		10
> > >
> > > @@ -64,6 +67,12 @@
> > >
> > >  #define to_ov8856(_sd)			container_of(_sd, struct
> ov8856, sd)
> > >
> > > +static const char * const ov8856_supply_names[] = {
> > > +	"dovdd",	/* Digital I/O power */
> > > +	"avdd",		/* Analog power */
> > > +	"dvdd",		/* Digital core power */
> > > +};
> > > +
> > >  enum {
> > >  	OV8856_LINK_FREQ_720MBPS,
> > >  	OV8856_LINK_FREQ_360MBPS,
> > > @@ -566,6 +575,11 @@ struct ov8856 {
> > >  	struct media_pad pad;
> > >  	struct v4l2_ctrl_handler ctrl_handler;
> > >
> > > +	struct device		*dev;
> > > +	struct clk		*xvclk;
> > > +	struct gpio_desc	*reset_gpio;
> > > +	struct regulator_bulk_data
> > > supplies[ARRAY_SIZE(ov8856_supply_names)];
> > > +
> > >  	/* V4L2 Controls */
> > >  	struct v4l2_ctrl *link_freq;
> > >  	struct v4l2_ctrl *pixel_rate;
> > > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev
> > > *sd, int enable)
> > >  	return ret;
> > >  }
> > >
> > > +static int __ov8856_power_on(struct ov8856 *ov8856) {
> > > +	struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > > +	int ret;
> > > +
> > > +	if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > > +		return 0;
> > > +
> > > +	ret = clk_prepare_enable(ov8856->xvclk);
> > > +	if (ret < 0) {
> > > +		dev_err(&client->dev, "failed to enable xvclk\n");
> > > +		return ret;
> > > +	}
> > > +
> > > +	if (ov8856->reset_gpio) {
> > > +		gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +		usleep_range(1000, 2000);
> > > +	}
> > > +
> > > +	ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> > > +				    ov8856->supplies);
> > > +	if (ret < 0) {
> > > +		dev_err(&client->dev, "failed to enable regulators\n");
> > > +		goto disable_clk;
> > > +	}
> > > +
> > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> > > +	usleep_range(1500, 1800);
> > > +
> > > +	return 0;
> > > +
> > > +disable_clk:
> > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +	clk_disable_unprepare(ov8856->xvclk);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static void __ov8856_power_off(struct ov8856 *ov8856) {
> > > +	gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +	regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > > +			       ov8856->supplies);
> > > +	clk_disable_unprepare(ov8856->xvclk);
> > > +}
> > > +
> > >  static int __maybe_unused ov8856_suspend(struct device *dev)  {
> > >  	struct i2c_client *client = to_i2c_client(dev); @@ -918,6 +978,7
> > > @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> > >  	if (ov8856->streaming)
> > >  		ov8856_stop_streaming(ov8856);
> > >
> > > +	__ov8856_power_off(ov8856);
> > >  	mutex_unlock(&ov8856->mutex);
> > >
> > >  	return 0;
> > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct
> > > device *dev)
> > >  	int ret;
> > >
> > >  	mutex_lock(&ov8856->mutex);
> > > +
> > > +	__ov8856_power_on(ov8856);
> > >  	if (ov8856->streaming) {
> > >  		ret = ov8856_start_streaming(ov8856);
> > >  		if (ret) {
> > > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct
> > > ov8856
> > > *ov8856)
> > >  	return 0;
> > >  }
> > >
> > > -static int ov8856_check_hwcfg(struct device *dev)
> > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> > >  {
> > > +	struct device *dev = ov8856->dev;
> > >  	struct fwnode_handle *ep;
> > >  	struct fwnode_handle *fwnode = dev_fwnode(dev);
> > >  	struct v4l2_fwnode_endpoint bus_cfg = {
> > >  		.bus_type = V4L2_MBUS_CSI2_DPHY
> > >  	};
> > > -	u32 mclk;
> > > +	u32 xvclk_rate;
> > >  	int ret;
> > >  	unsigned int i, j;
> > >
> > >  	if (!fwnode)
> > >  		return -ENXIO;
> > >
> > > -	ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> > > +	ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > > +		&xvclk_rate);
> > >  	if (ret)
> > >  		return ret;
> > >
> > > -	if (mclk != OV8856_MCLK) {
> > > -		dev_err(dev, "external clock %d is not supported", mclk);
> > > -		return -EINVAL;
> > > +	if (!is_acpi_node(fwnode)) {
> > > +		ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > +		if (IS_ERR(ov8856->xvclk)) {
> > > +			dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > +					ov8856->xvclk);
> > > +			return PTR_ERR(ov8856->xvclk);
> > > +		}
> > > +
> > > +		clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > +		xvclk_rate = clk_get_rate(ov8856->xvclk);
> > >  	}
> > >
> > > +	if (xvclk_rate != OV8856_XVCLK_19_2)
> > > +		dev_warn(dev, "external clock rate %d is unsupported",
> > > xvclk_rate);
> > > +
> > > +	ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > > +		GPIOD_OUT_LOW);
> > > +	if (IS_ERR(ov8856->reset_gpio))
> > > +		return PTR_ERR(ov8856->reset_gpio);
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> > > +		ov8856->supplies[i].supply = ov8856_supply_names[i];
> > > +
> > > +	ret = devm_regulator_bulk_get(dev,
> > > ARRAY_SIZE(ov8856_supply_names),
> > > +				      ov8856->supplies);
> > > +	if (ret)
> > > +		return ret;
> > > +
> >
> > In case of ACPI this cannot get ov8856->reset_gpio  and ov8856->supplies,
> please add the check for ACPI case:
> > if (!is_acpi_node(fwnode)) { }
> 
> I tought that dummy-regulators will be created in case of ACPI?
You are right, the check is unnecessary.

Ben
> 
> Regards,
>   Marco
> 
> > Thanks.
> > Ben
> >
> > >  	ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> > >  	if (!ep)
> > >  		return -ENXIO;
> > > @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
> > >  	pm_runtime_disable(&client->dev);
> > >  	mutex_destroy(&ov8856->mutex);
> > >
> > > +	__ov8856_power_off(ov8856);
> > > +
> > >  	return 0;
> > >  }
> > >
> > > @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
> > >  	struct ov8856 *ov8856;
> > >  	int ret;
> > >
> > > -	ret = ov8856_check_hwcfg(&client->dev);
> > > +	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > > +	if (!ov8856)
> > > +		return -ENOMEM;
> > > +
> > > +	ov8856->dev = &client->dev;
> > > +
> > > +	ret = ov8856_get_hwcfg(ov8856);
> > >  	if (ret) {
> > > -		dev_err(&client->dev, "failed to check HW configuration: %d",
> > > +		dev_err(&client->dev, "failed to get HW configuration: %d",
> > >  			ret);
> > >  		return ret;
> > >  	}
> > >
> > > -	ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > > -	if (!ov8856)
> > > -		return -ENOMEM;
> > > -
> > >  	v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> > > +
> > > +	ret = __ov8856_power_on(ov8856);
> > > +	if (ret) {
> > > +		dev_err(&client->dev, "failed to power on\n");
> > > +		return ret;
> > > +	}
> > > +
> > >  	ret = ov8856_identify_module(ov8856);
> > >  	if (ret) {
> > >  		dev_err(&client->dev, "failed to find sensor: %d", ret);
> > > -		return ret;
> > > +		goto probe_power_off;
> > >  	}
> > >
> > >  	mutex_init(&ov8856->mutex);
> > > @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
> > >  	v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
> > >  	mutex_destroy(&ov8856->mutex);
> > >
> > > +probe_power_off:
> > > +	__ov8856_power_off(ov8856);
> > > +
> > >  	return ret;
> > >  }
> > >
> > > @@ -1254,11 +1356,18 @@ static const struct acpi_device_id
> > > ov8856_acpi_ids[] = {  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);
> > > #endif
> > >
> > > +static const struct of_device_id ov8856_of_match[] = {
> > > +	{ .compatible = "ovti,ov8856" },
> > > +	{ /* sentinel */ }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> > > +
> > >  static struct i2c_driver ov8856_i2c_driver = {
> > >  	.driver = {
> > >  		.name = "ov8856",
> > >  		.pm = &ov8856_pm_ops,
> > >  		.acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> > > +		.of_match_table = ov8856_of_match,
> > >  	},
> > >  	.probe_new = ov8856_probe,
> > >  	.remove = ov8856_remove,
> > > --
> > > 2.25.1
> >
> >
> 
> --
> Pengutronix e.K.                           |                             |
> Steuerwalder Str. 21                       | http://www.pengutronix.de/  |
> 31137 Hildesheim, Germany                  | Phone: +49-5121-206917-0    |
> Amtsgericht Hildesheim, HRA 2686           | Fax:   +49-5121-206917-5555 |
Kao, Ben May 8, 2020, 9:50 a.m. UTC | #9
Hi Robert,

On Thu, May 7, 2020 16:39 Robert Foss wrote:
> On Thu, 7 May 2020 at 10:06, Kao, Ben <ben.kao@intel.com> wrote:
> >
> > Hi Robert,
> >
> > On 20-05-05 12:01, Robert Foss wrote:
> > > Add match table, enable ov8856_probe() to support both ACPI and DT modes.
> > >
> > > ACPI and DT modes are primarily distinguished from by checking for
> > > ACPI mode and by having resource like be NULL.
> > >
> > > Signed-off-by: Robert Foss <robert.foss@linaro.org>
> > > ---
> > >
> > > - Changes since v6:
> > >   * Marco: Bail out of __ov8856_power_on earlier if ACPI mode
> > >
> > > - Changes since v5:
> > >   * Maxime & Sakari: Replaced clock tolerance check with warning
> > >
> > > - Changes since v4:
> > >   * Maxime & Sakari: Switch to clock-frequency
> > >
> > > - Changes since v3:
> > >   * Remove redundant {}-brackets
> > >   * Compare xvclk_rate to 5% tolerance
> > >   * Andy: Use dev_fwnode()
> > >   * Andy: Use %pe instead of %ld + PTR_ERR()
> > >   * Andy: Invert reset_gpio logic
> > >   * Andy: Remove dev_dbg() from failing reset_gpio setup
> > >   * Andy: Use dev_err for logging for failures
> > >   * Andy: Remove dev_warn from EDEFER/regulator error path
> > >   * Andy & Sakari: Replaced GPIOD_OUT_XXX with 0/1
> > >   * Maxime & Sakari: Verify clock frequency from DT
> > >   * Sakari: Verify the 'xvclk_rate' is set correctly for ACPI/DT devices
> > >   * Sakari: Remove duplicate ov8856->dev assignment
> > >
> > > - Changes since v2:
> > >   * Added "struct device *dev" member to struct ov8856
> > >   * Andy: Switch to optional version of devm_gpiod_get
> > >   * Andy: Switch to optional version of devm_clk_get
> > >   * Fabio: Add reset sleep period
> > >   * Sakari: Unify defines for 19.2Mhz
> > >   * Sakari: Remove 24Mhz clock, since it isn't needed for supported modes
> > >   * Sakari: Replace dev_info() with dev_dbg()
> > >   * Sakari: Switch induction variable type to unsigned
> > >   * Sakari: Don't wait for reset_gpio when in ACPI mode
> > >   * Sakari: Pull reset GPIO high on power on failure
> > >   * Sakari: Add power on/off to resume/suspend
> > >   * Sakari: Fix indentation
> > >   * Sakari: Power off during ov8856_remove()
> > >   * Sakari: Don't sleep during power-on in ACPI mode
> > >   * Sakari: Switch to getting xvclk from clk_get_rate
> > >
> > > - Changes since v1:
> > >   * Andy & Sakari: Make XVCLK optional since to not break ACPI
> > >   * Fabio: Change n_shutdown_gpio name to reset_gpio
> > >   * Fabio: Invert reset_gpio due to GPIO_ACTIVE_HIGH ->
> > > GPIO_ACTIVE_LOW change
> > >   * Fabio: Remove empty line
> > >   * Fabio: Remove real error from devm_gpiod_get() failures
> > >   * Sakari: ARRAY_SIZE() directly instead of through OV8856_NUM_SUPPLIES
> > >   * Sakari: Use XVCLK rate as provided by DT
> > >
> > >  drivers/media/i2c/ov8856.c | 137
> > > +++++++++++++++++++++++++++++++++----
> > >  1 file changed, 123 insertions(+), 14 deletions(-)
> > >
> > > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > > index 8655842af275..e6418a79801e 100644
> > > --- a/drivers/media/i2c/ov8856.c
> > > +++ b/drivers/media/i2c/ov8856.c
> > > @@ -3,10 +3,13 @@
> > >
> > >  #include <asm/unaligned.h>
> > >  #include <linux/acpi.h>
> > > +#include <linux/clk.h>
> > >  #include <linux/delay.h>
> > > +#include <linux/gpio/consumer.h>
> > >  #include <linux/i2c.h>
> > >  #include <linux/module.h>
> > >  #include <linux/pm_runtime.h>
> > > +#include <linux/regulator/consumer.h>
> > >  #include <media/v4l2-ctrls.h>
> > >  #include <media/v4l2-device.h>
> > >  #include <media/v4l2-fwnode.h>
> > > @@ -18,7 +21,7 @@
> > >  #define OV8856_LINK_FREQ_360MHZ              360000000ULL
> > >  #define OV8856_LINK_FREQ_180MHZ              180000000ULL
> > >  #define OV8856_SCLK                  144000000ULL
> > > -#define OV8856_MCLK                  19200000
> > > +#define OV8856_XVCLK_19_2            19200000
> > >  #define OV8856_DATA_LANES            4
> > >  #define OV8856_RGB_DEPTH             10
> > >
> > > @@ -64,6 +67,12 @@
> > >
> > >  #define to_ov8856(_sd)                       container_of(_sd, struct ov8856, sd)
> > >
> > > +static const char * const ov8856_supply_names[] = {
> > > +     "dovdd",        /* Digital I/O power */
> > > +     "avdd",         /* Analog power */
> > > +     "dvdd",         /* Digital core power */
> > > +};
> > > +
> > >  enum {
> > >       OV8856_LINK_FREQ_720MBPS,
> > >       OV8856_LINK_FREQ_360MBPS,
> > > @@ -566,6 +575,11 @@ struct ov8856 {
> > >       struct media_pad pad;
> > >       struct v4l2_ctrl_handler ctrl_handler;
> > >
> > > +     struct device           *dev;
> > > +     struct clk              *xvclk;
> > > +     struct gpio_desc        *reset_gpio;
> > > +     struct regulator_bulk_data
> > > supplies[ARRAY_SIZE(ov8856_supply_names)];
> > > +
> > >       /* V4L2 Controls */
> > >       struct v4l2_ctrl *link_freq;
> > >       struct v4l2_ctrl *pixel_rate;
> > > @@ -908,6 +922,52 @@ static int ov8856_set_stream(struct v4l2_subdev
> > > *sd, int enable)
> > >       return ret;
> > >  }
> > >
> > > +static int __ov8856_power_on(struct ov8856 *ov8856) {
> > > +     struct i2c_client *client = v4l2_get_subdevdata(&ov8856->sd);
> > > +     int ret;
> > > +
> > > +     if (is_acpi_node(dev_fwnode(ov8856->dev)))
> > > +             return 0;
> > > +
> > > +     ret = clk_prepare_enable(ov8856->xvclk);
> > > +     if (ret < 0) {
> > > +             dev_err(&client->dev, "failed to enable xvclk\n");
> > > +             return ret;
> > > +     }
> > > +
> > > +     if (ov8856->reset_gpio) {
> > > +             gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +             usleep_range(1000, 2000);
> > > +     }
> > > +
> > > +     ret = regulator_bulk_enable(ARRAY_SIZE(ov8856_supply_names),
> > > +                                 ov8856->supplies);
> > > +     if (ret < 0) {
> > > +             dev_err(&client->dev, "failed to enable regulators\n");
> > > +             goto disable_clk;
> > > +     }
> > > +
> > > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 0);
> > > +     usleep_range(1500, 1800);
> > > +
> > > +     return 0;
> > > +
> > > +disable_clk:
> > > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +     clk_disable_unprepare(ov8856->xvclk);
> > > +
> > > +     return ret;
> > > +}
> > > +
> > > +static void __ov8856_power_off(struct ov8856 *ov8856) {
> > > +     gpiod_set_value_cansleep(ov8856->reset_gpio, 1);
> > > +     regulator_bulk_disable(ARRAY_SIZE(ov8856_supply_names),
> > > +                            ov8856->supplies);
> > > +     clk_disable_unprepare(ov8856->xvclk);
> > > +}
> > > +
> > >  static int __maybe_unused ov8856_suspend(struct device *dev)  {
> > >       struct i2c_client *client = to_i2c_client(dev); @@ -918,6
> > > +978,7 @@ static int __maybe_unused ov8856_suspend(struct device *dev)
> > >       if (ov8856->streaming)
> > >               ov8856_stop_streaming(ov8856);
> > >
> > > +     __ov8856_power_off(ov8856);
> > >       mutex_unlock(&ov8856->mutex);
> > >
> > >       return 0;
> > > @@ -931,6 +992,8 @@ static int __maybe_unused ov8856_resume(struct
> > > device *dev)
> > >       int ret;
> > >
> > >       mutex_lock(&ov8856->mutex);
> > > +
> > > +     __ov8856_power_on(ov8856);
> > >       if (ov8856->streaming) {
> > >               ret = ov8856_start_streaming(ov8856);
> > >               if (ret) {
> > > @@ -1092,29 +1155,54 @@ static int ov8856_identify_module(struct
> > > ov8856
> > > *ov8856)
> > >       return 0;
> > >  }
> > >
> > > -static int ov8856_check_hwcfg(struct device *dev)
> > > +static int ov8856_get_hwcfg(struct ov8856 *ov8856)
> > >  {
> > > +     struct device *dev = ov8856->dev;
> > >       struct fwnode_handle *ep;
> > >       struct fwnode_handle *fwnode = dev_fwnode(dev);
> > >       struct v4l2_fwnode_endpoint bus_cfg = {
> > >               .bus_type = V4L2_MBUS_CSI2_DPHY
> > >       };
> > > -     u32 mclk;
> > > +     u32 xvclk_rate;
> > >       int ret;
> > >       unsigned int i, j;
> > >
> > >       if (!fwnode)
> > >               return -ENXIO;
> > >
> > > -     ret = fwnode_property_read_u32(fwnode, "clock-frequency", &mclk);
> > > +     ret = fwnode_property_read_u32(fwnode, "clock-frequency",
> > > +             &xvclk_rate);
> > >       if (ret)
> > >               return ret;
> > >
> > > -     if (mclk != OV8856_MCLK) {
> > > -             dev_err(dev, "external clock %d is not supported", mclk);
> > > -             return -EINVAL;
> > > +     if (!is_acpi_node(fwnode)) {
> > > +             ov8856->xvclk = devm_clk_get(dev, "xvclk");
> > > +             if (IS_ERR(ov8856->xvclk)) {
> > > +                     dev_err(dev, "could not get xvclk clock (%pe)\n",
> > > +                                     ov8856->xvclk);
> > > +                     return PTR_ERR(ov8856->xvclk);
> > > +             }
> > > +
> > > +             clk_set_rate(ov8856->xvclk, xvclk_rate);
> > > +             xvclk_rate = clk_get_rate(ov8856->xvclk);
> > >       }
> > >
> > > +     if (xvclk_rate != OV8856_XVCLK_19_2)
> > > +             dev_warn(dev, "external clock rate %d is unsupported",
> > > xvclk_rate);
> > > +
> > > +     ov8856->reset_gpio = devm_gpiod_get_optional(dev, "reset",
> > > +             GPIOD_OUT_LOW);
> > > +     if (IS_ERR(ov8856->reset_gpio))
> > > +             return PTR_ERR(ov8856->reset_gpio);
> > > +
> > > +     for (i = 0; i < ARRAY_SIZE(ov8856_supply_names); i++)
> > > +             ov8856->supplies[i].supply = ov8856_supply_names[i];
> > > +
> > > +     ret = devm_regulator_bulk_get(dev,
> > > ARRAY_SIZE(ov8856_supply_names),
> > > +                                   ov8856->supplies);
> > > +     if (ret)
> > > +             return ret;
> > > +
> >
> > In case of ACPI this cannot get ov8856->reset_gpio  and ov8856->supplies,
> please add the check for ACPI case:
> > if (!is_acpi_node(fwnode)) { }
> 
> Do you prefer the explicit check for clarity reasons or for functional reasons?
> 
> As far as I understand it, reset_gpio will be NULL and supplies will be populated
> with dummy supplies in the ACPI case.
> Both can be treated as if they were initialized fully during later calls to their
> respective APIs.
Understood, the check is unnecessary.

Ben.
> 
> >
> > Thanks.
> > Ben
> >
> > >       ep = fwnode_graph_get_next_endpoint(fwnode, NULL);
> > >       if (!ep)
> > >               return -ENXIO;
> > > @@ -1169,6 +1257,8 @@ static int ov8856_remove(struct i2c_client *client)
> > >       pm_runtime_disable(&client->dev);
> > >       mutex_destroy(&ov8856->mutex);
> > >
> > > +     __ov8856_power_off(ov8856);
> > > +
> > >       return 0;
> > >  }
> > >
> > > @@ -1177,22 +1267,31 @@ static int ov8856_probe(struct i2c_client *client)
> > >       struct ov8856 *ov8856;
> > >       int ret;
> > >
> > > -     ret = ov8856_check_hwcfg(&client->dev);
> > > +     ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > > +     if (!ov8856)
> > > +             return -ENOMEM;
> > > +
> > > +     ov8856->dev = &client->dev;
> > > +
> > > +     ret = ov8856_get_hwcfg(ov8856);
> > >       if (ret) {
> > > -             dev_err(&client->dev, "failed to check HW configuration: %d",
> > > +             dev_err(&client->dev, "failed to get HW configuration:
> > > + %d",
> > >                       ret);
> > >               return ret;
> > >       }
> > >
> > > -     ov8856 = devm_kzalloc(&client->dev, sizeof(*ov8856), GFP_KERNEL);
> > > -     if (!ov8856)
> > > -             return -ENOMEM;
> > > -
> > >       v4l2_i2c_subdev_init(&ov8856->sd, client, &ov8856_subdev_ops);
> > > +
> > > +     ret = __ov8856_power_on(ov8856);
> > > +     if (ret) {
> > > +             dev_err(&client->dev, "failed to power on\n");
> > > +             return ret;
> > > +     }
> > > +
> > >       ret = ov8856_identify_module(ov8856);
> > >       if (ret) {
> > >               dev_err(&client->dev, "failed to find sensor: %d", ret);
> > > -             return ret;
> > > +             goto probe_power_off;
> > >       }
> > >
> > >       mutex_init(&ov8856->mutex);
> > > @@ -1238,6 +1337,9 @@ static int ov8856_probe(struct i2c_client *client)
> > >       v4l2_ctrl_handler_free(ov8856->sd.ctrl_handler);
> > >       mutex_destroy(&ov8856->mutex);
> > >
> > > +probe_power_off:
> > > +     __ov8856_power_off(ov8856);
> > > +
> > >       return ret;
> > >  }
> > >
> > > @@ -1254,11 +1356,18 @@ static const struct acpi_device_id
> > > ov8856_acpi_ids[] = {  MODULE_DEVICE_TABLE(acpi, ov8856_acpi_ids);
> > > #endif
> > >
> > > +static const struct of_device_id ov8856_of_match[] = {
> > > +     { .compatible = "ovti,ov8856" },
> > > +     { /* sentinel */ }
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ov8856_of_match);
> > > +
> > >  static struct i2c_driver ov8856_i2c_driver = {
> > >       .driver = {
> > >               .name = "ov8856",
> > >               .pm = &ov8856_pm_ops,
> > >               .acpi_match_table = ACPI_PTR(ov8856_acpi_ids),
> > > +             .of_match_table = ov8856_of_match,
> > >       },
> > >       .probe_new = ov8856_probe,
> > >       .remove = ov8856_remove,
> > > --
> > > 2.25.1
> >