diff mbox series

[06/12] i2c: omap: Add the master_xfer_irqless hook

Message ID 20190403124019.8947-7-wsa+renesas@sang-engineering.com
State Deferred
Headers show
Series i2c: core: introduce atomic transfers | expand

Commit Message

Wolfram Sang April 3, 2019, 12:40 p.m. UTC 
Add the master_xfer_irqless hook to enable i2c transactions
in irq disabled contexts like the poweroff case.

Signed-off-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>
[wsa: simplified code a little: 'timeout = !ret']
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 drivers/i2c/busses/i2c-omap.c | 76 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 63 insertions(+), 13 deletions(-)

Comments

Stefan Lengfeld April 15, 2019, 10:05 p.m. UTC | #1 
Hi Wolfram,

the subject line of this patch

    i2c: omap: Add the master_xfer_irqless hook

still contains the old name of the callback '_irqless'. It should be
'_atomic' instead.


On Wed, Apr 03, 2019 at 02:40:13PM +0200, Wolfram Sang wrote:
> Add the master_xfer_irqless hook to enable i2c transactions

Here again. It should be 'master_xfer_atomic'.


> in irq disabled contexts like the poweroff case.
> 
> Signed-off-by: Tero Kristo <t-kristo@ti.com>
> Signed-off-by: Keerthy <j-keerthy@ti.com>
> [wsa: simplified code a little: 'timeout = !ret']
> Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  drivers/i2c/busses/i2c-omap.c | 76 +++++++++++++++++++++++++++++++++++--------
>  1 file changed, 63 insertions(+), 13 deletions(-)
> 

snipped 

> @@ -648,15 +650,28 @@ static void omap_i2c_resize_fifo(struct omap_i2c_dev *omap, u8 size, bool is_rx)
>  			(1000 * omap->speed / 8);
>  }
>  
> +static void omap_i2c_wait(struct omap_i2c_dev *omap)
> +{
> +	u16 stat;
> +	u16 mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG);
> +	int count = 0;
> +
> +	do {
> +		stat = omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG);
> +		count++;
> +	} while (!(stat & mask) && count < 5);
> +}
> +
>  /*
>   * Low level master read/write transaction.
>   */
>  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
> -			     struct i2c_msg *msg, int stop)
> +			     struct i2c_msg *msg, int stop, bool polling)

Nitpick. In the patches for the other drivers the boolean flag is called
'atomic' and not 'polling'.

>  {
>  	struct omap_i2c_dev *omap = i2c_get_adapdata(adap);
>  	unsigned long timeout;
>  	u16 w;
> +	int ret;
>  
>  	dev_dbg(omap->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
>  		msg->addr, msg->len, msg->flags, stop);

sniped

> @@ -1165,14 +1204,25 @@ omap_i2c_isr_thread(int this_irq, void *dev_id)
>  		}
>  	} while (stat);
>  
> -	omap_i2c_complete_cmd(omap, err);
> +	return err;
> +}
> +
> +static irqreturn_t
> +omap_i2c_isr_thread(int this_irq, void *dev_id)
> +{
> +	int ret;
> +	struct omap_i2c_dev *omap = dev_id;
> +
> +	ret = omap_i2c_xfer_data(omap);
> +	if (ret != -EAGAIN)
> +		omap_i2c_complete_cmd(omap, ret);
>  
> -out:
>  	return IRQ_HANDLED;
>  }
>  
>  static const struct i2c_algorithm omap_i2c_algo = {
> -	.master_xfer	= omap_i2c_xfer,
> +	.master_xfer	= omap_i2c_xfer_irq,
> +	.master_xfer_atomic	= omap_i2c_xfer_polling,

When consistency with other drivers is a goal, the functions should be
named like:

    .master_xfe = omap_i2c_xfer,
    .master_xfer_atomic = omap_i2c_xfer_atomic,

The first without a suffix and the second with the '_atomic' suffix.

Kind regards,
Stefan
Wolfram Sang April 16, 2019, 10:52 a.m. UTC | #2 
> the subject line of this patch
> 
>     i2c: omap: Add the master_xfer_irqless hook
> 
> still contains the old name of the callback '_irqless'. It should be
> '_atomic' instead.
> 
> 
> On Wed, Apr 03, 2019 at 02:40:13PM +0200, Wolfram Sang wrote:
> > Add the master_xfer_irqless hook to enable i2c transactions
> 
> Here again. It should be 'master_xfer_atomic'.

Yes, thanks, fixed!

> >  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
> > -			     struct i2c_msg *msg, int stop)
> > +			     struct i2c_msg *msg, int stop, bool polling)
> 
> Nitpick. In the patches for the other drivers the boolean flag is called
> 'atomic' and not 'polling'.

This patch originally is not from me, so I prefer to not change it.
Also, I don't want to enforce strict naming within drivers. As long as
it is readable, I am fine with it.

> >  static const struct i2c_algorithm omap_i2c_algo = {
> > -	.master_xfer	= omap_i2c_xfer,
> > +	.master_xfer	= omap_i2c_xfer_irq,
> > +	.master_xfer_atomic	= omap_i2c_xfer_polling,
> 
> When consistency with other drivers is a goal, the functions should be
> named like:
> 
>     .master_xfe = omap_i2c_xfer,
>     .master_xfer_atomic = omap_i2c_xfer_atomic,
> 
> The first without a suffix and the second with the '_atomic' suffix.

ditto.
diff mbox series

Patch

diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
index cd9c65f3d404..faa0394048a0 100644
--- a/drivers/i2c/busses/i2c-omap.c
+++ b/drivers/i2c/busses/i2c-omap.c
@@ -269,6 +269,8 @@  static const u8 reg_map_ip_v2[] = {
 	[OMAP_I2C_IP_V2_IRQENABLE_CLR] = 0x30,
 };
 
+static int omap_i2c_xfer_data(struct omap_i2c_dev *omap);
+
 static inline void omap_i2c_write_reg(struct omap_i2c_dev *omap,
 				      int reg, u16 val)
 {
@@ -648,15 +650,28 @@  static void omap_i2c_resize_fifo(struct omap_i2c_dev *omap, u8 size, bool is_rx)
 			(1000 * omap->speed / 8);
 }
 
+static void omap_i2c_wait(struct omap_i2c_dev *omap)
+{
+	u16 stat;
+	u16 mask = omap_i2c_read_reg(omap, OMAP_I2C_IE_REG);
+	int count = 0;
+
+	do {
+		stat = omap_i2c_read_reg(omap, OMAP_I2C_STAT_REG);
+		count++;
+	} while (!(stat & mask) && count < 5);
+}
+
 /*
  * Low level master read/write transaction.
  */
 static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
-			     struct i2c_msg *msg, int stop)
+			     struct i2c_msg *msg, int stop, bool polling)
 {
 	struct omap_i2c_dev *omap = i2c_get_adapdata(adap);
 	unsigned long timeout;
 	u16 w;
+	int ret;
 
 	dev_dbg(omap->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 		msg->addr, msg->len, msg->flags, stop);
@@ -680,7 +695,8 @@  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 	w |= OMAP_I2C_BUF_RXFIF_CLR | OMAP_I2C_BUF_TXFIF_CLR;
 	omap_i2c_write_reg(omap, OMAP_I2C_BUF_REG, w);
 
-	reinit_completion(&omap->cmd_complete);
+	if (!polling)
+		reinit_completion(&omap->cmd_complete);
 	omap->cmd_err = 0;
 
 	w = OMAP_I2C_CON_EN | OMAP_I2C_CON_MST | OMAP_I2C_CON_STT;
@@ -732,8 +748,18 @@  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
 	 * REVISIT: We should abort the transfer on signals, but the bus goes
 	 * into arbitration and we're currently unable to recover from it.
 	 */
-	timeout = wait_for_completion_timeout(&omap->cmd_complete,
-						OMAP_I2C_TIMEOUT);
+	if (!polling) {
+		timeout = wait_for_completion_timeout(&omap->cmd_complete,
+						      OMAP_I2C_TIMEOUT);
+	} else {
+		do {
+			omap_i2c_wait(omap);
+			ret = omap_i2c_xfer_data(omap);
+		} while (ret == -EAGAIN);
+
+		timeout = !ret;
+	}
+
 	if (timeout == 0) {
 		dev_err(omap->dev, "controller timed out\n");
 		omap_i2c_reset(omap);
@@ -772,7 +798,8 @@  static int omap_i2c_xfer_msg(struct i2c_adapter *adap,
  * to do the work during IRQ processing.
  */
 static int
-omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+omap_i2c_xfer_common(struct i2c_adapter *adap, struct i2c_msg msgs[], int num,
+		     bool polling)
 {
 	struct omap_i2c_dev *omap = i2c_get_adapdata(adap);
 	int i;
@@ -794,7 +821,8 @@  omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 		omap->set_mpu_wkup_lat(omap->dev, omap->latency);
 
 	for (i = 0; i < num; i++) {
-		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)));
+		r = omap_i2c_xfer_msg(adap, &msgs[i], (i == (num - 1)),
+				      polling);
 		if (r != 0)
 			break;
 	}
@@ -813,6 +841,18 @@  omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 	return r;
 }
 
+static int
+omap_i2c_xfer_irq(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	return omap_i2c_xfer_common(adap, msgs, num, false);
+}
+
+static int
+omap_i2c_xfer_polling(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	return omap_i2c_xfer_common(adap, msgs, num, true);
+}
+
 static u32
 omap_i2c_func(struct i2c_adapter *adap)
 {
@@ -1035,10 +1075,8 @@  omap_i2c_isr(int irq, void *dev_id)
 	return ret;
 }
 
-static irqreturn_t
-omap_i2c_isr_thread(int this_irq, void *dev_id)
+static int omap_i2c_xfer_data(struct omap_i2c_dev *omap)
 {
-	struct omap_i2c_dev *omap = dev_id;
 	u16 bits;
 	u16 stat;
 	int err = 0, count = 0;
@@ -1056,7 +1094,8 @@  omap_i2c_isr_thread(int this_irq, void *dev_id)
 
 		if (!stat) {
 			/* my work here is done */
-			goto out;
+			err = -EAGAIN;
+			break;
 		}
 
 		dev_dbg(omap->dev, "IRQ (ISR = 0x%04x)\n", stat);
@@ -1165,14 +1204,25 @@  omap_i2c_isr_thread(int this_irq, void *dev_id)
 		}
 	} while (stat);
 
-	omap_i2c_complete_cmd(omap, err);
+	return err;
+}
+
+static irqreturn_t
+omap_i2c_isr_thread(int this_irq, void *dev_id)
+{
+	int ret;
+	struct omap_i2c_dev *omap = dev_id;
+
+	ret = omap_i2c_xfer_data(omap);
+	if (ret != -EAGAIN)
+		omap_i2c_complete_cmd(omap, ret);
 
-out:
 	return IRQ_HANDLED;
 }
 
 static const struct i2c_algorithm omap_i2c_algo = {
-	.master_xfer	= omap_i2c_xfer,
+	.master_xfer	= omap_i2c_xfer_irq,
+	.master_xfer_atomic	= omap_i2c_xfer_polling,
 	.functionality	= omap_i2c_func,
 };