[v16] pwm: opencores: Add PWM driver support

Add driver for OpenCores PWM Controller. And add compatibility code
which based on StarFive SoC.

Co-developed-by: Hal Feng <hal.feng@starfivetech.com>
Signed-off-by: Hal Feng <hal.feng@starfivetech.com>
Signed-off-by: William Qiu <william.qiu@starfivetech.com>
---
 MAINTAINERS              |   7 ++
 drivers/pwm/Kconfig      |  12 ++
 drivers/pwm/Makefile     |   1 +
 drivers/pwm/pwm-ocores.c | 241 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 261 insertions(+)
 create mode 100644 drivers/pwm/pwm-ocores.c

> -----Original Message-----
> From: William Qiu
> Sent: 2024年10月28日 9:46
> To: linux-kernel@vger.kernel.org; linux-pwm@vger.kernel.org
> Cc: Uwe Kleine-König <ukleinek@kernel.org>; Hal Feng
> <hal.feng@starfivetech.com>; Philipp Zabel <p.zabel@pengutronix.de>; William
> Qiu <william.qiu@starfivetech.com>
> Subject: [PATCH v16] pwm: opencores: Add PWM driver support
> 
> Add driver for OpenCores PWM Controller. And add compatibility code which
> based on StarFive SoC.
> 
> Co-developed-by: Hal Feng <hal.feng@starfivetech.com>
> Signed-off-by: Hal Feng <hal.feng@starfivetech.com>
> Signed-off-by: William Qiu <william.qiu@starfivetech.com>
> ---
>  MAINTAINERS              |   7 ++
>  drivers/pwm/Kconfig      |  12 ++
>  drivers/pwm/Makefile     |   1 +
>  drivers/pwm/pwm-ocores.c | 241
> +++++++++++++++++++++++++++++++++++++++
>  4 files changed, 261 insertions(+)
>  create mode 100644 drivers/pwm/pwm-ocores.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index a097afd76ded..5db90c1d9854 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -17373,6 +17373,13 @@ F:	Documentation/i2c/busses/i2c-ocores.rst
>  F:	drivers/i2c/busses/i2c-ocores.c
>  F:	include/linux/platform_data/i2c-ocores.h
> 
> +OPENCORES PWM DRIVER
> +M:	William Qiu <william.qiu@starfivetech.com>
> +M:	Hal Feng <hal.feng@starfivetech.com>
> +S:	Supported
> +F:	Documentation/devicetree/bindings/pwm/opencores,pwm.yaml
> +F:	drivers/pwm/pwm-ocores.c
> +
>  OPENRISC ARCHITECTURE
>  M:	Jonas Bonn <jonas@southpole.se>
>  M:	Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index
> 0915c1e7df16..33819cb585be 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -471,6 +471,18 @@ config PWM_NTXEC
>  	  controller found in certain e-book readers designed by the original
>  	  design manufacturer Netronix.
> 
> +config PWM_OCORES
> +	tristate "OpenCores PTC PWM support"
> +	depends on HAS_IOMEM && OF
> +	depends on COMMON_CLK
> +	depends on ARCH_STARFIVE || COMPILE_TEST
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  OpenCores PWM. For details see https://opencores.org/projects/ptc.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called pwm-ocores.
> +
>  config PWM_OMAP_DMTIMER
>  	tristate "OMAP Dual-Mode Timer PWM support"
>  	depends on OF
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index
> 9081e0c0e9e0..e55997490dcb 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -42,6 +42,7 @@ obj-$(CONFIG_PWM_MICROCHIP_CORE)	+=
> pwm-microchip-core.o
>  obj-$(CONFIG_PWM_MTK_DISP)	+= pwm-mtk-disp.o
>  obj-$(CONFIG_PWM_MXS)		+= pwm-mxs.o
>  obj-$(CONFIG_PWM_NTXEC)		+= pwm-ntxec.o
> +obj-$(CONFIG_PWM_OCORES)	+= pwm-ocores.o
>  obj-$(CONFIG_PWM_OMAP_DMTIMER)	+= pwm-omap-dmtimer.o
>  obj-$(CONFIG_PWM_PCA9685)	+= pwm-pca9685.o
>  obj-$(CONFIG_PWM_PXA)		+= pwm-pxa.o
> diff --git a/drivers/pwm/pwm-ocores.c b/drivers/pwm/pwm-ocores.c new file
> mode 100644 index 000000000000..1ba29f4fe0a6
> --- /dev/null
> +++ b/drivers/pwm/pwm-ocores.c
> @@ -0,0 +1,241 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * OpenCores PWM Driver
> + *
> + * https://opencores.org/projects/ptc
> + *
> + * Copyright (C) 2018-2023 StarFive Technology Co., Ltd.
> + *
> + * Limitations:
> + * - The hardware only supports inverted polarity.
> + * - The hardware minimum period / duty_cycle is (1 / pwm_apb clock
> frequency).
> + * - The hardware maximum period / duty_cycle is (U32_MAX / pwm_apb clock
> frequency).
> + * - The output is set to a low level immediately when disabled.
> + * - When configuration changes are done, they get active immediately without
> resetting
> + *   the counter. This might result in one period affected by both old and new
> settings.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/reset.h>
> +#include <linux/slab.h>
> +
> +/* OpenCores Register offsets */
> +#define REG_OCPWM_CNTR    0x0
> +#define REG_OCPWM_HRC     0x4
> +#define REG_OCPWM_LRC     0x8
> +#define REG_OCPWM_CTRL    0xC
> +
> +/* OCPWM_CTRL register bits*/
> +#define REG_OCPWM_CNTR_EN      BIT(0)
> +#define REG_OCPWM_CNTR_ECLK    BIT(1)
> +#define REG_OCPWM_CNTR_NEC     BIT(2)
> +#define REG_OCPWM_CNTR_OE      BIT(3)
> +#define REG_OCPWM_CNTR_SIGNLE  BIT(4)
> +#define REG_OCPWM_CNTR_INTE    BIT(5)
> +#define REG_OCPWM_CNTR_INT     BIT(6)
> +#define REG_OCPWM_CNTR_RST     BIT(7)
> +#define REG_OCPWM_CNTR_CAPTE   BIT(8)
> +
> +struct ocores_pwm_data {
> +	void __iomem *(*get_ch_base)(void __iomem *base, unsigned int
> +channel); };
> +
> +struct ocores_pwm_device {
> +	const struct ocores_pwm_data *data;
> +	void __iomem *regs;
> +	u32 clk_rate; /* PWM APB clock frequency */ };
> +
> +static inline u32 ocores_pwm_readl(struct ocores_pwm_device *ddata,
> +				   unsigned int channel,
> +				   unsigned int offset)
> +{
> +	void __iomem *base = ddata->data->get_ch_base ?
> +			     ddata->data->get_ch_base(ddata->regs, channel) :
> ddata->regs;
> +
> +	return readl(base + offset);
> +}
> +
> +static inline void ocores_pwm_writel(struct ocores_pwm_device *ddata,
> +				     unsigned int channel,
> +				     unsigned int offset, u32 val)
> +{
> +	void __iomem *base = ddata->data->get_ch_base ?
> +			     ddata->data->get_ch_base(ddata->regs, channel) :
> ddata->regs;
> +
> +	writel(val, base + offset);
> +}
> +
> +static inline struct ocores_pwm_device *chip_to_ocores(struct pwm_chip
> +*chip) {
> +	return pwmchip_get_drvdata(chip);
> +}
> +
> +static void __iomem *ocores_pwm_get_ch_base(void __iomem *base,
> +					    unsigned int channel)
> +{
> +	unsigned int offset = (channel & 4) << 13 | (channel & 3) << 4;
> +
> +	return base + offset;
> +}
> +
> +static int ocores_pwm_get_state(struct pwm_chip *chip,
> +				struct pwm_device *pwm,
> +				struct pwm_state *state)
> +{
> +	struct ocores_pwm_device *ddata = chip_to_ocores(chip);
> +	u32 period_data, duty_data, ctrl_data;
> +
> +	period_data = ocores_pwm_readl(ddata, pwm->hwpwm,
> REG_OCPWM_LRC);
> +	duty_data = ocores_pwm_readl(ddata, pwm->hwpwm,
> REG_OCPWM_HRC);
> +	ctrl_data = ocores_pwm_readl(ddata, pwm->hwpwm,
> REG_OCPWM_CTRL);
> +
> +	state->period = DIV_ROUND_UP_ULL((u64)period_data * NSEC_PER_SEC,
> ddata->clk_rate);
> +	state->duty_cycle = DIV_ROUND_UP_ULL((u64)duty_data *
> NSEC_PER_SEC, ddata->clk_rate);
> +	state->polarity = PWM_POLARITY_INVERSED;
> +	state->enabled = (ctrl_data & REG_OCPWM_CNTR_EN) ? true : false;
> +
> +	return 0;
> +}
> +
> +static int ocores_pwm_apply(struct pwm_chip *chip,
> +			    struct pwm_device *pwm,
> +			    const struct pwm_state *state)
> +{
> +	struct ocores_pwm_device *ddata = chip_to_ocores(chip);
> +	u32 ctrl_data = 0;
> +	u64 period_data, duty_data;
> +
> +	if (state->polarity != PWM_POLARITY_INVERSED)
> +		return -EINVAL;
> +
> +	period_data = mul_u64_u32_div(state->period, ddata->clk_rate,
> NSEC_PER_SEC);
> +	if (!period_data)
> +		return -EINVAL;
> +
> +	if (period_data > U32_MAX)
> +		period_data = U32_MAX;
> +
> +	ocores_pwm_writel(ddata, pwm->hwpwm, REG_OCPWM_LRC,
> period_data);
> +
> +	duty_data = mul_u64_u32_div(state->duty_cycle, ddata->clk_rate,
> NSEC_PER_SEC);
> +	if (!duty_data)
> +		return -EINVAL;
> +
> +	if (duty_data > U32_MAX)
> +		duty_data = U32_MAX;
> +
> +	ocores_pwm_writel(ddata, pwm->hwpwm, REG_OCPWM_HRC,
> duty_data);
> +
> +	ctrl_data = ocores_pwm_readl(ddata, pwm->hwpwm,
> REG_OCPWM_CTRL);
> +	if (state->enabled)
> +		ocores_pwm_writel(ddata, pwm->hwpwm, REG_OCPWM_CTRL,
> +				  ctrl_data | REG_OCPWM_CNTR_EN |
> REG_OCPWM_CNTR_OE);
> +	else
> +		ocores_pwm_writel(ddata, pwm->hwpwm, REG_OCPWM_CTRL,
> +				  ctrl_data & ~(REG_OCPWM_CNTR_EN |
> REG_OCPWM_CNTR_OE));
> +
> +	return 0;
> +}
> +
> +static const struct pwm_ops ocores_pwm_ops = {
> +	.get_state = ocores_pwm_get_state,
> +	.apply = ocores_pwm_apply,
> +};
> +
> +static const struct ocores_pwm_data starfive_pwm_data = {
> +	.get_ch_base = ocores_pwm_get_ch_base, };
> +
> +static const struct of_device_id ocores_pwm_of_match[] = {
> +	{ .compatible = "opencores,pwm-v1" },
> +	{ .compatible = "starfive,jh7100-pwm", .data = &starfive_pwm_data},
> +	{ .compatible = "starfive,jh7110-pwm", .data = &starfive_pwm_data},
> +	{ /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, ocores_pwm_of_match);
> +
> +static void ocores_pwm_reset_control_assert(void *data) {
> +	reset_control_assert(data);
> +}
> +
> +static int ocores_pwm_probe(struct platform_device *pdev) {
> +	const struct of_device_id *id;
> +	struct device *dev = &pdev->dev;
> +	struct ocores_pwm_device *ddata;
> +	struct pwm_chip *chip;
> +	struct clk *clk;
> +	struct reset_control *rst;
> +	int ret;
> +
> +	id = of_device_get_match_data(&pdev->dev);
> +	if (!id)
> +		return -ENODEV;
> +
> +	chip = devm_pwmchip_alloc(&pdev->dev, 8, sizeof(*ddata));
> +	if (IS_ERR(chip))
> +		return -ENOMEM;
> +
> +	ddata = chip_to_ocores(chip);
> +	ddata->data = id->data;
> +	chip->ops = &ocores_pwm_ops;
> +
> +	ddata->regs = devm_platform_ioremap_resource(pdev, 0);
> +	if (IS_ERR(ddata->regs))
> +		return dev_err_probe(dev, PTR_ERR(ddata->regs),
> +				     "Unable to map IO resources\n");
> +
> +	clk = devm_clk_get_enabled(dev, NULL);
> +	if (IS_ERR(clk))
> +		return dev_err_probe(dev, PTR_ERR(clk),
> +				     "Unable to get pwm's clock\n");
> +
> +	ret = devm_clk_rate_exclusive_get(dev, clk);
> +	if (ret)
> +		return ret;
> +
> +	rst = devm_reset_control_get_optional_exclusive(dev, NULL);
> +	if (IS_ERR(rst))
> +		return dev_err_probe(dev, PTR_ERR(rst),
> +				     "Unable to get pwm's reset\n");
> +
> +	ret = reset_control_deassert(rst);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_add_action_or_reset(dev, ocores_pwm_reset_control_assert,
> rst);
> +	if (ret)
> +		return ret;
> +
> +	ddata->clk_rate = clk_get_rate(clk);
> +	if (ddata->clk_rate > NSEC_PER_SEC)
> +		return -EINVAL;
> +
> +	ret = devm_pwmchip_add(dev, chip);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Could not register PWM chip\n");
> +
> +	return 0;
> +}
> +
> +static struct platform_driver ocores_pwm_driver = {
> +	.probe = ocores_pwm_probe,
> +	.driver = {
> +		.name = "ocores-pwm",
> +		.of_match_table = ocores_pwm_of_match,
> +	},
> +};
> +module_platform_driver(ocores_pwm_driver);
> +
> +MODULE_AUTHOR("Jieqin Chen");
> +MODULE_AUTHOR("Hal Feng <hal.feng@starfivetech.com>");
> +MODULE_DESCRIPTION("OpenCores PTC PWM driver");
> MODULE_LICENSE("GPL");
> --
> 2.43.0

Hi Uwe,

Could you please help me review this patch series to see if there is anything that needs to be modified? If not, could you help me integrate this patch into the mainline? Thanks.

Thanks for taking time to review this patch series.
 
Best Regards,
William