[RFC v4 2/4] pwm: starfive: Add PWM driver support
Emil Renner Berthing
emil.renner.berthing at canonical.com
Tue Sep 12 08:04:03 PDT 2023
William Qiu wrote:
> Add Pulse Width Modulation driver support for StarFive
> JH7100 and JH7110 SoC.
>
> Co-developed-by: Hal Feng <hal.feng at starfivetech.com>
> Signed-off-by: Hal Feng <hal.feng at starfivetech.com>
> Signed-off-by: William Qiu <william.qiu at starfivetech.com>
> ---
> MAINTAINERS | 7 ++
> drivers/pwm/Kconfig | 9 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-starfive-ptc.c | 192 +++++++++++++++++++++++++++++++++
> 4 files changed, 209 insertions(+)
> create mode 100644 drivers/pwm/pwm-starfive-ptc.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index d590ce31aa72..0e47818c6f64 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -20299,6 +20299,13 @@ F: drivers/pinctrl/starfive/pinctrl-starfive-jh71*
> F: include/dt-bindings/pinctrl/pinctrl-starfive-jh7100.h
> F: include/dt-bindings/pinctrl/starfive,jh7110-pinctrl.h
>
> +STARFIVE JH71X0 PWM DRIVERS
> +M: William Qiu <william.qiu at starfivetech.com>
> +M: Hal Feng <hal.feng at starfivetech.com>
> +S: Supported
> +F: Documentation/devicetree/bindings/pwm/starfive,jh7100-pwm.yaml
> +F: drivers/pwm/pwm-starfive-ptc.c
> +
> STARFIVE JH71X0 RESET CONTROLLER DRIVERS
> M: Emil Renner Berthing <kernel at esmil.dk>
> M: Hal Feng <hal.feng at starfivetech.com>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 6210babb0741..48800f33b5c1 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -569,6 +569,15 @@ config PWM_SPRD
> To compile this driver as a module, choose M here: the module
> will be called pwm-sprd.
>
> +config PWM_STARFIVE_PTC
> + tristate "StarFive PWM PTC support"
> + depends on ARCH_STARFIVE || COMPILE_TEST
> + help
> + Generic PWM framework driver for StarFive SoCs.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-starfive-ptc.
What is PTC short for? Are there other PWM peripherals on the JH7100 or JH7110
that are not PTCs?
If there are both PTC and non-PTC PWMs on these SoCs then the device tree
compatible strings should reflect that.
If not, maybe just call this driver pwm-starfive / PWM_STARFIVE, or maybe
pwm-starfive-jh7100 / PWM_STARFIVE_JH7110 if you already know the PWMs on the
JH81xx will be different.
> +
> config PWM_STI
> tristate "STiH4xx PWM support"
> depends on ARCH_STI || COMPILE_TEST
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index c822389c2a24..d2b2a3aeea22 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -52,6 +52,7 @@ obj-$(CONFIG_PWM_SIFIVE) += pwm-sifive.o
> obj-$(CONFIG_PWM_SL28CPLD) += pwm-sl28cpld.o
> obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
> obj-$(CONFIG_PWM_SPRD) += pwm-sprd.o
> +obj-$(CONFIG_PWM_STARFIVE_PTC) += pwm-starfive-ptc.o
> obj-$(CONFIG_PWM_STI) += pwm-sti.o
> obj-$(CONFIG_PWM_STM32) += pwm-stm32.o
> obj-$(CONFIG_PWM_STM32_LP) += pwm-stm32-lp.o
> diff --git a/drivers/pwm/pwm-starfive-ptc.c b/drivers/pwm/pwm-starfive-ptc.c
> new file mode 100644
> index 000000000000..57b5736f6732
> --- /dev/null
> +++ b/drivers/pwm/pwm-starfive-ptc.c
> @@ -0,0 +1,192 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PWM driver for the StarFive JH71x0 SoC
> + *
> + * Copyright (C) 2018-2023 StarFive Technology Co., Ltd.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/io.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/reset.h>
> +#include <linux/slab.h>
> +
> +/* Access PTC register (CNTR, HRC, LRC and CTRL) */
> +#define REG_PTC_BASE_ADDR_SUB(base, N) \
> +((base) + (((N) > 3) ? (((N) % 4) * 0x10 + (1 << 15)) : ((N) * 0x10)))
Please indent the line above.
> +#define REG_PTC_RPTC_CNTR(base, N) (REG_PTC_BASE_ADDR_SUB(base, N))
> +#define REG_PTC_RPTC_HRC(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0x4)
> +#define REG_PTC_RPTC_LRC(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0x8)
> +#define REG_PTC_RPTC_CTRL(base, N) (REG_PTC_BASE_ADDR_SUB(base, N) + 0xC)
> +
> +/* PTC_RPTC_CTRL register bits*/
> +#define PTC_EN BIT(0)
> +#define PTC_ECLK BIT(1)
> +#define PTC_NEC BIT(2)
> +#define PTC_OE BIT(3)
> +#define PTC_SIGNLE BIT(4)
> +#define PTC_INTE BIT(5)
> +#define PTC_INT BIT(6)
> +#define PTC_CNTRRST BIT(7)
> +#define PTC_CAPTE BIT(8)
> +
> +struct starfive_pwm_ptc_device {
> + struct pwm_chip chip;
> + struct clk *clk;
> + struct reset_control *rst;
> + void __iomem *regs;
> + u32 clk_rate; /* PWM APB clock frequency */
> +};
> +
> +static inline
> +struct starfive_pwm_ptc_device *chip_to_starfive_ptc(struct pwm_chip *c)
This looks weird. Either just put it on a single line or split between the type
and function name. Also there was recently a patch to always name pwm_chip
variables "chip". Eg.
static inline struct starfive_pwm_ptc_device *
chip_to_starfive_ptc(struct pwm_chip *chip)
{
> +{
> + return container_of(c, struct starfive_pwm_ptc_device, chip);
> +}
> +
> +static int starfive_pwm_ptc_get_state(struct pwm_chip *chip,
> + struct pwm_device *dev,
> + struct pwm_state *state)
> +{
> + struct starfive_pwm_ptc_device *pwm = chip_to_starfive_ptc(chip);
> + u32 period_data, duty_data, ctrl_data;
> +
> + period_data = readl(REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm));
> + duty_data = readl(REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm));
> + ctrl_data = readl(REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
> +
> + state->period = DIV_ROUND_CLOSEST_ULL((u64)period_data * NSEC_PER_SEC, pwm->clk_rate);
> + state->duty_cycle = DIV_ROUND_CLOSEST_ULL((u64)duty_data * NSEC_PER_SEC, pwm->clk_rate);
> + state->polarity = PWM_POLARITY_INVERSED;
> + state->enabled = (ctrl_data & PTC_EN) ? true : false;
> +
> + return 0;
> +}
> +
> +static int starfive_pwm_ptc_apply(struct pwm_chip *chip,
> + struct pwm_device *dev,
> + const struct pwm_state *state)
> +{
> + struct starfive_pwm_ptc_device *pwm = chip_to_starfive_ptc(chip);
> + u32 period_data, duty_data, ctrl_data = 0;
> +
> + if (state->polarity != PWM_POLARITY_INVERSED)
> + return -EINVAL;
> +
> + period_data = DIV_ROUND_CLOSEST_ULL(state->period * pwm->clk_rate,
> + NSEC_PER_SEC);
> + duty_data = DIV_ROUND_CLOSEST_ULL(state->duty_cycle * pwm->clk_rate,
> + NSEC_PER_SEC);
> +
> + writel(period_data, REG_PTC_RPTC_LRC(pwm->regs, dev->hwpwm));
> + writel(duty_data, REG_PTC_RPTC_HRC(pwm->regs, dev->hwpwm));
> + writel(0, REG_PTC_RPTC_CNTR(pwm->regs, dev->hwpwm));
> +
> + ctrl_data = readl(REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
> + if (state->enabled)
> + writel(ctrl_data | PTC_EN | PTC_OE, REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
> + else
> + writel(ctrl_data & ~(PTC_EN | PTC_OE), REG_PTC_RPTC_CTRL(pwm->regs, dev->hwpwm));
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops starfive_pwm_ptc_ops = {
> + .get_state = starfive_pwm_ptc_get_state,
> + .apply = starfive_pwm_ptc_apply,
> + .owner = THIS_MODULE,
> +};
> +
> +static int starfive_pwm_ptc_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct starfive_pwm_ptc_device *pwm;
> + struct pwm_chip *chip;
> + int ret;
> +
> + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL);
> + if (!pwm)
> + return -ENOMEM;
> +
> + chip = &pwm->chip;
> + chip->dev = dev;
> + chip->ops = &starfive_pwm_ptc_ops;
> + chip->npwm = 8;
> + chip->of_pwm_n_cells = 3;
> +
> + pwm->regs = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(pwm->regs))
> + return dev_err_probe(dev, PTR_ERR(pwm->regs),
> + "Unable to map IO resources\n");
> +
> + pwm->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(pwm->clk))
> + return dev_err_probe(dev, PTR_ERR(pwm->clk),
> + "Unable to get pwm's clock\n");
I think you can use devm_clk_get_enabled() here and drop the .clk field and
clk_prepare_enable() and clk_disable_unprepare() calls below.
> +
> + pwm->rst = devm_reset_control_get_exclusive(dev, NULL);
> + if (IS_ERR(pwm->rst))
> + return dev_err_probe(dev, PTR_ERR(pwm->rst),
> + "Unable to get pwm's reset\n");
> +
> + ret = clk_prepare_enable(pwm->clk);
> + if (ret) {
> + dev_err(dev,
> + "Failed to enable clock for pwm: %d\n", ret);
> + return ret;
> + }
> +
> + reset_control_deassert(pwm->rst);
This returns an int that you ignore. Please don't do that.
> +
> + pwm->clk_rate = clk_get_rate(pwm->clk);
> + if (pwm->clk_rate <= 0) {
> + dev_warn(dev, "Failed to get APB clock rate\n");
> + return -EINVAL;
> + }
> +
> + ret = devm_pwmchip_add(dev, chip);
> + if (ret < 0) {
> + dev_err(dev, "Cannot register PTC: %d\n", ret);
> + clk_disable_unprepare(pwm->clk);
> + reset_control_assert(pwm->rst);
> + return ret;
> + }
> +
> + platform_set_drvdata(pdev, pwm);
> +
> + return 0;
> +}
> +
> +static int starfive_pwm_ptc_remove(struct platform_device *dev)
> +{
> + struct starfive_pwm_ptc_device *pwm = platform_get_drvdata(dev);
> +
> + reset_control_assert(pwm->rst);
> + clk_disable_unprepare(pwm->clk);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id starfive_pwm_ptc_of_match[] = {
> + { .compatible = "starfive,jh7100-pwm" },
> + { .compatible = "starfive,jh7110-pwm" },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, starfive_pwm_ptc_of_match);
> +
> +static struct platform_driver starfive_pwm_ptc_driver = {
> + .probe = starfive_pwm_ptc_probe,
> + .remove = starfive_pwm_ptc_remove,
> + .driver = {
> + .name = "pwm-starfive-ptc",
> + .of_match_table = starfive_pwm_ptc_of_match,
> + },
> +};
> +module_platform_driver(starfive_pwm_ptc_driver);
> +
> +MODULE_AUTHOR("Jieqin Chen");
> +MODULE_AUTHOR("Hal Feng <hal.feng at starfivetech.com>");
> +MODULE_DESCRIPTION("StarFive PWM PTC driver");
> +MODULE_LICENSE("GPL");
> --
> 2.34.1
>
>
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