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Date: Tue, 28 Feb 2023 15:34:25 +0100
From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To: William Qiu <william.qiu@...rfivetech.com>,
devicetree@...r.kernel.org, linux-pwm@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Philipp Zabel <p.zabel@...gutronix.de>,
Thierry Reding <thierry.reding@...il.com>,
Hal Feng <hal.feng@...rfivetech.com>
Subject: Re: [PATCH v1 2/2] pwm: starfive: Add PWM driver support
On 28/02/2023 10:13, William Qiu wrote:
> Add Pulse Width Modulation driver support for StarFive
> JH7110 soc.
>
> Signed-off-by: Hal Feng <hal.feng@...rfivetech.com>
> Signed-off-by: William Qiu <william.qiu@...rfivetech.com>
> ---
> MAINTAINERS | 7 +
> drivers/pwm/Kconfig | 10 ++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-starfive-ptc.c | 256 +++++++++++++++++++++++++++++++++
> 4 files changed, 274 insertions(+)
> create mode 100644 drivers/pwm/pwm-starfive-ptc.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index ac151975d0d3..05b59605d864 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19929,6 +19929,13 @@ 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@...rfivetech.com>
> +M: Hal Feng <hal.feng@...rfivetech.com>
> +S: Supported
> +F: Documentation/devicetree/bindings/pwm/pwm-starfive.yaml
> +F: drivers/pwm/pwm-starfive-ptc.c
> +
> STARFIVE JH71X0 RESET CONTROLLER DRIVERS
> M: Emil Renner Berthing <kernel@...il.dk>
> M: Hal Feng <hal.feng@...rfivetech.com>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index dae023d783a2..2307a0099994 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -536,6 +536,16 @@ 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 OF
> + depends on COMMON_CLK
> + 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.
> +
> config PWM_STI
> tristate "STiH4xx PWM support"
> depends on ARCH_STI || COMPILE_TEST
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 7bf1a29f02b8..577f69904baa 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -49,6 +49,7 @@ 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..58831c600168
> --- /dev/null
> +++ b/drivers/pwm/pwm-starfive-ptc.c
> @@ -0,0 +1,256 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PWM driver for the StarFive JH7110 SoC
> + *
> + * Copyright (C) 2018 StarFive Technology Co., Ltd.
> + */
> +
> +#include <dt-bindings/pwm/pwm.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/slab.h>
> +#include <linux/clk.h>
> +#include <linux/reset.h>
> +#include <linux/io.h>
> +
> +/* how many parameters can be transferred to ptc */
> +#define OF_PWM_N_CELLS 3
> +
> +/* PTC Register offsets */
> +#define REG_RPTC_CNTR 0x0
> +#define REG_RPTC_HRC 0x4
> +#define REG_RPTC_LRC 0x8
> +#define REG_RPTC_CTRL 0xC
> +
> +/* Bit for PWM clock */
> +#define BIT_PWM_CLOCK_EN 31
> +
> +/* Bit for clock gen soft reset */
> +#define BIT_CLK_GEN_SOFT_RESET 13
> +
> +#define NS_PER_SECOND 1000000000
> +#define DEFAULT_FREQ_HZ 2000000
Drop unused defines.
> +
> +/*
> + * Access PTC register (cntr hrc lrc and ctrl),
> + * need to replace PWM_BASE_ADDR
> + */
> +#define REG_PTC_BASE_ADDR_SUB(base, N) \
> +((base) + (((N) > 3) ? (((N) % 4) * 0x10 + (1 << 15)) : ((N) * 0x10)))
> +#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 */
> +#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;
> + int irq;
> + /*pwm apb clock frequency*/
Missing spaces. Use Linux coding style.
> + unsigned int approx_freq;
> +};
> +
> +static inline struct starfive_pwm_ptc_device *
> + chip_to_starfive_ptc(struct pwm_chip *c)
> +{
> + return container_of(c, struct starfive_pwm_ptc_device, chip);
> +}
> +
(...)
> +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;
> + struct resource *res;
> + unsigned int clk_apb_freq;
> + 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 = OF_PWM_N_CELLS;
> + chip->base = -1;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + pwm->regs = devm_ioremap_resource(dev, res);
Combine these two, there is a helper for it.
> + if (IS_ERR(pwm->regs)) {
> + dev_err(dev, "Unable to map IO resources\n");
return dev_err_probe(), everywhere probably.
> + return PTR_ERR(pwm->regs);
> + }
> +
> + pwm->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(pwm->clk)) {
> + dev_err(dev, "Unable to get pwm clock\n");
> + return PTR_ERR(pwm->clk);
> + }
> +
> + pwm->rst = devm_reset_control_get_exclusive(dev, NULL);
> + if (IS_ERR(pwm->rst)) {
> + dev_err(dev, "Unable to get pwm reset\n");
> + return PTR_ERR(pwm->rst);
> + }
> +
> + ret = clk_prepare_enable(pwm->clk);
> + if (ret) {
> + dev_err(dev,
> + "Failed to enable pwm clock, %d\n", ret);
> + return ret;
> + }
> +
> + reset_control_deassert(pwm->rst);
> +
> + clk_apb_freq = (unsigned int)clk_get_rate(pwm->clk);
Why do you need this local variable? And why the cast?
> + if (!clk_apb_freq)
> + dev_warn(dev,
> + "get pwm apb clock rate failed.\n");
and pwm->approx_freq stays 0 which you later use for dividing. Did you
actually test it? It should produce big splat...
> + else
> + pwm->approx_freq = clk_apb_freq;
> +
> + ret = pwmchip_add(chip);
devm
> + if (ret < 0) {
> + dev_err(dev, "cannot register PTC: %d\n", ret);
> + clk_disable_unprepare(pwm->clk);
> + 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);
> + struct pwm_chip *chip = &pwm->chip;
> +
> + pwmchip_remove(chip);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id starfive_pwm_ptc_of_match[] = {
> + { .compatible = "starfive,jh7110-pwm" },
> + {},
> +};
> +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 = of_match_ptr(starfive_pwm_ptc_of_match),
of_match_ptr goes with maybe_unused, which you do not have. Anyway I am
not sure what's the benefit of having it here, so just drop it.
Best regards,
Krzysztof
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