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Message-ID: <45b3f679-df20-a560-6fdc-70fc67d33188@starfivetech.com>
Date:   Mon, 25 Sep 2023 18:48:25 +0800
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Subject: Re: [PATCH v5 2/4] pwm: starfive: Add PWM driver support
To:     Emil Renner Berthing <emil.renner.berthing@canonical.com>,
        <devicetree@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-riscv@lists.infradead.org>, <linux-pwm@vger.kernel.org>
CC:     Emil Renner Berthing <kernel@esmil.dk>,
        Rob Herring <robh+dt@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        =?UTF-8?Q?Uwe_Kleine-K=c3=b6nig?= <u.kleine-koenig@pengutronix.de>,
        Hal Feng <hal.feng@starfivetech.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        "Palmer Dabbelt" <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>
References: <20230922092848.72664-1-william.qiu@starfivetech.com>
 <20230922092848.72664-3-william.qiu@starfivetech.com>
 <CAJM55Z8d368MAQPpnRO8giKmasN5XETP40i3JVdW_0gTF3Ktqg@mail.gmail.com>
 <ade1c061-63d8-8b48-b8e2-69416cd8aa48@starfivetech.com>
 <CAJM55Z83VUkoTNCMbd9GJ7NpwgeQqMjCxPmYonEAXBjr5Tx9Zg@mail.gmail.com>
Content-Language: en-US
From:   William Qiu <william.qiu@starfivetech.com>
In-Reply-To: <CAJM55Z83VUkoTNCMbd9GJ7NpwgeQqMjCxPmYonEAXBjr5Tx9Zg@mail.gmail.com>
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On 2023/9/25 18:31, Emil Renner Berthing wrote:
> William Qiu wrote:
>>
>>
>> On 2023/9/23 20:08, Emil Renner Berthing wrote:
>> > William Qiu wrote:
>> >> Add Pulse Width Modulation driver support for StarFive
>> >> JH7100 and JH7110 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        |   9 ++
>> >>  drivers/pwm/Makefile       |   1 +
>> >>  drivers/pwm/pwm-starfive.c | 190 +++++++++++++++++++++++++++++++++++++
>> >>  4 files changed, 207 insertions(+)
>> >>  create mode 100644 drivers/pwm/pwm-starfive.c
>> >>
>> >> diff --git a/MAINTAINERS b/MAINTAINERS
>> >> index bf0f54c24f81..bc2155bd2712 100644
>> >> --- a/MAINTAINERS
>> >> +++ b/MAINTAINERS
>> >> @@ -20495,6 +20495,13 @@ 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@starfivetech.com>
>> >> +M:	Hal Feng <hal.feng@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@esmil.dk>
>> >>  M:	Hal Feng <hal.feng@starfivetech.com>
>> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
>> >> index 8ebcddf91f7b..e2ee0169f6e4 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
>> >> +	tristate "StarFive PWM 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.
>> >> +
>> >>  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..93b954376873 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-$(CONFIG_PWM_STARFIVE)	+= pwm-starfive.o
>> >>  obj-$(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.c b/drivers/pwm/pwm-starfive.c
>> >
>> > Hi William,
>> >
>> > You never answered my questions about what PTC is short for and if there are
>> > other PWMs on the JH7110. You just removed -ptc from the name of this file..
>> >
>> Hi Emil,
>>
>> The PTC, short for PWM/TIMER/CONUTER, comes from OpenCore's ip, but only PWM
>> mode is used in the JH7110. So the register still has the word "PTC".
>> s the best way to change all the prefix to STARFIVE?
> 
> I see. Yeah, since you're only using the P from PTC the PTC name doesn't make a
> lot of sense anymore. I'd just call this whole driver
> STARFIVE_PWM_/starfive_pwm_ consistently.
> 

I see, I'll update it in next version.
>>
>> Best regards,
>> William
>> >> new file mode 100644
>> >> index 000000000000..d390349fc95d
>> >> --- /dev/null
>> >> +++ b/drivers/pwm/pwm-starfive.c
>> >> @@ -0,0 +1,190 @@
>> >> +// 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)))
>> >> +#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)
>> >
>> > ..but these defines
>> >
>> >> +
>> >> +/* 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)
>> >
>> > ..and these defines are still prefixed with *PTC where I'd expect something like
>> > STARFIVE_PWM_, and below structs and function names are also still
>> > using starfive_pwm_ptc_
>> > where I'd expect starfive_pwm_. Please be consistant in your naming.
>> >
>> >> +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 *chip)
>> >> +
>> >> +{
>> >> +	return container_of(chip, 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_enabled(dev, NULL);
>> >> +	if (IS_ERR(pwm->clk))
>> >> +		return dev_err_probe(dev, PTR_ERR(pwm->clk),
>> >> +				     "Unable to get pwm's clock\n");
>> >> +
>> >> +	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 = reset_control_deassert(pwm->rst);
>> >> +	if (ret) {
>> >> +		dev_err(dev, "Failed to enable clock for pwm: %d\n", ret);
>> >> +		return ret;
>> >> +	}
>> >> +
>> >> +	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",
>> >
>> > Here
>> >
>> >> +		.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@starfivetech.com>");
>> >> +MODULE_DESCRIPTION("StarFive PWM PTC driver");
>> >
>> > ..and here you're also still calling the driver PTC without explaining why.
>> >
>> >> +MODULE_LICENSE("GPL");
>> >> --
>> >> 2.34.1
>> >>