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Message-ID: <dmfnpq57n3s32o33pm7wfppr5nttdvtuthe7hf32psmykotrox@mogq35gj6rjq>
Date: Thu, 19 Dec 2024 22:53:24 +0100
From: Uwe Kleine-König <ukleinek@...nel.org>
To: mathieu.dubois-briand@...tlin.com
Cc: Lee Jones <lee@...nel.org>, Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>,
Kamel Bouhara <kamel.bouhara@...tlin.com>, Linus Walleij <linus.walleij@...aro.org>,
Bartosz Golaszewski <brgl@...ev.pl>, Dmitry Torokhov <dmitry.torokhov@...il.com>,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org, linux-gpio@...r.kernel.org,
linux-input@...r.kernel.org, linux-pwm@...r.kernel.org,
Grégory Clement <gregory.clement@...tlin.com>, Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH 4/8] pwm: max7360: Add MAX7360 PWM support
Hello,
On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@...tlin.com wrote:
> From: Kamel Bouhara <kamel.bouhara@...tlin.com>
>
> Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
> 8 independent PWM outputs.
>
> Signed-off-by: Kamel Bouhara <kamel.bouhara@...tlin.com>
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@...tlin.com>
> ---
> drivers/pwm/Kconfig | 11 +++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-max7360.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 185 insertions(+)
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 0915c1e7df16..399dc3f76e92 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -745,4 +745,15 @@ config PWM_XILINX
> To compile this driver as a module, choose M here: the module
> will be called pwm-xilinx.
>
> +config PWM_MAX7360
> + tristate "MAX7360 PWMs"
> + depends on MFD_MAX7360
> + depends on OF_GPIO
> + help
> + PWM driver for Maxim Integrated MAX7360 multifunction device, with
> + support for up to 8 PWM outputs.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-max7360.
> +
> endif
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 9081e0c0e9e0..ae8908ffc892 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -36,6 +36,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
> obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o
> obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o
> obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o
> +obj-$(CONFIG_PWM_MAX7360) += pwm-max7360.o
> obj-$(CONFIG_PWM_MESON) += pwm-meson.o
> obj-$(CONFIG_PWM_MEDIATEK) += pwm-mediatek.o
> obj-$(CONFIG_PWM_MICROCHIP_CORE) += pwm-microchip-core.o
> diff --git a/drivers/pwm/pwm-max7360.c b/drivers/pwm/pwm-max7360.c
> new file mode 100644
> index 000000000000..b1cde3e86864
> --- /dev/null
> +++ b/drivers/pwm/pwm-max7360.c
> @@ -0,0 +1,173 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright 2024 Bootlin
> + *
> + * Author: Kamel BOUHARA <kamel.bouhara@...tlin.com>
> + */
> +#include <linux/math.h>
> +#include <linux/mfd/max7360.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
> +
> +#define MAX7360_NUM_PWMS 8
> +#define MAX7360_PWM_MAX_RES 256
> +#define MAX7360_PWM_PERIOD_NS 2000000 /* 500 Hz */
> +#define MAX7360_PWM_COMMON_PWN BIT(5)
> +#define MAX7360_PWM_CTRL_ENABLE(n) BIT(n)
> +#define MAX7360_PWM_PORT(n) BIT(n)
> +
> +struct max7360_pwm {
> + struct device *dev;
> + struct regmap *regmap;
> +};
> +
> +static inline struct max7360_pwm *to_max7360_pwm(struct pwm_chip *chip)
> +{
> + return pwmchip_get_drvdata(chip);
> +}
> +
> +static int max7360_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct max7360_pwm *max7360_pwm;
> + int ret;
> +
> + max7360_pwm = to_max7360_pwm(chip);
> + ret = max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
> + true);
> + if (ret) {
> + dev_err(&chip->dev, "failed to request pwm-%d\n", pwm->hwpwm);
Please no error messages after probe.
> + return ret;
> + }
> +
> + ret = regmap_write_bits(max7360_pwm->regmap,
> + MAX7360_REG_PWMCFG + pwm->hwpwm,
> + MAX7360_PWM_COMMON_PWN,
> + 0);
> + if (ret) {
> + dev_err(&chip->dev, "failed to write pwm-%d cfg register, error %d\n",
> + pwm->hwpwm, ret);
> + return ret;
> + }
> +
> + ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_PORTS,
> + MAX7360_PWM_PORT(pwm->hwpwm),
> + MAX7360_PWM_PORT(pwm->hwpwm));
> + if (ret) {
> + dev_err(&chip->dev, "failed to write pwm-%d ports register, error %d\n",
> + pwm->hwpwm, ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void max7360_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
> +{
> + struct max7360_pwm *max7360_pwm;
> + int ret;
> +
> + max7360_pwm = to_max7360_pwm(chip);
> + ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
> + MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
> + 0);
> + if (ret)
> + dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
> + pwm->hwpwm, ret);
> +
> + max7360_port_pin_request(max7360_pwm->dev->parent, pwm->hwpwm,
> + false);
> +}
> +
> +static int max7360_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm,
> + const struct pwm_state *state)
> +{
> + struct max7360_pwm *max7360_pwm;
> + u64 duty_steps = state->duty_cycle * MAX7360_PWM_MAX_RES;
This might overflow.
> + int ret;
> +
> + if (state->polarity != PWM_POLARITY_NORMAL)
> + return -EINVAL;
> +
> + max7360_pwm = to_max7360_pwm(chip);
> + ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
> + MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm),
> + MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm));
> + if (ret) {
> + dev_err(&chip->dev, "failed to enable pwm-%d , error %d\n",
> + pwm->hwpwm, ret);
> + return ret;
> + }
> +
> + do_div(duty_steps, MAX7360_PWM_PERIOD_NS);
> +
> + ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWMBASE + pwm->hwpwm,
> + duty_steps >= 255 ? 255 : duty_steps);
> + if (ret) {
> + dev_err(&chip->dev,
> + "failed to apply pwm duty_cycle %llu on pwm-%d, error %d\n",
> + duty_steps, pwm->hwpwm, ret);
> + return ret;
> + }
Huh, state->period isn't used at all. That is wrong for sure.
> +
> + return 0;
> +}
> +
> +static const struct pwm_ops max7360_pwm_ops = {
> + .request = max7360_pwm_request,
> + .free = max7360_pwm_free,
> + .apply = max7360_pwm_apply,
Please implement .get_state() (or the new waveform callbacks)
> +};
> +
> +static int max7360_pwm_probe(struct platform_device *pdev)
> +{
> + struct max7360_pwm *max7360_pwm;
> + struct pwm_chip *chip;
> +
> + if (!pdev->dev.parent) {
> + dev_err(&pdev->dev, "no parent device\n");
> + return -ENODEV;
return dev_err_probe(...);
> + }
> +
> + chip = devm_pwmchip_alloc(&pdev->dev, MAX7360_NUM_PWMS,
> + sizeof(*max7360_pwm));
> + if (IS_ERR(chip))
> + return PTR_ERR(chip);
> + chip->ops = &max7360_pwm_ops;
> +
> + max7360_pwm = to_max7360_pwm(chip);
> + max7360_pwm->dev = &pdev->dev;
This is only ever used to get max7360_pwm->dev->parent; so better store
the parent directly in max7360_pwm.
> +
> + max7360_pwm->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + if (!max7360_pwm->regmap) {
> + dev_err(&pdev->dev, "could not get parent regmap\n");
> + return -ENODEV;
> + }
> +
> + return devm_pwmchip_add(&pdev->dev, chip);
error message please
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id max7360_pwm_of_match[] = {
> + { .compatible = "maxim,max7360-pwm", },
> + { }
> +};
> +MODULE_DEVICE_TABLE(of, max7360_pwm_of_match);
> +#endif
Please drop the CONFIG_OF guard.
> +
> +static struct platform_driver max7360_pwm_driver = {
> + .driver = {
> + .name = "max7360-pwm",
> + .of_match_table = of_match_ptr(max7360_pwm_of_match),
> + },
> + .probe = max7360_pwm_probe,
> +};
> +module_platform_driver(max7360_pwm_driver);
> +
> +MODULE_DESCRIPTION("MAX7360 PWM driver");
> +MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@...tlin.com>");
> +MODULE_ALIAS("platform:max7360-pwm");
> +MODULE_LICENSE("GPL");
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