From: Kamel Bouhara <kamel.bouhara@bootlin.com>
Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
8 independent PWM outputs.
Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.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@bootlin.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);
+ 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;
+ 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;
+ }
+
+ return 0;
+}
+
+static const struct pwm_ops max7360_pwm_ops = {
+ .request = max7360_pwm_request,
+ .free = max7360_pwm_free,
+ .apply = max7360_pwm_apply,
+};
+
+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;
+ }
+
+ 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;
+
+ 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);
+}
+
+#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
+
+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@bootlin.com>");
+MODULE_ALIAS("platform:max7360-pwm");
+MODULE_LICENSE("GPL");
--
2.39.5On 19/12/2024 17:21, mathieu.dubois-briand@bootlin.com wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
>
> Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
> 8 independent PWM outputs.
>
...
> +
> +#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
> +
> +static struct platform_driver max7360_pwm_driver = {
> + .driver = {
> + .name = "max7360-pwm",
> + .of_match_table = of_match_ptr(max7360_pwm_of_match),
Better to drop of_match_ptr and #ifdef earlier, so ACPI could use it.
> + },
> + .probe = max7360_pwm_probe,
> +};
> +module_platform_driver(max7360_pwm_driver);
> +
> +MODULE_DESCRIPTION("MAX7360 PWM driver");
> +MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
> +MODULE_ALIAS("platform:max7360-pwm");
You should not need MODULE_ALIAS() in normal cases. If you need it,
usually it means your device ID table is wrong (e.g. misses either
entries or MODULE_DEVICE_TABLE()). MODULE_ALIAS() is not a substitute
for incomplete ID table.
Maybe you need it because OF table will get dropped, then it would be
fine. But in current code it's unnecessary and copy-pasta from other
drivers.
Best regards,
Krzysztof
Hello again, On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@bootlin.com wrote: > 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 > + * I forgot: Please also add a paragraph here describing the relevant features here in the format that several other drivers use. Such that sed -rn '/Limitations:/,/\*\/?$/p' drivers/pwm/*.c emits it. Relevant are at least: - Only supports normal polarity - How does it behave on disable? (Constant low? Freeze at the level where it just happens to be? High-Z?) - How does it behave on reconfiguration? (counter reset? Mixed output possible? Best regards Uwe
Hello,
On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@bootlin.com wrote:
> From: Kamel Bouhara <kamel.bouhara@bootlin.com>
>
> Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
> 8 independent PWM outputs.
>
> Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
> ---
> drivers/pwm/Kconfig | 11 +++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-max7360.c | 173 ++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 185 insertions(+)
>
> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
> index 0915c1e7df16..399dc3f76e92 100644
> --- a/drivers/pwm/Kconfig
> +++ b/drivers/pwm/Kconfig
> @@ -745,4 +745,15 @@ config PWM_XILINX
> To compile this driver as a module, choose M here: the module
> will be called pwm-xilinx.
>
> +config PWM_MAX7360
> + tristate "MAX7360 PWMs"
> + depends on MFD_MAX7360
> + depends on OF_GPIO
> + help
> + PWM driver for Maxim Integrated MAX7360 multifunction device, with
> + support for up to 8 PWM outputs.
> +
> + To compile this driver as a module, choose M here: the module
> + will be called pwm-max7360.
> +
> endif
> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
> index 9081e0c0e9e0..ae8908ffc892 100644
> --- a/drivers/pwm/Makefile
> +++ b/drivers/pwm/Makefile
> @@ -36,6 +36,7 @@ obj-$(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@bootlin.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@bootlin.com>");
> +MODULE_ALIAS("platform:max7360-pwm");
> +MODULE_LICENSE("GPL");
On Thu Dec 19, 2024 at 10:53 PM CET, Uwe Kleine-König wrote:
> Hello,
>
> On Thu, Dec 19, 2024 at 05:21:21PM +0100, mathieu.dubois-briand@bootlin.com wrote:
> > From: Kamel Bouhara <kamel.bouhara@bootlin.com>
> >
> > + 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.
>
Yes this was definitely missing. Period is fixed by the chip, so I will
make sure the requested one is valid or return -EINVAL.
Thanks a lot for your review, I am preparing a new version of this
series that should address all your comments.
--
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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