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>
Co-developed-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
drivers/pwm/Kconfig | 10 +++
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-max7360.c | 213 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 224 insertions(+)
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0915c1e7df16..fac811ee46b5 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -745,4 +745,14 @@ 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
+ 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..f1257c20add2
--- /dev/null
+++ b/drivers/pwm/pwm-max7360.c
@@ -0,0 +1,213 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Bootlin
+ *
+ * Author: Kamel BOUHARA <kamel.bouhara@bootlin.com>
+ * Author: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
+ *
+ * Limitations:
+ * - Only supports normal polarity.
+ * - The period is fixed to 2 ms.
+ * - Only the duty cycle can be changed, new values are applied at the beginning
+ * of the next cycle.
+ * - When disabled, the output is put in Hi-Z.
+ */
+#include <linux/err.h>
+#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 255
+#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 *parent;
+ struct regmap *regmap;
+};
+
+struct max7360_pwm_waveform {
+ u8 duty_steps;
+};
+
+static inline struct max7360_pwm *max7360_pwm_from_chip(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 = max7360_pwm_from_chip(chip);
+ ret = max7360_port_pin_request(max7360_pwm->parent, pwm->hwpwm, true);
+ if (ret) {
+ dev_warn(&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)
+ return ret;
+
+ return regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_PORTS,
+ MAX7360_PWM_PORT(pwm->hwpwm),
+ MAX7360_PWM_PORT(pwm->hwpwm));
+}
+
+static void max7360_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct max7360_pwm *max7360_pwm;
+
+ max7360_pwm = max7360_pwm_from_chip(chip);
+ max7360_port_pin_request(max7360_pwm->parent, pwm->hwpwm, false);
+}
+
+static int max7360_pwm_round_waveform_tohw(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ const struct pwm_waveform *wf,
+ void *_wfhw)
+{
+ struct max7360_pwm_waveform *wfhw = _wfhw;
+ u64 duty_steps;
+
+ /*
+ * Ignore user provided values for period_length_ns and duty_offset_ns:
+ * we only support fixed period of MAX7360_PWM_PERIOD_NS and offset of
+ * 0.
+ */
+
+ duty_steps = mul_u64_u64_div_u64(wf->duty_length_ns, MAX7360_PWM_MAX_RES,
+ MAX7360_PWM_PERIOD_NS);
+
+ wfhw->duty_steps = min(MAX7360_PWM_MAX_RES, duty_steps);
+
+ return 0;
+}
+
+static int max7360_pwm_round_waveform_fromhw(struct pwm_chip *chip, struct pwm_device *pwm,
+ const void *_wfhw, struct pwm_waveform *wf)
+{
+ const struct max7360_pwm_waveform *wfhw = _wfhw;
+
+ wf->period_length_ns = MAX7360_PWM_PERIOD_NS;
+ wf->duty_offset_ns = 0;
+ wf->duty_length_ns = DIV64_U64_ROUND_UP(wfhw->duty_steps * MAX7360_PWM_PERIOD_NS,
+ MAX7360_PWM_MAX_RES);
+
+ return 0;
+}
+
+static int max7360_pwm_write_waveform(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ const void *_wfhw)
+{
+ const struct max7360_pwm_waveform *wfhw = _wfhw;
+ struct max7360_pwm *max7360_pwm;
+ unsigned int val;
+ int ret;
+
+ max7360_pwm = max7360_pwm_from_chip(chip);
+
+ val = (wfhw->duty_steps == 0) ? 0 : MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm);
+ ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
+ MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm), val);
+
+ if (!ret && wfhw->duty_steps != 0) {
+ ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWM(pwm->hwpwm),
+ wfhw->duty_steps);
+ }
+
+ return ret;
+}
+
+static int max7360_pwm_read_waveform(struct pwm_chip *chip,
+ struct pwm_device *pwm,
+ void *_wfhw)
+{
+ struct max7360_pwm_waveform *wfhw = _wfhw;
+ struct max7360_pwm *max7360_pwm;
+ unsigned int val;
+ int ret;
+
+ max7360_pwm = max7360_pwm_from_chip(chip);
+
+ ret = regmap_read(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL, &val);
+ if (ret)
+ return ret;
+
+ if (val & MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm)) {
+ ret = regmap_read(max7360_pwm->regmap, MAX7360_REG_PWM(pwm->hwpwm),
+ &val);
+ val = wfhw->duty_steps;
+ } else {
+ wfhw->duty_steps = 0;
+ }
+
+ return ret;
+}
+
+static const struct pwm_ops max7360_pwm_ops = {
+ .request = max7360_pwm_request,
+ .free = max7360_pwm_free,
+ .round_waveform_tohw = max7360_pwm_round_waveform_tohw,
+ .round_waveform_fromhw = max7360_pwm_round_waveform_fromhw,
+ .read_waveform = max7360_pwm_read_waveform,
+ .write_waveform = max7360_pwm_write_waveform,
+};
+
+static int max7360_pwm_probe(struct platform_device *pdev)
+{
+ struct max7360_pwm *max7360_pwm;
+ struct pwm_chip *chip;
+ int ret;
+
+ if (!pdev->dev.parent)
+ return dev_err_probe(&pdev->dev, -ENODEV, "no parent device\n");
+
+ chip = devm_pwmchip_alloc(pdev->dev.parent, MAX7360_NUM_PWMS,
+ sizeof(*max7360_pwm));
+ if (IS_ERR(chip))
+ return PTR_ERR(chip);
+ chip->ops = &max7360_pwm_ops;
+
+ max7360_pwm = max7360_pwm_from_chip(chip);
+ max7360_pwm->parent = pdev->dev.parent;
+
+ max7360_pwm->regmap = dev_get_regmap(pdev->dev.parent, NULL);
+ if (!max7360_pwm->regmap)
+ return dev_err_probe(&pdev->dev, -ENODEV,
+ "could not get parent regmap\n");
+
+ ret = devm_pwmchip_add(&pdev->dev, chip);
+ if (ret != 0)
+ return dev_err_probe(&pdev->dev, ret,
+ "failed to add PWM chip\n");
+
+ return 0;
+}
+
+static struct platform_driver max7360_pwm_driver = {
+ .driver = {
+ .name = "max7360-pwm",
+ },
+ .probe = max7360_pwm_probe,
+};
+module_platform_driver(max7360_pwm_driver);
+
+MODULE_DESCRIPTION("MAX7360 PWM driver");
+MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@bootlin.com>");
+MODULE_AUTHOR("Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>");
+MODULE_LICENSE("GPL");
--
2.39.5On Fri, Feb 14, 2025 at 12:49:53PM +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.
...
+ bits.h
+ dev_printk.h
> +#include <linux/err.h>
> +#include <linux/math.h>
Other way around, id est you need math64.h (see below).
> +#include <linux/mfd/max7360.h>
+ minmax.h
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
Is this used? Cargo cult?
> +#include <linux/platform_device.h>
> +#include <linux/pwm.h>
> +#include <linux/regmap.h>
+ types.h
...
> +#define MAX7360_PWM_PERIOD_NS 2000000 /* 500 Hz */
Comment is superfluous, if you need HZ units, define the respective one.
Also you can use something like (2 * NSEC_PER_MSEC) which will immediately
gives a hint of how long this is and reduces potential 0:s miscalculations.
This will need time.h
...
> +#define MAX7360_PWM_CTRL_ENABLE(n) BIT(n)
> +#define MAX7360_PWM_PORT(n) BIT(n)
Personally I find these macros overkill. The value of them much shorter and
equally readable.
...
> +struct max7360_pwm {
> + struct device *parent;
Is it not the same as you can derive from regmap?
> + struct regmap *regmap;
Btw, have you checked the code generation if you place regmap the first in the
structure? It might affect it.
> +};
...
> + /*
> + * Ignore user provided values for period_length_ns and duty_offset_ns:
> + * we only support fixed period of MAX7360_PWM_PERIOD_NS and offset of
> + * 0.
Easy to read with 0 be on previous line.
> + */
> +
No need for this blank line.
> + duty_steps = mul_u64_u64_div_u64(wf->duty_length_ns, MAX7360_PWM_MAX_RES,
> + MAX7360_PWM_PERIOD_NS);
This comes from math64.h
> +
> + wfhw->duty_steps = min(MAX7360_PWM_MAX_RES, duty_steps);
...
> +static int max7360_pwm_write_waveform(struct pwm_chip *chip,
> + struct pwm_device *pwm,
> + const void *_wfhw)
> +{
> + const struct max7360_pwm_waveform *wfhw = _wfhw;
> + struct max7360_pwm *max7360_pwm;
> + unsigned int val;
> + int ret;
> +
> + max7360_pwm = max7360_pwm_from_chip(chip);
> +
> + val = (wfhw->duty_steps == 0) ? 0 : MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm);
> + ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
> + MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm), val);
> +
> + if (!ret && wfhw->duty_steps != 0) {
> + ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWM(pwm->hwpwm),
> + wfhw->duty_steps);
> + }
> +
> + return ret;
Please, improve readability by rewriting like this:
ret = regmap_write_bits(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL,
MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm), val);
if (ret)
return ret;
if (wfhw->duty_steps)
return regmap_write(max7360_pwm->regmap, MAX7360_REG_PWM(pwm->hwpwm),
wfhw->duty_steps);
return 0;
> +}
...
> +static int max7360_pwm_probe(struct platform_device *pdev)
> +{
With
struct device *dev = &pdev->dev;
all below will look shorter and nicer.
> + struct max7360_pwm *max7360_pwm;
> + struct pwm_chip *chip;
> + int ret;
> +
> + if (!pdev->dev.parent)
> + return dev_err_probe(&pdev->dev, -ENODEV, "no parent device\n");
> +
> + chip = devm_pwmchip_alloc(pdev->dev.parent, MAX7360_NUM_PWMS,
> + sizeof(*max7360_pwm));
> + if (IS_ERR(chip))
> + return PTR_ERR(chip);
> + chip->ops = &max7360_pwm_ops;
> +
> + max7360_pwm = max7360_pwm_from_chip(chip);
> + max7360_pwm->parent = pdev->dev.parent;
> +
> + max7360_pwm->regmap = dev_get_regmap(pdev->dev.parent, NULL);
> + if (!max7360_pwm->regmap)
> + return dev_err_probe(&pdev->dev, -ENODEV,
> + "could not get parent regmap\n");
Will become one line (with the above suggestion).
> + ret = devm_pwmchip_add(&pdev->dev, chip);
> + if (ret != 0)
Please, be consistent with the style, and moreover this style is unusual.
> + return dev_err_probe(&pdev->dev, ret,
> + "failed to add PWM chip\n");
> +
> + return 0;
> +}
--
With Best Regards,
Andy Shevchenko
On Fri Feb 14, 2025 at 4:10 PM CET, Andy Shevchenko wrote:
> On Fri, Feb 14, 2025 at 12:49:53PM +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.
>
> ...
>
> > +#include <linux/of.h>
>
> Is this used? Cargo cult?
>
Right, not used anymore.
>
> > +struct max7360_pwm {
>
> > + struct device *parent;
>
> Is it not the same as you can derive from regmap?
>
It is. I'm removing it.
Also, max7360_pwm structure will only contain the regmap, so I will
remove the structure and set the regmap directly as the pwm chip driver
data.
> ...
>
I have fixed all other points. Thanks for your review!
--
Mathieu Dubois-Briand, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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