[PATCH v2 3/7] pwm: max7360: Add MAX7360 PWM support

[mathieu.dubois-briand@xxxxxxxxxxx]

From: Kamel Bouhara <kamel.bouhara@xxxxxxxxxxx>

Add driver for Maxim Integrated MAX7360 PWM controller, supporting up to
8 independent PWM outputs.

Signed-off-by: Kamel Bouhara <kamel.bouhara@xxxxxxxxxxx>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@xxxxxxxxxxx>
---
 drivers/pwm/Kconfig       |  11 +++
 drivers/pwm/Makefile      |   1 +
 drivers/pwm/pwm-max7360.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 231 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..28de6c6140e1
--- /dev/null
+++ b/drivers/pwm/pwm-max7360.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2024 Bootlin
+ *
+ * Author: Kamel BOUHARA <kamel.bouhara@xxxxxxxxxxx>
+ *
+ * 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/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 *parent;
+	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->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) {
+		dev_warn(&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_warn(&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_warn(&chip->dev, "failed to disable pwm-%d , error %d\n",
+			 pwm->hwpwm, ret);
+
+	max7360_port_pin_request(max7360_pwm->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;
+	int ret;
+
+	if (state->polarity != PWM_POLARITY_NORMAL)
+		return -EINVAL;
+
+	if (state->period != MAX7360_PWM_PERIOD_NS) {
+		dev_warn(&chip->dev,
+			 "unsupported pwm period: %llu, should be %u\n",
+			 state->period, MAX7360_PWM_PERIOD_NS);
+		return -EINVAL;
+	}
+
+	duty_steps = mul_u64_u64_div_u64(state->duty_cycle, MAX7360_PWM_MAX_RES,
+					 MAX7360_PWM_PERIOD_NS);
+
+	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_warn(&chip->dev, "failed to enable pwm-%d , error %d\n",
+			 pwm->hwpwm, ret);
+		return ret;
+	}
+
+	ret = regmap_write(max7360_pwm->regmap, MAX7360_REG_PWMBASE + pwm->hwpwm,
+			   duty_steps >= 255 ? 255 : duty_steps);
+	if (ret) {
+		dev_warn(&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 int max7360_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm,
+				 struct pwm_state *state)
+{
+	struct max7360_pwm *max7360_pwm;
+	unsigned int val;
+	int ret;
+
+	max7360_pwm = to_max7360_pwm(chip);
+
+	state->period = MAX7360_PWM_PERIOD_NS;
+	state->polarity = PWM_POLARITY_NORMAL;
+
+	ret = regmap_read(max7360_pwm->regmap, MAX7360_REG_GPIOCTRL, &val);
+	if (ret) {
+		dev_warn(&chip->dev,
+			 "failed to read pwm configuration on pwm-%d, error %d\n",
+			 pwm->hwpwm, ret);
+		return ret;
+	}
+	state->enabled = !!(val & MAX7360_PWM_CTRL_ENABLE(pwm->hwpwm));
+
+	ret = regmap_read(max7360_pwm->regmap, MAX7360_REG_PWMBASE + pwm->hwpwm,
+			  &val);
+	if (ret) {
+		dev_warn(&chip->dev,
+			 "failed to read pwm duty_cycle on pwm-%d, error %d\n",
+			 pwm->hwpwm, ret);
+		return ret;
+	}
+	state->duty_cycle = mul_u64_u64_div_u64(val, MAX7360_PWM_PERIOD_NS,
+						MAX7360_PWM_MAX_RES);
+
+	return 0;
+}
+
+static const struct pwm_ops max7360_pwm_ops = {
+	.request = max7360_pwm_request,
+	.free = max7360_pwm_free,
+	.apply = max7360_pwm_apply,
+	.get_state = max7360_pwm_get_state,
+};
+
+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 = to_max7360_pwm(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)
+		dev_err_probe(&pdev->dev, ret, "failed to add PWM chip");
+
+	return 0;
+}
+
+static struct platform_driver max7360_pwm_driver = {
+	.driver = {
+		.name = MAX7360_DRVNAME_PWM,
+	},
+	.probe = max7360_pwm_probe,
+};
+module_platform_driver(max7360_pwm_driver);
+
+MODULE_DESCRIPTION("MAX7360 PWM driver");
+MODULE_AUTHOR("Kamel BOUHARA <kamel.bouhara@xxxxxxxxxxx>");
+MODULE_ALIAS("platform:" MAX7360_DRVNAME_PWM);
+MODULE_LICENSE("GPL");

-- 
2.39.5