drivers: pwm: it8801: Add I2C-based PWM device driver

Add I2C-based PWM device driver. Supports 7 open-drain/push-pull
outputs.

Signed-off-by: Tim Lin <tim2.lin@ite.corp-partner.google.com>

drivers/pwm/CMakeLists.txt

@@ -13,6 +13,7 @@ zephyr_library_sources_ifdef(CONFIG_PWM_NRFX		pwm_nrfx.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_MCUX_FTM 	pwm_mcux_ftm.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_IMX		pwm_imx.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_ITE_IT8XXX2	pwm_ite_it8xxx2.c)
+zephyr_library_sources_ifdef(CONFIG_PWM_ITE_IT8801	pwm_ite_it8801.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_LED_ESP32	pwm_led_esp32.c)
 zephyr_library_sources_ifdef(CONFIG_MCPWM_ESP32		pwm_mc_esp32.c)
 zephyr_library_sources_ifdef(CONFIG_PWM_SAM		pwm_sam.c)

drivers/pwm/Kconfig

@@ -50,6 +50,8 @@ source "drivers/pwm/Kconfig.imx"
 
 source "drivers/pwm/Kconfig.it8xxx2"
 
+source "drivers/pwm/Kconfig.it8801"
+
 source "drivers/pwm/Kconfig.esp32"
 
 source "drivers/pwm/Kconfig.sam"

drivers/pwm/Kconfig.it8801

@@ -0,0 +1,12 @@
+# Copyright (c) 2024 ITE Corporation. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+config PWM_ITE_IT8801
+	bool "ITE IT8801 PWM device driver"
+	default y
+	depends on DT_HAS_ITE_IT8801_PWM_ENABLED
+	select I2C
+	select MFD
+	help
+	   Enable driver for ITE IT8801 I2C-based PWM.
+	   Supports 7 open-drain/push-pull outputs.

drivers/pwm/pwm_ite_it8801.c

@@ -0,0 +1,174 @@
+/*
+ * Copyright (c) 2024 ITE Corporation. All Rights Reserved.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT ite_it8801_pwm
+
+#include <zephyr/device.h>
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/mfd/mfd_ite_it8801.h>
+#include <zephyr/drivers/pwm.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(pwm_ite_it8801, CONFIG_PWM_LOG_LEVEL);
+
+struct it8801_pwm_map {
+	uint8_t pushpull_en;
+};
+const static struct it8801_pwm_map it8801_pwm_gpio_map[] = {
+	[1] = {.pushpull_en = BIT(0)}, [2] = {.pushpull_en = BIT(1)}, [3] = {.pushpull_en = BIT(2)},
+	[4] = {.pushpull_en = BIT(3)}, [7] = {.pushpull_en = BIT(4)}, [8] = {.pushpull_en = BIT(5)},
+	[9] = {.pushpull_en = BIT(6)},
+};
+
+struct it8801_mfd_pwm_altctrl_cfg {
+	/* GPIO control device structure */
+	const struct device *gpiocr;
+	/* GPIO control pin */
+	uint8_t pin;
+	/* GPIO function select */
+	uint8_t alt_func;
+};
+
+struct pwm_it8801_config {
+	/* IT8801 controller dev */
+	const struct device *mfd;
+	/* I2C device for the MFD parent */
+	const struct i2c_dt_spec i2c_dev;
+	/* PWM alternate configuration */
+	const struct it8801_mfd_pwm_altctrl_cfg *altctrl;
+	int mfdctrl_len;
+	int channel;
+	/* PWM mode control register */
+	uint8_t reg_mcr;
+	/* PWM duty cycle register */
+	uint8_t reg_dcr;
+	/* PWM prescale LSB register */
+	uint8_t reg_prslr;
+	/* PWM prescale MSB register */
+	uint8_t reg_prsmr;
+};
+
+static void pwm_enable(const struct device *dev, int enabled)
+{
+	const struct pwm_it8801_config *config = dev->config;
+	int ret;
+
+	if (enabled) {
+		ret = i2c_reg_update_byte_dt(&config->i2c_dev, config->reg_mcr,
+					     IT8801_PWMMCR_MCR_MASK, IT8801_PWMMCR_MCR_BLINKING);
+	} else {
+		ret = i2c_reg_update_byte_dt(&config->i2c_dev, config->reg_mcr,
+					     IT8801_PWMMCR_MCR_MASK, 0);
+	}
+	if (ret != 0) {
+		LOG_ERR("Failed to enable pwm (ret %d)", ret);
+		return;
+	}
+}
+
+static int pwm_it8801_get_cycles_per_sec(const struct device *dev, uint32_t channel,
+					 uint64_t *cycles)
+{
+	ARG_UNUSED(dev);
+	ARG_UNUSED(channel);
+
+	*cycles = (uint64_t)PWM_IT8801_FREQ;
+
+	return 0;
+}
+
+static int pwm_it8801_set_cycles(const struct device *dev, uint32_t channel, uint32_t period_cycles,
+				 uint32_t pulse_cycles, pwm_flags_t flags)
+{
+	ARG_UNUSED(channel);
+
+	const struct pwm_it8801_config *config = dev->config;
+	int ch = config->channel, ret;
+	uint8_t duty, mask;
+
+	/* Enable PWM output push-pull */
+	if (flags & PWM_IT8801_PUSH_PULL) {
+		mask = it8801_pwm_gpio_map[ch].pushpull_en;
+
+		ret = i2c_reg_update_byte_dt(&config->i2c_dev, IT8801_REG_PWMODDSR, mask, mask);
+		if (ret != 0) {
+			LOG_ERR("Failed to set push-pull (ret %d)", ret);
+			return ret;
+		}
+	}
+
+	/* Set PWM channel duty cycle */
+	if (pulse_cycles == 0) {
+		duty = 0;
+	} else {
+		duty = pulse_cycles * 256 / period_cycles - 1;
+	}
+	LOG_DBG("IT8801 pwm duty cycles = %d", duty);
+
+	ret = i2c_reg_write_byte_dt(&config->i2c_dev, config->reg_dcr, duty);
+	if (ret != 0) {
+		LOG_ERR("Failed to set cycles (ret %d)", ret);
+		return ret;
+	}
+
+	/* PWM channel clock source not gating */
+	pwm_enable(dev, 1);
+
+	return 0;
+}
+
+static int pwm_it8801_init(const struct device *dev)
+{
+	const struct pwm_it8801_config *config = dev->config;
+	int ret;
+
+	/* Verify multi-function parent is ready */
+	if (!device_is_ready(config->mfd)) {
+		LOG_ERR("(pwm)%s is not ready", config->mfd->name);
+		return -ENODEV;
+	}
+
+	/* PWM channel clock source gating before configuring */
+	pwm_enable(dev, 0);
+
+	for (int i = 0; i < config->mfdctrl_len; i++) {
+		/* Switching the pin to PWM alternate function */
+		ret = mfd_it8801_configure_pins(&config->i2c_dev, config->altctrl[i].gpiocr,
+						config->altctrl[i].pin,
+						config->altctrl[i].alt_func);
+		if (ret != 0) {
+			LOG_ERR("Failed to configure pins (ret %d)", ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static const struct pwm_driver_api pwm_it8801_api = {
+	.set_cycles = pwm_it8801_set_cycles,
+	.get_cycles_per_sec = pwm_it8801_get_cycles_per_sec,
+};
+
+#define PWM_IT8801_INIT(inst)                                                                      \
+	static const struct it8801_mfd_pwm_altctrl_cfg                                             \
+		it8801_pwm_altctrl##inst[IT8801_DT_INST_MFDCTRL_LEN(inst)] =                       \
+			IT8801_DT_MFD_ITEMS_LIST(inst);                                            \
+	static const struct pwm_it8801_config pwm_it8801_cfg_##inst = {                            \
+		.mfd = DEVICE_DT_GET(DT_INST_PARENT(inst)),                                        \
+		.i2c_dev = I2C_DT_SPEC_GET(DT_INST_PARENT(inst)),                                  \
+		.altctrl = it8801_pwm_altctrl##inst,                                               \
+		.mfdctrl_len = IT8801_DT_INST_MFDCTRL_LEN(inst),                                   \
+		.channel = DT_INST_PROP(inst, channel),                                            \
+		.reg_mcr = DT_INST_REG_ADDR_BY_IDX(inst, 0),                                       \
+		.reg_dcr = DT_INST_REG_ADDR_BY_IDX(inst, 1),                                       \
+		.reg_prslr = DT_INST_REG_ADDR_BY_IDX(inst, 2),                                     \
+		.reg_prsmr = DT_INST_REG_ADDR_BY_IDX(inst, 3),                                     \
+	};                                                                                         \
+	DEVICE_DT_INST_DEFINE(inst, &pwm_it8801_init, NULL, NULL, &pwm_it8801_cfg_##inst,          \
+			      POST_KERNEL, CONFIG_MFD_INIT_PRIORITY, &pwm_it8801_api);
+
+DT_INST_FOREACH_STATUS_OKAY(PWM_IT8801_INIT)

dts/bindings/pwm/ite,it8801-pwm.yaml

@@ -0,0 +1,39 @@
+# Copyright (c) 2024 ITE Corporation. All Rights Reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+description: ITE IT8801 I2C-based PWM device driver
+
+compatible: "ite,it8801-pwm"
+
+include: [base.yaml, pinctrl-device.yaml, pwm-controller.yaml]
+
+properties:
+  reg:
+    required: true
+
+  mfdctrl:
+    type: phandle
+    required: true
+    description: |
+      Switching the pin to PWM alternate function.
+
+  channel:
+    type: int
+    required: true
+    enum:
+      - 1
+      - 2
+      - 3
+      - 4
+      - 7
+      - 8
+      - 9
+    description: |
+      1 = PWM_CHANNEL_1, 2 = PWM_CHANNEL_2, 3 = PWM_CHANNEL_3,
+      4 = PWM_CHANNEL_4, 7 = PWM_CHANNEL_7, 8 = PWM_CHANNEL_8,
+      9 = PWM_CHANNEL_9
+
+pwm-cells:
+  - channel
+  - period
+  - flags