drivers: led: Implemented PCA9533 driver with PM support

• Supports led_on/off, led_set_brightness (0–100 %, 152 Hz default),
  and led_blink (7 ms – 1.685 s) with automatic sharing of the two
  on-chip PWM engines; returns –EBUSY when a third distinct pair is
  requested.

• Includes basic runtime-PM boilerplate to honour power-domain control;
  the device itself has no dedicated low-power states.

Signed-off-by: Van Petrosyan <van.petrosyan@sensirion.com>

Author: petrosyan-van

drivers/led/CMakeLists.txt

@@ -21,6 +21,7 @@ zephyr_library_sources_ifdef(CONFIG_LP5562 lp5562.c)
 zephyr_library_sources_ifdef(CONFIG_LP5569 lp5569.c)
 zephyr_library_sources_ifdef(CONFIG_MODULINO_BUTTONS_LEDS modulino_buttons_leds.c)
 zephyr_library_sources_ifdef(CONFIG_NCP5623 ncp5623.c)
+zephyr_library_sources_ifdef(CONFIG_PCA9533 pca9533.c)
 zephyr_library_sources_ifdef(CONFIG_PCA9633 pca9633.c)
 zephyr_library_sources_ifdef(CONFIG_TLC59108 tlc59108.c)
 # zephyr-keep-sorted-stop

drivers/led/Kconfig

@@ -41,6 +41,7 @@ source "drivers/led/Kconfig.lp5569"
 source "drivers/led/Kconfig.modulino"
 source "drivers/led/Kconfig.ncp5623"
 source "drivers/led/Kconfig.npm13xx"
+source "drivers/led/Kconfig.pca9533"
 source "drivers/led/Kconfig.pca9633"
 source "drivers/led/Kconfig.pwm"
 source "drivers/led/Kconfig.tlc59108"

drivers/led/Kconfig.pca9533

@@ -0,0 +1,10 @@
+# Copyright (c) 2025 Van Petrosyan
+# SPDX-License-Identifier: Apache-2.0
+
+config PCA9533
+	bool "PCA9533 LED driver"
+	default y
+	depends on DT_HAS_NXP_PCA9533_ENABLED
+	select I2C
+	help
+	  Enable driver support for the NXP PCA9533 4-bit LED dimmer.

drivers/led/pca9533.c

@@ -0,0 +1,365 @@
+/*
+ * Copyright (c) 2025 Van Petrosyan.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT nxp_pca9533
+
+/**
+ * @file
+ * @brief LED driver for the PCA9533 I2C LED driver (7-bit slave address 0x62)
+ */
+
+#include <zephyr/drivers/i2c.h>
+#include <zephyr/drivers/led.h>
+#include <zephyr/pm/device.h>
+#include <zephyr/sys/util.h>
+#include <zephyr/kernel.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(pca9533, CONFIG_LED_LOG_LEVEL);
+
+#define PCA9533_CHANNELS 4U /* LED0…LED3 */
+#define PCA9533_ENGINES  2U
+
+#define PCA9533_INPUT 0x00 /* read-only pin state            */
+#define PCA9533_PSC0  0x01 /* BLINK0 period prescaler        */
+#define PCA9533_PWM0  0x02 /* BLINK0 duty                    */
+#define PCA9533_PSC1  0x03
+#define PCA9533_PWM1  0x04
+#define PCA9533_LS0   0x05 /* LED selector (2 bits per LED)  */
+
+/* LS register bit fields (§6.3.6, Table 10) */
+#define LS_FUNC_OFF  0x0 /* high-Z → LED off               */
+#define LS_FUNC_ON   0x1 /* output LOW → LED on            */
+#define LS_FUNC_PWM0 0x2
+#define LS_FUNC_PWM1 0x3
+#define LS_SHIFT(ch) ((ch) * 2) /* 2 bits per LED in LS register */
+#define LS_MASK(ch)  (0x3u << LS_SHIFT(ch))
+
+/* Blink period limits derived from PSC range 0…255 (§6.3.2/6.3.4) */
+#define BLINK_MIN_MS 7U    /* (0+1)/152 ≈ 6.58 ms  → ceil   */
+#define BLINK_MAX_MS 1685U /* (255+1)/152 ≈ 1.684 s → ceil  */
+
+/* Default PWM frequency when using set_brightness (152 Hz) */
+#define PCA9533_DEFAULT_PSC 0x00
+
+struct pca9533_config {
+	struct i2c_dt_spec i2c;
+};
+
+struct pca9533_data {
+	/* run-time bookkeeping for the two PWM engines */
+	uint8_t pwm_val[PCA9533_ENGINES];      /* duty (0-255) programmed into PWMx         */
+	uint8_t psc_val[PCA9533_ENGINES];      /* prescaler programmed into PSCx            */
+	uint8_t engine_users[PCA9533_ENGINES]; /* bitmask of LEDs using engine 0 / 1        */
+	uint8_t led_engine[PCA9533_CHANNELS];  /* map LED→engine (0xFF = not used) */
+};
+
+/**
+ * @brief Convert period in ms to PSC register value
+ *
+ * Formula: psc = round(period_ms * 152 / 1000) - 1
+ *
+ * @param period_ms Blink period in milliseconds
+ * @return uint8_t PSC register value (clamped to 0-255)
+ */
+static uint8_t ms_to_psc(uint32_t period_ms)
+{
+	uint32_t tmp = (period_ms * 152U + 500U) / 1000U;
+
+	return (uint8_t)CLAMP(tmp - 1U, 0U, 255U);
+}
+
+/**
+ * @brief Update LS bits for one LED (RMW operation)
+ *
+ * @param i2c I2C device specification
+ * @param led LED index (0-3)
+ * @param func Desired function (LS_FUNC_*)
+ * @return int 0 on success, negative errno on error
+ */
+static int ls_update(const struct i2c_dt_spec *i2c, uint8_t led, uint8_t func)
+{
+	return i2c_reg_update_byte_dt(i2c, PCA9533_LS0, LS_MASK(led), func << LS_SHIFT(led));
+}
+
+/**
+ * @brief Claim a PWM engine matching (psc,duty) or find a free one
+ *
+ * Engine allocation strategy:
+ * 1. Reuse engine with exact (duty, psc) if exists
+ * 2. Use free engine if available
+ * 3. Return -EBUSY if no match
+ *
+ * @param data Driver data
+ * @param duty Desired duty cycle (0-255)
+ * @param psc Desired prescaler value
+ * @param[out] out_ch Acquired engine ID (0 or 1)
+ * @return int 0 on success, -EBUSY if no engine available
+ */
+static int engine_acquire(struct pca9533_data *data, uint8_t duty, uint8_t psc, uint8_t *out_ch)
+{
+	/* Check for existing engine with matching parameters */
+	for (uint8_t ch = 0; ch < PCA9533_ENGINES; ch++) {
+		if (data->engine_users[ch] && data->pwm_val[ch] == duty &&
+		    data->psc_val[ch] == psc) {
+			*out_ch = ch;
+			return 0;
+		}
+	}
+	/* Find free engine */
+	for (uint8_t ch = 0; ch < PCA9533_ENGINES; ch++) {
+		if (data->engine_users[ch] == 0) {
+			*out_ch = ch;
+			return 0;
+		}
+	}
+
+	return -EBUSY;
+}
+
+/**
+ * @brief Bind LED to a PWM engine
+ *
+ * @param data Driver data
+ * @param led LED index (0-3)
+ * @param ch Engine ID (0 or 1)
+ */
+static void engine_bind(struct pca9533_data *data, uint8_t led, uint8_t ch)
+{
+	data->led_engine[led] = ch;
+	data->engine_users[ch] |= BIT(led);
+}
+
+/**
+ * @brief Release LED from its current PWM engine
+ *
+ * @param data Driver data
+ * @param led LED index (0-3)
+ */
+static void engine_release(struct pca9533_data *data, uint8_t led)
+{
+	uint8_t ch = data->led_engine[led];
+
+	if (ch < PCA9533_ENGINES) {
+		data->engine_users[ch] &= ~BIT(led);
+	}
+	data->led_engine[led] = 0xFF;
+}
+
+static int pca9533_led_set_brightness(const struct device *dev, uint32_t led, uint8_t percent)
+{
+	const struct pca9533_config *config = dev->config;
+	struct pca9533_data *data = dev->data;
+	int ret;
+	uint8_t ch;
+
+	uint8_t duty = (percent * 255U) / LED_BRIGHTNESS_MAX;
+	uint8_t cur = data->led_engine[led];
+
+	if (led >= PCA9533_CHANNELS) {
+		LOG_ERR("Invalid LED index: %u", led);
+		return -EINVAL;
+	}
+
+	if (percent == 0) {
+		LOG_DBG("LED%u -> OFF", led);
+		ret = ls_update(&config->i2c, led, LS_FUNC_OFF);
+		if (ret == 0) {
+			engine_release(data, led);
+		}
+		return ret;
+	}
+	if (percent == LED_BRIGHTNESS_MAX) {
+		LOG_DBG("LED%u -> ON", led);
+		ret = ls_update(&config->i2c, led, LS_FUNC_ON);
+		if (ret == 0) {
+			engine_release(data, led);
+		}
+		return ret;
+	}
+
+	/*
+	 * If LED is sole user of its current engine, we can retune it in place.
+	 * This avoids engine thrashing when adjusting brightness.
+	 */
+	if (cur < PCA9533_ENGINES && data->engine_users[cur] == BIT(led)) {
+		/* Only update if duty has changed */
+		if (data->pwm_val[cur] != duty) {
+			LOG_DBG("LED%u retune duty %u on engine %u", led, duty, cur);
+			ret = i2c_reg_write_byte_dt(&config->i2c, cur ? PCA9533_PWM1 : PCA9533_PWM0,
+						    duty);
+			if (ret == 0) {
+				data->pwm_val[cur] = duty;
+			}
+		}
+		return 0;
+	}
+
+	/* Acquire new engine - use default PSC for brightness control */
+	ret = engine_acquire(data, duty, PCA9533_DEFAULT_PSC, &ch);
+	if (ret) {
+		LOG_WRN("No PWM engine available for LED %u", led);
+		return ret;
+	}
+
+	/* If engine is new (no users), program its registers */
+	if (data->engine_users[ch] == 0) {
+		/* Set default period (152 Hz) */
+		ret = i2c_reg_write_byte_dt(&config->i2c, ch ? PCA9533_PSC1 : PCA9533_PSC0,
+					    PCA9533_DEFAULT_PSC);
+		if (ret == 0) {
+			ret = i2c_reg_write_byte_dt(&config->i2c, ch ? PCA9533_PWM1 : PCA9533_PWM0,
+						    duty);
+		}
+		if (ret) {
+			LOG_ERR("Failed to program engine %u: %d", ch, ret);
+			return ret;
+		}
+		data->psc_val[ch] = PCA9533_DEFAULT_PSC;
+		data->pwm_val[ch] = duty;
+	}
+
+	/* Bind LED to new engine and update hardware */
+	LOG_DBG("LED%u uses engine %u (duty %u)", led, ch, duty);
+	engine_release(data, led);
+	engine_bind(data, led, ch);
+	return ls_update(&config->i2c, led, ch ? LS_FUNC_PWM1 : LS_FUNC_PWM0);
+}
+
+static int pca9533_led_blink(const struct device *dev, uint32_t led, uint32_t delay_on,
+			     uint32_t delay_off)
+{
+	const struct pca9533_config *config = dev->config;
+	struct pca9533_data *data = dev->data;
+	int ret;
+
+	uint32_t period = delay_on + delay_off;
+
+	if (led >= PCA9533_CHANNELS) {
+		LOG_ERR("Invalid LED index: %u", led);
+		return -EINVAL;
+	}
+
+	if (period < BLINK_MIN_MS || period > BLINK_MAX_MS) {
+		LOG_ERR("Invalid blink period: %u ms (min: %u, max: %u)", period, BLINK_MIN_MS,
+			BLINK_MAX_MS);
+		return -ENOTSUP;
+	}
+
+	/* Calculate duty cycle with overflow protection */
+	uint32_t duty32 = (delay_on * 256U) / period;
+	uint8_t duty = CLAMP(duty32, 0, 255);
+	uint8_t psc = ms_to_psc(period);
+	uint8_t cur = data->led_engine[led];
+
+	/* If LED is sole user of its engine, update in place */
+	if (cur < PCA9533_ENGINES && data->engine_users[cur] == BIT(led)) {
+		/* Only update if parameters changed */
+		if (data->pwm_val[cur] != duty || data->psc_val[cur] != psc) {
+			ret = i2c_reg_write_byte_dt(&config->i2c, cur ? PCA9533_PSC1 : PCA9533_PSC0,
+						    psc);
+			if (ret == 0) {
+				ret = i2c_reg_write_byte_dt(
+					&config->i2c, cur ? PCA9533_PWM1 : PCA9533_PWM0, duty);
+			}
+			if (ret == 0) {
+				data->psc_val[cur] = psc;
+				data->pwm_val[cur] = duty;
+			}
+		}
+		return 0;
+	}
+
+	/* Acquire new engine with desired parameters */
+	uint8_t ch;
+
+	ret = engine_acquire(data, duty, psc, &ch);
+	if (ret) {
+		LOG_WRN("No PWM engine available for LED %u blink", led);
+		return ret;
+	}
+
+	/* If engine is new (no users), program it */
+	if (data->engine_users[ch] == 0) {
+		ret = i2c_reg_write_byte_dt(&config->i2c, ch ? PCA9533_PSC1 : PCA9533_PSC0, psc);
+		if (ret == 0) {
+			ret = i2c_reg_write_byte_dt(&config->i2c, ch ? PCA9533_PWM1 : PCA9533_PWM0,
+						    duty);
+		}
+		if (ret) {
+			LOG_ERR("Failed to program engine %u: %d", ch, ret);
+			return ret;
+		}
+		data->psc_val[ch] = psc;
+		data->pwm_val[ch] = duty;
+	}
+
+	LOG_DBG("LED%u now on engine %u (psc %u duty %u)", led, ch, psc, duty);
+	engine_release(data, led);
+	engine_bind(data, led, ch);
+	return ls_update(&config->i2c, led, ch ? LS_FUNC_PWM1 : LS_FUNC_PWM0);
+}
+
+static int pca9533_led_init_chip(const struct device *dev)
+{
+	struct pca9533_data *data = dev->data;
+
+	for (uint8_t i = 0; i < PCA9533_CHANNELS; i++) {
+		data->led_engine[i] = 0xFF;
+	}
+	data->engine_users[0] = 0;
+	data->engine_users[1] = 0;
+
+	/* The Power-On Reset already initializes the registers to their default state
+	 * no need to write them here. We'll just reset bookkeeping
+	 */
+
+	return 0;
+}
+
+static int pca9533_pm_action(const struct device *dev, enum pm_device_action action)
+{
+	switch (action) {
+	case PM_DEVICE_ACTION_TURN_ON:
+		return pca9533_led_init_chip(dev);
+	case PM_DEVICE_ACTION_RESUME:
+	case PM_DEVICE_ACTION_SUSPEND:
+	case PM_DEVICE_ACTION_TURN_OFF:
+		return 0;
+
+	default:
+		return -ENOTSUP;
+	}
+}
+
+static int pca9533_led_init(const struct device *dev)
+{
+	const struct pca9533_config *config = dev->config;
+
+	if (!device_is_ready(config->i2c.bus)) {
+		LOG_ERR("I²C bus not ready");
+		return -ENODEV;
+	}
+
+	return pm_device_driver_init(dev, pca9533_pm_action);
+}
+
+static const struct led_driver_api pca9533_led_api = {
+	.blink = pca9533_led_blink,
+	.set_brightness = pca9533_led_set_brightness,
+};
+
+#define PCA9533_DEVICE(id)                                                                         \
+	static const struct pca9533_config pca9533_##id##_cfg = {                                  \
+		.i2c = I2C_DT_SPEC_INST_GET(id),                                                   \
+	};                                                                                         \
+	static struct pca9533_data pca9533_##id##_data;                                            \
+	PM_DEVICE_DT_INST_DEFINE(id, pca9533_pm_action);                                           \
+	DEVICE_DT_INST_DEFINE(id, &pca9533_led_init, PM_DEVICE_DT_INST_GET(id),                    \
+			      &pca9533_##id##_data, &pca9533_##id##_cfg, POST_KERNEL,              \
+			      CONFIG_LED_INIT_PRIORITY, &pca9533_led_api);
+
+DT_INST_FOREACH_STATUS_OKAY(PCA9533_DEVICE)