zephyr/drivers/led/lp3943.c

/*
 * Copyright (c) 2018 Linaro Ltd.
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#define DT_DRV_COMPAT ti_lp3943

/**
 * @file
 * @brief LP3943 LED driver
 *
 * Limitations:
 * - Blink period and brightness value are controlled by two sets of PSCx/PWMx
 *   registers. This driver partitions the available LEDs into two groups as
 *   0 to 7 and 8 to 15 and assigns PSC0/PWM0 to LEDs from 0 to 7 and PSC1/PWM1
 *   to LEDs from 8 to 15. So, it is not possible to set unique blink period
 *   and brightness value for LEDs in a group, changing either of these
 *   values for a LED will affect other LEDs also.
 */

#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/led.h>
#include <zephyr/sys/util.h>
#include <zephyr/kernel.h>

#define LOG_LEVEL CONFIG_LED_LOG_LEVEL
#include <zephyr/logging/log.h>
LOG_MODULE_REGISTER(lp3943);

/* LP3943 Registers */
#define LP3943_INPUT_1 0x00
#define LP3943_INPUT_2 0x01
#define LP3943_PSC0 0x02
#define LP3943_PWM0 0x03
#define LP3943_PSC1 0x04
#define LP3943_PWM1 0x05
#define LP3943_LS0 0x06
#define LP3943_LS1 0x07
#define LP3943_LS2 0x08
#define LP3943_LS3 0x09

#define LP3943_MASK 0x03

#define LP3943_MAX_PERIOD 1600U

enum lp3943_modes {
	LP3943_OFF,
	LP3943_ON,
	LP3943_DIM0,
	LP3943_DIM1,
};

struct lp3943_config {
	struct i2c_dt_spec bus;
};

static int lp3943_get_led_reg(uint32_t *led, uint8_t *reg)
{
	switch (*led) {
	case 0:
	case 1:
	case 2:
		__fallthrough;
	case 3:
		*reg = LP3943_LS0;
		break;
	case 4:
	case 5:
	case 6:
		__fallthrough;
	case 7:
		*reg = LP3943_LS1;
		*led -= 4U;
		break;
	case 8:
	case 9:
	case 10:
		__fallthrough;
	case 11:
		*reg = LP3943_LS2;
		*led -= 8U;
		break;
	case 12:
	case 13:
	case 14:
		__fallthrough;
	case 15:
		*reg = LP3943_LS3;
		*led -= 12U;
		break;
	default:
		LOG_ERR("Invalid LED specified");
		return -EINVAL;
	}

	return 0;
}

static int lp3943_set_dim_states(const struct lp3943_config *config,
				 uint32_t led, uint8_t mode)
{
	int ret;
	uint8_t reg;

	ret = lp3943_get_led_reg(&led, &reg);
	if (ret) {
		return ret;
	}

	/* Set DIMx states for the LEDs */
	if (i2c_reg_update_byte_dt(&config->bus, reg, LP3943_MASK << (led << 1),
				   mode << (led << 1))) {
		LOG_ERR("LED reg update failed");
		return -EIO;
	}

	return 0;
}

static int lp3943_led_blink(const struct device *dev, uint32_t led,
			    uint32_t delay_on, uint32_t delay_off)
{
	const struct lp3943_config *config = dev->config;
	int ret;
	uint16_t period;
	uint8_t reg, val, mode;

	period = delay_on + delay_off;
	if (period > LP3943_MAX_PERIOD) {
		return -EINVAL;
	}

	/* Use DIM0 for LEDs 0 to 7 and DIM1 for LEDs 8 to 15 */
	if (led < 8) {
		mode = LP3943_DIM0;
	} else {
		mode = LP3943_DIM1;
	}

	if (mode == LP3943_DIM0) {
		reg = LP3943_PSC0;
	} else {
		reg = LP3943_PSC1;
	}

	val = period * 255U / LP3943_MAX_PERIOD;
	if (i2c_reg_write_byte_dt(&config->bus, reg, val)) {
		LOG_ERR("LED write failed");
		return -EIO;
	}

	ret = lp3943_set_dim_states(config, led, mode);
	if (ret) {
		return ret;
	}

	return 0;
}

static int lp3943_led_set_brightness(const struct device *dev, uint32_t led,
				     uint8_t value)
{
	const struct lp3943_config *config = dev->config;
	int ret;
	uint8_t reg, val, mode;

	/* Use DIM0 for LEDs 0 to 7 and DIM1 for LEDs 8 to 15 */
	if (led < 8) {
		mode = LP3943_DIM0;
	} else {
		mode = LP3943_DIM1;
	}

	if (mode == LP3943_DIM0) {
		reg = LP3943_PWM0;
	} else {
		reg = LP3943_PWM1;
	}

	val = (value * 255U) / LED_BRIGHTNESS_MAX;
	if (i2c_reg_write_byte_dt(&config->bus, reg, val)) {
		LOG_ERR("LED write failed");
		return -EIO;
	}

	ret = lp3943_set_dim_states(config, led, mode);
	if (ret) {
		return ret;
	}

	return 0;
}

static inline int lp3943_led_on(const struct device *dev, uint32_t led)
{
	const struct lp3943_config *config = dev->config;
	int ret;
	uint8_t reg, mode;

	ret = lp3943_get_led_reg(&led, &reg);
	if (ret) {
		return ret;
	}

	/* Set LED state to ON */
	mode = LP3943_ON;
	if (i2c_reg_update_byte_dt(&config->bus, reg, LP3943_MASK << (led << 1),
				   mode << (led << 1))) {
		LOG_ERR("LED reg update failed");
		return -EIO;
	}

	return 0;
}

static inline int lp3943_led_off(const struct device *dev, uint32_t led)
{
	const struct lp3943_config *config = dev->config;
	int ret;
	uint8_t reg;

	ret = lp3943_get_led_reg(&led, &reg);
	if (ret) {
		return ret;
	}

	/* Set LED state to OFF */
	if (i2c_reg_update_byte_dt(&config->bus, reg, LP3943_MASK << (led << 1),
				   0)) {
		LOG_ERR("LED reg update failed");
		return -EIO;
	}

	return 0;
}

static int lp3943_led_init(const struct device *dev)
{
	const struct lp3943_config *config = dev->config;

	if (!device_is_ready(config->bus.bus)) {
		LOG_ERR("I2C device not ready");
		return -ENODEV;
	}

	return 0;
}

static const struct lp3943_config lp3943_led_config = {
	.bus = I2C_DT_SPEC_INST_GET(0),
};

static DEVICE_API(led, lp3943_led_api) = {
	.blink = lp3943_led_blink,
	.set_brightness = lp3943_led_set_brightness,
	.on = lp3943_led_on,
	.off = lp3943_led_off,
};

DEVICE_DT_INST_DEFINE(0, &lp3943_led_init, NULL, NULL,
		      &lp3943_led_config, POST_KERNEL, CONFIG_LED_INIT_PRIORITY,
		      &lp3943_led_api);