// SPDX-License-Identifier: GPL-2.0-only /* * LED driver for STMicroelectronics LED1202 chip * * Copyright (C) 2024 Remote-Tech Ltd. UK */ #include #include #include #include #include #include #include #include #include #include #define ST1202_CHAN_DISABLE_ALL 0x00 #define ST1202_CHAN_ENABLE_HIGH 0x03 #define ST1202_CHAN_ENABLE_LOW 0x02 #define ST1202_CONFIG_REG 0x04 /* PATS: Pattern sequence feature enable */ #define ST1202_CONFIG_REG_PATS BIT(7) /* PATSR: Pattern sequence runs (self-clear when sequence is finished) */ #define ST1202_CONFIG_REG_PATSR BIT(6) #define ST1202_CONFIG_REG_SHFT BIT(3) #define ST1202_DEV_ENABLE 0x01 #define ST1202_DEV_ENABLE_ON BIT(0) #define ST1202_DEV_ENABLE_RESET BIT(7) #define ST1202_DEVICE_ID 0x00 #define ST1202_ILED_REG0 0x09 #define ST1202_MAX_LEDS 12 #define ST1202_MAX_PATTERNS 8 #define ST1202_MILLIS_PATTERN_DUR_MAX 5660 #define ST1202_MILLIS_PATTERN_DUR_MIN 22 #define ST1202_PATTERN_DUR 0x16 #define ST1202_PATTERN_PWM 0x1E #define ST1202_PATTERN_REP 0x15 struct st1202_led { struct fwnode_handle *fwnode; struct led_classdev led_cdev; struct st1202_chip *chip; bool is_active; int led_num; }; struct st1202_chip { struct i2c_client *client; struct mutex lock; struct st1202_led leds[ST1202_MAX_LEDS]; }; static struct st1202_led *cdev_to_st1202_led(struct led_classdev *cdev) { return container_of(cdev, struct st1202_led, led_cdev); } static int st1202_read_reg(struct st1202_chip *chip, int reg, uint8_t *val) { struct device *dev = &chip->client->dev; int ret; ret = i2c_smbus_read_byte_data(chip->client, reg); if (ret < 0) { dev_err(dev, "Failed to read register [0x%x]: %d\n", reg, ret); return ret; } *val = (uint8_t)ret; return 0; } static int st1202_write_reg(struct st1202_chip *chip, int reg, uint8_t val) { struct device *dev = &chip->client->dev; int ret; ret = i2c_smbus_write_byte_data(chip->client, reg, val); if (ret != 0) dev_err(dev, "Failed to write %d to register [0x%x]: %d\n", val, reg, ret); return ret; } static uint8_t st1202_prescalar_to_miliseconds(unsigned int value) { return value / ST1202_MILLIS_PATTERN_DUR_MIN - 1; } static int st1202_pwm_pattern_write(struct st1202_chip *chip, int led_num, int pattern, unsigned int value) { u8 value_l, value_h; int ret; value_l = (u8)value; value_h = (u8)(value >> 8); /* * Datasheet: Register address low = 1Eh + 2*(xh) + 18h*(yh), * where x is the channel number (led number) in hexadecimal (x = 00h .. 0Bh) * and y is the pattern number in hexadecimal (y = 00h .. 07h) */ ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern), value_l); if (ret != 0) return ret; /* * Datasheet: Register address high = 1Eh + 01h + 2(xh) +18h*(yh), * where x is the channel number in hexadecimal (x = 00h .. 0Bh) * and y is the pattern number in hexadecimal (y = 00h .. 07h) */ ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern), value_h); if (ret != 0) return ret; return 0; } static int st1202_duration_pattern_write(struct st1202_chip *chip, int pattern, unsigned int value) { return st1202_write_reg(chip, (ST1202_PATTERN_DUR + pattern), st1202_prescalar_to_miliseconds(value)); } static void st1202_brightness_set(struct led_classdev *led_cdev, enum led_brightness value) { struct st1202_led *led = cdev_to_st1202_led(led_cdev); struct st1202_chip *chip = led->chip; guard(mutex)(&chip->lock); st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value); } static enum led_brightness st1202_brightness_get(struct led_classdev *led_cdev) { struct st1202_led *led = cdev_to_st1202_led(led_cdev); struct st1202_chip *chip = led->chip; u8 value = 0; guard(mutex)(&chip->lock); st1202_read_reg(chip, ST1202_ILED_REG0 + led->led_num, &value); return value; } static int st1202_channel_set(struct st1202_chip *chip, int led_num, bool active) { u8 chan_low, chan_high; int ret; guard(mutex)(&chip->lock); if (led_num <= 7) { ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_LOW, &chan_low); if (ret < 0) return ret; chan_low = active ? chan_low | BIT(led_num) : chan_low & ~BIT(led_num); ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, chan_low); if (ret < 0) return ret; } else { ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_HIGH, &chan_high); if (ret < 0) return ret; chan_high = active ? chan_high | (BIT(led_num) >> 8) : chan_high & ~(BIT(led_num) >> 8); ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, chan_high); if (ret < 0) return ret; } return 0; } static int st1202_led_set(struct led_classdev *ldev, enum led_brightness value) { struct st1202_led *led = cdev_to_st1202_led(ldev); struct st1202_chip *chip = led->chip; return st1202_channel_set(chip, led->led_num, value == LED_OFF ? false : true); } static int st1202_led_pattern_clear(struct led_classdev *ldev) { struct st1202_led *led = cdev_to_st1202_led(ldev); struct st1202_chip *chip = led->chip; int ret; guard(mutex)(&chip->lock); for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++) { ret = st1202_pwm_pattern_write(chip, led->led_num, patt, LED_OFF); if (ret != 0) return ret; ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN); if (ret != 0) return ret; } return 0; } static int st1202_led_pattern_set(struct led_classdev *ldev, struct led_pattern *pattern, u32 len, int repeat) { struct st1202_led *led = cdev_to_st1202_led(ldev); struct st1202_chip *chip = led->chip; int ret; if (len > ST1202_MAX_PATTERNS) return -EINVAL; guard(mutex)(&chip->lock); for (int patt = 0; patt < len; patt++) { if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN || pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX) return -EINVAL; ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness); if (ret != 0) return ret; ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t); if (ret != 0) return ret; } ret = st1202_write_reg(chip, ST1202_PATTERN_REP, repeat); if (ret != 0) return ret; ret = st1202_write_reg(chip, ST1202_CONFIG_REG, (ST1202_CONFIG_REG_PATSR | ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_SHFT)); if (ret != 0) return ret; return 0; } static int st1202_dt_init(struct st1202_chip *chip) { struct device *dev = &chip->client->dev; struct st1202_led *led; int err, reg; for_each_available_child_of_node_scoped(dev_of_node(dev), child) { struct led_init_data init_data = {}; err = of_property_read_u32(child, "reg", ®); if (err) return dev_err_probe(dev, err, "Invalid register\n"); led = &chip->leds[reg]; led->is_active = true; led->fwnode = of_fwnode_handle(child); led->led_cdev.max_brightness = U8_MAX; led->led_cdev.brightness_set_blocking = st1202_led_set; led->led_cdev.pattern_set = st1202_led_pattern_set; led->led_cdev.pattern_clear = st1202_led_pattern_clear; led->led_cdev.default_trigger = "pattern"; init_data.fwnode = led->fwnode; init_data.devicename = "st1202"; init_data.default_label = ":"; err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data); if (err < 0) return dev_err_probe(dev, err, "Failed to register LED class device\n"); led->led_cdev.brightness_set = st1202_brightness_set; led->led_cdev.brightness_get = st1202_brightness_get; } return 0; } static int st1202_setup(struct st1202_chip *chip) { int ret; guard(mutex)(&chip->lock); /* * Once the supply voltage is applied, the LED1202 executes some internal checks, * afterwords it stops the oscillator and puts the internal LDO in quiescent mode. * To start the device, EN bit must be set inside the “Device Enable” register at * address 01h. As soon as EN is set, the LED1202 loads the adjustment parameters * from the internal non-volatile memory and performs an auto-calibration procedure * in order to increase the output current precision. * Such initialization lasts about 6.5 ms. */ /* Reset the chip during setup */ ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_RESET); if (ret < 0) return ret; /* Enable phase-shift delay feature */ ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT); if (ret < 0) return ret; /* Enable the device */ ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON); if (ret < 0) return ret; /* Duration of initialization */ usleep_range(6500, 10000); /* Deactivate all LEDS (channels) and activate only the ones found in Device Tree */ ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL); if (ret < 0) return ret; ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL); if (ret < 0) return ret; ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR); if (ret < 0) return ret; return 0; } static int st1202_probe(struct i2c_client *client) { struct st1202_chip *chip; struct st1202_led *led; int ret; if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n"); chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; devm_mutex_init(&client->dev, &chip->lock); chip->client = client; ret = st1202_dt_init(chip); if (ret < 0) return ret; ret = st1202_setup(chip); if (ret < 0) return ret; for (int i = 0; i < ST1202_MAX_LEDS; i++) { led = &chip->leds[i]; led->chip = chip; led->led_num = i; if (!led->is_active) continue; ret = st1202_channel_set(led->chip, led->led_num, true); if (ret < 0) return dev_err_probe(&client->dev, ret, "Failed to activate LED channel\n"); ret = st1202_led_pattern_clear(&led->led_cdev); if (ret < 0) return dev_err_probe(&client->dev, ret, "Failed to clear LED pattern\n"); } return 0; } static const struct i2c_device_id st1202_id[] = { { "st1202-i2c" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(i2c, st1202_id); static const struct of_device_id st1202_dt_ids[] = { { .compatible = "st,led1202" }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, st1202_dt_ids); static struct i2c_driver st1202_driver = { .driver = { .name = "leds-st1202", .of_match_table = of_match_ptr(st1202_dt_ids), }, .probe = st1202_probe, .id_table = st1202_id, }; module_i2c_driver(st1202_driver); MODULE_AUTHOR("Remote Tech LTD"); MODULE_DESCRIPTION("STMicroelectronics LED1202 : 12-channel constant current LED driver"); MODULE_LICENSE("GPL");