[PATCH v13 2/2] leds: ltc3220: Add Support for LTC3220 18 channel LED Driver
Edelweise Escala <[email protected]>
| Newsgroups | org.kernel.vger.linux-leds,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Add driver for the LTC3220 18-channel LED driver with I2C interface, individual brightness control, and hardware-assisted blink/gradation features. Signed-off-by: Edelweise Escala <[email protected]> --- MAINTAINERS | 1 + drivers/leds/Kconfig | 13 + drivers/leds/Makefile | 1 + drivers/leds/leds-ltc3220.c | 586 ++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 601 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index c8a242577d2f..0f553ada61d9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -15229,6 +15229,7 @@ L: [email protected] S: Maintained W: https://ez.analog.com/linux-software-drivers F: Documentation/devicetree/bindings/leds/adi,ltc3220.yaml +F: drivers/leds/leds-ltc3220.c LTC4282 HARDWARE MONITOR DRIVER M: Nuno Sa <[email protected]> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index f4a0a3c8c870..31b1e3ff094c 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -1000,6 +1000,19 @@ config LEDS_ST1202 Say Y to enable support for LEDs connected to LED1202 LED driver chips accessed via the I2C bus. +config LEDS_LTC3220 + tristate "LED Driver for Analog Devices Inc. LTC3220" + depends on I2C && LEDS_CLASS + select REGMAP_I2C + help + Say Y to enable support for the Analog Devices LTC3220 + 18-channel LED controller with I2C interface. + The driver supports individual LED brightness control (64 steps), + hardware-assisted blinking and gradation effects. + + To compile this driver as a module, choose M here: the module will + be called leds-ltc3220. + config LEDS_TPS6105X tristate "LED support for TI TPS6105X" depends on LEDS_CLASS diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile index 7db3768912ca..a68244bd50fb 100644 --- a/drivers/leds/Makefile +++ b/drivers/leds/Makefile @@ -61,6 +61,7 @@ obj-$(CONFIG_LEDS_LP8788) += leds-lp8788.o obj-$(CONFIG_LEDS_LP8860) += leds-lp8860.o obj-$(CONFIG_LEDS_LP8864) += leds-lp8864.o obj-$(CONFIG_LEDS_LT3593) += leds-lt3593.o +obj-$(CONFIG_LEDS_LTC3220) += leds-ltc3220.o obj-$(CONFIG_LEDS_MAX5970) += leds-max5970.o obj-$(CONFIG_LEDS_MAX77650) += leds-max77650.o obj-$(CONFIG_LEDS_MAX77705) += leds-max77705.o diff --git a/drivers/leds/leds-ltc3220.c b/drivers/leds/leds-ltc3220.c new file mode 100644 index 000000000000..5060d5042fe1 --- /dev/null +++ b/drivers/leds/leds-ltc3220.c @@ -0,0 +1,586 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * LTC3220 18-Channel LED Driver + * + * Copyright 2026 Analog Devices Inc. + * + * Author: Edelweise Escala <[email protected]> + */ + +#include <linux/bitfield.h> +#include <linux/delay.h> +#include <linux/device.h> +#include <linux/gpio/consumer.h> +#include <linux/i2c.h> +#include <linux/leds.h> +#include <linux/module.h> +#include <linux/property.h> +#include <linux/regmap.h> +#include <linux/types.h> + +/* LTC3220 Registers */ +#define LTC3220_COMMAND_REG 0x00 +#define LTC3220_QUICK_WRITE_MASK BIT(0) +#define LTC3220_SHUTDOWN_MASK BIT(3) + +#define LTC3220_ULED_REG(x) (0x01 + (x)) +#define LTC3220_LED_CURRENT_MASK GENMASK(5, 0) +#define LTC3220_LED_MODE_MASK GENMASK(7, 6) + +#define LTC3220_GRAD_BLINK_REG 0x13 +#define LTC3220_GRADATION_MASK GENMASK(2, 0) +#define LTC3220_GRADATION_DIRECTION_MASK BIT(0) +#define LTC3220_GRADATION_PERIOD_MASK GENMASK(2, 1) +#define LTC3220_BLINK_MASK GENMASK(4, 3) + +#define LTC3220_NUM_LEDS 18 +#define LTC3220_MAX_BRIGHTNESS 63 + +#define LTC3220_GRADATION_RAMP_TIME_240MS 240 +#define LTC3220_GRADATION_RAMP_TIME_480MS 480 + +#define LTC3220_BLINK_ON_156MS 156 +#define LTC3220_BLINK_ON_625MS 625 +#define LTC3220_BLINK_PERIOD_1250MS 1250 +#define LTC3220_BLINK_PERIOD_2500MS 2500 + +#define LTC3220_BLINK_SHORT_ON_TIME BIT(0) +#define LTC3220_BLINK_LONG_PERIOD BIT(1) + +enum ltc3220_led_mode { + LTC3220_NORMAL_MODE, + LTC3220_BLINK_MODE, + LTC3220_GRADATION_MODE, +}; + +enum ltc3220_blink_mode { + LTC3220_BLINK_MODE_625MS_1250MS, + LTC3220_BLINK_MODE_156MS_1250MS, + LTC3220_BLINK_MODE_625MS_2500MS, + LTC3220_BLINK_MODE_156MS_2500MS +}; + +enum ltc3220_gradation_mode { + LTC3220_GRADATION_MODE_DISABLED, + LTC3220_GRADATION_MODE_240MS_RAMP_TIME, + LTC3220_GRADATION_MODE_480MS_RAMP_TIME, + LTC3220_GRADATION_MODE_960MS_RAMP_TIME +}; + +static const struct regmap_config ltc3220_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = LTC3220_GRAD_BLINK_REG, + .cache_type = REGCACHE_FLAT_S, +}; + +struct ltc3220_uled_cfg { + struct led_classdev led_cdev; + u8 reg_value; + u8 led_index; + bool registered; +}; + +struct ltc3220 { + struct ltc3220_uled_cfg uled_cfg[LTC3220_NUM_LEDS]; + struct regmap *regmap; + struct mutex lock; +}; + +/* + * Set LED brightness. Hardware supports 0-63 brightness levels. + * Mode switching (blink/gradation) is handled through dedicated callbacks. + * + * In aggregated mode only a single LED (reg = 1) is registered and the + * hardware quick-write feature propagates the write to all 18 channels, so + * there is no need to update the other registers explicitly. + */ +static int __ltc3220_set_led_data(struct ltc3220 *ltc3220, + struct ltc3220_uled_cfg *uled_cfg, + enum led_brightness brightness) +{ + int ret; + + brightness &= LTC3220_LED_CURRENT_MASK; + + ret = regmap_write(ltc3220->regmap, LTC3220_ULED_REG(uled_cfg->led_index), + brightness); + if (ret) + return ret; + + uled_cfg->reg_value = brightness; + + return 0; +} + +static int ltc3220_set_led_data(struct led_classdev *led_cdev, + enum led_brightness brightness) +{ + struct ltc3220_uled_cfg *uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, + led_cdev); + struct ltc3220 *ltc3220 = container_of(uled_cfg - uled_cfg->led_index, struct ltc3220, + uled_cfg[0]); + int ret; + + mutex_lock(<c3220->lock); + ret = __ltc3220_set_led_data(ltc3220, uled_cfg, brightness); + mutex_unlock(<c3220->lock); + + return ret; +} + +static enum led_brightness ltc3220_get_led_data(struct led_classdev *led_cdev) +{ + struct ltc3220_uled_cfg *uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, + led_cdev); + + return uled_cfg->reg_value; +} + +/* + * LTC3220 pattern support for hardware-assisted breathing/gradation. + * The hardware supports 3 gradation ramp times (240ms, 480ms, 960ms) + * and can ramp up or down. The gradation period and direction are chip-global + * registers (LTC3220_GRAD_BLINK_REG), affecting all 18 channels simultaneously. + * This is a hardware limitation, not a driver bug. + * + * Pattern array interpretation: + * pattern[0].brightness = start brightness (0-63) + * pattern[0].delta_t = ramp time in milliseconds + * pattern[1].brightness = end brightness (0-63) + * pattern[1].delta_t = (optional, can be 0 or same as pattern[0].delta_t) + */ +static int ltc3220_pattern_set(struct led_classdev *led_cdev, + struct led_pattern *pattern, + u32 len, int repeat) +{ + struct ltc3220_uled_cfg *uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, + led_cdev); + struct ltc3220 *ltc3220 = container_of(uled_cfg - uled_cfg->led_index, struct ltc3220, + uled_cfg[0]); + u8 gradation_period; + u8 start_brightness; + u8 end_brightness; + u8 gradation_val; + u8 led_mode; + bool is_increasing; + int ret; + + if (len != 2) + return -EINVAL; + + start_brightness = clamp_val(pattern[0].brightness, 0, LTC3220_LED_CURRENT_MASK); + end_brightness = clamp_val(pattern[1].brightness, 0, LTC3220_LED_CURRENT_MASK); + + is_increasing = end_brightness > start_brightness; + + if (pattern[0].delta_t == 0) + gradation_period = LTC3220_GRADATION_MODE_DISABLED; + else if (pattern[0].delta_t <= LTC3220_GRADATION_RAMP_TIME_240MS) + gradation_period = LTC3220_GRADATION_MODE_240MS_RAMP_TIME; + else if (pattern[0].delta_t <= LTC3220_GRADATION_RAMP_TIME_480MS) + gradation_period = LTC3220_GRADATION_MODE_480MS_RAMP_TIME; + else + gradation_period = LTC3220_GRADATION_MODE_960MS_RAMP_TIME; + + gradation_val = FIELD_PREP(LTC3220_GRADATION_PERIOD_MASK, gradation_period); + gradation_val |= FIELD_PREP(LTC3220_GRADATION_DIRECTION_MASK, is_increasing); + + /* + * With the ramp disabled (delta_t == 0) there is no gradation to run, + * so apply the end brightness directly in NORMAL mode instead of + * leaving the channel in gradation mode with a disabled ramp. + */ + led_mode = gradation_period == LTC3220_GRADATION_MODE_DISABLED ? + LTC3220_NORMAL_MODE : LTC3220_GRADATION_MODE; + + mutex_lock(<c3220->lock); + + ret = regmap_update_bits(ltc3220->regmap, LTC3220_GRAD_BLINK_REG, + LTC3220_GRADATION_MASK, gradation_val); + if (ret) + goto unlock; + + if (led_mode == LTC3220_GRADATION_MODE) { + ret = regmap_write(ltc3220->regmap, LTC3220_ULED_REG(uled_cfg->led_index), + start_brightness & LTC3220_LED_CURRENT_MASK); + if (ret) + goto unlock; + + ret = regmap_write(ltc3220->regmap, LTC3220_ULED_REG(uled_cfg->led_index), + FIELD_PREP(LTC3220_LED_MODE_MASK, led_mode) | + (end_brightness & LTC3220_LED_CURRENT_MASK)); + if (ret) + goto unlock; + + uled_cfg->reg_value = end_brightness; + } else { + ret = __ltc3220_set_led_data(ltc3220, uled_cfg, end_brightness); + if (ret) + goto unlock; + } + +unlock: + mutex_unlock(<c3220->lock); + return ret; +} + +static int ltc3220_pattern_clear(struct led_classdev *led_cdev) +{ + struct ltc3220_uled_cfg *uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, + led_cdev); + struct ltc3220 *ltc3220 = container_of(uled_cfg - uled_cfg->led_index, struct ltc3220, + uled_cfg[0]); + int ret; + + mutex_lock(<c3220->lock); + + ret = regmap_update_bits(ltc3220->regmap, LTC3220_ULED_REG(uled_cfg->led_index), + LTC3220_LED_MODE_MASK, LTC3220_NORMAL_MODE); + if (ret) + goto unlock; + + ret = __ltc3220_set_led_data(ltc3220, uled_cfg, LED_OFF); + +unlock: + mutex_unlock(<c3220->lock); + return ret; +} + +/* + * LTC3220 has a global blink configuration that affects all LEDs. + * This implementation allows per-LED blink requests via sysfs, but setting + * blink on any LED reprograms the timing for all 18 channels simultaneously. + * The delay values are mapped to the hardware's discrete blink rates. + * + * HARDWARE LIMITATION: This is not a driver bug. Per-LED blink timing control + * is not possible with this hardware due to the global blink register. + */ +static int ltc3220_blink_set(struct led_classdev *led_cdev, + unsigned long *delay_on, + unsigned long *delay_off) +{ + struct ltc3220_uled_cfg *uled_cfg = container_of(led_cdev, struct ltc3220_uled_cfg, + led_cdev); + struct ltc3220 *ltc3220 = container_of(uled_cfg - uled_cfg->led_index, struct ltc3220, + uled_cfg[0]); + u8 blink_brightness; + u8 blink_mode = 0; + int ret; + + if (*delay_on <= LTC3220_BLINK_ON_156MS) + blink_mode = LTC3220_BLINK_SHORT_ON_TIME; + + if (*delay_on + *delay_off > LTC3220_BLINK_PERIOD_1250MS) + blink_mode |= LTC3220_BLINK_LONG_PERIOD; + + switch (blink_mode) { + case LTC3220_BLINK_MODE_625MS_1250MS: + *delay_on = LTC3220_BLINK_ON_625MS; + *delay_off = LTC3220_BLINK_PERIOD_1250MS - LTC3220_BLINK_ON_625MS; + break; + case LTC3220_BLINK_MODE_156MS_1250MS: + *delay_on = LTC3220_BLINK_ON_156MS; + *delay_off = LTC3220_BLINK_PERIOD_1250MS - LTC3220_BLINK_ON_156MS; + break; + case LTC3220_BLINK_MODE_625MS_2500MS: + *delay_on = LTC3220_BLINK_ON_625MS; + *delay_off = LTC3220_BLINK_PERIOD_2500MS - LTC3220_BLINK_ON_625MS; + break; + case LTC3220_BLINK_MODE_156MS_2500MS: + *delay_on = LTC3220_BLINK_ON_156MS; + *delay_off = LTC3220_BLINK_PERIOD_2500MS - LTC3220_BLINK_ON_156MS; + break; + } + + mutex_lock(<c3220->lock); + + ret = regmap_update_bits(ltc3220->regmap, LTC3220_GRAD_BLINK_REG, + LTC3220_BLINK_MASK, FIELD_PREP(LTC3220_BLINK_MASK, blink_mode)); + if (ret) + goto unlock; + + blink_brightness = uled_cfg->reg_value ? : led_cdev->max_brightness; + + ret = regmap_write(ltc3220->regmap, LTC3220_ULED_REG(uled_cfg->led_index), + FIELD_PREP(LTC3220_LED_MODE_MASK, LTC3220_BLINK_MODE) | + (blink_brightness & LTC3220_LED_CURRENT_MASK)); + if (ret) + goto unlock; + + uled_cfg->reg_value = blink_brightness; + +unlock: + mutex_unlock(<c3220->lock); + return ret; +} + +static void ltc3220_reset_gpio_action(void *data) +{ + struct gpio_desc *reset_gpio = data; + + gpiod_set_value_cansleep(reset_gpio, 1); +} + +static int ltc3220_reset(struct ltc3220 *ltc3220, struct i2c_client *client) +{ + struct gpio_desc *reset_gpio; + int ret; + + reset_gpio = devm_gpiod_get_optional(&client->dev, "reset", GPIOD_OUT_HIGH); + if (IS_ERR(reset_gpio)) + return dev_err_probe(&client->dev, PTR_ERR(reset_gpio), "Failed on reset GPIO\n"); + + if (reset_gpio) { + usleep_range(10000, 12000); + gpiod_set_value_cansleep(reset_gpio, 0); + usleep_range(10000, 12000); + + ret = devm_add_action_or_reset(&client->dev, ltc3220_reset_gpio_action, + reset_gpio); + if (ret) + return ret; + } + + ret = regmap_write(ltc3220->regmap, LTC3220_COMMAND_REG, 0); + if (ret) + return ret; + + for (int i = 0; i < LTC3220_NUM_LEDS; i++) { + ret = regmap_write(ltc3220->regmap, LTC3220_ULED_REG(i), 0); + if (ret) + return ret; + } + + return regmap_write(ltc3220->regmap, LTC3220_GRAD_BLINK_REG, 0); +} + +static int ltc3220_suspend(struct device *dev) +{ + struct ltc3220 *ltc3220 = i2c_get_clientdata(to_i2c_client(dev)); + int ret; + + ret = regmap_update_bits(ltc3220->regmap, LTC3220_COMMAND_REG, + LTC3220_SHUTDOWN_MASK, LTC3220_SHUTDOWN_MASK); + if (ret) + return ret; + + regcache_mark_dirty(ltc3220->regmap); + + return 0; +} + +static int ltc3220_resume(struct device *dev) +{ + struct ltc3220 *ltc3220 = i2c_get_clientdata(to_i2c_client(dev)); + bool quick_write_enabled; + unsigned int command_reg; + int ret; + + ret = regmap_read(ltc3220->regmap, LTC3220_COMMAND_REG, &command_reg); + if (ret) + return ret; + + quick_write_enabled = command_reg & LTC3220_QUICK_WRITE_MASK; + + if (quick_write_enabled) { + ret = regmap_update_bits(ltc3220->regmap, LTC3220_COMMAND_REG, + LTC3220_QUICK_WRITE_MASK, 0); + if (ret) + return ret; + } + + ret = regmap_update_bits(ltc3220->regmap, LTC3220_COMMAND_REG, + LTC3220_SHUTDOWN_MASK, 0); + if (ret) + return ret; + + usleep_range(10000, 12000); + + ret = regcache_sync(ltc3220->regmap); + if (ret) + return ret; + + if (quick_write_enabled) { + ret = regmap_update_bits(ltc3220->regmap, LTC3220_COMMAND_REG, + LTC3220_QUICK_WRITE_MASK, + LTC3220_QUICK_WRITE_MASK); + if (ret) + return ret; + } + + return 0; +} + +static DEFINE_SIMPLE_DEV_PM_OPS(ltc3220_pm_ops, ltc3220_suspend, ltc3220_resume); + +static int ltc3220_probe(struct i2c_client *client) +{ + struct ltc3220 *ltc3220; + bool aggregated_led_found = false; + int num_leds = 0; + u8 led_index = 0; + int ret; + + ltc3220 = devm_kzalloc(&client->dev, sizeof(*ltc3220), GFP_KERNEL); + if (!ltc3220) + return -ENOMEM; + + ltc3220->regmap = devm_regmap_init_i2c(client, <c3220_regmap_config); + if (IS_ERR(ltc3220->regmap)) + return dev_err_probe(&client->dev, PTR_ERR(ltc3220->regmap), + "Failed to initialize regmap\n"); + + ret = devm_mutex_init(&client->dev, <c3220->lock); + if (ret) + return ret; + + i2c_set_clientdata(client, ltc3220); + + ret = ltc3220_reset(ltc3220, client); + if (ret) + return dev_err_probe(&client->dev, ret, "Failed to reset device\n"); + + /* First pass: validate configuration and set up LED structures */ + device_for_each_child_node_scoped(&client->dev, child) { + struct ltc3220_uled_cfg *led; + u32 source; + + ret = fwnode_property_read_u32(child, "reg", &source); + if (ret) + return dev_err_probe(&client->dev, ret, "Couldn't read LED address\n"); + + if (!source || source > LTC3220_NUM_LEDS) + return dev_err_probe(&client->dev, -EINVAL, "LED address out of range\n"); + + if (fwnode_property_present(child, "led-sources")) { + u32 led_sources[LTC3220_NUM_LEDS]; + int count; + + if (source != 1) + return dev_err_probe(&client->dev, -EINVAL, + "Aggregated LED out of range\n"); + + if (aggregated_led_found) + return dev_err_probe(&client->dev, -EINVAL, + "One Aggregated LED only\n"); + + count = fwnode_property_count_u32(child, "led-sources"); + if (count != LTC3220_NUM_LEDS) + return dev_err_probe(&client->dev, -EINVAL, + "Aggregated mode requires all %d outputs in led-sources, got %d\n", + LTC3220_NUM_LEDS, count); + + ret = fwnode_property_read_u32_array(child, "led-sources", + led_sources, LTC3220_NUM_LEDS); + if (ret) + return dev_err_probe(&client->dev, ret, + "Failed to read led-sources array\n"); + + /* + * Validate array contents for DT correctness. The hardware + * quick-write broadcasts to all 18 channels regardless of + * array contents, but checking helps catch DT mistakes. + */ + for (int i = 0; i < LTC3220_NUM_LEDS; i++) { + if (led_sources[i] < 1 || led_sources[i] > LTC3220_NUM_LEDS) + return dev_err_probe(&client->dev, -EINVAL, + "Invalid output %u in led-sources\n", + led_sources[i]); + } + + aggregated_led_found = true; + } + + num_leds++; + + /* LED node reg/index/address goes from 1 to 18 */ + led_index = source - 1; + led = <c3220->uled_cfg[led_index]; + + if (led->registered) + return dev_err_probe(&client->dev, -EINVAL, + "Duplicate LED reg %u found\n", source); + + led->registered = true; + led->led_index = led_index; + led->reg_value = 0; + led->led_cdev.brightness_set_blocking = ltc3220_set_led_data; + led->led_cdev.brightness_get = ltc3220_get_led_data; + led->led_cdev.max_brightness = LTC3220_MAX_BRIGHTNESS; + led->led_cdev.blink_set = ltc3220_blink_set; + led->led_cdev.pattern_set = ltc3220_pattern_set; + led->led_cdev.pattern_clear = ltc3220_pattern_clear; + } + + /* + * Aggregated LED mode uses hardware quick-write to control all 18 LEDs + * simultaneously. This is mutually exclusive with individual LED control. + * See Documentation/devicetree/bindings/leds/adi,ltc3220.yaml for details + * on how to configure aggregated LED mode. + */ + if (aggregated_led_found && num_leds > 1) + return dev_err_probe(&client->dev, -EINVAL, + "Aggregated LED must be the only LED node\n"); + + if (num_leds == 0) + return dev_err_probe(&client->dev, -EINVAL, + "No LED nodes found in device tree\n"); + + if (aggregated_led_found) { + ret = regmap_update_bits(ltc3220->regmap, + LTC3220_COMMAND_REG, + LTC3220_QUICK_WRITE_MASK, + LTC3220_QUICK_WRITE_MASK); + if (ret) + return dev_err_probe(&client->dev, ret, + "Failed to set quick write mode\n"); + } + + /* Second pass: register LEDs after validation */ + device_for_each_child_node_scoped(&client->dev, child) { + struct led_init_data init_data = {}; + struct ltc3220_uled_cfg *led; + u32 source; + + ret = fwnode_property_read_u32(child, "reg", &source); + if (ret) + return ret; + + if (!source || source > LTC3220_NUM_LEDS) + return dev_err_probe(&client->dev, -EINVAL, + "LED address out of range in second pass\n"); + + init_data.fwnode = child; + init_data.devicename = "ltc3220"; + + led_index = source - 1; + led = <c3220->uled_cfg[led_index]; + + ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data); + if (ret) + return dev_err_probe(&client->dev, ret, "Failed to register LED class\n"); + } + + return 0; +} + +static const struct of_device_id ltc3220_of_match[] = { + { .compatible = "adi,ltc3220" }, + { } +}; +MODULE_DEVICE_TABLE(of, ltc3220_of_match); + +static struct i2c_driver ltc3220_led_driver = { + .driver = { + .name = "ltc3220", + .of_match_table = ltc3220_of_match, + .pm = pm_sleep_ptr(<c3220_pm_ops), + }, + .probe = ltc3220_probe, +}; +module_i2c_driver(ltc3220_led_driver); + +MODULE_AUTHOR("Edelweise Escala <[email protected]>"); +MODULE_DESCRIPTION("LED driver for LTC3220 controllers"); +MODULE_LICENSE("GPL"); -- 2.43.0