The output current can be adjusted separately for each channel by 8-bit
analog (current sink input) and 12-bit digital (PWM) dimming control. The
LED1202 implements 12 low-side current generators with independent dimming
control. Internal volatile memory allows the user to store up to 8 different
patterns, each pattern is a particular output configuration in terms of PWM
duty-cycle (on 4096 steps). Analog dimming (on 256 steps) is per channel but
common to all patterns. Each device tree LED node will have a corresponding
entry in /sys/class/leds with the label name. The brightness property
corresponds to the per channel analog dimming, while the patterns[1-8] to the
PWM dimming control.
Signed-off-by: Vicentiu Galanopulo <vicentiu.galanopulo@xxxxxxxxxxxxxxxxx>
---
Changes in v5:
- remove unused macros
- switch to using devm_led_classdev_register_ext (struct st1202_led update)
- add prescalar_to_milliseconds (convert [22..5660]ms to [0..255] reg value)
- remove register range check in dt_init (range protected by yaml)
- address all review comments in v4
Changes in v4:
- Remove attributes/extended attributes implementation
- Use /sys/class/leds/<led>/hw_pattern (Pavel suggestion)
- Implement review findings of Christophe JAILLET
Changes in v3:
- Rename all ll1202 to st1202, including driver file name
- Convert all magic numbers to defines
- Refactor the show/store callbacks as per Lee's and Thomas's review
- Remove ll1202_get_channel and use dev_ext_attributes instead
- Log all error values for all the functions
- Use sysfs_emit for show callbacks
Changes in v2:
- Fix build error for device_attribute modes
---
drivers/leds/Kconfig | 11 +
drivers/leds/Makefile | 1 +
drivers/leds/leds-st1202.c | 510 +++++++++++++++++++++++++++++++++++++
3 files changed, 522 insertions(+)
create mode 100644 drivers/leds/leds-st1202.c
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
index b784bb74a837..c4fdacc00066 100644
--- a/drivers/leds/Kconfig
+++ b/drivers/leds/Kconfig
@@ -931,6 +931,17 @@ config LEDS_LM36274
Say Y to enable the LM36274 LED driver for TI LMU devices.
This supports the LED device LM36274.
+config LEDS_ST1202
+ tristate "LED Support for STMicroelectronics LED1202 I2C chips"
+ depends on LEDS_CLASS
+ depends on I2C
+ depends on OF
+ select LEDS_TRIGGERS
+ help
+ Say Y to enable support for LEDs connected to LED1202
+ LED driver chips accessed via the I2C bus.
+ Supported devices include LED1202.
+
config LEDS_TPS6105X
tristate "LED support for TI TPS6105X"
depends on LEDS_CLASS
diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
index 18afbb5a23ee..e8b39ef760cc 100644
--- a/drivers/leds/Makefile
+++ b/drivers/leds/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_LEDS_POWERNV) += leds-powernv.o
obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
+obj-$(CONFIG_LEDS_ST1202) += leds-st1202.o
obj-$(CONFIG_LEDS_SUN50I_A100) += leds-sun50i-a100.o
obj-$(CONFIG_LEDS_SUNFIRE) += leds-sunfire.o
obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
diff --git a/drivers/leds/leds-st1202.c b/drivers/leds/leds-st1202.c
new file mode 100644
index 000000000000..565c8fbfe515
--- /dev/null
+++ b/drivers/leds/leds-st1202.c
@@ -0,0 +1,510 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * LED driver for STMicroelectronics LED1202 chip
+ *
+ * Copyright (C) 2024 Remote-Tech Ltd. UK
+ */
+
+#include <linux/ctype.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/i2c.h>
+#include <linux/leds.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#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)
+{
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(chip->client, reg);
+ if (ret < 0)
+ return ret;
+
+ *val = (uint8_t)ret;
+ return 0;
+}
+
+static int st1202_write_reg(struct st1202_chip *chip, int reg, uint8_t val)
+{
+ return i2c_smbus_write_byte_data(chip->client, reg, val);
+}
+
+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) {
+ dev_err(&chip->client->dev, "Failed writing value %d to register [0x%x], error: %d\n",
+ value_l, ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern, ret);
+ 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) {
+ dev_err(&chip->client->dev, "Failed writing value %d to register [0x%x], error: %d\n",
+ value_h, ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int st1202_duration_pattern_write(struct st1202_chip *chip, int pattern,
+ unsigned int value)
+{
+ int ret;
+
+ ret = st1202_write_reg(chip, (ST1202_PATTERN_DUR + pattern),
+ st1202_prescalar_to_miliseconds(value));
+ if (ret != 0) {
+ dev_err(&chip->client->dev, "Writing to register [0x%x] failed, value %u\n",
+ ST1202_PATTERN_DUR + pattern, value);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void st1202_brightness_set(struct led_classdev *led_cdev,
+ enum led_brightness value)
+{
+ struct st1202_led *led;
+ struct st1202_chip *chip;
+ int ret;
+
+ led = cdev_to_st1202_led(led_cdev);
+ chip = led->chip;
+
+ mutex_lock(&chip->lock);
+
+ ret = st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value);
+ if (ret != 0)
+ dev_err(&chip->client->dev, "Reading register [0x%x] failed, error: %d\n",
+ ST1202_ILED_REG0 + led->led_num, ret);
+
+ mutex_unlock(&chip->lock);
+}
+
+static enum led_brightness st1202_brightness_get(struct led_classdev *led_cdev)
+{
+ struct st1202_led *led;
+ struct st1202_chip *chip;
+ u8 value;
+ int ret;
+
+ led = cdev_to_st1202_led(led_cdev);
+ chip = led->chip;
+
+ mutex_lock(&chip->lock);
+
+ ret = st1202_read_reg(chip, ST1202_ILED_REG0 + led->led_num,
+ &value);
+ if (ret != 0)
+ dev_err(&chip->client->dev, "Reading register [0x%x] failed, error: %d\n",
+ ST1202_ILED_REG0 + led->led_num, ret);
+
+ mutex_unlock(&chip->lock);
+
+ return value;
+}
+
+static int st1202_channel_set(struct st1202_chip *chip, int led_num, bool active)
+{
+ u8 chan_low, chan_high;
+ int ret;
+
+ mutex_lock(&chip->lock);
+
+ if (led_num <= 7) {
+ ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_LOW, &chan_low);
+ if (ret < 0) {
+ dev_err(&chip->client->dev, "Failed reading register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_LOW, ret);
+ goto exit;
+ }
+
+ 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) {
+ dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_LOW, ret);
+ goto exit;
+ }
+ } else {
+ ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_HIGH, &chan_high);
+ if (ret < 0) {
+ dev_err(&chip->client->dev, "Failed reading register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_HIGH, ret);
+ goto exit;
+ }
+
+ 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)
+ dev_err(&chip->client->dev, "Failed writing to register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_HIGH, ret);
+ }
+
+exit:
+ mutex_unlock(&chip->lock);
+ return ret;
+}
+
+static int st1202_led_set(struct led_classdev *ldev, enum led_brightness value)
+{
+ struct st1202_led *led;
+ struct st1202_chip *chip;
+ int ret;
+
+ led = cdev_to_st1202_led(ldev);
+ chip = led->chip;
+
+ ret = st1202_channel_set(chip, led->led_num, value == LED_OFF ? false : true);
+
+ return ret;
+}
+
+static int st1202_led_pattern_clear(struct led_classdev *ldev)
+{
+ struct st1202_led *led;
+ struct st1202_chip *chip;
+ int ret;
+
+ led = cdev_to_st1202_led(ldev);
+ chip = led->chip;
+
+ mutex_lock(&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)
+ goto exit;
+
+ ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN);
+ if (ret != 0)
+ goto exit;
+ }
+
+exit:
+ mutex_unlock(&chip->lock);
+
+ return ret;
+}
+
+static int st1202_led_pattern_set(struct led_classdev *ldev,
+ struct led_pattern *pattern,
+ u32 len, int repeat)
+{
+ struct st1202_led *led;
+ struct st1202_chip *chip;
+ int ret;
+
+ led = cdev_to_st1202_led(ldev);
+ chip = led->chip;
+
+ if (len > ST1202_MAX_PATTERNS)
+ return -EINVAL;
+
+ mutex_lock(&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) {
+ ret = -EINVAL;
+ goto exit;
+ }
+
+ ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness);
+ if (ret != 0)
+ goto exit;
+
+ ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t);
+ if (ret != 0)
+ goto exit;
+ }
+
+ ret = st1202_write_reg(chip, ST1202_PATTERN_REP, repeat);
+ if (ret != 0) {
+ dev_err(&chip->client->dev, "Writing register [0x%x] failed, error: %d\n",
+ ST1202_PATTERN_REP, ret);
+ goto exit;
+ }
+
+ ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+ (ST1202_CONFIG_REG_PATSR | ST1202_CONFIG_REG_PATS |
+ ST1202_CONFIG_REG_SHFT));
+ if (ret != 0) {
+ dev_err(&chip->client->dev, "Failed writing value %ld to register [0x%x], error: %d\n",
+ (ST1202_CONFIG_REG_PATSR | ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_SHFT),
+ ST1202_CONFIG_REG, ret);
+ goto exit;
+ }
+
+exit:
+ mutex_unlock(&chip->lock);
+
+ return ret;
+}
+
+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) {
+ of_node_put(child);
+ return dev_err_probe(dev, err, "Invalid register, error: %d\n", err);
+ }
+
+ 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) {
+ dev_err_probe(dev, err, "Failed to register LED class dev,
+ error: %d\n", err);
+ return err;
+ }
+ 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;
+
+ mutex_lock(&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) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed to write to register [0x%x], error: %d\n",
+ ST1202_DEV_ENABLE, ret);
+ goto exit;
+ }
+
+ /* Enable phase-shift delay feature */
+ ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT);
+ if (ret < 0) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed to write to register [0x%x], error: %d\n",
+ ST1202_CONFIG_REG, ret);
+ goto exit;
+ }
+
+ /* Enable the device */
+ ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON);
+ if (ret < 0) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed to write to register [0x%x], error: %d\n",
+ ST1202_DEV_ENABLE, ret);
+ goto exit;
+ }
+
+ /* 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) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed writing to register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_LOW, ret);
+ goto exit;
+ }
+
+ ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL);
+ if (ret < 0) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed writing to register [0x%x], error: %d\n",
+ ST1202_CHAN_ENABLE_HIGH, ret);
+ goto exit;
+ }
+
+ ret = st1202_write_reg(chip, ST1202_CONFIG_REG,
+ ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR);
+ if (ret < 0) {
+ dev_err_probe(&chip->client->dev, -EIO,
+ "Failed writing to register [0x%lx], error: %d\n",
+ ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR, ret);
+ goto exit;
+ }
+
+exit:
+ mutex_unlock(&chip->lock);
+ return ret;
+}
+
+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;
+
+ i2c_set_clientdata(client, chip);
+
+ 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) {
+ ret = st1202_channel_set(led->chip, led->led_num, true);
+ if (ret < 0) {
+ return dev_err_probe(&client->dev, -EIO,
+ "Failed to activate LED channel, error: %d\n", ret);
+ }
+
+ ret = st1202_led_pattern_clear(&led->led_cdev);
+ if (ret < 0) {
+ return dev_err_probe(&client->dev, -EIO,
+ "Failed to clear LED pattern, error: %d\n", ret);
+ }
+ }
+ }
+
+ 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");
--
2.25.1
