1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * LED driver for STMicroelectronics LED1202 chip 4 * 5 * Copyright (C) 2024 Remote-Tech Ltd. UK 6 */ 7 8 #include <linux/cleanup.h> 9 #include <linux/ctype.h> 10 #include <linux/delay.h> 11 #include <linux/err.h> 12 #include <linux/gpio.h> 13 #include <linux/i2c.h> 14 #include <linux/leds.h> 15 #include <linux/module.h> 16 #include <linux/slab.h> 17 #include <linux/string.h> 18 19 #define ST1202_CHAN_DISABLE_ALL 0x00 20 #define ST1202_CHAN_ENABLE_HIGH 0x03 21 #define ST1202_CHAN_ENABLE_LOW 0x02 22 #define ST1202_CONFIG_REG 0x04 23 /* PATS: Pattern sequence feature enable */ 24 #define ST1202_CONFIG_REG_PATS BIT(7) 25 /* PATSR: Pattern sequence runs (self-clear when sequence is finished) */ 26 #define ST1202_CONFIG_REG_PATSR BIT(6) 27 #define ST1202_CONFIG_REG_SHFT BIT(3) 28 #define ST1202_DEV_ENABLE 0x01 29 #define ST1202_DEV_ENABLE_ON BIT(0) 30 #define ST1202_DEV_ENABLE_RESET BIT(7) 31 #define ST1202_DEVICE_ID 0x00 32 #define ST1202_ILED_REG0 0x09 33 #define ST1202_MAX_LEDS 12 34 #define ST1202_MAX_PATTERNS 8 35 #define ST1202_MILLIS_PATTERN_DUR_MAX 5660 36 #define ST1202_MILLIS_PATTERN_DUR_MIN 22 37 #define ST1202_PATTERN_DUR 0x16 38 #define ST1202_PATTERN_PWM 0x1E 39 #define ST1202_PATTERN_REP 0x15 40 41 struct st1202_led { 42 struct fwnode_handle *fwnode; 43 struct led_classdev led_cdev; 44 struct st1202_chip *chip; 45 bool is_active; 46 int led_num; 47 }; 48 49 struct st1202_chip { 50 struct i2c_client *client; 51 struct mutex lock; 52 struct st1202_led leds[ST1202_MAX_LEDS]; 53 }; 54 55 static struct st1202_led *cdev_to_st1202_led(struct led_classdev *cdev) 56 { 57 return container_of(cdev, struct st1202_led, led_cdev); 58 } 59 60 static int st1202_read_reg(struct st1202_chip *chip, int reg, uint8_t *val) 61 { 62 struct device *dev = &chip->client->dev; 63 int ret; 64 65 ret = i2c_smbus_read_byte_data(chip->client, reg); 66 if (ret < 0) { 67 dev_err(dev, "Failed to read register [0x%x]: %d\n", reg, ret); 68 return ret; 69 } 70 71 *val = (uint8_t)ret; 72 return 0; 73 } 74 75 static int st1202_write_reg(struct st1202_chip *chip, int reg, uint8_t val) 76 { 77 struct device *dev = &chip->client->dev; 78 int ret; 79 80 ret = i2c_smbus_write_byte_data(chip->client, reg, val); 81 if (ret != 0) 82 dev_err(dev, "Failed to write %d to register [0x%x]: %d\n", val, reg, ret); 83 84 return ret; 85 } 86 87 static uint8_t st1202_prescalar_to_miliseconds(unsigned int value) 88 { 89 return value / ST1202_MILLIS_PATTERN_DUR_MIN - 1; 90 } 91 92 static int st1202_pwm_pattern_write(struct st1202_chip *chip, int led_num, 93 int pattern, unsigned int value) 94 { 95 u8 value_l, value_h; 96 int ret; 97 98 value_l = (u8)value; 99 value_h = (u8)(value >> 8); 100 101 /* 102 * Datasheet: Register address low = 1Eh + 2*(xh) + 18h*(yh), 103 * where x is the channel number (led number) in hexadecimal (x = 00h .. 0Bh) 104 * and y is the pattern number in hexadecimal (y = 00h .. 07h) 105 */ 106 ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + (led_num * 2) + 0x18 * pattern), 107 value_l); 108 if (ret != 0) 109 return ret; 110 111 /* 112 * Datasheet: Register address high = 1Eh + 01h + 2(xh) +18h*(yh), 113 * where x is the channel number in hexadecimal (x = 00h .. 0Bh) 114 * and y is the pattern number in hexadecimal (y = 00h .. 07h) 115 */ 116 ret = st1202_write_reg(chip, (ST1202_PATTERN_PWM + 0x1 + (led_num * 2) + 0x18 * pattern), 117 value_h); 118 if (ret != 0) 119 return ret; 120 121 return 0; 122 } 123 124 static int st1202_duration_pattern_write(struct st1202_chip *chip, int pattern, 125 unsigned int value) 126 { 127 return st1202_write_reg(chip, (ST1202_PATTERN_DUR + pattern), 128 st1202_prescalar_to_miliseconds(value)); 129 } 130 131 static void st1202_brightness_set(struct led_classdev *led_cdev, 132 enum led_brightness value) 133 { 134 struct st1202_led *led = cdev_to_st1202_led(led_cdev); 135 struct st1202_chip *chip = led->chip; 136 137 guard(mutex)(&chip->lock); 138 139 st1202_write_reg(chip, ST1202_ILED_REG0 + led->led_num, value); 140 } 141 142 static enum led_brightness st1202_brightness_get(struct led_classdev *led_cdev) 143 { 144 struct st1202_led *led = cdev_to_st1202_led(led_cdev); 145 struct st1202_chip *chip = led->chip; 146 u8 value = 0; 147 148 guard(mutex)(&chip->lock); 149 150 st1202_read_reg(chip, ST1202_ILED_REG0 + led->led_num, &value); 151 152 return value; 153 } 154 155 static int st1202_channel_set(struct st1202_chip *chip, int led_num, bool active) 156 { 157 u8 chan_low, chan_high; 158 int ret; 159 160 guard(mutex)(&chip->lock); 161 162 if (led_num <= 7) { 163 ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_LOW, &chan_low); 164 if (ret < 0) 165 return ret; 166 167 chan_low = active ? chan_low | BIT(led_num) : chan_low & ~BIT(led_num); 168 169 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, chan_low); 170 if (ret < 0) 171 return ret; 172 173 } else { 174 ret = st1202_read_reg(chip, ST1202_CHAN_ENABLE_HIGH, &chan_high); 175 if (ret < 0) 176 return ret; 177 178 chan_high = active ? chan_high | (BIT(led_num) >> 8) : 179 chan_high & ~(BIT(led_num) >> 8); 180 181 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, chan_high); 182 if (ret < 0) 183 return ret; 184 } 185 186 return 0; 187 } 188 189 static int st1202_led_set(struct led_classdev *ldev, enum led_brightness value) 190 { 191 struct st1202_led *led = cdev_to_st1202_led(ldev); 192 193 return st1202_channel_set(led->chip, led->led_num, !!value); 194 } 195 196 static int st1202_led_pattern_clear(struct led_classdev *ldev) 197 { 198 struct st1202_led *led = cdev_to_st1202_led(ldev); 199 struct st1202_chip *chip = led->chip; 200 int ret; 201 202 guard(mutex)(&chip->lock); 203 204 for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++) { 205 ret = st1202_pwm_pattern_write(chip, led->led_num, patt, LED_OFF); 206 if (ret != 0) 207 return ret; 208 209 ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN); 210 if (ret != 0) 211 return ret; 212 } 213 214 return 0; 215 } 216 217 static int st1202_led_pattern_set(struct led_classdev *ldev, 218 struct led_pattern *pattern, 219 u32 len, int repeat) 220 { 221 struct st1202_led *led = cdev_to_st1202_led(ldev); 222 struct st1202_chip *chip = led->chip; 223 int ret; 224 225 if (len > ST1202_MAX_PATTERNS) 226 return -EINVAL; 227 228 guard(mutex)(&chip->lock); 229 230 for (int patt = 0; patt < len; patt++) { 231 if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN || 232 pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX) 233 return -EINVAL; 234 235 ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness); 236 if (ret != 0) 237 return ret; 238 239 ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t); 240 if (ret != 0) 241 return ret; 242 } 243 244 ret = st1202_write_reg(chip, ST1202_PATTERN_REP, repeat); 245 if (ret != 0) 246 return ret; 247 248 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, (ST1202_CONFIG_REG_PATSR | 249 ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_SHFT)); 250 if (ret != 0) 251 return ret; 252 253 return 0; 254 } 255 256 static int st1202_dt_init(struct st1202_chip *chip) 257 { 258 struct device *dev = &chip->client->dev; 259 struct st1202_led *led; 260 int err, reg; 261 262 for_each_available_child_of_node_scoped(dev_of_node(dev), child) { 263 err = of_property_read_u32(child, "reg", ®); 264 if (err) 265 return dev_err_probe(dev, err, "Invalid register\n"); 266 267 led = &chip->leds[reg]; 268 led->is_active = true; 269 led->fwnode = of_fwnode_handle(child); 270 271 led->led_cdev.max_brightness = U8_MAX; 272 led->led_cdev.brightness_set_blocking = st1202_led_set; 273 led->led_cdev.pattern_set = st1202_led_pattern_set; 274 led->led_cdev.pattern_clear = st1202_led_pattern_clear; 275 led->led_cdev.default_trigger = "pattern"; 276 led->led_cdev.brightness_set = st1202_brightness_set; 277 led->led_cdev.brightness_get = st1202_brightness_get; 278 } 279 280 return 0; 281 } 282 283 static int st1202_setup(struct st1202_chip *chip) 284 { 285 int ret; 286 287 guard(mutex)(&chip->lock); 288 289 /* 290 * Once the supply voltage is applied, the LED1202 executes some internal checks. 291 * Afterwards, it stops the oscillator and puts the internal LDO in quiescent mode. 292 * To start the device, EN bit must be set inside the “Device Enable” register at 293 * address 01h. As soon as EN is set, the LED1202 loads the adjustment parameters 294 * from the internal non-volatile memory and performs an auto-calibration procedure 295 * in order to increase the output current precision. 296 * Such initialization lasts about 6.5 ms. 297 */ 298 299 /* Reset the chip during setup */ 300 ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_RESET); 301 if (ret < 0) 302 return ret; 303 304 /* Enable phase-shift delay feature */ 305 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT); 306 if (ret < 0) 307 return ret; 308 309 /* Enable the device */ 310 ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON); 311 if (ret < 0) 312 return ret; 313 314 /* Duration of initialization */ 315 usleep_range(6500, 10000); 316 317 /* Deactivate all LEDS (channels) and activate only the ones found in Device Tree */ 318 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL); 319 if (ret < 0) 320 return ret; 321 322 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL); 323 if (ret < 0) 324 return ret; 325 326 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, 327 ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR); 328 if (ret < 0) 329 return ret; 330 331 return 0; 332 } 333 334 static int st1202_probe(struct i2c_client *client) 335 { 336 struct st1202_chip *chip; 337 struct st1202_led *led; 338 int ret; 339 340 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 341 return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n"); 342 343 chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); 344 if (!chip) 345 return -ENOMEM; 346 347 ret = devm_mutex_init(&client->dev, &chip->lock); 348 if (ret < 0) 349 return ret; 350 chip->client = client; 351 352 ret = st1202_setup(chip); 353 if (ret < 0) 354 return ret; 355 356 ret = st1202_dt_init(chip); 357 if (ret < 0) 358 return ret; 359 360 for (int i = 0; i < ST1202_MAX_LEDS; i++) { 361 struct led_init_data init_data = {}; 362 led = &chip->leds[i]; 363 led->chip = chip; 364 led->led_num = i; 365 366 if (!led->is_active) 367 continue; 368 369 ret = st1202_channel_set(led->chip, led->led_num, true); 370 if (ret < 0) 371 return dev_err_probe(&client->dev, ret, 372 "Failed to activate LED channel\n"); 373 374 ret = st1202_led_pattern_clear(&led->led_cdev); 375 if (ret < 0) 376 return dev_err_probe(&client->dev, ret, 377 "Failed to clear LED pattern\n"); 378 379 init_data.fwnode = led->fwnode; 380 init_data.devicename = "st1202"; 381 init_data.default_label = ":"; 382 383 ret = devm_led_classdev_register_ext(&client->dev, &led->led_cdev, &init_data); 384 if (ret < 0) 385 return dev_err_probe(&client->dev, ret, 386 "Failed to register LED class device\n"); 387 } 388 389 return 0; 390 } 391 392 static const struct i2c_device_id st1202_id[] = { 393 { "st1202-i2c" }, 394 { /* sentinel */ } 395 }; 396 MODULE_DEVICE_TABLE(i2c, st1202_id); 397 398 static const struct of_device_id st1202_dt_ids[] = { 399 { .compatible = "st,led1202" }, 400 { /* sentinel */ } 401 }; 402 MODULE_DEVICE_TABLE(of, st1202_dt_ids); 403 404 static struct i2c_driver st1202_driver = { 405 .driver = { 406 .name = "leds-st1202", 407 .of_match_table = of_match_ptr(st1202_dt_ids), 408 }, 409 .probe = st1202_probe, 410 .id_table = st1202_id, 411 }; 412 module_i2c_driver(st1202_driver); 413 414 MODULE_AUTHOR("Remote Tech LTD"); 415 MODULE_DESCRIPTION("STMicroelectronics LED1202 : 12-channel constant current LED driver"); 416 MODULE_LICENSE("GPL"); 417