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 struct st1202_chip *chip = led->chip; 193 194 return st1202_channel_set(chip, led->led_num, value == LED_OFF ? false : true); 195 } 196 197 static int st1202_led_pattern_clear(struct led_classdev *ldev) 198 { 199 struct st1202_led *led = cdev_to_st1202_led(ldev); 200 struct st1202_chip *chip = led->chip; 201 int ret; 202 203 guard(mutex)(&chip->lock); 204 205 for (int patt = 0; patt < ST1202_MAX_PATTERNS; patt++) { 206 ret = st1202_pwm_pattern_write(chip, led->led_num, patt, LED_OFF); 207 if (ret != 0) 208 return ret; 209 210 ret = st1202_duration_pattern_write(chip, patt, ST1202_MILLIS_PATTERN_DUR_MIN); 211 if (ret != 0) 212 return ret; 213 } 214 215 return 0; 216 } 217 218 static int st1202_led_pattern_set(struct led_classdev *ldev, 219 struct led_pattern *pattern, 220 u32 len, int repeat) 221 { 222 struct st1202_led *led = cdev_to_st1202_led(ldev); 223 struct st1202_chip *chip = led->chip; 224 int ret; 225 226 if (len > ST1202_MAX_PATTERNS) 227 return -EINVAL; 228 229 guard(mutex)(&chip->lock); 230 231 for (int patt = 0; patt < len; patt++) { 232 if (pattern[patt].delta_t < ST1202_MILLIS_PATTERN_DUR_MIN || 233 pattern[patt].delta_t > ST1202_MILLIS_PATTERN_DUR_MAX) 234 return -EINVAL; 235 236 ret = st1202_pwm_pattern_write(chip, led->led_num, patt, pattern[patt].brightness); 237 if (ret != 0) 238 return ret; 239 240 ret = st1202_duration_pattern_write(chip, patt, pattern[patt].delta_t); 241 if (ret != 0) 242 return ret; 243 } 244 245 ret = st1202_write_reg(chip, ST1202_PATTERN_REP, repeat); 246 if (ret != 0) 247 return ret; 248 249 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, (ST1202_CONFIG_REG_PATSR | 250 ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_SHFT)); 251 if (ret != 0) 252 return ret; 253 254 return 0; 255 } 256 257 static int st1202_dt_init(struct st1202_chip *chip) 258 { 259 struct device *dev = &chip->client->dev; 260 struct st1202_led *led; 261 int err, reg; 262 263 for_each_available_child_of_node_scoped(dev_of_node(dev), child) { 264 struct led_init_data init_data = {}; 265 266 err = of_property_read_u32(child, "reg", ®); 267 if (err) 268 return dev_err_probe(dev, err, "Invalid register\n"); 269 270 led = &chip->leds[reg]; 271 led->is_active = true; 272 led->fwnode = of_fwnode_handle(child); 273 274 led->led_cdev.max_brightness = U8_MAX; 275 led->led_cdev.brightness_set_blocking = st1202_led_set; 276 led->led_cdev.pattern_set = st1202_led_pattern_set; 277 led->led_cdev.pattern_clear = st1202_led_pattern_clear; 278 led->led_cdev.default_trigger = "pattern"; 279 280 init_data.fwnode = led->fwnode; 281 init_data.devicename = "st1202"; 282 init_data.default_label = ":"; 283 284 err = devm_led_classdev_register_ext(dev, &led->led_cdev, &init_data); 285 if (err < 0) 286 return dev_err_probe(dev, err, "Failed to register LED class device\n"); 287 288 led->led_cdev.brightness_set = st1202_brightness_set; 289 led->led_cdev.brightness_get = st1202_brightness_get; 290 } 291 292 return 0; 293 } 294 295 static int st1202_setup(struct st1202_chip *chip) 296 { 297 int ret; 298 299 guard(mutex)(&chip->lock); 300 301 /* 302 * Once the supply voltage is applied, the LED1202 executes some internal checks, 303 * afterwords it stops the oscillator and puts the internal LDO in quiescent mode. 304 * To start the device, EN bit must be set inside the “Device Enable” register at 305 * address 01h. As soon as EN is set, the LED1202 loads the adjustment parameters 306 * from the internal non-volatile memory and performs an auto-calibration procedure 307 * in order to increase the output current precision. 308 * Such initialization lasts about 6.5 ms. 309 */ 310 311 /* Reset the chip during setup */ 312 ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_RESET); 313 if (ret < 0) 314 return ret; 315 316 /* Enable phase-shift delay feature */ 317 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, ST1202_CONFIG_REG_SHFT); 318 if (ret < 0) 319 return ret; 320 321 /* Enable the device */ 322 ret = st1202_write_reg(chip, ST1202_DEV_ENABLE, ST1202_DEV_ENABLE_ON); 323 if (ret < 0) 324 return ret; 325 326 /* Duration of initialization */ 327 usleep_range(6500, 10000); 328 329 /* Deactivate all LEDS (channels) and activate only the ones found in Device Tree */ 330 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_LOW, ST1202_CHAN_DISABLE_ALL); 331 if (ret < 0) 332 return ret; 333 334 ret = st1202_write_reg(chip, ST1202_CHAN_ENABLE_HIGH, ST1202_CHAN_DISABLE_ALL); 335 if (ret < 0) 336 return ret; 337 338 ret = st1202_write_reg(chip, ST1202_CONFIG_REG, 339 ST1202_CONFIG_REG_PATS | ST1202_CONFIG_REG_PATSR); 340 if (ret < 0) 341 return ret; 342 343 return 0; 344 } 345 346 static int st1202_probe(struct i2c_client *client) 347 { 348 struct st1202_chip *chip; 349 struct st1202_led *led; 350 int ret; 351 352 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA)) 353 return dev_err_probe(&client->dev, -EIO, "SMBUS Byte Data not Supported\n"); 354 355 chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL); 356 if (!chip) 357 return -ENOMEM; 358 359 devm_mutex_init(&client->dev, &chip->lock); 360 chip->client = client; 361 362 ret = st1202_dt_init(chip); 363 if (ret < 0) 364 return ret; 365 366 ret = st1202_setup(chip); 367 if (ret < 0) 368 return ret; 369 370 for (int i = 0; i < ST1202_MAX_LEDS; i++) { 371 led = &chip->leds[i]; 372 led->chip = chip; 373 led->led_num = i; 374 375 if (!led->is_active) 376 continue; 377 378 ret = st1202_channel_set(led->chip, led->led_num, true); 379 if (ret < 0) 380 return dev_err_probe(&client->dev, ret, 381 "Failed to activate LED channel\n"); 382 383 ret = st1202_led_pattern_clear(&led->led_cdev); 384 if (ret < 0) 385 return dev_err_probe(&client->dev, ret, 386 "Failed to clear LED pattern\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