1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * TI LP855x Backlight Driver 4 * 5 * Copyright (C) 2011 Texas Instruments 6 */ 7 8 #include <linux/module.h> 9 #include <linux/slab.h> 10 #include <linux/i2c.h> 11 #include <linux/backlight.h> 12 #include <linux/delay.h> 13 #include <linux/err.h> 14 #include <linux/of.h> 15 #include <linux/platform_data/lp855x.h> 16 #include <linux/pwm.h> 17 #include <linux/regulator/consumer.h> 18 19 /* LP8550/1/2/3/6 Registers */ 20 #define LP855X_BRIGHTNESS_CTRL 0x00 21 #define LP855X_DEVICE_CTRL 0x01 22 #define LP855X_EEPROM_START 0xA0 23 #define LP855X_EEPROM_END 0xA7 24 #define LP8556_EPROM_START 0xA0 25 #define LP8556_EPROM_END 0xAF 26 27 /* LP8555/7 Registers */ 28 #define LP8557_BL_CMD 0x00 29 #define LP8557_BL_MASK 0x01 30 #define LP8557_BL_ON 0x01 31 #define LP8557_BL_OFF 0x00 32 #define LP8557_BRIGHTNESS_CTRL 0x04 33 #define LP8557_CONFIG 0x10 34 #define LP8555_EPROM_START 0x10 35 #define LP8555_EPROM_END 0x7A 36 #define LP8557_EPROM_START 0x10 37 #define LP8557_EPROM_END 0x1E 38 39 #define DEFAULT_BL_NAME "lcd-backlight" 40 #define MAX_BRIGHTNESS 255 41 42 enum lp855x_brightness_ctrl_mode { 43 PWM_BASED = 1, 44 REGISTER_BASED, 45 }; 46 47 struct lp855x; 48 49 /* 50 * struct lp855x_device_config 51 * @pre_init_device: init device function call before updating the brightness 52 * @reg_brightness: register address for brigthenss control 53 * @reg_devicectrl: register address for device control 54 * @post_init_device: late init device function call 55 */ 56 struct lp855x_device_config { 57 int (*pre_init_device)(struct lp855x *); 58 u8 reg_brightness; 59 u8 reg_devicectrl; 60 int (*post_init_device)(struct lp855x *); 61 }; 62 63 struct lp855x { 64 const char *chipname; 65 enum lp855x_chip_id chip_id; 66 enum lp855x_brightness_ctrl_mode mode; 67 struct lp855x_device_config *cfg; 68 struct i2c_client *client; 69 struct backlight_device *bl; 70 struct device *dev; 71 struct lp855x_platform_data *pdata; 72 struct pwm_device *pwm; 73 struct regulator *supply; /* regulator for VDD input */ 74 struct regulator *enable; /* regulator for EN/VDDIO input */ 75 }; 76 77 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) 78 { 79 return i2c_smbus_write_byte_data(lp->client, reg, data); 80 } 81 82 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data) 83 { 84 int ret; 85 u8 tmp; 86 87 ret = i2c_smbus_read_byte_data(lp->client, reg); 88 if (ret < 0) { 89 dev_err(lp->dev, "failed to read 0x%.2x\n", reg); 90 return ret; 91 } 92 93 tmp = (u8)ret; 94 tmp &= ~mask; 95 tmp |= data & mask; 96 97 return lp855x_write_byte(lp, reg, tmp); 98 } 99 100 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) 101 { 102 u8 start, end; 103 104 switch (lp->chip_id) { 105 case LP8550: 106 case LP8551: 107 case LP8552: 108 case LP8553: 109 start = LP855X_EEPROM_START; 110 end = LP855X_EEPROM_END; 111 break; 112 case LP8556: 113 start = LP8556_EPROM_START; 114 end = LP8556_EPROM_END; 115 break; 116 case LP8555: 117 start = LP8555_EPROM_START; 118 end = LP8555_EPROM_END; 119 break; 120 case LP8557: 121 start = LP8557_EPROM_START; 122 end = LP8557_EPROM_END; 123 break; 124 default: 125 return false; 126 } 127 128 return addr >= start && addr <= end; 129 } 130 131 static int lp8557_bl_off(struct lp855x *lp) 132 { 133 /* BL_ON = 0 before updating EPROM settings */ 134 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 135 LP8557_BL_OFF); 136 } 137 138 static int lp8557_bl_on(struct lp855x *lp) 139 { 140 /* BL_ON = 1 after updating EPROM settings */ 141 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 142 LP8557_BL_ON); 143 } 144 145 static struct lp855x_device_config lp855x_dev_cfg = { 146 .reg_brightness = LP855X_BRIGHTNESS_CTRL, 147 .reg_devicectrl = LP855X_DEVICE_CTRL, 148 }; 149 150 static struct lp855x_device_config lp8557_dev_cfg = { 151 .reg_brightness = LP8557_BRIGHTNESS_CTRL, 152 .reg_devicectrl = LP8557_CONFIG, 153 .pre_init_device = lp8557_bl_off, 154 .post_init_device = lp8557_bl_on, 155 }; 156 157 /* 158 * Device specific configuration flow 159 * 160 * a) pre_init_device(optional) 161 * b) update the brightness register 162 * c) update device control register 163 * d) update ROM area(optional) 164 * e) post_init_device(optional) 165 * 166 */ 167 static int lp855x_configure(struct lp855x *lp) 168 { 169 u8 val, addr; 170 int i, ret; 171 struct lp855x_platform_data *pd = lp->pdata; 172 173 switch (lp->chip_id) { 174 case LP8550: 175 case LP8551: 176 case LP8552: 177 case LP8553: 178 case LP8556: 179 lp->cfg = &lp855x_dev_cfg; 180 break; 181 case LP8555: 182 case LP8557: 183 lp->cfg = &lp8557_dev_cfg; 184 break; 185 default: 186 return -EINVAL; 187 } 188 189 if (lp->cfg->pre_init_device) { 190 ret = lp->cfg->pre_init_device(lp); 191 if (ret) { 192 dev_err(lp->dev, "pre init device err: %d\n", ret); 193 goto err; 194 } 195 } 196 197 val = pd->initial_brightness; 198 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 199 if (ret) 200 goto err; 201 202 val = pd->device_control; 203 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); 204 if (ret) 205 goto err; 206 207 if (pd->size_program > 0) { 208 for (i = 0; i < pd->size_program; i++) { 209 addr = pd->rom_data[i].addr; 210 val = pd->rom_data[i].val; 211 if (!lp855x_is_valid_rom_area(lp, addr)) 212 continue; 213 214 ret = lp855x_write_byte(lp, addr, val); 215 if (ret) 216 goto err; 217 } 218 } 219 220 if (lp->cfg->post_init_device) { 221 ret = lp->cfg->post_init_device(lp); 222 if (ret) { 223 dev_err(lp->dev, "post init device err: %d\n", ret); 224 goto err; 225 } 226 } 227 228 return 0; 229 230 err: 231 return ret; 232 } 233 234 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) 235 { 236 unsigned int period = lp->pdata->period_ns; 237 unsigned int duty = br * period / max_br; 238 struct pwm_device *pwm; 239 240 /* request pwm device with the consumer name */ 241 if (!lp->pwm) { 242 pwm = devm_pwm_get(lp->dev, lp->chipname); 243 if (IS_ERR(pwm)) 244 return; 245 246 lp->pwm = pwm; 247 248 /* 249 * FIXME: pwm_apply_args() should be removed when switching to 250 * the atomic PWM API. 251 */ 252 pwm_apply_args(pwm); 253 } 254 255 pwm_config(lp->pwm, duty, period); 256 if (duty) 257 pwm_enable(lp->pwm); 258 else 259 pwm_disable(lp->pwm); 260 } 261 262 static int lp855x_bl_update_status(struct backlight_device *bl) 263 { 264 struct lp855x *lp = bl_get_data(bl); 265 int brightness = bl->props.brightness; 266 267 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 268 brightness = 0; 269 270 if (lp->mode == PWM_BASED) 271 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness); 272 else if (lp->mode == REGISTER_BASED) 273 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness); 274 275 return 0; 276 } 277 278 static const struct backlight_ops lp855x_bl_ops = { 279 .options = BL_CORE_SUSPENDRESUME, 280 .update_status = lp855x_bl_update_status, 281 }; 282 283 static int lp855x_backlight_register(struct lp855x *lp) 284 { 285 struct backlight_device *bl; 286 struct backlight_properties props; 287 struct lp855x_platform_data *pdata = lp->pdata; 288 const char *name = pdata->name ? : DEFAULT_BL_NAME; 289 290 memset(&props, 0, sizeof(props)); 291 props.type = BACKLIGHT_PLATFORM; 292 props.max_brightness = MAX_BRIGHTNESS; 293 294 if (pdata->initial_brightness > props.max_brightness) 295 pdata->initial_brightness = props.max_brightness; 296 297 props.brightness = pdata->initial_brightness; 298 299 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 300 &lp855x_bl_ops, &props); 301 if (IS_ERR(bl)) 302 return PTR_ERR(bl); 303 304 lp->bl = bl; 305 306 return 0; 307 } 308 309 static ssize_t lp855x_get_chip_id(struct device *dev, 310 struct device_attribute *attr, char *buf) 311 { 312 struct lp855x *lp = dev_get_drvdata(dev); 313 314 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 315 } 316 317 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 318 struct device_attribute *attr, char *buf) 319 { 320 struct lp855x *lp = dev_get_drvdata(dev); 321 char *strmode = NULL; 322 323 if (lp->mode == PWM_BASED) 324 strmode = "pwm based"; 325 else if (lp->mode == REGISTER_BASED) 326 strmode = "register based"; 327 328 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 329 } 330 331 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 332 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 333 334 static struct attribute *lp855x_attributes[] = { 335 &dev_attr_chip_id.attr, 336 &dev_attr_bl_ctl_mode.attr, 337 NULL, 338 }; 339 340 static const struct attribute_group lp855x_attr_group = { 341 .attrs = lp855x_attributes, 342 }; 343 344 #ifdef CONFIG_OF 345 static int lp855x_parse_dt(struct lp855x *lp) 346 { 347 struct device *dev = lp->dev; 348 struct device_node *node = dev->of_node; 349 struct lp855x_platform_data *pdata; 350 int rom_length; 351 352 if (!node) { 353 dev_err(dev, "no platform data\n"); 354 return -EINVAL; 355 } 356 357 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 358 if (!pdata) 359 return -ENOMEM; 360 361 of_property_read_string(node, "bl-name", &pdata->name); 362 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 363 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 364 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 365 366 /* Fill ROM platform data if defined */ 367 rom_length = of_get_child_count(node); 368 if (rom_length > 0) { 369 struct lp855x_rom_data *rom; 370 struct device_node *child; 371 int i = 0; 372 373 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL); 374 if (!rom) 375 return -ENOMEM; 376 377 for_each_child_of_node(node, child) { 378 of_property_read_u8(child, "rom-addr", &rom[i].addr); 379 of_property_read_u8(child, "rom-val", &rom[i].val); 380 i++; 381 } 382 383 pdata->size_program = rom_length; 384 pdata->rom_data = &rom[0]; 385 } 386 387 lp->pdata = pdata; 388 389 return 0; 390 } 391 #else 392 static int lp855x_parse_dt(struct lp855x *lp) 393 { 394 return -EINVAL; 395 } 396 #endif 397 398 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 399 { 400 struct lp855x *lp; 401 int ret; 402 403 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 404 return -EIO; 405 406 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 407 if (!lp) 408 return -ENOMEM; 409 410 lp->client = cl; 411 lp->dev = &cl->dev; 412 lp->chipname = id->name; 413 lp->chip_id = id->driver_data; 414 lp->pdata = dev_get_platdata(&cl->dev); 415 416 if (!lp->pdata) { 417 ret = lp855x_parse_dt(lp); 418 if (ret < 0) 419 return ret; 420 } 421 422 if (lp->pdata->period_ns > 0) 423 lp->mode = PWM_BASED; 424 else 425 lp->mode = REGISTER_BASED; 426 427 lp->supply = devm_regulator_get(lp->dev, "power"); 428 if (IS_ERR(lp->supply)) { 429 if (PTR_ERR(lp->supply) == -EPROBE_DEFER) 430 return -EPROBE_DEFER; 431 lp->supply = NULL; 432 } 433 434 lp->enable = devm_regulator_get_optional(lp->dev, "enable"); 435 if (IS_ERR(lp->enable)) { 436 ret = PTR_ERR(lp->enable); 437 if (ret == -ENODEV) { 438 lp->enable = NULL; 439 } else { 440 if (ret != -EPROBE_DEFER) 441 dev_err(lp->dev, "error getting enable regulator: %d\n", 442 ret); 443 return ret; 444 } 445 } 446 447 if (lp->supply) { 448 ret = regulator_enable(lp->supply); 449 if (ret < 0) { 450 dev_err(&cl->dev, "failed to enable supply: %d\n", ret); 451 return ret; 452 } 453 } 454 455 if (lp->enable) { 456 ret = regulator_enable(lp->enable); 457 if (ret < 0) { 458 dev_err(lp->dev, "failed to enable vddio: %d\n", ret); 459 return ret; 460 } 461 462 /* 463 * LP8555 datasheet says t_RESPONSE (time between VDDIO and 464 * I2C) is 1ms. 465 */ 466 usleep_range(1000, 2000); 467 } 468 469 i2c_set_clientdata(cl, lp); 470 471 ret = lp855x_configure(lp); 472 if (ret) { 473 dev_err(lp->dev, "device config err: %d", ret); 474 return ret; 475 } 476 477 ret = lp855x_backlight_register(lp); 478 if (ret) { 479 dev_err(lp->dev, 480 "failed to register backlight. err: %d\n", ret); 481 return ret; 482 } 483 484 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 485 if (ret) { 486 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 487 return ret; 488 } 489 490 backlight_update_status(lp->bl); 491 return 0; 492 } 493 494 static int lp855x_remove(struct i2c_client *cl) 495 { 496 struct lp855x *lp = i2c_get_clientdata(cl); 497 498 lp->bl->props.brightness = 0; 499 backlight_update_status(lp->bl); 500 if (lp->supply) 501 regulator_disable(lp->supply); 502 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 503 504 return 0; 505 } 506 507 static const struct of_device_id lp855x_dt_ids[] = { 508 { .compatible = "ti,lp8550", }, 509 { .compatible = "ti,lp8551", }, 510 { .compatible = "ti,lp8552", }, 511 { .compatible = "ti,lp8553", }, 512 { .compatible = "ti,lp8555", }, 513 { .compatible = "ti,lp8556", }, 514 { .compatible = "ti,lp8557", }, 515 { } 516 }; 517 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 518 519 static const struct i2c_device_id lp855x_ids[] = { 520 {"lp8550", LP8550}, 521 {"lp8551", LP8551}, 522 {"lp8552", LP8552}, 523 {"lp8553", LP8553}, 524 {"lp8555", LP8555}, 525 {"lp8556", LP8556}, 526 {"lp8557", LP8557}, 527 { } 528 }; 529 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 530 531 static struct i2c_driver lp855x_driver = { 532 .driver = { 533 .name = "lp855x", 534 .of_match_table = of_match_ptr(lp855x_dt_ids), 535 }, 536 .probe = lp855x_probe, 537 .remove = lp855x_remove, 538 .id_table = lp855x_ids, 539 }; 540 541 module_i2c_driver(lp855x_driver); 542 543 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 544 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 545 MODULE_LICENSE("GPL"); 546