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/acpi.h> 9 #include <linux/module.h> 10 #include <linux/slab.h> 11 #include <linux/i2c.h> 12 #include <linux/backlight.h> 13 #include <linux/delay.h> 14 #include <linux/err.h> 15 #include <linux/of.h> 16 #include <linux/platform_data/lp855x.h> 17 #include <linux/pwm.h> 18 #include <linux/regulator/consumer.h> 19 20 /* LP8550/1/2/3/6 Registers */ 21 #define LP855X_BRIGHTNESS_CTRL 0x00 22 #define LP855X_DEVICE_CTRL 0x01 23 #define LP855X_EEPROM_START 0xA0 24 #define LP855X_EEPROM_END 0xA7 25 #define LP8556_EPROM_START 0xA0 26 #define LP8556_EPROM_END 0xAF 27 28 /* LP8555/7 Registers */ 29 #define LP8557_BL_CMD 0x00 30 #define LP8557_BL_MASK 0x01 31 #define LP8557_BL_ON 0x01 32 #define LP8557_BL_OFF 0x00 33 #define LP8557_BRIGHTNESS_CTRL 0x04 34 #define LP8557_CONFIG 0x10 35 #define LP8555_EPROM_START 0x10 36 #define LP8555_EPROM_END 0x7A 37 #define LP8557_EPROM_START 0x10 38 #define LP8557_EPROM_END 0x1E 39 40 #define DEFAULT_BL_NAME "lcd-backlight" 41 #define MAX_BRIGHTNESS 255 42 43 enum lp855x_brightness_ctrl_mode { 44 PWM_BASED = 1, 45 REGISTER_BASED, 46 }; 47 48 struct lp855x; 49 50 /* 51 * struct lp855x_device_config 52 * @pre_init_device: init device function call before updating the brightness 53 * @reg_brightness: register address for brigthenss control 54 * @reg_devicectrl: register address for device control 55 * @post_init_device: late init device function call 56 */ 57 struct lp855x_device_config { 58 int (*pre_init_device)(struct lp855x *); 59 u8 reg_brightness; 60 u8 reg_devicectrl; 61 int (*post_init_device)(struct lp855x *); 62 }; 63 64 struct lp855x { 65 const char *chipname; 66 enum lp855x_chip_id chip_id; 67 enum lp855x_brightness_ctrl_mode mode; 68 struct lp855x_device_config *cfg; 69 struct i2c_client *client; 70 struct backlight_device *bl; 71 struct device *dev; 72 struct lp855x_platform_data *pdata; 73 struct pwm_device *pwm; 74 bool needs_pwm_init; 75 struct regulator *supply; /* regulator for VDD input */ 76 struct regulator *enable; /* regulator for EN/VDDIO input */ 77 }; 78 79 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) 80 { 81 return i2c_smbus_write_byte_data(lp->client, reg, data); 82 } 83 84 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data) 85 { 86 int ret; 87 u8 tmp; 88 89 ret = i2c_smbus_read_byte_data(lp->client, reg); 90 if (ret < 0) { 91 dev_err(lp->dev, "failed to read 0x%.2x\n", reg); 92 return ret; 93 } 94 95 tmp = (u8)ret; 96 tmp &= ~mask; 97 tmp |= data & mask; 98 99 return lp855x_write_byte(lp, reg, tmp); 100 } 101 102 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) 103 { 104 u8 start, end; 105 106 switch (lp->chip_id) { 107 case LP8550: 108 case LP8551: 109 case LP8552: 110 case LP8553: 111 start = LP855X_EEPROM_START; 112 end = LP855X_EEPROM_END; 113 break; 114 case LP8556: 115 start = LP8556_EPROM_START; 116 end = LP8556_EPROM_END; 117 break; 118 case LP8555: 119 start = LP8555_EPROM_START; 120 end = LP8555_EPROM_END; 121 break; 122 case LP8557: 123 start = LP8557_EPROM_START; 124 end = LP8557_EPROM_END; 125 break; 126 default: 127 return false; 128 } 129 130 return addr >= start && addr <= end; 131 } 132 133 static int lp8557_bl_off(struct lp855x *lp) 134 { 135 /* BL_ON = 0 before updating EPROM settings */ 136 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 137 LP8557_BL_OFF); 138 } 139 140 static int lp8557_bl_on(struct lp855x *lp) 141 { 142 /* BL_ON = 1 after updating EPROM settings */ 143 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 144 LP8557_BL_ON); 145 } 146 147 static struct lp855x_device_config lp855x_dev_cfg = { 148 .reg_brightness = LP855X_BRIGHTNESS_CTRL, 149 .reg_devicectrl = LP855X_DEVICE_CTRL, 150 }; 151 152 static struct lp855x_device_config lp8557_dev_cfg = { 153 .reg_brightness = LP8557_BRIGHTNESS_CTRL, 154 .reg_devicectrl = LP8557_CONFIG, 155 .pre_init_device = lp8557_bl_off, 156 .post_init_device = lp8557_bl_on, 157 }; 158 159 /* 160 * Device specific configuration flow 161 * 162 * a) pre_init_device(optional) 163 * b) update the brightness register 164 * c) update device control register 165 * d) update ROM area(optional) 166 * e) post_init_device(optional) 167 * 168 */ 169 static int lp855x_configure(struct lp855x *lp) 170 { 171 u8 val, addr; 172 int i, ret; 173 struct lp855x_platform_data *pd = lp->pdata; 174 175 if (lp->cfg->pre_init_device) { 176 ret = lp->cfg->pre_init_device(lp); 177 if (ret) { 178 dev_err(lp->dev, "pre init device err: %d\n", ret); 179 goto err; 180 } 181 } 182 183 val = pd->initial_brightness; 184 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 185 if (ret) 186 goto err; 187 188 val = pd->device_control; 189 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); 190 if (ret) 191 goto err; 192 193 if (pd->size_program > 0) { 194 for (i = 0; i < pd->size_program; i++) { 195 addr = pd->rom_data[i].addr; 196 val = pd->rom_data[i].val; 197 if (!lp855x_is_valid_rom_area(lp, addr)) 198 continue; 199 200 ret = lp855x_write_byte(lp, addr, val); 201 if (ret) 202 goto err; 203 } 204 } 205 206 if (lp->cfg->post_init_device) { 207 ret = lp->cfg->post_init_device(lp); 208 if (ret) { 209 dev_err(lp->dev, "post init device err: %d\n", ret); 210 goto err; 211 } 212 } 213 214 return 0; 215 216 err: 217 return ret; 218 } 219 220 static int lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) 221 { 222 struct pwm_state state; 223 224 if (lp->needs_pwm_init) { 225 pwm_init_state(lp->pwm, &state); 226 /* Legacy platform data compatibility */ 227 if (lp->pdata->period_ns > 0) 228 state.period = lp->pdata->period_ns; 229 lp->needs_pwm_init = false; 230 } else { 231 pwm_get_state(lp->pwm, &state); 232 } 233 234 state.duty_cycle = div_u64(br * state.period, max_br); 235 state.enabled = state.duty_cycle; 236 237 return pwm_apply_might_sleep(lp->pwm, &state); 238 } 239 240 static int lp855x_bl_update_status(struct backlight_device *bl) 241 { 242 struct lp855x *lp = bl_get_data(bl); 243 int brightness = bl->props.brightness; 244 245 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 246 brightness = 0; 247 248 if (lp->mode == PWM_BASED) 249 return lp855x_pwm_ctrl(lp, brightness, 250 bl->props.max_brightness); 251 else if (lp->mode == REGISTER_BASED) 252 return lp855x_write_byte(lp, lp->cfg->reg_brightness, 253 (u8)brightness); 254 return -EINVAL; 255 } 256 257 static const struct backlight_ops lp855x_bl_ops = { 258 .options = BL_CORE_SUSPENDRESUME, 259 .update_status = lp855x_bl_update_status, 260 }; 261 262 static int lp855x_backlight_register(struct lp855x *lp) 263 { 264 struct backlight_device *bl; 265 struct backlight_properties props; 266 struct lp855x_platform_data *pdata = lp->pdata; 267 const char *name = pdata->name ? : DEFAULT_BL_NAME; 268 269 memset(&props, 0, sizeof(props)); 270 props.type = BACKLIGHT_PLATFORM; 271 props.max_brightness = MAX_BRIGHTNESS; 272 273 if (pdata->initial_brightness > props.max_brightness) 274 pdata->initial_brightness = props.max_brightness; 275 276 props.brightness = pdata->initial_brightness; 277 278 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 279 &lp855x_bl_ops, &props); 280 if (IS_ERR(bl)) 281 return PTR_ERR(bl); 282 283 lp->bl = bl; 284 285 return 0; 286 } 287 288 static ssize_t lp855x_get_chip_id(struct device *dev, 289 struct device_attribute *attr, char *buf) 290 { 291 struct lp855x *lp = dev_get_drvdata(dev); 292 293 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 294 } 295 296 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 297 struct device_attribute *attr, char *buf) 298 { 299 struct lp855x *lp = dev_get_drvdata(dev); 300 char *strmode = NULL; 301 302 if (lp->mode == PWM_BASED) 303 strmode = "pwm based"; 304 else if (lp->mode == REGISTER_BASED) 305 strmode = "register based"; 306 307 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 308 } 309 310 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 311 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 312 313 static struct attribute *lp855x_attributes[] = { 314 &dev_attr_chip_id.attr, 315 &dev_attr_bl_ctl_mode.attr, 316 NULL, 317 }; 318 319 static const struct attribute_group lp855x_attr_group = { 320 .attrs = lp855x_attributes, 321 }; 322 323 #ifdef CONFIG_OF 324 static int lp855x_parse_dt(struct lp855x *lp) 325 { 326 struct device *dev = lp->dev; 327 struct device_node *node = dev->of_node; 328 struct lp855x_platform_data *pdata = lp->pdata; 329 int rom_length; 330 331 if (!node) { 332 dev_err(dev, "no platform data\n"); 333 return -EINVAL; 334 } 335 336 of_property_read_string(node, "bl-name", &pdata->name); 337 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 338 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 339 /* Deprecated, specify period in pwms property instead */ 340 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 341 342 /* Fill ROM platform data if defined */ 343 rom_length = of_get_child_count(node); 344 if (rom_length > 0) { 345 struct lp855x_rom_data *rom; 346 struct device_node *child; 347 int i = 0; 348 349 rom = devm_kcalloc(dev, rom_length, sizeof(*rom), GFP_KERNEL); 350 if (!rom) 351 return -ENOMEM; 352 353 for_each_child_of_node(node, child) { 354 of_property_read_u8(child, "rom-addr", &rom[i].addr); 355 of_property_read_u8(child, "rom-val", &rom[i].val); 356 i++; 357 } 358 359 pdata->size_program = rom_length; 360 pdata->rom_data = &rom[0]; 361 } 362 363 return 0; 364 } 365 #else 366 static int lp855x_parse_dt(struct lp855x *lp) 367 { 368 return -EINVAL; 369 } 370 #endif 371 372 static int lp855x_parse_acpi(struct lp855x *lp) 373 { 374 int ret; 375 376 /* 377 * On ACPI the device has already been initialized by the firmware 378 * and is in register mode, so we can read back the settings from 379 * the registers. 380 */ 381 ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_brightness); 382 if (ret < 0) 383 return ret; 384 385 lp->pdata->initial_brightness = ret; 386 387 ret = i2c_smbus_read_byte_data(lp->client, lp->cfg->reg_devicectrl); 388 if (ret < 0) 389 return ret; 390 391 lp->pdata->device_control = ret; 392 return 0; 393 } 394 395 static int lp855x_probe(struct i2c_client *cl) 396 { 397 const struct i2c_device_id *id = i2c_client_get_device_id(cl); 398 const struct acpi_device_id *acpi_id = NULL; 399 struct device *dev = &cl->dev; 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(dev, sizeof(struct lp855x), GFP_KERNEL); 407 if (!lp) 408 return -ENOMEM; 409 410 lp->client = cl; 411 lp->dev = dev; 412 lp->pdata = dev_get_platdata(dev); 413 414 if (id) { 415 lp->chipname = id->name; 416 lp->chip_id = id->driver_data; 417 } else { 418 acpi_id = acpi_match_device(dev->driver->acpi_match_table, dev); 419 if (!acpi_id) 420 return -ENODEV; 421 422 lp->chipname = acpi_id->id; 423 lp->chip_id = acpi_id->driver_data; 424 } 425 426 switch (lp->chip_id) { 427 case LP8550: 428 case LP8551: 429 case LP8552: 430 case LP8553: 431 case LP8556: 432 lp->cfg = &lp855x_dev_cfg; 433 break; 434 case LP8555: 435 case LP8557: 436 lp->cfg = &lp8557_dev_cfg; 437 break; 438 default: 439 return -EINVAL; 440 } 441 442 if (!lp->pdata) { 443 lp->pdata = devm_kzalloc(dev, sizeof(*lp->pdata), GFP_KERNEL); 444 if (!lp->pdata) 445 return -ENOMEM; 446 447 if (id) { 448 ret = lp855x_parse_dt(lp); 449 if (ret < 0) 450 return ret; 451 } else { 452 ret = lp855x_parse_acpi(lp); 453 if (ret < 0) 454 return ret; 455 } 456 } 457 458 lp->supply = devm_regulator_get(dev, "power"); 459 if (IS_ERR(lp->supply)) { 460 if (PTR_ERR(lp->supply) == -EPROBE_DEFER) 461 return -EPROBE_DEFER; 462 lp->supply = NULL; 463 } 464 465 lp->enable = devm_regulator_get_optional(dev, "enable"); 466 if (IS_ERR(lp->enable)) { 467 ret = PTR_ERR(lp->enable); 468 if (ret == -ENODEV) 469 lp->enable = NULL; 470 else 471 return dev_err_probe(dev, ret, "getting enable regulator\n"); 472 } 473 474 lp->pwm = devm_pwm_get(lp->dev, lp->chipname); 475 if (IS_ERR(lp->pwm)) { 476 ret = PTR_ERR(lp->pwm); 477 if (ret == -ENODEV || ret == -EINVAL) 478 lp->pwm = NULL; 479 else 480 return dev_err_probe(dev, ret, "getting PWM\n"); 481 482 lp->needs_pwm_init = false; 483 lp->mode = REGISTER_BASED; 484 dev_dbg(dev, "mode: register based\n"); 485 } else { 486 lp->needs_pwm_init = true; 487 lp->mode = PWM_BASED; 488 dev_dbg(dev, "mode: PWM based\n"); 489 } 490 491 if (lp->supply) { 492 ret = regulator_enable(lp->supply); 493 if (ret < 0) { 494 dev_err(dev, "failed to enable supply: %d\n", ret); 495 return ret; 496 } 497 } 498 499 if (lp->enable) { 500 ret = regulator_enable(lp->enable); 501 if (ret < 0) { 502 dev_err(dev, "failed to enable vddio: %d\n", ret); 503 goto disable_supply; 504 } 505 506 /* 507 * LP8555 datasheet says t_RESPONSE (time between VDDIO and 508 * I2C) is 1ms. 509 */ 510 usleep_range(1000, 2000); 511 } 512 513 i2c_set_clientdata(cl, lp); 514 515 ret = lp855x_configure(lp); 516 if (ret) { 517 dev_err(dev, "device config err: %d", ret); 518 goto disable_vddio; 519 } 520 521 ret = lp855x_backlight_register(lp); 522 if (ret) { 523 dev_err(dev, "failed to register backlight. err: %d\n", ret); 524 goto disable_vddio; 525 } 526 527 ret = sysfs_create_group(&dev->kobj, &lp855x_attr_group); 528 if (ret) { 529 dev_err(dev, "failed to register sysfs. err: %d\n", ret); 530 goto disable_vddio; 531 } 532 533 backlight_update_status(lp->bl); 534 535 return 0; 536 537 disable_vddio: 538 if (lp->enable) 539 regulator_disable(lp->enable); 540 disable_supply: 541 if (lp->supply) 542 regulator_disable(lp->supply); 543 544 return ret; 545 } 546 547 static void lp855x_remove(struct i2c_client *cl) 548 { 549 struct lp855x *lp = i2c_get_clientdata(cl); 550 551 lp->bl->props.brightness = 0; 552 backlight_update_status(lp->bl); 553 if (lp->enable) 554 regulator_disable(lp->enable); 555 if (lp->supply) 556 regulator_disable(lp->supply); 557 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 558 } 559 560 static const struct of_device_id lp855x_dt_ids[] __maybe_unused = { 561 { .compatible = "ti,lp8550", }, 562 { .compatible = "ti,lp8551", }, 563 { .compatible = "ti,lp8552", }, 564 { .compatible = "ti,lp8553", }, 565 { .compatible = "ti,lp8555", }, 566 { .compatible = "ti,lp8556", }, 567 { .compatible = "ti,lp8557", }, 568 { } 569 }; 570 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 571 572 static const struct i2c_device_id lp855x_ids[] = { 573 {"lp8550", LP8550}, 574 {"lp8551", LP8551}, 575 {"lp8552", LP8552}, 576 {"lp8553", LP8553}, 577 {"lp8555", LP8555}, 578 {"lp8556", LP8556}, 579 {"lp8557", LP8557}, 580 { } 581 }; 582 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 583 584 #ifdef CONFIG_ACPI 585 static const struct acpi_device_id lp855x_acpi_match[] = { 586 /* Xiaomi specific HID used for the LP8556 on the Mi Pad 2 */ 587 { "XMCC0001", LP8556 }, 588 { } 589 }; 590 MODULE_DEVICE_TABLE(acpi, lp855x_acpi_match); 591 #endif 592 593 static struct i2c_driver lp855x_driver = { 594 .driver = { 595 .name = "lp855x", 596 .of_match_table = of_match_ptr(lp855x_dt_ids), 597 .acpi_match_table = ACPI_PTR(lp855x_acpi_match), 598 }, 599 .probe = lp855x_probe, 600 .remove = lp855x_remove, 601 .id_table = lp855x_ids, 602 }; 603 604 module_i2c_driver(lp855x_driver); 605 606 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 607 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 608 MODULE_LICENSE("GPL"); 609