1 /* 2 * TI LP855x Backlight Driver 3 * 4 * Copyright (C) 2011 Texas Instruments 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 * 10 */ 11 12 #include <linux/module.h> 13 #include <linux/slab.h> 14 #include <linux/i2c.h> 15 #include <linux/backlight.h> 16 #include <linux/err.h> 17 #include <linux/of.h> 18 #include <linux/platform_data/lp855x.h> 19 #include <linux/pwm.h> 20 #include <linux/regulator/consumer.h> 21 22 /* LP8550/1/2/3/6 Registers */ 23 #define LP855X_BRIGHTNESS_CTRL 0x00 24 #define LP855X_DEVICE_CTRL 0x01 25 #define LP855X_EEPROM_START 0xA0 26 #define LP855X_EEPROM_END 0xA7 27 #define LP8556_EPROM_START 0xA0 28 #define LP8556_EPROM_END 0xAF 29 30 /* LP8555/7 Registers */ 31 #define LP8557_BL_CMD 0x00 32 #define LP8557_BL_MASK 0x01 33 #define LP8557_BL_ON 0x01 34 #define LP8557_BL_OFF 0x00 35 #define LP8557_BRIGHTNESS_CTRL 0x04 36 #define LP8557_CONFIG 0x10 37 #define LP8555_EPROM_START 0x10 38 #define LP8555_EPROM_END 0x7A 39 #define LP8557_EPROM_START 0x10 40 #define LP8557_EPROM_END 0x1E 41 42 #define DEFAULT_BL_NAME "lcd-backlight" 43 #define MAX_BRIGHTNESS 255 44 45 enum lp855x_brightness_ctrl_mode { 46 PWM_BASED = 1, 47 REGISTER_BASED, 48 }; 49 50 struct lp855x; 51 52 /* 53 * struct lp855x_device_config 54 * @pre_init_device: init device function call before updating the brightness 55 * @reg_brightness: register address for brigthenss control 56 * @reg_devicectrl: register address for device control 57 * @post_init_device: late init device function call 58 */ 59 struct lp855x_device_config { 60 int (*pre_init_device)(struct lp855x *); 61 u8 reg_brightness; 62 u8 reg_devicectrl; 63 int (*post_init_device)(struct lp855x *); 64 }; 65 66 struct lp855x { 67 const char *chipname; 68 enum lp855x_chip_id chip_id; 69 enum lp855x_brightness_ctrl_mode mode; 70 struct lp855x_device_config *cfg; 71 struct i2c_client *client; 72 struct backlight_device *bl; 73 struct device *dev; 74 struct lp855x_platform_data *pdata; 75 struct pwm_device *pwm; 76 struct regulator *supply; /* regulator for VDD 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 switch (lp->chip_id) { 176 case LP8550: 177 case LP8551: 178 case LP8552: 179 case LP8553: 180 case LP8556: 181 lp->cfg = &lp855x_dev_cfg; 182 break; 183 case LP8555: 184 case LP8557: 185 lp->cfg = &lp8557_dev_cfg; 186 break; 187 default: 188 return -EINVAL; 189 } 190 191 if (lp->cfg->pre_init_device) { 192 ret = lp->cfg->pre_init_device(lp); 193 if (ret) { 194 dev_err(lp->dev, "pre init device err: %d\n", ret); 195 goto err; 196 } 197 } 198 199 val = pd->initial_brightness; 200 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 201 if (ret) 202 goto err; 203 204 val = pd->device_control; 205 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); 206 if (ret) 207 goto err; 208 209 if (pd->size_program > 0) { 210 for (i = 0; i < pd->size_program; i++) { 211 addr = pd->rom_data[i].addr; 212 val = pd->rom_data[i].val; 213 if (!lp855x_is_valid_rom_area(lp, addr)) 214 continue; 215 216 ret = lp855x_write_byte(lp, addr, val); 217 if (ret) 218 goto err; 219 } 220 } 221 222 if (lp->cfg->post_init_device) { 223 ret = lp->cfg->post_init_device(lp); 224 if (ret) { 225 dev_err(lp->dev, "post init device err: %d\n", ret); 226 goto err; 227 } 228 } 229 230 return 0; 231 232 err: 233 return ret; 234 } 235 236 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) 237 { 238 unsigned int period = lp->pdata->period_ns; 239 unsigned int duty = br * period / max_br; 240 struct pwm_device *pwm; 241 242 /* request pwm device with the consumer name */ 243 if (!lp->pwm) { 244 pwm = devm_pwm_get(lp->dev, lp->chipname); 245 if (IS_ERR(pwm)) 246 return; 247 248 lp->pwm = pwm; 249 } 250 251 pwm_config(lp->pwm, duty, period); 252 if (duty) 253 pwm_enable(lp->pwm); 254 else 255 pwm_disable(lp->pwm); 256 } 257 258 static int lp855x_bl_update_status(struct backlight_device *bl) 259 { 260 struct lp855x *lp = bl_get_data(bl); 261 int brightness = bl->props.brightness; 262 263 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 264 brightness = 0; 265 266 if (lp->mode == PWM_BASED) 267 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness); 268 else if (lp->mode == REGISTER_BASED) 269 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness); 270 271 return 0; 272 } 273 274 static const struct backlight_ops lp855x_bl_ops = { 275 .options = BL_CORE_SUSPENDRESUME, 276 .update_status = lp855x_bl_update_status, 277 }; 278 279 static int lp855x_backlight_register(struct lp855x *lp) 280 { 281 struct backlight_device *bl; 282 struct backlight_properties props; 283 struct lp855x_platform_data *pdata = lp->pdata; 284 const char *name = pdata->name ? : DEFAULT_BL_NAME; 285 286 memset(&props, 0, sizeof(props)); 287 props.type = BACKLIGHT_PLATFORM; 288 props.max_brightness = MAX_BRIGHTNESS; 289 290 if (pdata->initial_brightness > props.max_brightness) 291 pdata->initial_brightness = props.max_brightness; 292 293 props.brightness = pdata->initial_brightness; 294 295 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 296 &lp855x_bl_ops, &props); 297 if (IS_ERR(bl)) 298 return PTR_ERR(bl); 299 300 lp->bl = bl; 301 302 return 0; 303 } 304 305 static ssize_t lp855x_get_chip_id(struct device *dev, 306 struct device_attribute *attr, char *buf) 307 { 308 struct lp855x *lp = dev_get_drvdata(dev); 309 310 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 311 } 312 313 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 314 struct device_attribute *attr, char *buf) 315 { 316 struct lp855x *lp = dev_get_drvdata(dev); 317 char *strmode = NULL; 318 319 if (lp->mode == PWM_BASED) 320 strmode = "pwm based"; 321 else if (lp->mode == REGISTER_BASED) 322 strmode = "register based"; 323 324 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 325 } 326 327 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 328 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 329 330 static struct attribute *lp855x_attributes[] = { 331 &dev_attr_chip_id.attr, 332 &dev_attr_bl_ctl_mode.attr, 333 NULL, 334 }; 335 336 static const struct attribute_group lp855x_attr_group = { 337 .attrs = lp855x_attributes, 338 }; 339 340 #ifdef CONFIG_OF 341 static int lp855x_parse_dt(struct lp855x *lp) 342 { 343 struct device *dev = lp->dev; 344 struct device_node *node = dev->of_node; 345 struct lp855x_platform_data *pdata; 346 int rom_length; 347 348 if (!node) { 349 dev_err(dev, "no platform data\n"); 350 return -EINVAL; 351 } 352 353 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 354 if (!pdata) 355 return -ENOMEM; 356 357 of_property_read_string(node, "bl-name", &pdata->name); 358 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 359 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 360 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 361 362 /* Fill ROM platform data if defined */ 363 rom_length = of_get_child_count(node); 364 if (rom_length > 0) { 365 struct lp855x_rom_data *rom; 366 struct device_node *child; 367 int i = 0; 368 369 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); 370 if (!rom) 371 return -ENOMEM; 372 373 for_each_child_of_node(node, child) { 374 of_property_read_u8(child, "rom-addr", &rom[i].addr); 375 of_property_read_u8(child, "rom-val", &rom[i].val); 376 i++; 377 } 378 379 pdata->size_program = rom_length; 380 pdata->rom_data = &rom[0]; 381 } 382 383 lp->pdata = pdata; 384 385 return 0; 386 } 387 #else 388 static int lp855x_parse_dt(struct lp855x *lp) 389 { 390 return -EINVAL; 391 } 392 #endif 393 394 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 395 { 396 struct lp855x *lp; 397 int ret; 398 399 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 400 return -EIO; 401 402 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 403 if (!lp) 404 return -ENOMEM; 405 406 lp->client = cl; 407 lp->dev = &cl->dev; 408 lp->chipname = id->name; 409 lp->chip_id = id->driver_data; 410 lp->pdata = dev_get_platdata(&cl->dev); 411 412 if (!lp->pdata) { 413 ret = lp855x_parse_dt(lp); 414 if (ret < 0) 415 return ret; 416 } 417 418 if (lp->pdata->period_ns > 0) 419 lp->mode = PWM_BASED; 420 else 421 lp->mode = REGISTER_BASED; 422 423 lp->supply = devm_regulator_get(lp->dev, "power"); 424 if (IS_ERR(lp->supply)) { 425 if (PTR_ERR(lp->supply) == -EPROBE_DEFER) 426 return -EPROBE_DEFER; 427 lp->supply = NULL; 428 } 429 430 if (lp->supply) { 431 ret = regulator_enable(lp->supply); 432 if (ret < 0) { 433 dev_err(&cl->dev, "failed to enable supply: %d\n", ret); 434 return ret; 435 } 436 } 437 438 i2c_set_clientdata(cl, lp); 439 440 ret = lp855x_configure(lp); 441 if (ret) { 442 dev_err(lp->dev, "device config err: %d", ret); 443 return ret; 444 } 445 446 ret = lp855x_backlight_register(lp); 447 if (ret) { 448 dev_err(lp->dev, 449 "failed to register backlight. err: %d\n", ret); 450 return ret; 451 } 452 453 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 454 if (ret) { 455 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 456 return ret; 457 } 458 459 backlight_update_status(lp->bl); 460 return 0; 461 } 462 463 static int lp855x_remove(struct i2c_client *cl) 464 { 465 struct lp855x *lp = i2c_get_clientdata(cl); 466 467 lp->bl->props.brightness = 0; 468 backlight_update_status(lp->bl); 469 if (lp->supply) 470 regulator_disable(lp->supply); 471 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 472 473 return 0; 474 } 475 476 static const struct of_device_id lp855x_dt_ids[] = { 477 { .compatible = "ti,lp8550", }, 478 { .compatible = "ti,lp8551", }, 479 { .compatible = "ti,lp8552", }, 480 { .compatible = "ti,lp8553", }, 481 { .compatible = "ti,lp8555", }, 482 { .compatible = "ti,lp8556", }, 483 { .compatible = "ti,lp8557", }, 484 { } 485 }; 486 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 487 488 static const struct i2c_device_id lp855x_ids[] = { 489 {"lp8550", LP8550}, 490 {"lp8551", LP8551}, 491 {"lp8552", LP8552}, 492 {"lp8553", LP8553}, 493 {"lp8555", LP8555}, 494 {"lp8556", LP8556}, 495 {"lp8557", LP8557}, 496 { } 497 }; 498 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 499 500 static struct i2c_driver lp855x_driver = { 501 .driver = { 502 .name = "lp855x", 503 .of_match_table = of_match_ptr(lp855x_dt_ids), 504 }, 505 .probe = lp855x_probe, 506 .remove = lp855x_remove, 507 .id_table = lp855x_ids, 508 }; 509 510 module_i2c_driver(lp855x_driver); 511 512 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 513 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 514 MODULE_LICENSE("GPL"); 515