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 props.type = BACKLIGHT_PLATFORM; 287 props.max_brightness = MAX_BRIGHTNESS; 288 289 if (pdata->initial_brightness > props.max_brightness) 290 pdata->initial_brightness = props.max_brightness; 291 292 props.brightness = pdata->initial_brightness; 293 294 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 295 &lp855x_bl_ops, &props); 296 if (IS_ERR(bl)) 297 return PTR_ERR(bl); 298 299 lp->bl = bl; 300 301 return 0; 302 } 303 304 static ssize_t lp855x_get_chip_id(struct device *dev, 305 struct device_attribute *attr, char *buf) 306 { 307 struct lp855x *lp = dev_get_drvdata(dev); 308 309 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 310 } 311 312 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 313 struct device_attribute *attr, char *buf) 314 { 315 struct lp855x *lp = dev_get_drvdata(dev); 316 char *strmode = NULL; 317 318 if (lp->mode == PWM_BASED) 319 strmode = "pwm based"; 320 else if (lp->mode == REGISTER_BASED) 321 strmode = "register based"; 322 323 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 324 } 325 326 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 327 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 328 329 static struct attribute *lp855x_attributes[] = { 330 &dev_attr_chip_id.attr, 331 &dev_attr_bl_ctl_mode.attr, 332 NULL, 333 }; 334 335 static const struct attribute_group lp855x_attr_group = { 336 .attrs = lp855x_attributes, 337 }; 338 339 #ifdef CONFIG_OF 340 static int lp855x_parse_dt(struct lp855x *lp) 341 { 342 struct device *dev = lp->dev; 343 struct device_node *node = dev->of_node; 344 struct lp855x_platform_data *pdata; 345 int rom_length; 346 347 if (!node) { 348 dev_err(dev, "no platform data\n"); 349 return -EINVAL; 350 } 351 352 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 353 if (!pdata) 354 return -ENOMEM; 355 356 of_property_read_string(node, "bl-name", &pdata->name); 357 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 358 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 359 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 360 361 /* Fill ROM platform data if defined */ 362 rom_length = of_get_child_count(node); 363 if (rom_length > 0) { 364 struct lp855x_rom_data *rom; 365 struct device_node *child; 366 int i = 0; 367 368 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); 369 if (!rom) 370 return -ENOMEM; 371 372 for_each_child_of_node(node, child) { 373 of_property_read_u8(child, "rom-addr", &rom[i].addr); 374 of_property_read_u8(child, "rom-val", &rom[i].val); 375 i++; 376 } 377 378 pdata->size_program = rom_length; 379 pdata->rom_data = &rom[0]; 380 } 381 382 lp->pdata = pdata; 383 384 return 0; 385 } 386 #else 387 static int lp855x_parse_dt(struct lp855x *lp) 388 { 389 return -EINVAL; 390 } 391 #endif 392 393 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 394 { 395 struct lp855x *lp; 396 int ret; 397 398 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 399 return -EIO; 400 401 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 402 if (!lp) 403 return -ENOMEM; 404 405 lp->client = cl; 406 lp->dev = &cl->dev; 407 lp->chipname = id->name; 408 lp->chip_id = id->driver_data; 409 lp->pdata = dev_get_platdata(&cl->dev); 410 411 if (!lp->pdata) { 412 ret = lp855x_parse_dt(lp); 413 if (ret < 0) 414 return ret; 415 } 416 417 if (lp->pdata->period_ns > 0) 418 lp->mode = PWM_BASED; 419 else 420 lp->mode = REGISTER_BASED; 421 422 lp->supply = devm_regulator_get(lp->dev, "power"); 423 if (IS_ERR(lp->supply)) { 424 if (PTR_ERR(lp->supply) == -EPROBE_DEFER) 425 return -EPROBE_DEFER; 426 lp->supply = NULL; 427 } 428 429 if (lp->supply) { 430 ret = regulator_enable(lp->supply); 431 if (ret < 0) { 432 dev_err(&cl->dev, "failed to enable supply: %d\n", ret); 433 return ret; 434 } 435 } 436 437 i2c_set_clientdata(cl, lp); 438 439 ret = lp855x_configure(lp); 440 if (ret) { 441 dev_err(lp->dev, "device config err: %d", ret); 442 return ret; 443 } 444 445 ret = lp855x_backlight_register(lp); 446 if (ret) { 447 dev_err(lp->dev, 448 "failed to register backlight. err: %d\n", ret); 449 return ret; 450 } 451 452 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 453 if (ret) { 454 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 455 return ret; 456 } 457 458 backlight_update_status(lp->bl); 459 return 0; 460 } 461 462 static int lp855x_remove(struct i2c_client *cl) 463 { 464 struct lp855x *lp = i2c_get_clientdata(cl); 465 466 lp->bl->props.brightness = 0; 467 backlight_update_status(lp->bl); 468 if (lp->supply) 469 regulator_disable(lp->supply); 470 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 471 472 return 0; 473 } 474 475 static const struct of_device_id lp855x_dt_ids[] = { 476 { .compatible = "ti,lp8550", }, 477 { .compatible = "ti,lp8551", }, 478 { .compatible = "ti,lp8552", }, 479 { .compatible = "ti,lp8553", }, 480 { .compatible = "ti,lp8555", }, 481 { .compatible = "ti,lp8556", }, 482 { .compatible = "ti,lp8557", }, 483 { } 484 }; 485 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 486 487 static const struct i2c_device_id lp855x_ids[] = { 488 {"lp8550", LP8550}, 489 {"lp8551", LP8551}, 490 {"lp8552", LP8552}, 491 {"lp8553", LP8553}, 492 {"lp8555", LP8555}, 493 {"lp8556", LP8556}, 494 {"lp8557", LP8557}, 495 { } 496 }; 497 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 498 499 static struct i2c_driver lp855x_driver = { 500 .driver = { 501 .name = "lp855x", 502 .of_match_table = of_match_ptr(lp855x_dt_ids), 503 }, 504 .probe = lp855x_probe, 505 .remove = lp855x_remove, 506 .id_table = lp855x_ids, 507 }; 508 509 module_i2c_driver(lp855x_driver); 510 511 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 512 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 513 MODULE_LICENSE("GPL"); 514