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 * FIXME: pwm_apply_args() should be removed when switching to 252 * the atomic PWM API. 253 */ 254 pwm_apply_args(pwm); 255 } 256 257 pwm_config(lp->pwm, duty, period); 258 if (duty) 259 pwm_enable(lp->pwm); 260 else 261 pwm_disable(lp->pwm); 262 } 263 264 static int lp855x_bl_update_status(struct backlight_device *bl) 265 { 266 struct lp855x *lp = bl_get_data(bl); 267 int brightness = bl->props.brightness; 268 269 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 270 brightness = 0; 271 272 if (lp->mode == PWM_BASED) 273 lp855x_pwm_ctrl(lp, brightness, bl->props.max_brightness); 274 else if (lp->mode == REGISTER_BASED) 275 lp855x_write_byte(lp, lp->cfg->reg_brightness, (u8)brightness); 276 277 return 0; 278 } 279 280 static const struct backlight_ops lp855x_bl_ops = { 281 .options = BL_CORE_SUSPENDRESUME, 282 .update_status = lp855x_bl_update_status, 283 }; 284 285 static int lp855x_backlight_register(struct lp855x *lp) 286 { 287 struct backlight_device *bl; 288 struct backlight_properties props; 289 struct lp855x_platform_data *pdata = lp->pdata; 290 const char *name = pdata->name ? : DEFAULT_BL_NAME; 291 292 memset(&props, 0, sizeof(props)); 293 props.type = BACKLIGHT_PLATFORM; 294 props.max_brightness = MAX_BRIGHTNESS; 295 296 if (pdata->initial_brightness > props.max_brightness) 297 pdata->initial_brightness = props.max_brightness; 298 299 props.brightness = pdata->initial_brightness; 300 301 bl = devm_backlight_device_register(lp->dev, name, lp->dev, lp, 302 &lp855x_bl_ops, &props); 303 if (IS_ERR(bl)) 304 return PTR_ERR(bl); 305 306 lp->bl = bl; 307 308 return 0; 309 } 310 311 static ssize_t lp855x_get_chip_id(struct device *dev, 312 struct device_attribute *attr, char *buf) 313 { 314 struct lp855x *lp = dev_get_drvdata(dev); 315 316 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 317 } 318 319 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 320 struct device_attribute *attr, char *buf) 321 { 322 struct lp855x *lp = dev_get_drvdata(dev); 323 char *strmode = NULL; 324 325 if (lp->mode == PWM_BASED) 326 strmode = "pwm based"; 327 else if (lp->mode == REGISTER_BASED) 328 strmode = "register based"; 329 330 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 331 } 332 333 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 334 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 335 336 static struct attribute *lp855x_attributes[] = { 337 &dev_attr_chip_id.attr, 338 &dev_attr_bl_ctl_mode.attr, 339 NULL, 340 }; 341 342 static const struct attribute_group lp855x_attr_group = { 343 .attrs = lp855x_attributes, 344 }; 345 346 #ifdef CONFIG_OF 347 static int lp855x_parse_dt(struct lp855x *lp) 348 { 349 struct device *dev = lp->dev; 350 struct device_node *node = dev->of_node; 351 struct lp855x_platform_data *pdata; 352 int rom_length; 353 354 if (!node) { 355 dev_err(dev, "no platform data\n"); 356 return -EINVAL; 357 } 358 359 pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL); 360 if (!pdata) 361 return -ENOMEM; 362 363 of_property_read_string(node, "bl-name", &pdata->name); 364 of_property_read_u8(node, "dev-ctrl", &pdata->device_control); 365 of_property_read_u8(node, "init-brt", &pdata->initial_brightness); 366 of_property_read_u32(node, "pwm-period", &pdata->period_ns); 367 368 /* Fill ROM platform data if defined */ 369 rom_length = of_get_child_count(node); 370 if (rom_length > 0) { 371 struct lp855x_rom_data *rom; 372 struct device_node *child; 373 int i = 0; 374 375 rom = devm_kzalloc(dev, sizeof(*rom) * rom_length, GFP_KERNEL); 376 if (!rom) 377 return -ENOMEM; 378 379 for_each_child_of_node(node, child) { 380 of_property_read_u8(child, "rom-addr", &rom[i].addr); 381 of_property_read_u8(child, "rom-val", &rom[i].val); 382 i++; 383 } 384 385 pdata->size_program = rom_length; 386 pdata->rom_data = &rom[0]; 387 } 388 389 lp->pdata = pdata; 390 391 return 0; 392 } 393 #else 394 static int lp855x_parse_dt(struct lp855x *lp) 395 { 396 return -EINVAL; 397 } 398 #endif 399 400 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id) 401 { 402 struct lp855x *lp; 403 int ret; 404 405 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 406 return -EIO; 407 408 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 409 if (!lp) 410 return -ENOMEM; 411 412 lp->client = cl; 413 lp->dev = &cl->dev; 414 lp->chipname = id->name; 415 lp->chip_id = id->driver_data; 416 lp->pdata = dev_get_platdata(&cl->dev); 417 418 if (!lp->pdata) { 419 ret = lp855x_parse_dt(lp); 420 if (ret < 0) 421 return ret; 422 } 423 424 if (lp->pdata->period_ns > 0) 425 lp->mode = PWM_BASED; 426 else 427 lp->mode = REGISTER_BASED; 428 429 lp->supply = devm_regulator_get(lp->dev, "power"); 430 if (IS_ERR(lp->supply)) { 431 if (PTR_ERR(lp->supply) == -EPROBE_DEFER) 432 return -EPROBE_DEFER; 433 lp->supply = NULL; 434 } 435 436 if (lp->supply) { 437 ret = regulator_enable(lp->supply); 438 if (ret < 0) { 439 dev_err(&cl->dev, "failed to enable supply: %d\n", ret); 440 return ret; 441 } 442 } 443 444 i2c_set_clientdata(cl, lp); 445 446 ret = lp855x_configure(lp); 447 if (ret) { 448 dev_err(lp->dev, "device config err: %d", ret); 449 return ret; 450 } 451 452 ret = lp855x_backlight_register(lp); 453 if (ret) { 454 dev_err(lp->dev, 455 "failed to register backlight. err: %d\n", ret); 456 return ret; 457 } 458 459 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 460 if (ret) { 461 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 462 return ret; 463 } 464 465 backlight_update_status(lp->bl); 466 return 0; 467 } 468 469 static int lp855x_remove(struct i2c_client *cl) 470 { 471 struct lp855x *lp = i2c_get_clientdata(cl); 472 473 lp->bl->props.brightness = 0; 474 backlight_update_status(lp->bl); 475 if (lp->supply) 476 regulator_disable(lp->supply); 477 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 478 479 return 0; 480 } 481 482 static const struct of_device_id lp855x_dt_ids[] = { 483 { .compatible = "ti,lp8550", }, 484 { .compatible = "ti,lp8551", }, 485 { .compatible = "ti,lp8552", }, 486 { .compatible = "ti,lp8553", }, 487 { .compatible = "ti,lp8555", }, 488 { .compatible = "ti,lp8556", }, 489 { .compatible = "ti,lp8557", }, 490 { } 491 }; 492 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 493 494 static const struct i2c_device_id lp855x_ids[] = { 495 {"lp8550", LP8550}, 496 {"lp8551", LP8551}, 497 {"lp8552", LP8552}, 498 {"lp8553", LP8553}, 499 {"lp8555", LP8555}, 500 {"lp8556", LP8556}, 501 {"lp8557", LP8557}, 502 { } 503 }; 504 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 505 506 static struct i2c_driver lp855x_driver = { 507 .driver = { 508 .name = "lp855x", 509 .of_match_table = of_match_ptr(lp855x_dt_ids), 510 }, 511 .probe = lp855x_probe, 512 .remove = lp855x_remove, 513 .id_table = lp855x_ids, 514 }; 515 516 module_i2c_driver(lp855x_driver); 517 518 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 519 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 520 MODULE_LICENSE("GPL"); 521