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