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 21 /* LP8550/1/2/3/6 Registers */ 22 #define LP855X_BRIGHTNESS_CTRL 0x00 23 #define LP855X_DEVICE_CTRL 0x01 24 #define LP855X_EEPROM_START 0xA0 25 #define LP855X_EEPROM_END 0xA7 26 #define LP8556_EPROM_START 0xA0 27 #define LP8556_EPROM_END 0xAF 28 29 /* LP8557 Registers */ 30 #define LP8557_BL_CMD 0x00 31 #define LP8557_BL_MASK 0x01 32 #define LP8557_BL_ON 0x01 33 #define LP8557_BL_OFF 0x00 34 #define LP8557_BRIGHTNESS_CTRL 0x04 35 #define LP8557_CONFIG 0x10 36 #define LP8557_EPROM_START 0x10 37 #define LP8557_EPROM_END 0x1E 38 39 #define DEFAULT_BL_NAME "lcd-backlight" 40 #define MAX_BRIGHTNESS 255 41 42 enum lp855x_brightness_ctrl_mode { 43 PWM_BASED = 1, 44 REGISTER_BASED, 45 }; 46 47 struct lp855x; 48 49 /* 50 * struct lp855x_device_config 51 * @pre_init_device: init device function call before updating the brightness 52 * @reg_brightness: register address for brigthenss control 53 * @reg_devicectrl: register address for device control 54 * @post_init_device: late init device function call 55 */ 56 struct lp855x_device_config { 57 int (*pre_init_device)(struct lp855x *); 58 u8 reg_brightness; 59 u8 reg_devicectrl; 60 int (*post_init_device)(struct lp855x *); 61 }; 62 63 struct lp855x { 64 const char *chipname; 65 enum lp855x_chip_id chip_id; 66 enum lp855x_brightness_ctrl_mode mode; 67 struct lp855x_device_config *cfg; 68 struct i2c_client *client; 69 struct backlight_device *bl; 70 struct device *dev; 71 struct lp855x_platform_data *pdata; 72 struct pwm_device *pwm; 73 }; 74 75 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data) 76 { 77 return i2c_smbus_write_byte_data(lp->client, reg, data); 78 } 79 80 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data) 81 { 82 int ret; 83 u8 tmp; 84 85 ret = i2c_smbus_read_byte_data(lp->client, reg); 86 if (ret < 0) { 87 dev_err(lp->dev, "failed to read 0x%.2x\n", reg); 88 return ret; 89 } 90 91 tmp = (u8)ret; 92 tmp &= ~mask; 93 tmp |= data & mask; 94 95 return lp855x_write_byte(lp, reg, tmp); 96 } 97 98 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr) 99 { 100 u8 start, end; 101 102 switch (lp->chip_id) { 103 case LP8550: 104 case LP8551: 105 case LP8552: 106 case LP8553: 107 start = LP855X_EEPROM_START; 108 end = LP855X_EEPROM_END; 109 break; 110 case LP8556: 111 start = LP8556_EPROM_START; 112 end = LP8556_EPROM_END; 113 break; 114 case LP8557: 115 start = LP8557_EPROM_START; 116 end = LP8557_EPROM_END; 117 break; 118 default: 119 return false; 120 } 121 122 return (addr >= start && addr <= end); 123 } 124 125 static int lp8557_bl_off(struct lp855x *lp) 126 { 127 /* BL_ON = 0 before updating EPROM settings */ 128 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 129 LP8557_BL_OFF); 130 } 131 132 static int lp8557_bl_on(struct lp855x *lp) 133 { 134 /* BL_ON = 1 after updating EPROM settings */ 135 return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK, 136 LP8557_BL_ON); 137 } 138 139 static struct lp855x_device_config lp855x_dev_cfg = { 140 .reg_brightness = LP855X_BRIGHTNESS_CTRL, 141 .reg_devicectrl = LP855X_DEVICE_CTRL, 142 }; 143 144 static struct lp855x_device_config lp8557_dev_cfg = { 145 .reg_brightness = LP8557_BRIGHTNESS_CTRL, 146 .reg_devicectrl = LP8557_CONFIG, 147 .pre_init_device = lp8557_bl_off, 148 .post_init_device = lp8557_bl_on, 149 }; 150 151 /* 152 * Device specific configuration flow 153 * 154 * a) pre_init_device(optional) 155 * b) update the brightness register 156 * c) update device control register 157 * d) update ROM area(optional) 158 * e) post_init_device(optional) 159 * 160 */ 161 static int lp855x_configure(struct lp855x *lp) 162 { 163 u8 val, addr; 164 int i, ret; 165 struct lp855x_platform_data *pd = lp->pdata; 166 167 switch (lp->chip_id) { 168 case LP8550 ... LP8556: 169 lp->cfg = &lp855x_dev_cfg; 170 break; 171 case LP8557: 172 lp->cfg = &lp8557_dev_cfg; 173 break; 174 default: 175 return -EINVAL; 176 } 177 178 if (lp->cfg->pre_init_device) { 179 ret = lp->cfg->pre_init_device(lp); 180 if (ret) { 181 dev_err(lp->dev, "pre init device err: %d\n", ret); 182 goto err; 183 } 184 } 185 186 val = pd->initial_brightness; 187 ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 188 if (ret) 189 goto err; 190 191 val = pd->device_control; 192 ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val); 193 if (ret) 194 goto err; 195 196 if (pd->size_program > 0) { 197 for (i = 0; i < pd->size_program; i++) { 198 addr = pd->rom_data[i].addr; 199 val = pd->rom_data[i].val; 200 if (!lp855x_is_valid_rom_area(lp, addr)) 201 continue; 202 203 ret = lp855x_write_byte(lp, addr, val); 204 if (ret) 205 goto err; 206 } 207 } 208 209 if (lp->cfg->post_init_device) { 210 ret = lp->cfg->post_init_device(lp); 211 if (ret) { 212 dev_err(lp->dev, "post init device err: %d\n", ret); 213 goto err; 214 } 215 } 216 217 return 0; 218 219 err: 220 return ret; 221 } 222 223 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br) 224 { 225 unsigned int period = lp->pdata->period_ns; 226 unsigned int duty = br * period / max_br; 227 struct pwm_device *pwm; 228 229 /* request pwm device with the consumer name */ 230 if (!lp->pwm) { 231 pwm = devm_pwm_get(lp->dev, lp->chipname); 232 if (IS_ERR(pwm)) 233 return; 234 235 lp->pwm = pwm; 236 } 237 238 pwm_config(lp->pwm, duty, period); 239 if (duty) 240 pwm_enable(lp->pwm); 241 else 242 pwm_disable(lp->pwm); 243 } 244 245 static int lp855x_bl_update_status(struct backlight_device *bl) 246 { 247 struct lp855x *lp = bl_get_data(bl); 248 249 if (bl->props.state & (BL_CORE_SUSPENDED | BL_CORE_FBBLANK)) 250 bl->props.brightness = 0; 251 252 if (lp->mode == PWM_BASED) { 253 int br = bl->props.brightness; 254 int max_br = bl->props.max_brightness; 255 256 lp855x_pwm_ctrl(lp, br, max_br); 257 258 } else if (lp->mode == REGISTER_BASED) { 259 u8 val = bl->props.brightness; 260 lp855x_write_byte(lp, lp->cfg->reg_brightness, val); 261 } 262 263 return 0; 264 } 265 266 static int lp855x_bl_get_brightness(struct backlight_device *bl) 267 { 268 return bl->props.brightness; 269 } 270 271 static const struct backlight_ops lp855x_bl_ops = { 272 .options = BL_CORE_SUSPENDRESUME, 273 .update_status = lp855x_bl_update_status, 274 .get_brightness = lp855x_bl_get_brightness, 275 }; 276 277 static int lp855x_backlight_register(struct lp855x *lp) 278 { 279 struct backlight_device *bl; 280 struct backlight_properties props; 281 struct lp855x_platform_data *pdata = lp->pdata; 282 const char *name = pdata->name ? : DEFAULT_BL_NAME; 283 284 props.type = BACKLIGHT_PLATFORM; 285 props.max_brightness = MAX_BRIGHTNESS; 286 287 if (pdata->initial_brightness > props.max_brightness) 288 pdata->initial_brightness = props.max_brightness; 289 290 props.brightness = pdata->initial_brightness; 291 292 bl = backlight_device_register(name, lp->dev, lp, 293 &lp855x_bl_ops, &props); 294 if (IS_ERR(bl)) 295 return PTR_ERR(bl); 296 297 lp->bl = bl; 298 299 return 0; 300 } 301 302 static void lp855x_backlight_unregister(struct lp855x *lp) 303 { 304 if (lp->bl) 305 backlight_device_unregister(lp->bl); 306 } 307 308 static ssize_t lp855x_get_chip_id(struct device *dev, 309 struct device_attribute *attr, char *buf) 310 { 311 struct lp855x *lp = dev_get_drvdata(dev); 312 return scnprintf(buf, PAGE_SIZE, "%s\n", lp->chipname); 313 } 314 315 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev, 316 struct device_attribute *attr, char *buf) 317 { 318 struct lp855x *lp = dev_get_drvdata(dev); 319 char *strmode = NULL; 320 321 if (lp->mode == PWM_BASED) 322 strmode = "pwm based"; 323 else if (lp->mode == REGISTER_BASED) 324 strmode = "register based"; 325 326 return scnprintf(buf, PAGE_SIZE, "%s\n", strmode); 327 } 328 329 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL); 330 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL); 331 332 static struct attribute *lp855x_attributes[] = { 333 &dev_attr_chip_id.attr, 334 &dev_attr_bl_ctl_mode.attr, 335 NULL, 336 }; 337 338 static const struct attribute_group lp855x_attr_group = { 339 .attrs = lp855x_attributes, 340 }; 341 342 #ifdef CONFIG_OF 343 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 344 { 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 dev->platform_data = pdata; 384 385 return 0; 386 } 387 #else 388 static int lp855x_parse_dt(struct device *dev, struct device_node *node) 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 struct lp855x_platform_data *pdata = cl->dev.platform_data; 398 struct device_node *node = cl->dev.of_node; 399 int ret; 400 401 if (!pdata) { 402 ret = lp855x_parse_dt(&cl->dev, node); 403 if (ret < 0) 404 return ret; 405 406 pdata = cl->dev.platform_data; 407 } 408 409 if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK)) 410 return -EIO; 411 412 lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL); 413 if (!lp) 414 return -ENOMEM; 415 416 if (pdata->period_ns > 0) 417 lp->mode = PWM_BASED; 418 else 419 lp->mode = REGISTER_BASED; 420 421 lp->client = cl; 422 lp->dev = &cl->dev; 423 lp->pdata = pdata; 424 lp->chipname = id->name; 425 lp->chip_id = id->driver_data; 426 i2c_set_clientdata(cl, lp); 427 428 ret = lp855x_configure(lp); 429 if (ret) { 430 dev_err(lp->dev, "device config err: %d", ret); 431 goto err_dev; 432 } 433 434 ret = lp855x_backlight_register(lp); 435 if (ret) { 436 dev_err(lp->dev, 437 "failed to register backlight. err: %d\n", ret); 438 goto err_dev; 439 } 440 441 ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group); 442 if (ret) { 443 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret); 444 goto err_sysfs; 445 } 446 447 backlight_update_status(lp->bl); 448 return 0; 449 450 err_sysfs: 451 lp855x_backlight_unregister(lp); 452 err_dev: 453 return ret; 454 } 455 456 static int lp855x_remove(struct i2c_client *cl) 457 { 458 struct lp855x *lp = i2c_get_clientdata(cl); 459 460 lp->bl->props.brightness = 0; 461 backlight_update_status(lp->bl); 462 sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group); 463 lp855x_backlight_unregister(lp); 464 465 return 0; 466 } 467 468 static const struct of_device_id lp855x_dt_ids[] = { 469 { .compatible = "ti,lp8550", }, 470 { .compatible = "ti,lp8551", }, 471 { .compatible = "ti,lp8552", }, 472 { .compatible = "ti,lp8553", }, 473 { .compatible = "ti,lp8556", }, 474 { .compatible = "ti,lp8557", }, 475 { } 476 }; 477 MODULE_DEVICE_TABLE(of, lp855x_dt_ids); 478 479 static const struct i2c_device_id lp855x_ids[] = { 480 {"lp8550", LP8550}, 481 {"lp8551", LP8551}, 482 {"lp8552", LP8552}, 483 {"lp8553", LP8553}, 484 {"lp8556", LP8556}, 485 {"lp8557", LP8557}, 486 { } 487 }; 488 MODULE_DEVICE_TABLE(i2c, lp855x_ids); 489 490 static struct i2c_driver lp855x_driver = { 491 .driver = { 492 .name = "lp855x", 493 .of_match_table = of_match_ptr(lp855x_dt_ids), 494 }, 495 .probe = lp855x_probe, 496 .remove = lp855x_remove, 497 .id_table = lp855x_ids, 498 }; 499 500 module_i2c_driver(lp855x_driver); 501 502 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver"); 503 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>"); 504 MODULE_LICENSE("GPL"); 505