drivers/video/backlight/lp855x_bl.c

   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/platform_data/lp855x.h>
  18 #include <linux/pwm.h>
  19
  20 /* LP8550/1/2/3/6 Registers */
  21 #define LP855X_BRIGHTNESS_CTRL          0x00
  22 #define LP855X_DEVICE_CTRL              0x01
  23 #define LP855X_EEPROM_START             0xA0
  24 #define LP855X_EEPROM_END               0xA7
  25 #define LP8556_EPROM_START              0xA0
  26 #define LP8556_EPROM_END                0xAF
  27
  28 /* LP8557 Registers */
  29 #define LP8557_BL_CMD                   0x00
  30 #define LP8557_BL_MASK                  0x01
  31 #define LP8557_BL_ON                    0x01
  32 #define LP8557_BL_OFF                   0x00
  33 #define LP8557_BRIGHTNESS_CTRL          0x04
  34 #define LP8557_CONFIG                   0x10
  35 #define LP8557_EPROM_START              0x10
  36 #define LP8557_EPROM_END                0x1E
  37
  38 #define BUF_SIZE                20
  39 #define DEFAULT_BL_NAME         "lcd-backlight"
  40 #define MAX_BRIGHTNESS          255
  41
  42 struct lp855x;
  43
  44 /*
  45  * struct lp855x_device_config
  46  * @pre_init_device: init device function call before updating the brightness
  47  * @reg_brightness: register address for brigthenss control
  48  * @reg_devicectrl: register address for device control
  49  * @post_init_device: late init device function call
  50  */
  51 struct lp855x_device_config {
  52         int (*pre_init_device)(struct lp855x *);
  53         u8 reg_brightness;
  54         u8 reg_devicectrl;
  55         int (*post_init_device)(struct lp855x *);
  56 };
  57
  58 struct lp855x {
  59         const char *chipname;
  60         enum lp855x_chip_id chip_id;
  61         struct lp855x_device_config *cfg;
  62         struct i2c_client *client;
  63         struct backlight_device *bl;
  64         struct device *dev;
  65         struct lp855x_platform_data *pdata;
  66         struct pwm_device *pwm;
  67 };
  68
  69 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  70 {
  71         return i2c_smbus_write_byte_data(lp->client, reg, data);
  72 }
  73
  74 static int lp855x_update_bit(struct lp855x *lp, u8 reg, u8 mask, u8 data)
  75 {
  76         int ret;
  77         u8 tmp;
  78
  79         ret = i2c_smbus_read_byte_data(lp->client, reg);
  80         if (ret < 0) {
  81                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  82                 return ret;
  83         }
  84
  85         tmp = (u8)ret;
  86         tmp &= ~mask;
  87         tmp |= data & mask;
  88
  89         return lp855x_write_byte(lp, reg, tmp);
  90 }
  91
  92 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
  93 {
  94         u8 start, end;
  95
  96         switch (lp->chip_id) {
  97         case LP8550:
  98         case LP8551:
  99         case LP8552:
 100         case LP8553:
 101                 start = LP855X_EEPROM_START;
 102                 end = LP855X_EEPROM_END;
 103                 break;
 104         case LP8556:
 105                 start = LP8556_EPROM_START;
 106                 end = LP8556_EPROM_END;
 107                 break;
 108         case LP8557:
 109                 start = LP8557_EPROM_START;
 110                 end = LP8557_EPROM_END;
 111                 break;
 112         default:
 113                 return false;
 114         }
 115
 116         return (addr >= start && addr <= end);
 117 }
 118
 119 static int lp8557_bl_off(struct lp855x *lp)
 120 {
 121         /* BL_ON = 0 before updating EPROM settings */
 122         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 123                                 LP8557_BL_OFF);
 124 }
 125
 126 static int lp8557_bl_on(struct lp855x *lp)
 127 {
 128         /* BL_ON = 1 after updating EPROM settings */
 129         return lp855x_update_bit(lp, LP8557_BL_CMD, LP8557_BL_MASK,
 130                                 LP8557_BL_ON);
 131 }
 132
 133 static struct lp855x_device_config lp855x_dev_cfg = {
 134         .reg_brightness = LP855X_BRIGHTNESS_CTRL,
 135         .reg_devicectrl = LP855X_DEVICE_CTRL,
 136 };
 137
 138 static struct lp855x_device_config lp8557_dev_cfg = {
 139         .reg_brightness = LP8557_BRIGHTNESS_CTRL,
 140         .reg_devicectrl = LP8557_CONFIG,
 141         .pre_init_device = lp8557_bl_off,
 142         .post_init_device = lp8557_bl_on,
 143 };
 144
 145 /*
 146  * Device specific configuration flow
 147  *
 148  *    a) pre_init_device(optional)
 149  *    b) update the brightness register
 150  *    c) update device control register
 151  *    d) update ROM area(optional)
 152  *    e) post_init_device(optional)
 153  *
 154  */
 155 static int lp855x_configure(struct lp855x *lp)
 156 {
 157         u8 val, addr;
 158         int i, ret;
 159         struct lp855x_platform_data *pd = lp->pdata;
 160
 161         switch (lp->chip_id) {
 162         case LP8550 ... LP8556:
 163                 lp->cfg = &lp855x_dev_cfg;
 164                 break;
 165         case LP8557:
 166                 lp->cfg = &lp8557_dev_cfg;
 167                 break;
 168         default:
 169                 return -EINVAL;
 170         }
 171
 172         if (lp->cfg->pre_init_device) {
 173                 ret = lp->cfg->pre_init_device(lp);
 174                 if (ret) {
 175                         dev_err(lp->dev, "pre init device err: %d\n", ret);
 176                         goto err;
 177                 }
 178         }
 179
 180         val = pd->initial_brightness;
 181         ret = lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 182         if (ret)
 183                 goto err;
 184
 185         val = pd->device_control;
 186         ret = lp855x_write_byte(lp, lp->cfg->reg_devicectrl, val);
 187         if (ret)
 188                 goto err;
 189
 190         if (pd->load_new_rom_data && pd->size_program) {
 191                 for (i = 0; i < pd->size_program; i++) {
 192                         addr = pd->rom_data[i].addr;
 193                         val = pd->rom_data[i].val;
 194                         if (!lp855x_is_valid_rom_area(lp, addr))
 195                                 continue;
 196
 197                         ret = lp855x_write_byte(lp, addr, val);
 198                         if (ret)
 199                                 goto err;
 200                 }
 201         }
 202
 203         if (lp->cfg->post_init_device) {
 204                 ret = lp->cfg->post_init_device(lp);
 205                 if (ret) {
 206                         dev_err(lp->dev, "post init device err: %d\n", ret);
 207                         goto err;
 208                 }
 209         }
 210
 211         return 0;
 212
 213 err:
 214         return ret;
 215 }
 216
 217 static void lp855x_pwm_ctrl(struct lp855x *lp, int br, int max_br)
 218 {
 219         unsigned int period = lp->pdata->period_ns;
 220         unsigned int duty = br * period / max_br;
 221         struct pwm_device *pwm;
 222
 223         /* request pwm device with the consumer name */
 224         if (!lp->pwm) {
 225                 pwm = devm_pwm_get(lp->dev, lp->chipname);
 226                 if (IS_ERR(pwm))
 227                         return;
 228
 229                 lp->pwm = pwm;
 230         }
 231
 232         pwm_config(lp->pwm, duty, period);
 233         if (duty)
 234                 pwm_enable(lp->pwm);
 235         else
 236                 pwm_disable(lp->pwm);
 237 }
 238
 239 static int lp855x_bl_update_status(struct backlight_device *bl)
 240 {
 241         struct lp855x *lp = bl_get_data(bl);
 242         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 243
 244         if (bl->props.state & BL_CORE_SUSPENDED)
 245                 bl->props.brightness = 0;
 246
 247         if (mode == PWM_BASED) {
 248                 int br = bl->props.brightness;
 249                 int max_br = bl->props.max_brightness;
 250
 251                 lp855x_pwm_ctrl(lp, br, max_br);
 252
 253         } else if (mode == REGISTER_BASED) {
 254                 u8 val = bl->props.brightness;
 255                 lp855x_write_byte(lp, lp->cfg->reg_brightness, val);
 256         }
 257
 258         return 0;
 259 }
 260
 261 static int lp855x_bl_get_brightness(struct backlight_device *bl)
 262 {
 263         return bl->props.brightness;
 264 }
 265
 266 static const struct backlight_ops lp855x_bl_ops = {
 267         .options = BL_CORE_SUSPENDRESUME,
 268         .update_status = lp855x_bl_update_status,
 269         .get_brightness = lp855x_bl_get_brightness,
 270 };
 271
 272 static int lp855x_backlight_register(struct lp855x *lp)
 273 {
 274         struct backlight_device *bl;
 275         struct backlight_properties props;
 276         struct lp855x_platform_data *pdata = lp->pdata;
 277         char *name = pdata->name ? : DEFAULT_BL_NAME;
 278
 279         props.type = BACKLIGHT_PLATFORM;
 280         props.max_brightness = MAX_BRIGHTNESS;
 281
 282         if (pdata->initial_brightness > props.max_brightness)
 283                 pdata->initial_brightness = props.max_brightness;
 284
 285         props.brightness = pdata->initial_brightness;
 286
 287         bl = backlight_device_register(name, lp->dev, lp,
 288                                        &lp855x_bl_ops, &props);
 289         if (IS_ERR(bl))
 290                 return PTR_ERR(bl);
 291
 292         lp->bl = bl;
 293
 294         return 0;
 295 }
 296
 297 static void lp855x_backlight_unregister(struct lp855x *lp)
 298 {
 299         if (lp->bl)
 300                 backlight_device_unregister(lp->bl);
 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         return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname);
 308 }
 309
 310 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 311                                      struct device_attribute *attr, char *buf)
 312 {
 313         struct lp855x *lp = dev_get_drvdata(dev);
 314         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 315         char *strmode = NULL;
 316
 317         if (mode == PWM_BASED)
 318                 strmode = "pwm based";
 319         else if (mode == REGISTER_BASED)
 320                 strmode = "register based";
 321
 322         return scnprintf(buf, BUF_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 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 339 {
 340         struct lp855x *lp;
 341         struct lp855x_platform_data *pdata = cl->dev.platform_data;
 342         enum lp855x_brightness_ctrl_mode mode;
 343         int ret;
 344
 345         if (!pdata) {
 346                 dev_err(&cl->dev, "no platform data supplied\n");
 347                 return -EINVAL;
 348         }
 349
 350         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 351                 return -EIO;
 352
 353         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 354         if (!lp)
 355                 return -ENOMEM;
 356
 357         mode = pdata->mode;
 358         lp->client = cl;
 359         lp->dev = &cl->dev;
 360         lp->pdata = pdata;
 361         lp->chipname = id->name;
 362         lp->chip_id = id->driver_data;
 363         i2c_set_clientdata(cl, lp);
 364
 365         ret = lp855x_configure(lp);
 366         if (ret) {
 367                 dev_err(lp->dev, "device config err: %d", ret);
 368                 goto err_dev;
 369         }
 370
 371         ret = lp855x_backlight_register(lp);
 372         if (ret) {
 373                 dev_err(lp->dev,
 374                         "failed to register backlight. err: %d\n", ret);
 375                 goto err_dev;
 376         }
 377
 378         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 379         if (ret) {
 380                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 381                 goto err_sysfs;
 382         }
 383
 384         backlight_update_status(lp->bl);
 385         return 0;
 386
 387 err_sysfs:
 388         lp855x_backlight_unregister(lp);
 389 err_dev:
 390         return ret;
 391 }
 392
 393 static int lp855x_remove(struct i2c_client *cl)
 394 {
 395         struct lp855x *lp = i2c_get_clientdata(cl);
 396
 397         lp->bl->props.brightness = 0;
 398         backlight_update_status(lp->bl);
 399         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 400         lp855x_backlight_unregister(lp);
 401
 402         return 0;
 403 }
 404
 405 static const struct i2c_device_id lp855x_ids[] = {
 406         {"lp8550", LP8550},
 407         {"lp8551", LP8551},
 408         {"lp8552", LP8552},
 409         {"lp8553", LP8553},
 410         {"lp8556", LP8556},
 411         {"lp8557", LP8557},
 412         { }
 413 };
 414 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 415
 416 static struct i2c_driver lp855x_driver = {
 417         .driver = {
 418                    .name = "lp855x",
 419                    },
 420         .probe = lp855x_probe,
 421         .remove = lp855x_remove,
 422         .id_table = lp855x_ids,
 423 };
 424
 425 module_i2c_driver(lp855x_driver);
 426
 427 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 428 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 429 MODULE_LICENSE("GPL");