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
  19 /* Registers */
  20 #define BRIGHTNESS_CTRL         0x00
  21 #define DEVICE_CTRL             0x01
  22 #define EEPROM_START            0xA0
  23 #define EEPROM_END              0xA7
  24 #define EPROM_START             0xA0
  25 #define EPROM_END               0xAF
  26
  27 #define BUF_SIZE                20
  28 #define DEFAULT_BL_NAME         "lcd-backlight"
  29 #define MAX_BRIGHTNESS          255
  30
  31 struct lp855x {
  32         const char *chipname;
  33         enum lp855x_chip_id chip_id;
  34         struct i2c_client *client;
  35         struct backlight_device *bl;
  36         struct device *dev;
  37         struct mutex xfer_lock;
  38         struct lp855x_platform_data *pdata;
  39 };
  40
  41 static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
  42 {
  43         int ret;
  44
  45         mutex_lock(&lp->xfer_lock);
  46         ret = i2c_smbus_read_byte_data(lp->client, reg);
  47         if (ret < 0) {
  48                 mutex_unlock(&lp->xfer_lock);
  49                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  50                 return ret;
  51         }
  52         mutex_unlock(&lp->xfer_lock);
  53
  54         *data = (u8)ret;
  55         return 0;
  56 }
  57
  58 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  59 {
  60         int ret;
  61
  62         mutex_lock(&lp->xfer_lock);
  63         ret = i2c_smbus_write_byte_data(lp->client, reg, data);
  64         mutex_unlock(&lp->xfer_lock);
  65
  66         return ret;
  67 }
  68
  69 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
  70 {
  71         u8 start, end;
  72
  73         switch (lp->chip_id) {
  74         case LP8550:
  75         case LP8551:
  76         case LP8552:
  77         case LP8553:
  78                 start = EEPROM_START;
  79                 end = EEPROM_END;
  80                 break;
  81         case LP8556:
  82                 start = EPROM_START;
  83                 end = EPROM_END;
  84                 break;
  85         default:
  86                 return false;
  87         }
  88
  89         return (addr >= start && addr <= end);
  90 }
  91
  92 static int lp855x_init_registers(struct lp855x *lp)
  93 {
  94         u8 val, addr;
  95         int i, ret;
  96         struct lp855x_platform_data *pd = lp->pdata;
  97
  98         val = pd->initial_brightness;
  99         ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
 100         if (ret)
 101                 return ret;
 102
 103         val = pd->device_control;
 104         ret = lp855x_write_byte(lp, DEVICE_CTRL, val);
 105         if (ret)
 106                 return ret;
 107
 108         if (pd->load_new_rom_data && pd->size_program) {
 109                 for (i = 0; i < pd->size_program; i++) {
 110                         addr = pd->rom_data[i].addr;
 111                         val = pd->rom_data[i].val;
 112                         if (!lp855x_is_valid_rom_area(lp, addr))
 113                                 continue;
 114
 115                         ret = lp855x_write_byte(lp, addr, val);
 116                         if (ret)
 117                                 return ret;
 118                 }
 119         }
 120
 121         return ret;
 122 }
 123
 124 static int lp855x_bl_update_status(struct backlight_device *bl)
 125 {
 126         struct lp855x *lp = bl_get_data(bl);
 127         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 128
 129         if (bl->props.state & BL_CORE_SUSPENDED)
 130                 bl->props.brightness = 0;
 131
 132         if (mode == PWM_BASED) {
 133                 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
 134                 int br = bl->props.brightness;
 135                 int max_br = bl->props.max_brightness;
 136
 137                 if (pd->pwm_set_intensity)
 138                         pd->pwm_set_intensity(br, max_br);
 139
 140         } else if (mode == REGISTER_BASED) {
 141                 u8 val = bl->props.brightness;
 142                 lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
 143         }
 144
 145         return 0;
 146 }
 147
 148 static int lp855x_bl_get_brightness(struct backlight_device *bl)
 149 {
 150         struct lp855x *lp = bl_get_data(bl);
 151         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 152
 153         if (mode == PWM_BASED) {
 154                 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
 155                 int max_br = bl->props.max_brightness;
 156
 157                 if (pd->pwm_get_intensity)
 158                         bl->props.brightness = pd->pwm_get_intensity(max_br);
 159
 160         } else if (mode == REGISTER_BASED) {
 161                 u8 val = 0;
 162
 163                 lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
 164                 bl->props.brightness = val;
 165         }
 166
 167         return bl->props.brightness;
 168 }
 169
 170 static const struct backlight_ops lp855x_bl_ops = {
 171         .options = BL_CORE_SUSPENDRESUME,
 172         .update_status = lp855x_bl_update_status,
 173         .get_brightness = lp855x_bl_get_brightness,
 174 };
 175
 176 static int lp855x_backlight_register(struct lp855x *lp)
 177 {
 178         struct backlight_device *bl;
 179         struct backlight_properties props;
 180         struct lp855x_platform_data *pdata = lp->pdata;
 181         char *name = pdata->name ? : DEFAULT_BL_NAME;
 182
 183         props.type = BACKLIGHT_PLATFORM;
 184         props.max_brightness = MAX_BRIGHTNESS;
 185
 186         if (pdata->initial_brightness > props.max_brightness)
 187                 pdata->initial_brightness = props.max_brightness;
 188
 189         props.brightness = pdata->initial_brightness;
 190
 191         bl = backlight_device_register(name, lp->dev, lp,
 192                                        &lp855x_bl_ops, &props);
 193         if (IS_ERR(bl))
 194                 return PTR_ERR(bl);
 195
 196         lp->bl = bl;
 197
 198         return 0;
 199 }
 200
 201 static void lp855x_backlight_unregister(struct lp855x *lp)
 202 {
 203         if (lp->bl)
 204                 backlight_device_unregister(lp->bl);
 205 }
 206
 207 static ssize_t lp855x_get_chip_id(struct device *dev,
 208                                 struct device_attribute *attr, char *buf)
 209 {
 210         struct lp855x *lp = dev_get_drvdata(dev);
 211         return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname);
 212 }
 213
 214 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 215                                      struct device_attribute *attr, char *buf)
 216 {
 217         struct lp855x *lp = dev_get_drvdata(dev);
 218         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 219         char *strmode = NULL;
 220
 221         if (mode == PWM_BASED)
 222                 strmode = "pwm based";
 223         else if (mode == REGISTER_BASED)
 224                 strmode = "register based";
 225
 226         return scnprintf(buf, BUF_SIZE, "%s\n", strmode);
 227 }
 228
 229 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 230 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 231
 232 static struct attribute *lp855x_attributes[] = {
 233         &dev_attr_chip_id.attr,
 234         &dev_attr_bl_ctl_mode.attr,
 235         NULL,
 236 };
 237
 238 static const struct attribute_group lp855x_attr_group = {
 239         .attrs = lp855x_attributes,
 240 };
 241
 242 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 243 {
 244         struct lp855x *lp;
 245         struct lp855x_platform_data *pdata = cl->dev.platform_data;
 246         enum lp855x_brightness_ctrl_mode mode;
 247         int ret;
 248
 249         if (!pdata) {
 250                 dev_err(&cl->dev, "no platform data supplied\n");
 251                 return -EINVAL;
 252         }
 253
 254         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 255                 return -EIO;
 256
 257         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 258         if (!lp)
 259                 return -ENOMEM;
 260
 261         mode = pdata->mode;
 262         lp->client = cl;
 263         lp->dev = &cl->dev;
 264         lp->pdata = pdata;
 265         lp->chipname = id->name;
 266         lp->chip_id = id->driver_data;
 267         i2c_set_clientdata(cl, lp);
 268
 269         mutex_init(&lp->xfer_lock);
 270
 271         ret = lp855x_init_registers(lp);
 272         if (ret) {
 273                 dev_err(lp->dev, "i2c communication err: %d", ret);
 274                 if (mode == REGISTER_BASED)
 275                         goto err_dev;
 276         }
 277
 278         ret = lp855x_backlight_register(lp);
 279         if (ret) {
 280                 dev_err(lp->dev,
 281                         "failed to register backlight. err: %d\n", ret);
 282                 goto err_dev;
 283         }
 284
 285         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 286         if (ret) {
 287                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 288                 goto err_sysfs;
 289         }
 290
 291         backlight_update_status(lp->bl);
 292         return 0;
 293
 294 err_sysfs:
 295         lp855x_backlight_unregister(lp);
 296 err_dev:
 297         return ret;
 298 }
 299
 300 static int __devexit lp855x_remove(struct i2c_client *cl)
 301 {
 302         struct lp855x *lp = i2c_get_clientdata(cl);
 303
 304         lp->bl->props.brightness = 0;
 305         backlight_update_status(lp->bl);
 306         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 307         lp855x_backlight_unregister(lp);
 308
 309         return 0;
 310 }
 311
 312 static const struct i2c_device_id lp855x_ids[] = {
 313         {"lp8550", LP8550},
 314         {"lp8551", LP8551},
 315         {"lp8552", LP8552},
 316         {"lp8553", LP8553},
 317         {"lp8556", LP8556},
 318         { }
 319 };
 320 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 321
 322 static struct i2c_driver lp855x_driver = {
 323         .driver = {
 324                    .name = "lp855x",
 325                    },
 326         .probe = lp855x_probe,
 327         .remove = __devexit_p(lp855x_remove),
 328         .id_table = lp855x_ids,
 329 };
 330
 331 module_i2c_driver(lp855x_driver);
 332
 333 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 334 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 335 MODULE_LICENSE("GPL");