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/lp855x.h>
  18
  19 /* Registers */
  20 #define BRIGHTNESS_CTRL         (0x00)
  21 #define DEVICE_CTRL             (0x01)
  22
  23 #define BUF_SIZE                20
  24 #define DEFAULT_BL_NAME         "lcd-backlight"
  25 #define MAX_BRIGHTNESS          255
  26
  27 struct lp855x {
  28         const char *chipname;
  29         enum lp855x_chip_id chip_id;
  30         struct i2c_client *client;
  31         struct backlight_device *bl;
  32         struct device *dev;
  33         struct mutex xfer_lock;
  34         struct lp855x_platform_data *pdata;
  35 };
  36
  37 static int lp855x_read_byte(struct lp855x *lp, u8 reg, u8 *data)
  38 {
  39         int ret;
  40
  41         mutex_lock(&lp->xfer_lock);
  42         ret = i2c_smbus_read_byte_data(lp->client, reg);
  43         if (ret < 0) {
  44                 mutex_unlock(&lp->xfer_lock);
  45                 dev_err(lp->dev, "failed to read 0x%.2x\n", reg);
  46                 return ret;
  47         }
  48         mutex_unlock(&lp->xfer_lock);
  49
  50         *data = (u8)ret;
  51         return 0;
  52 }
  53
  54 static int lp855x_write_byte(struct lp855x *lp, u8 reg, u8 data)
  55 {
  56         int ret;
  57
  58         mutex_lock(&lp->xfer_lock);
  59         ret = i2c_smbus_write_byte_data(lp->client, reg, data);
  60         mutex_unlock(&lp->xfer_lock);
  61
  62         return ret;
  63 }
  64
  65 static bool lp855x_is_valid_rom_area(struct lp855x *lp, u8 addr)
  66 {
  67         u8 start, end;
  68
  69         switch (lp->chip_id) {
  70         case LP8550:
  71         case LP8551:
  72         case LP8552:
  73         case LP8553:
  74                 start = EEPROM_START;
  75                 end = EEPROM_END;
  76                 break;
  77         case LP8556:
  78                 start = EPROM_START;
  79                 end = EPROM_END;
  80                 break;
  81         default:
  82                 return false;
  83         }
  84
  85         return (addr >= start && addr <= end);
  86 }
  87
  88 static int lp855x_init_registers(struct lp855x *lp)
  89 {
  90         u8 val, addr;
  91         int i, ret;
  92         struct lp855x_platform_data *pd = lp->pdata;
  93
  94         val = pd->initial_brightness;
  95         ret = lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
  96         if (ret)
  97                 return ret;
  98
  99         val = pd->device_control;
 100         ret = lp855x_write_byte(lp, DEVICE_CTRL, val);
 101         if (ret)
 102                 return ret;
 103
 104         if (pd->load_new_rom_data && pd->size_program) {
 105                 for (i = 0; i < pd->size_program; i++) {
 106                         addr = pd->rom_data[i].addr;
 107                         val = pd->rom_data[i].val;
 108                         if (!lp855x_is_valid_rom_area(lp, addr))
 109                                 continue;
 110
 111                         ret = lp855x_write_byte(lp, addr, val);
 112                         if (ret)
 113                                 return ret;
 114                 }
 115         }
 116
 117         return ret;
 118 }
 119
 120 static int lp855x_bl_update_status(struct backlight_device *bl)
 121 {
 122         struct lp855x *lp = bl_get_data(bl);
 123         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 124
 125         if (bl->props.state & BL_CORE_SUSPENDED)
 126                 bl->props.brightness = 0;
 127
 128         if (mode == PWM_BASED) {
 129                 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
 130                 int br = bl->props.brightness;
 131                 int max_br = bl->props.max_brightness;
 132
 133                 if (pd->pwm_set_intensity)
 134                         pd->pwm_set_intensity(br, max_br);
 135
 136         } else if (mode == REGISTER_BASED) {
 137                 u8 val = bl->props.brightness;
 138                 lp855x_write_byte(lp, BRIGHTNESS_CTRL, val);
 139         }
 140
 141         return 0;
 142 }
 143
 144 static int lp855x_bl_get_brightness(struct backlight_device *bl)
 145 {
 146         struct lp855x *lp = bl_get_data(bl);
 147         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 148
 149         if (mode == PWM_BASED) {
 150                 struct lp855x_pwm_data *pd = &lp->pdata->pwm_data;
 151                 int max_br = bl->props.max_brightness;
 152
 153                 if (pd->pwm_get_intensity)
 154                         bl->props.brightness = pd->pwm_get_intensity(max_br);
 155
 156         } else if (mode == REGISTER_BASED) {
 157                 u8 val = 0;
 158
 159                 lp855x_read_byte(lp, BRIGHTNESS_CTRL, &val);
 160                 bl->props.brightness = val;
 161         }
 162
 163         return bl->props.brightness;
 164 }
 165
 166 static const struct backlight_ops lp855x_bl_ops = {
 167         .options = BL_CORE_SUSPENDRESUME,
 168         .update_status = lp855x_bl_update_status,
 169         .get_brightness = lp855x_bl_get_brightness,
 170 };
 171
 172 static int lp855x_backlight_register(struct lp855x *lp)
 173 {
 174         struct backlight_device *bl;
 175         struct backlight_properties props;
 176         struct lp855x_platform_data *pdata = lp->pdata;
 177         char *name = pdata->name ? : DEFAULT_BL_NAME;
 178
 179         props.type = BACKLIGHT_PLATFORM;
 180         props.max_brightness = MAX_BRIGHTNESS;
 181
 182         if (pdata->initial_brightness > props.max_brightness)
 183                 pdata->initial_brightness = props.max_brightness;
 184
 185         props.brightness = pdata->initial_brightness;
 186
 187         bl = backlight_device_register(name, lp->dev, lp,
 188                                        &lp855x_bl_ops, &props);
 189         if (IS_ERR(bl))
 190                 return PTR_ERR(bl);
 191
 192         lp->bl = bl;
 193
 194         return 0;
 195 }
 196
 197 static void lp855x_backlight_unregister(struct lp855x *lp)
 198 {
 199         if (lp->bl)
 200                 backlight_device_unregister(lp->bl);
 201 }
 202
 203 static ssize_t lp855x_get_chip_id(struct device *dev,
 204                                 struct device_attribute *attr, char *buf)
 205 {
 206         struct lp855x *lp = dev_get_drvdata(dev);
 207         return scnprintf(buf, BUF_SIZE, "%s\n", lp->chipname);
 208 }
 209
 210 static ssize_t lp855x_get_bl_ctl_mode(struct device *dev,
 211                                      struct device_attribute *attr, char *buf)
 212 {
 213         struct lp855x *lp = dev_get_drvdata(dev);
 214         enum lp855x_brightness_ctrl_mode mode = lp->pdata->mode;
 215         char *strmode = NULL;
 216
 217         if (mode == PWM_BASED)
 218                 strmode = "pwm based";
 219         else if (mode == REGISTER_BASED)
 220                 strmode = "register based";
 221
 222         return scnprintf(buf, BUF_SIZE, "%s\n", strmode);
 223 }
 224
 225 static DEVICE_ATTR(chip_id, S_IRUGO, lp855x_get_chip_id, NULL);
 226 static DEVICE_ATTR(bl_ctl_mode, S_IRUGO, lp855x_get_bl_ctl_mode, NULL);
 227
 228 static struct attribute *lp855x_attributes[] = {
 229         &dev_attr_chip_id.attr,
 230         &dev_attr_bl_ctl_mode.attr,
 231         NULL,
 232 };
 233
 234 static const struct attribute_group lp855x_attr_group = {
 235         .attrs = lp855x_attributes,
 236 };
 237
 238 static int lp855x_probe(struct i2c_client *cl, const struct i2c_device_id *id)
 239 {
 240         struct lp855x *lp;
 241         struct lp855x_platform_data *pdata = cl->dev.platform_data;
 242         enum lp855x_brightness_ctrl_mode mode;
 243         int ret;
 244
 245         if (!pdata) {
 246                 dev_err(&cl->dev, "no platform data supplied\n");
 247                 return -EINVAL;
 248         }
 249
 250         if (!i2c_check_functionality(cl->adapter, I2C_FUNC_SMBUS_I2C_BLOCK))
 251                 return -EIO;
 252
 253         lp = devm_kzalloc(&cl->dev, sizeof(struct lp855x), GFP_KERNEL);
 254         if (!lp)
 255                 return -ENOMEM;
 256
 257         mode = pdata->mode;
 258         lp->client = cl;
 259         lp->dev = &cl->dev;
 260         lp->pdata = pdata;
 261         lp->chipname = id->name;
 262         lp->chip_id = id->driver_data;
 263         i2c_set_clientdata(cl, lp);
 264
 265         mutex_init(&lp->xfer_lock);
 266
 267         ret = lp855x_init_registers(lp);
 268         if (ret) {
 269                 dev_err(lp->dev, "i2c communication err: %d", ret);
 270                 if (mode == REGISTER_BASED)
 271                         goto err_dev;
 272         }
 273
 274         ret = lp855x_backlight_register(lp);
 275         if (ret) {
 276                 dev_err(lp->dev,
 277                         "failed to register backlight. err: %d\n", ret);
 278                 goto err_dev;
 279         }
 280
 281         ret = sysfs_create_group(&lp->dev->kobj, &lp855x_attr_group);
 282         if (ret) {
 283                 dev_err(lp->dev, "failed to register sysfs. err: %d\n", ret);
 284                 goto err_sysfs;
 285         }
 286
 287         backlight_update_status(lp->bl);
 288         return 0;
 289
 290 err_sysfs:
 291         lp855x_backlight_unregister(lp);
 292 err_dev:
 293         return ret;
 294 }
 295
 296 static int __devexit lp855x_remove(struct i2c_client *cl)
 297 {
 298         struct lp855x *lp = i2c_get_clientdata(cl);
 299
 300         lp->bl->props.brightness = 0;
 301         backlight_update_status(lp->bl);
 302         sysfs_remove_group(&lp->dev->kobj, &lp855x_attr_group);
 303         lp855x_backlight_unregister(lp);
 304
 305         return 0;
 306 }
 307
 308 static const struct i2c_device_id lp855x_ids[] = {
 309         {"lp8550", LP8550},
 310         {"lp8551", LP8551},
 311         {"lp8552", LP8552},
 312         {"lp8553", LP8553},
 313         {"lp8556", LP8556},
 314         { }
 315 };
 316 MODULE_DEVICE_TABLE(i2c, lp855x_ids);
 317
 318 static struct i2c_driver lp855x_driver = {
 319         .driver = {
 320                    .name = "lp855x",
 321                    },
 322         .probe = lp855x_probe,
 323         .remove = __devexit_p(lp855x_remove),
 324         .id_table = lp855x_ids,
 325 };
 326
 327 module_i2c_driver(lp855x_driver);
 328
 329 MODULE_DESCRIPTION("Texas Instruments LP855x Backlight driver");
 330 MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
 331 MODULE_LICENSE("GPL");