drivers/misc/tsl2550.c

   1 /*
   2  *  tsl2550.c - Linux kernel modules for ambient light sensor
   3  *
   4  *  Copyright (C) 2007 Rodolfo Giometti <giometti@linux.it>
   5  *  Copyright (C) 2007 Eurotech S.p.A. <info@eurotech.it>
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/slab.h>
  24 #include <linux/i2c.h>
  25 #include <linux/mutex.h>
  26
  27 #define TSL2550_DRV_NAME        "tsl2550"
  28 #define DRIVER_VERSION          "1.2"
  29
  30 /*
  31  * Defines
  32  */
  33
  34 #define TSL2550_POWER_DOWN              0x00
  35 #define TSL2550_POWER_UP                0x03
  36 #define TSL2550_STANDARD_RANGE          0x18
  37 #define TSL2550_EXTENDED_RANGE          0x1d
  38 #define TSL2550_READ_ADC0               0x43
  39 #define TSL2550_READ_ADC1               0x83
  40
  41 /*
  42  * Structs
  43  */
  44
  45 struct tsl2550_data {
  46         struct i2c_client *client;
  47         struct mutex update_lock;
  48
  49         unsigned int power_state:1;
  50         unsigned int operating_mode:1;
  51 };
  52
  53 /*
  54  * Global data
  55  */
  56
  57 static const u8 TSL2550_MODE_RANGE[2] = {
  58         TSL2550_STANDARD_RANGE, TSL2550_EXTENDED_RANGE,
  59 };
  60
  61 /*
  62  * Management functions
  63  */
  64
  65 static int tsl2550_set_operating_mode(struct i2c_client *client, int mode)
  66 {
  67         struct tsl2550_data *data = i2c_get_clientdata(client);
  68
  69         int ret = i2c_smbus_write_byte(client, TSL2550_MODE_RANGE[mode]);
  70
  71         data->operating_mode = mode;
  72
  73         return ret;
  74 }
  75
  76 static int tsl2550_set_power_state(struct i2c_client *client, int state)
  77 {
  78         struct tsl2550_data *data = i2c_get_clientdata(client);
  79         int ret;
  80
  81         if (state == 0)
  82                 ret = i2c_smbus_write_byte(client, TSL2550_POWER_DOWN);
  83         else {
  84                 ret = i2c_smbus_write_byte(client, TSL2550_POWER_UP);
  85
  86                 /* On power up we should reset operating mode also... */
  87                 tsl2550_set_operating_mode(client, data->operating_mode);
  88         }
  89
  90         data->power_state = state;
  91
  92         return ret;
  93 }
  94
  95 static int tsl2550_get_adc_value(struct i2c_client *client, u8 cmd)
  96 {
  97         int ret;
  98
  99         ret = i2c_smbus_read_byte_data(client, cmd);
 100         if (ret < 0)
 101                 return ret;
 102         if (!(ret & 0x80))
 103                 return -EAGAIN;
 104         return ret & 0x7f;      /* remove the "valid" bit */
 105 }
 106
 107 /*
 108  * LUX calculation
 109  */
 110
 111 #define TSL2550_MAX_LUX         1846
 112
 113 static const u8 ratio_lut[] = {
 114         100, 100, 100, 100, 100, 100, 100, 100,
 115         100, 100, 100, 100, 100, 100, 99, 99,
 116         99, 99, 99, 99, 99, 99, 99, 99,
 117         99, 99, 99, 98, 98, 98, 98, 98,
 118         98, 98, 97, 97, 97, 97, 97, 96,
 119         96, 96, 96, 95, 95, 95, 94, 94,
 120         93, 93, 93, 92, 92, 91, 91, 90,
 121         89, 89, 88, 87, 87, 86, 85, 84,
 122         83, 82, 81, 80, 79, 78, 77, 75,
 123         74, 73, 71, 69, 68, 66, 64, 62,
 124         60, 58, 56, 54, 52, 49, 47, 44,
 125         42, 41, 40, 40, 39, 39, 38, 38,
 126         37, 37, 37, 36, 36, 36, 35, 35,
 127         35, 35, 34, 34, 34, 34, 33, 33,
 128         33, 33, 32, 32, 32, 32, 32, 31,
 129         31, 31, 31, 31, 30, 30, 30, 30,
 130         30,
 131 };
 132
 133 static const u16 count_lut[] = {
 134         0, 1, 2, 3, 4, 5, 6, 7,
 135         8, 9, 10, 11, 12, 13, 14, 15,
 136         16, 18, 20, 22, 24, 26, 28, 30,
 137         32, 34, 36, 38, 40, 42, 44, 46,
 138         49, 53, 57, 61, 65, 69, 73, 77,
 139         81, 85, 89, 93, 97, 101, 105, 109,
 140         115, 123, 131, 139, 147, 155, 163, 171,
 141         179, 187, 195, 203, 211, 219, 227, 235,
 142         247, 263, 279, 295, 311, 327, 343, 359,
 143         375, 391, 407, 423, 439, 455, 471, 487,
 144         511, 543, 575, 607, 639, 671, 703, 735,
 145         767, 799, 831, 863, 895, 927, 959, 991,
 146         1039, 1103, 1167, 1231, 1295, 1359, 1423, 1487,
 147         1551, 1615, 1679, 1743, 1807, 1871, 1935, 1999,
 148         2095, 2223, 2351, 2479, 2607, 2735, 2863, 2991,
 149         3119, 3247, 3375, 3503, 3631, 3759, 3887, 4015,
 150 };
 151
 152 /*
 153  * This function is described into Taos TSL2550 Designer's Notebook
 154  * pages 2, 3.
 155  */
 156 static int tsl2550_calculate_lux(u8 ch0, u8 ch1)
 157 {
 158         unsigned int lux;
 159
 160         /* Look up count from channel values */
 161         u16 c0 = count_lut[ch0];
 162         u16 c1 = count_lut[ch1];
 163
 164         /*
 165          * Calculate ratio.
 166          * Note: the "128" is a scaling factor
 167          */
 168         u8 r = 128;
 169
 170         /* Avoid division by 0 and count 1 cannot be greater than count 0 */
 171         if (c1 <= c0)
 172                 if (c0) {
 173                         r = c1 * 128 / c0;
 174
 175                         /* Calculate LUX */
 176                         lux = ((c0 - c1) * ratio_lut[r]) / 256;
 177                 } else
 178                         lux = 0;
 179         else
 180                 return -EAGAIN;
 181
 182         /* LUX range check */
 183         return lux > TSL2550_MAX_LUX ? TSL2550_MAX_LUX : lux;
 184 }
 185
 186 /*
 187  * SysFS support
 188  */
 189
 190 static ssize_t tsl2550_show_power_state(struct device *dev,
 191                 struct device_attribute *attr, char *buf)
 192 {
 193         struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
 194
 195         return sprintf(buf, "%u\n", data->power_state);
 196 }
 197
 198 static ssize_t tsl2550_store_power_state(struct device *dev,
 199                 struct device_attribute *attr, const char *buf, size_t count)
 200 {
 201         struct i2c_client *client = to_i2c_client(dev);
 202         struct tsl2550_data *data = i2c_get_clientdata(client);
 203         unsigned long val = simple_strtoul(buf, NULL, 10);
 204         int ret;
 205
 206         if (val > 1)
 207                 return -EINVAL;
 208
 209         mutex_lock(&data->update_lock);
 210         ret = tsl2550_set_power_state(client, val);
 211         mutex_unlock(&data->update_lock);
 212
 213         if (ret < 0)
 214                 return ret;
 215
 216         return count;
 217 }
 218
 219 static DEVICE_ATTR(power_state, S_IWUSR | S_IRUGO,
 220                    tsl2550_show_power_state, tsl2550_store_power_state);
 221
 222 static ssize_t tsl2550_show_operating_mode(struct device *dev,
 223                 struct device_attribute *attr, char *buf)
 224 {
 225         struct tsl2550_data *data = i2c_get_clientdata(to_i2c_client(dev));
 226
 227         return sprintf(buf, "%u\n", data->operating_mode);
 228 }
 229
 230 static ssize_t tsl2550_store_operating_mode(struct device *dev,
 231                 struct device_attribute *attr, const char *buf, size_t count)
 232 {
 233         struct i2c_client *client = to_i2c_client(dev);
 234         struct tsl2550_data *data = i2c_get_clientdata(client);
 235         unsigned long val = simple_strtoul(buf, NULL, 10);
 236         int ret;
 237
 238         if (val > 1)
 239                 return -EINVAL;
 240
 241         if (data->power_state == 0)
 242                 return -EBUSY;
 243
 244         mutex_lock(&data->update_lock);
 245         ret = tsl2550_set_operating_mode(client, val);
 246         mutex_unlock(&data->update_lock);
 247
 248         if (ret < 0)
 249                 return ret;
 250
 251         return count;
 252 }
 253
 254 static DEVICE_ATTR(operating_mode, S_IWUSR | S_IRUGO,
 255                    tsl2550_show_operating_mode, tsl2550_store_operating_mode);
 256
 257 static ssize_t __tsl2550_show_lux(struct i2c_client *client, char *buf)
 258 {
 259         struct tsl2550_data *data = i2c_get_clientdata(client);
 260         u8 ch0, ch1;
 261         int ret;
 262
 263         ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC0);
 264         if (ret < 0)
 265                 return ret;
 266         ch0 = ret;
 267
 268         ret = tsl2550_get_adc_value(client, TSL2550_READ_ADC1);
 269         if (ret < 0)
 270                 return ret;
 271         ch1 = ret;
 272
 273         /* Do the job */
 274         ret = tsl2550_calculate_lux(ch0, ch1);
 275         if (ret < 0)
 276                 return ret;
 277         if (data->operating_mode == 1)
 278                 ret *= 5;
 279
 280         return sprintf(buf, "%d\n", ret);
 281 }
 282
 283 static ssize_t tsl2550_show_lux1_input(struct device *dev,
 284                         struct device_attribute *attr, char *buf)
 285 {
 286         struct i2c_client *client = to_i2c_client(dev);
 287         struct tsl2550_data *data = i2c_get_clientdata(client);
 288         int ret;
 289
 290         /* No LUX data if not operational */
 291         if (!data->power_state)
 292                 return -EBUSY;
 293
 294         mutex_lock(&data->update_lock);
 295         ret = __tsl2550_show_lux(client, buf);
 296         mutex_unlock(&data->update_lock);
 297
 298         return ret;
 299 }
 300
 301 static DEVICE_ATTR(lux1_input, S_IRUGO,
 302                    tsl2550_show_lux1_input, NULL);
 303
 304 static struct attribute *tsl2550_attributes[] = {
 305         &dev_attr_power_state.attr,
 306         &dev_attr_operating_mode.attr,
 307         &dev_attr_lux1_input.attr,
 308         NULL
 309 };
 310
 311 static const struct attribute_group tsl2550_attr_group = {
 312         .attrs = tsl2550_attributes,
 313 };
 314
 315 /*
 316  * Initialization function
 317  */
 318
 319 static int tsl2550_init_client(struct i2c_client *client)
 320 {
 321         struct tsl2550_data *data = i2c_get_clientdata(client);
 322         int err;
 323
 324         /*
 325          * Probe the chip. To do so we try to power up the device and then to
 326          * read back the 0x03 code
 327          */
 328         err = i2c_smbus_read_byte_data(client, TSL2550_POWER_UP);
 329         if (err < 0)
 330                 return err;
 331         if (err != TSL2550_POWER_UP)
 332                 return -ENODEV;
 333         data->power_state = 1;
 334
 335         /* Set the default operating mode */
 336         err = i2c_smbus_write_byte(client,
 337                                    TSL2550_MODE_RANGE[data->operating_mode]);
 338         if (err < 0)
 339                 return err;
 340
 341         return 0;
 342 }
 343
 344 /*
 345  * I2C init/probing/exit functions
 346  */
 347
 348 static struct i2c_driver tsl2550_driver;
 349 static int tsl2550_probe(struct i2c_client *client,
 350                                    const struct i2c_device_id *id)
 351 {
 352         struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
 353         struct tsl2550_data *data;
 354         int *opmode, err = 0;
 355
 356         if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WRITE_BYTE
 357                                             | I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
 358                 err = -EIO;
 359                 goto exit;
 360         }
 361
 362         data = kzalloc(sizeof(struct tsl2550_data), GFP_KERNEL);
 363         if (!data) {
 364                 err = -ENOMEM;
 365                 goto exit;
 366         }
 367         data->client = client;
 368         i2c_set_clientdata(client, data);
 369
 370         /* Check platform data */
 371         opmode = client->dev.platform_data;
 372         if (opmode) {
 373                 if (*opmode < 0 || *opmode > 1) {
 374                         dev_err(&client->dev, "invalid operating_mode (%d)\n",
 375                                         *opmode);
 376                         err = -EINVAL;
 377                         goto exit_kfree;
 378                 }
 379                 data->operating_mode = *opmode;
 380         } else
 381                 data->operating_mode = 0;       /* default mode is standard */
 382         dev_info(&client->dev, "%s operating mode\n",
 383                         data->operating_mode ? "extended" : "standard");
 384
 385         mutex_init(&data->update_lock);
 386
 387         /* Initialize the TSL2550 chip */
 388         err = tsl2550_init_client(client);
 389         if (err)
 390                 goto exit_kfree;
 391
 392         /* Register sysfs hooks */
 393         err = sysfs_create_group(&client->dev.kobj, &tsl2550_attr_group);
 394         if (err)
 395                 goto exit_kfree;
 396
 397         dev_info(&client->dev, "support ver. %s enabled\n", DRIVER_VERSION);
 398
 399         return 0;
 400
 401 exit_kfree:
 402         kfree(data);
 403 exit:
 404         return err;
 405 }
 406
 407 static int tsl2550_remove(struct i2c_client *client)
 408 {
 409         sysfs_remove_group(&client->dev.kobj, &tsl2550_attr_group);
 410
 411         /* Power down the device */
 412         tsl2550_set_power_state(client, 0);
 413
 414         kfree(i2c_get_clientdata(client));
 415
 416         return 0;
 417 }
 418
 419 #ifdef CONFIG_PM_SLEEP
 420
 421 static int tsl2550_suspend(struct device *dev)
 422 {
 423         return tsl2550_set_power_state(to_i2c_client(dev), 0);
 424 }
 425
 426 static int tsl2550_resume(struct device *dev)
 427 {
 428         return tsl2550_set_power_state(to_i2c_client(dev), 1);
 429 }
 430
 431 static SIMPLE_DEV_PM_OPS(tsl2550_pm_ops, tsl2550_suspend, tsl2550_resume);
 432 #define TSL2550_PM_OPS (&tsl2550_pm_ops)
 433
 434 #else
 435
 436 #define TSL2550_PM_OPS NULL
 437
 438 #endif /* CONFIG_PM_SLEEP */
 439
 440 static const struct i2c_device_id tsl2550_id[] = {
 441         { "tsl2550", 0 },
 442         { }
 443 };
 444 MODULE_DEVICE_TABLE(i2c, tsl2550_id);
 445
 446 static struct i2c_driver tsl2550_driver = {
 447         .driver = {
 448                 .name   = TSL2550_DRV_NAME,
 449                 .pm     = TSL2550_PM_OPS,
 450         },
 451         .probe  = tsl2550_probe,
 452         .remove = tsl2550_remove,
 453         .id_table = tsl2550_id,
 454 };
 455
 456 module_i2c_driver(tsl2550_driver);
 457
 458 MODULE_AUTHOR("Rodolfo Giometti <giometti@linux.it>");
 459 MODULE_DESCRIPTION("TSL2550 ambient light sensor driver");
 460 MODULE_LICENSE("GPL");
 461 MODULE_VERSION(DRIVER_VERSION);