drivers/input/touchscreen/bu21013_ts.c

   1 /*
   2  * Copyright (C) ST-Ericsson SA 2010
   3  * Author: Naveen Kumar G <naveen.gaddipati@stericsson.com> for ST-Ericsson
   4  * License terms:GNU General Public License (GPL) version 2
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/delay.h>
   9 #include <linux/interrupt.h>
  10 #include <linux/i2c.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/input.h>
  13 #include <linux/input/bu21013.h>
  14 #include <linux/slab.h>
  15 #include <linux/regulator/consumer.h>
  16 #include <linux/module.h>
  17
  18 #define PEN_DOWN_INTR   0
  19 #define MAX_FINGERS     2
  20 #define RESET_DELAY     30
  21 #define PENUP_TIMEOUT   (10)
  22 #define DELTA_MIN       16
  23 #define MASK_BITS       0x03
  24 #define SHIFT_8         8
  25 #define SHIFT_2         2
  26 #define LENGTH_OF_BUFFER        11
  27 #define I2C_RETRY_COUNT 5
  28
  29 #define BU21013_SENSORS_BTN_0_7_REG     0x70
  30 #define BU21013_SENSORS_BTN_8_15_REG    0x71
  31 #define BU21013_SENSORS_BTN_16_23_REG   0x72
  32 #define BU21013_X1_POS_MSB_REG          0x73
  33 #define BU21013_X1_POS_LSB_REG          0x74
  34 #define BU21013_Y1_POS_MSB_REG          0x75
  35 #define BU21013_Y1_POS_LSB_REG          0x76
  36 #define BU21013_X2_POS_MSB_REG          0x77
  37 #define BU21013_X2_POS_LSB_REG          0x78
  38 #define BU21013_Y2_POS_MSB_REG          0x79
  39 #define BU21013_Y2_POS_LSB_REG          0x7A
  40 #define BU21013_INT_CLR_REG             0xE8
  41 #define BU21013_INT_MODE_REG            0xE9
  42 #define BU21013_GAIN_REG                0xEA
  43 #define BU21013_OFFSET_MODE_REG         0xEB
  44 #define BU21013_XY_EDGE_REG             0xEC
  45 #define BU21013_RESET_REG               0xED
  46 #define BU21013_CALIB_REG               0xEE
  47 #define BU21013_DONE_REG                0xEF
  48 #define BU21013_SENSOR_0_7_REG          0xF0
  49 #define BU21013_SENSOR_8_15_REG         0xF1
  50 #define BU21013_SENSOR_16_23_REG        0xF2
  51 #define BU21013_POS_MODE1_REG           0xF3
  52 #define BU21013_POS_MODE2_REG           0xF4
  53 #define BU21013_CLK_MODE_REG            0xF5
  54 #define BU21013_IDLE_REG                0xFA
  55 #define BU21013_FILTER_REG              0xFB
  56 #define BU21013_TH_ON_REG               0xFC
  57 #define BU21013_TH_OFF_REG              0xFD
  58
  59
  60 #define BU21013_RESET_ENABLE            0x01
  61
  62 #define BU21013_SENSORS_EN_0_7          0x3F
  63 #define BU21013_SENSORS_EN_8_15         0xFC
  64 #define BU21013_SENSORS_EN_16_23        0x1F
  65
  66 #define BU21013_POS_MODE1_0             0x02
  67 #define BU21013_POS_MODE1_1             0x04
  68 #define BU21013_POS_MODE1_2             0x08
  69
  70 #define BU21013_POS_MODE2_ZERO          0x01
  71 #define BU21013_POS_MODE2_AVG1          0x02
  72 #define BU21013_POS_MODE2_AVG2          0x04
  73 #define BU21013_POS_MODE2_EN_XY         0x08
  74 #define BU21013_POS_MODE2_EN_RAW        0x10
  75 #define BU21013_POS_MODE2_MULTI         0x80
  76
  77 #define BU21013_CLK_MODE_DIV            0x01
  78 #define BU21013_CLK_MODE_EXT            0x02
  79 #define BU21013_CLK_MODE_CALIB          0x80
  80
  81 #define BU21013_IDLET_0                 0x01
  82 #define BU21013_IDLET_1                 0x02
  83 #define BU21013_IDLET_2                 0x04
  84 #define BU21013_IDLET_3                 0x08
  85 #define BU21013_IDLE_INTERMIT_EN        0x10
  86
  87 #define BU21013_DELTA_0_6       0x7F
  88 #define BU21013_FILTER_EN       0x80
  89
  90 #define BU21013_INT_MODE_LEVEL  0x00
  91 #define BU21013_INT_MODE_EDGE   0x01
  92
  93 #define BU21013_GAIN_0          0x01
  94 #define BU21013_GAIN_1          0x02
  95 #define BU21013_GAIN_2          0x04
  96
  97 #define BU21013_OFFSET_MODE_DEFAULT     0x00
  98 #define BU21013_OFFSET_MODE_MOVE        0x01
  99 #define BU21013_OFFSET_MODE_DISABLE     0x02
 100
 101 #define BU21013_TH_ON_0         0x01
 102 #define BU21013_TH_ON_1         0x02
 103 #define BU21013_TH_ON_2         0x04
 104 #define BU21013_TH_ON_3         0x08
 105 #define BU21013_TH_ON_4         0x10
 106 #define BU21013_TH_ON_5         0x20
 107 #define BU21013_TH_ON_6         0x40
 108 #define BU21013_TH_ON_7         0x80
 109 #define BU21013_TH_ON_MAX       0xFF
 110
 111 #define BU21013_TH_OFF_0        0x01
 112 #define BU21013_TH_OFF_1        0x02
 113 #define BU21013_TH_OFF_2        0x04
 114 #define BU21013_TH_OFF_3        0x08
 115 #define BU21013_TH_OFF_4        0x10
 116 #define BU21013_TH_OFF_5        0x20
 117 #define BU21013_TH_OFF_6        0x40
 118 #define BU21013_TH_OFF_7        0x80
 119 #define BU21013_TH_OFF_MAX      0xFF
 120
 121 #define BU21013_X_EDGE_0        0x01
 122 #define BU21013_X_EDGE_1        0x02
 123 #define BU21013_X_EDGE_2        0x04
 124 #define BU21013_X_EDGE_3        0x08
 125 #define BU21013_Y_EDGE_0        0x10
 126 #define BU21013_Y_EDGE_1        0x20
 127 #define BU21013_Y_EDGE_2        0x40
 128 #define BU21013_Y_EDGE_3        0x80
 129
 130 #define BU21013_DONE    0x01
 131 #define BU21013_NUMBER_OF_X_SENSORS     (6)
 132 #define BU21013_NUMBER_OF_Y_SENSORS     (11)
 133
 134 #define DRIVER_TP       "bu21013_tp"
 135
 136 /**
 137  * struct bu21013_ts_data - touch panel data structure
 138  * @client: pointer to the i2c client
 139  * @wait: variable to wait_queue_head_t structure
 140  * @touch_stopped: touch stop flag
 141  * @chip: pointer to the touch panel controller
 142  * @in_dev: pointer to the input device structure
 143  * @intr_pin: interrupt pin value
 144  * @regulator: pointer to the Regulator used for touch screen
 145  *
 146  * Touch panel device data structure
 147  */
 148 struct bu21013_ts_data {
 149         struct i2c_client *client;
 150         wait_queue_head_t wait;
 151         bool touch_stopped;
 152         const struct bu21013_platform_device *chip;
 153         struct input_dev *in_dev;
 154         unsigned int intr_pin;
 155         struct regulator *regulator;
 156 };
 157
 158 /**
 159  * bu21013_read_block_data(): read the touch co-ordinates
 160  * @data: bu21013_ts_data structure pointer
 161  * @buf: byte pointer
 162  *
 163  * Read the touch co-ordinates using i2c read block into buffer
 164  * and returns integer.
 165  */
 166 static int bu21013_read_block_data(struct bu21013_ts_data *data, u8 *buf)
 167 {
 168         int ret, i;
 169
 170         for (i = 0; i < I2C_RETRY_COUNT; i++) {
 171                 ret = i2c_smbus_read_i2c_block_data
 172                         (data->client, BU21013_SENSORS_BTN_0_7_REG,
 173                                 LENGTH_OF_BUFFER, buf);
 174                 if (ret == LENGTH_OF_BUFFER)
 175                         return 0;
 176         }
 177         return -EINVAL;
 178 }
 179
 180 /**
 181  * bu21013_do_touch_report(): Get the touch co-ordinates
 182  * @data: bu21013_ts_data structure pointer
 183  *
 184  * Get the touch co-ordinates from touch sensor registers and writes
 185  * into device structure and returns integer.
 186  */
 187 static int bu21013_do_touch_report(struct bu21013_ts_data *data)
 188 {
 189         u8      buf[LENGTH_OF_BUFFER];
 190         unsigned int pos_x[2], pos_y[2];
 191         bool    has_x_sensors, has_y_sensors;
 192         int     finger_down_count = 0;
 193         int     i;
 194
 195         if (data == NULL)
 196                 return -EINVAL;
 197
 198         if (bu21013_read_block_data(data, buf) < 0)
 199                 return -EINVAL;
 200
 201         has_x_sensors = hweight32(buf[0] & BU21013_SENSORS_EN_0_7);
 202         has_y_sensors = hweight32(((buf[1] & BU21013_SENSORS_EN_8_15) |
 203                 ((buf[2] & BU21013_SENSORS_EN_16_23) << SHIFT_8)) >> SHIFT_2);
 204         if (!has_x_sensors || !has_y_sensors)
 205                 return 0;
 206
 207         for (i = 0; i < MAX_FINGERS; i++) {
 208                 const u8 *p = &buf[4 * i + 3];
 209                 unsigned int x = p[0] << SHIFT_2 | (p[1] & MASK_BITS);
 210                 unsigned int y = p[2] << SHIFT_2 | (p[3] & MASK_BITS);
 211                 if (x == 0 || y == 0)
 212                         continue;
 213                 pos_x[finger_down_count] = x;
 214                 pos_y[finger_down_count] = y;
 215                 finger_down_count++;
 216         }
 217
 218         if (finger_down_count) {
 219                 if (finger_down_count == 2 &&
 220                     (abs(pos_x[0] - pos_x[1]) < DELTA_MIN ||
 221                      abs(pos_y[0] - pos_y[1]) < DELTA_MIN)) {
 222                         return 0;
 223                 }
 224
 225                 for (i = 0; i < finger_down_count; i++) {
 226                         if (data->chip->x_flip)
 227                                 pos_x[i] = data->chip->touch_x_max - pos_x[i];
 228                         if (data->chip->y_flip)
 229                                 pos_y[i] = data->chip->touch_y_max - pos_y[i];
 230
 231                         input_report_abs(data->in_dev,
 232                                          ABS_MT_POSITION_X, pos_x[i]);
 233                         input_report_abs(data->in_dev,
 234                                          ABS_MT_POSITION_Y, pos_y[i]);
 235                         input_mt_sync(data->in_dev);
 236                 }
 237         } else
 238                 input_mt_sync(data->in_dev);
 239
 240         input_sync(data->in_dev);
 241
 242         return 0;
 243 }
 244 /**
 245  * bu21013_gpio_irq() - gpio thread function for touch interrupt
 246  * @irq: irq value
 247  * @device_data: void pointer
 248  *
 249  * This gpio thread function for touch interrupt
 250  * and returns irqreturn_t.
 251  */
 252 static irqreturn_t bu21013_gpio_irq(int irq, void *device_data)
 253 {
 254         struct bu21013_ts_data *data = device_data;
 255         struct i2c_client *i2c = data->client;
 256         int retval;
 257
 258         do {
 259                 retval = bu21013_do_touch_report(data);
 260                 if (retval < 0) {
 261                         dev_err(&i2c->dev, "bu21013_do_touch_report failed\n");
 262                         return IRQ_NONE;
 263                 }
 264
 265                 data->intr_pin = data->chip->irq_read_val();
 266                 if (data->intr_pin == PEN_DOWN_INTR)
 267                         wait_event_timeout(data->wait, data->touch_stopped,
 268                                            msecs_to_jiffies(2));
 269         } while (!data->intr_pin && !data->touch_stopped);
 270
 271         return IRQ_HANDLED;
 272 }
 273
 274 /**
 275  * bu21013_init_chip() - power on sequence for the bu21013 controller
 276  * @data: device structure pointer
 277  *
 278  * This function is used to power on
 279  * the bu21013 controller and returns integer.
 280  */
 281 static int bu21013_init_chip(struct bu21013_ts_data *data)
 282 {
 283         int retval;
 284         struct i2c_client *i2c = data->client;
 285
 286         retval = i2c_smbus_write_byte_data(i2c, BU21013_RESET_REG,
 287                                         BU21013_RESET_ENABLE);
 288         if (retval < 0) {
 289                 dev_err(&i2c->dev, "BU21013_RESET reg write failed\n");
 290                 return retval;
 291         }
 292         msleep(RESET_DELAY);
 293
 294         retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_0_7_REG,
 295                                         BU21013_SENSORS_EN_0_7);
 296         if (retval < 0) {
 297                 dev_err(&i2c->dev, "BU21013_SENSOR_0_7 reg write failed\n");
 298                 return retval;
 299         }
 300
 301         retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_8_15_REG,
 302                                                 BU21013_SENSORS_EN_8_15);
 303         if (retval < 0) {
 304                 dev_err(&i2c->dev, "BU21013_SENSOR_8_15 reg write failed\n");
 305                 return retval;
 306         }
 307
 308         retval = i2c_smbus_write_byte_data(i2c, BU21013_SENSOR_16_23_REG,
 309                                                 BU21013_SENSORS_EN_16_23);
 310         if (retval < 0) {
 311                 dev_err(&i2c->dev, "BU21013_SENSOR_16_23 reg write failed\n");
 312                 return retval;
 313         }
 314
 315         retval = i2c_smbus_write_byte_data(i2c, BU21013_POS_MODE1_REG,
 316                                 (BU21013_POS_MODE1_0 | BU21013_POS_MODE1_1));
 317         if (retval < 0) {
 318                 dev_err(&i2c->dev, "BU21013_POS_MODE1 reg write failed\n");
 319                 return retval;
 320         }
 321
 322         retval = i2c_smbus_write_byte_data(i2c, BU21013_POS_MODE2_REG,
 323                         (BU21013_POS_MODE2_ZERO | BU21013_POS_MODE2_AVG1 |
 324                         BU21013_POS_MODE2_AVG2 | BU21013_POS_MODE2_EN_RAW |
 325                         BU21013_POS_MODE2_MULTI));
 326         if (retval < 0) {
 327                 dev_err(&i2c->dev, "BU21013_POS_MODE2 reg write failed\n");
 328                 return retval;
 329         }
 330
 331         if (data->chip->ext_clk)
 332                 retval = i2c_smbus_write_byte_data(i2c, BU21013_CLK_MODE_REG,
 333                         (BU21013_CLK_MODE_EXT | BU21013_CLK_MODE_CALIB));
 334         else
 335                 retval = i2c_smbus_write_byte_data(i2c, BU21013_CLK_MODE_REG,
 336                         (BU21013_CLK_MODE_DIV | BU21013_CLK_MODE_CALIB));
 337         if (retval < 0) {
 338                 dev_err(&i2c->dev, "BU21013_CLK_MODE reg write failed\n");
 339                 return retval;
 340         }
 341
 342         retval = i2c_smbus_write_byte_data(i2c, BU21013_IDLE_REG,
 343                                 (BU21013_IDLET_0 | BU21013_IDLE_INTERMIT_EN));
 344         if (retval < 0) {
 345                 dev_err(&i2c->dev, "BU21013_IDLE reg write failed\n");
 346                 return retval;
 347         }
 348
 349         retval = i2c_smbus_write_byte_data(i2c, BU21013_INT_MODE_REG,
 350                                                 BU21013_INT_MODE_LEVEL);
 351         if (retval < 0) {
 352                 dev_err(&i2c->dev, "BU21013_INT_MODE reg write failed\n");
 353                 return retval;
 354         }
 355
 356         retval = i2c_smbus_write_byte_data(i2c, BU21013_FILTER_REG,
 357                                                 (BU21013_DELTA_0_6 |
 358                                                         BU21013_FILTER_EN));
 359         if (retval < 0) {
 360                 dev_err(&i2c->dev, "BU21013_FILTER reg write failed\n");
 361                 return retval;
 362         }
 363
 364         retval = i2c_smbus_write_byte_data(i2c, BU21013_TH_ON_REG,
 365                                         BU21013_TH_ON_5);
 366         if (retval < 0) {
 367                 dev_err(&i2c->dev, "BU21013_TH_ON reg write failed\n");
 368                 return retval;
 369         }
 370
 371         retval = i2c_smbus_write_byte_data(i2c, BU21013_TH_OFF_REG,
 372                                 BU21013_TH_OFF_4 | BU21013_TH_OFF_3);
 373         if (retval < 0) {
 374                 dev_err(&i2c->dev, "BU21013_TH_OFF reg write failed\n");
 375                 return retval;
 376         }
 377
 378         retval = i2c_smbus_write_byte_data(i2c, BU21013_GAIN_REG,
 379                                         (BU21013_GAIN_0 | BU21013_GAIN_1));
 380         if (retval < 0) {
 381                 dev_err(&i2c->dev, "BU21013_GAIN reg write failed\n");
 382                 return retval;
 383         }
 384
 385         retval = i2c_smbus_write_byte_data(i2c, BU21013_OFFSET_MODE_REG,
 386                                         BU21013_OFFSET_MODE_DEFAULT);
 387         if (retval < 0) {
 388                 dev_err(&i2c->dev, "BU21013_OFFSET_MODE reg write failed\n");
 389                 return retval;
 390         }
 391
 392         retval = i2c_smbus_write_byte_data(i2c, BU21013_XY_EDGE_REG,
 393                                 (BU21013_X_EDGE_0 | BU21013_X_EDGE_2 |
 394                                 BU21013_Y_EDGE_1 | BU21013_Y_EDGE_3));
 395         if (retval < 0) {
 396                 dev_err(&i2c->dev, "BU21013_XY_EDGE reg write failed\n");
 397                 return retval;
 398         }
 399
 400         retval = i2c_smbus_write_byte_data(i2c, BU21013_DONE_REG,
 401                                                         BU21013_DONE);
 402         if (retval < 0) {
 403                 dev_err(&i2c->dev, "BU21013_REG_DONE reg write failed\n");
 404                 return retval;
 405         }
 406
 407         return 0;
 408 }
 409
 410 /**
 411  * bu21013_free_irq() - frees IRQ registered for touchscreen
 412  * @bu21013_data: device structure pointer
 413  *
 414  * This function signals interrupt thread to stop processing and
 415  * frees interrupt.
 416  */
 417 static void bu21013_free_irq(struct bu21013_ts_data *bu21013_data)
 418 {
 419         bu21013_data->touch_stopped = true;
 420         wake_up(&bu21013_data->wait);
 421         free_irq(bu21013_data->chip->irq, bu21013_data);
 422 }
 423
 424 /**
 425  * bu21013_probe() - initializes the i2c-client touchscreen driver
 426  * @client: i2c client structure pointer
 427  * @id: i2c device id pointer
 428  *
 429  * This function used to initializes the i2c-client touchscreen
 430  * driver and returns integer.
 431  */
 432 static int __devinit bu21013_probe(struct i2c_client *client,
 433                                         const struct i2c_device_id *id)
 434 {
 435         struct bu21013_ts_data *bu21013_data;
 436         struct input_dev *in_dev;
 437         const struct bu21013_platform_device *pdata =
 438                                         client->dev.platform_data;
 439         int error;
 440
 441         if (!i2c_check_functionality(client->adapter,
 442                                         I2C_FUNC_SMBUS_BYTE_DATA)) {
 443                 dev_err(&client->dev, "i2c smbus byte data not supported\n");
 444                 return -EIO;
 445         }
 446
 447         if (!pdata) {
 448                 dev_err(&client->dev, "platform data not defined\n");
 449                 return -EINVAL;
 450         }
 451
 452         bu21013_data = kzalloc(sizeof(struct bu21013_ts_data), GFP_KERNEL);
 453         in_dev = input_allocate_device();
 454         if (!bu21013_data || !in_dev) {
 455                 dev_err(&client->dev, "device memory alloc failed\n");
 456                 error = -ENOMEM;
 457                 goto err_free_mem;
 458         }
 459
 460         bu21013_data->in_dev = in_dev;
 461         bu21013_data->chip = pdata;
 462         bu21013_data->client = client;
 463
 464         bu21013_data->regulator = regulator_get(&client->dev, "V-TOUCH");
 465         if (IS_ERR(bu21013_data->regulator)) {
 466                 dev_err(&client->dev, "regulator_get failed\n");
 467                 error = PTR_ERR(bu21013_data->regulator);
 468                 goto err_free_mem;
 469         }
 470
 471         error = regulator_enable(bu21013_data->regulator);
 472         if (error < 0) {
 473                 dev_err(&client->dev, "regulator enable failed\n");
 474                 goto err_put_regulator;
 475         }
 476
 477         bu21013_data->touch_stopped = false;
 478         init_waitqueue_head(&bu21013_data->wait);
 479
 480         /* configure the gpio pins */
 481         if (pdata->cs_en) {
 482                 error = pdata->cs_en(pdata->cs_pin);
 483                 if (error < 0) {
 484                         dev_err(&client->dev, "chip init failed\n");
 485                         goto err_disable_regulator;
 486                 }
 487         }
 488
 489         /* configure the touch panel controller */
 490         error = bu21013_init_chip(bu21013_data);
 491         if (error) {
 492                 dev_err(&client->dev, "error in bu21013 config\n");
 493                 goto err_cs_disable;
 494         }
 495
 496         /* register the device to input subsystem */
 497         in_dev->name = DRIVER_TP;
 498         in_dev->id.bustype = BUS_I2C;
 499         in_dev->dev.parent = &client->dev;
 500
 501         __set_bit(EV_SYN, in_dev->evbit);
 502         __set_bit(EV_KEY, in_dev->evbit);
 503         __set_bit(EV_ABS, in_dev->evbit);
 504
 505         input_set_abs_params(in_dev, ABS_MT_POSITION_X, 0,
 506                                                 pdata->touch_x_max, 0, 0);
 507         input_set_abs_params(in_dev, ABS_MT_POSITION_Y, 0,
 508                                                 pdata->touch_y_max, 0, 0);
 509         input_set_drvdata(in_dev, bu21013_data);
 510
 511         error = request_threaded_irq(pdata->irq, NULL, bu21013_gpio_irq,
 512                                      IRQF_TRIGGER_FALLING | IRQF_SHARED,
 513                                      DRIVER_TP, bu21013_data);
 514         if (error) {
 515                 dev_err(&client->dev, "request irq %d failed\n", pdata->irq);
 516                 goto err_cs_disable;
 517         }
 518
 519         error = input_register_device(in_dev);
 520         if (error) {
 521                 dev_err(&client->dev, "failed to register input device\n");
 522                 goto err_free_irq;
 523         }
 524
 525         device_init_wakeup(&client->dev, pdata->wakeup);
 526         i2c_set_clientdata(client, bu21013_data);
 527
 528         return 0;
 529
 530 err_free_irq:
 531         bu21013_free_irq(bu21013_data);
 532 err_cs_disable:
 533         pdata->cs_dis(pdata->cs_pin);
 534 err_disable_regulator:
 535         regulator_disable(bu21013_data->regulator);
 536 err_put_regulator:
 537         regulator_put(bu21013_data->regulator);
 538 err_free_mem:
 539         input_free_device(in_dev);
 540         kfree(bu21013_data);
 541
 542         return error;
 543 }
 544 /**
 545  * bu21013_remove() - removes the i2c-client touchscreen driver
 546  * @client: i2c client structure pointer
 547  *
 548  * This function uses to remove the i2c-client
 549  * touchscreen driver and returns integer.
 550  */
 551 static int __devexit bu21013_remove(struct i2c_client *client)
 552 {
 553         struct bu21013_ts_data *bu21013_data = i2c_get_clientdata(client);
 554
 555         bu21013_free_irq(bu21013_data);
 556
 557         bu21013_data->chip->cs_dis(bu21013_data->chip->cs_pin);
 558
 559         input_unregister_device(bu21013_data->in_dev);
 560
 561         regulator_disable(bu21013_data->regulator);
 562         regulator_put(bu21013_data->regulator);
 563
 564         kfree(bu21013_data);
 565
 566         device_init_wakeup(&client->dev, false);
 567
 568         return 0;
 569 }
 570
 571 #ifdef CONFIG_PM
 572 /**
 573  * bu21013_suspend() - suspend the touch screen controller
 574  * @dev: pointer to device structure
 575  *
 576  * This function is used to suspend the
 577  * touch panel controller and returns integer
 578  */
 579 static int bu21013_suspend(struct device *dev)
 580 {
 581         struct bu21013_ts_data *bu21013_data = dev_get_drvdata(dev);
 582         struct i2c_client *client = bu21013_data->client;
 583
 584         bu21013_data->touch_stopped = true;
 585         if (device_may_wakeup(&client->dev))
 586                 enable_irq_wake(bu21013_data->chip->irq);
 587         else
 588                 disable_irq(bu21013_data->chip->irq);
 589
 590         regulator_disable(bu21013_data->regulator);
 591
 592         return 0;
 593 }
 594
 595 /**
 596  * bu21013_resume() - resume the touch screen controller
 597  * @dev: pointer to device structure
 598  *
 599  * This function is used to resume the touch panel
 600  * controller and returns integer.
 601  */
 602 static int bu21013_resume(struct device *dev)
 603 {
 604         struct bu21013_ts_data *bu21013_data = dev_get_drvdata(dev);
 605         struct i2c_client *client = bu21013_data->client;
 606         int retval;
 607
 608         retval = regulator_enable(bu21013_data->regulator);
 609         if (retval < 0) {
 610                 dev_err(&client->dev, "bu21013 regulator enable failed\n");
 611                 return retval;
 612         }
 613
 614         retval = bu21013_init_chip(bu21013_data);
 615         if (retval < 0) {
 616                 dev_err(&client->dev, "bu21013 controller config failed\n");
 617                 return retval;
 618         }
 619
 620         bu21013_data->touch_stopped = false;
 621
 622         if (device_may_wakeup(&client->dev))
 623                 disable_irq_wake(bu21013_data->chip->irq);
 624         else
 625                 enable_irq(bu21013_data->chip->irq);
 626
 627         return 0;
 628 }
 629
 630 static const struct dev_pm_ops bu21013_dev_pm_ops = {
 631         .suspend = bu21013_suspend,
 632         .resume  = bu21013_resume,
 633 };
 634 #endif
 635
 636 static const struct i2c_device_id bu21013_id[] = {
 637         { DRIVER_TP, 0 },
 638         { }
 639 };
 640 MODULE_DEVICE_TABLE(i2c, bu21013_id);
 641
 642 static struct i2c_driver bu21013_driver = {
 643         .driver = {
 644                 .name   =       DRIVER_TP,
 645                 .owner  =       THIS_MODULE,
 646 #ifdef CONFIG_PM
 647                 .pm     =       &bu21013_dev_pm_ops,
 648 #endif
 649         },
 650         .probe          =       bu21013_probe,
 651         .remove         =       __devexit_p(bu21013_remove),
 652         .id_table       =       bu21013_id,
 653 };
 654
 655 /**
 656  * bu21013_init() - initializes the bu21013 touchscreen driver
 657  *
 658  * This function used to initializes the bu21013
 659  * touchscreen driver and returns integer.
 660  */
 661 static int __init bu21013_init(void)
 662 {
 663         return i2c_add_driver(&bu21013_driver);
 664 }
 665
 666 /**
 667  * bu21013_exit() - de-initializes the bu21013 touchscreen driver
 668  *
 669  * This function uses to de-initializes the bu21013
 670  * touchscreen driver and returns none.
 671  */
 672 static void __exit bu21013_exit(void)
 673 {
 674         i2c_del_driver(&bu21013_driver);
 675 }
 676
 677 module_init(bu21013_init);
 678 module_exit(bu21013_exit);
 679
 680 MODULE_LICENSE("GPL v2");
 681 MODULE_AUTHOR("Naveen Kumar G <naveen.gaddipati@stericsson.com>");
 682 MODULE_DESCRIPTION("bu21013 touch screen controller driver");