drivers/input/touchscreen/tsc2007.c

   1 /*
   2  * drivers/input/touchscreen/tsc2007.c
   3  *
   4  * Copyright (c) 2008 MtekVision Co., Ltd.
   5  *      Kwangwoo Lee <kwlee@mtekvision.com>
   6  *
   7  * Using code from:
   8  *  - ads7846.c
   9  *      Copyright (c) 2005 David Brownell
  10  *      Copyright (c) 2006 Nokia Corporation
  11  *  - corgi_ts.c
  12  *      Copyright (C) 2004-2005 Richard Purdie
  13  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  14  *      Copyright (C) 2002 MontaVista Software
  15  *      Copyright (C) 2004 Texas Instruments
  16  *      Copyright (C) 2005 Dirk Behme
  17  *
  18  *  This program is free software; you can redistribute it and/or modify
  19  *  it under the terms of the GNU General Public License version 2 as
  20  *  published by the Free Software Foundation.
  21  */
  22
  23 #include <linux/module.h>
  24 #include <linux/slab.h>
  25 #include <linux/input.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/i2c.h>
  28 #include <linux/i2c/tsc2007.h>
  29
  30 #define TS_POLL_DELAY                   1 /* ms delay between samples */
  31 #define TS_POLL_PERIOD                  1 /* ms delay between samples */
  32
  33 #define TSC2007_MEASURE_TEMP0           (0x0 << 4)
  34 #define TSC2007_MEASURE_AUX             (0x2 << 4)
  35 #define TSC2007_MEASURE_TEMP1           (0x4 << 4)
  36 #define TSC2007_ACTIVATE_XN             (0x8 << 4)
  37 #define TSC2007_ACTIVATE_YN             (0x9 << 4)
  38 #define TSC2007_ACTIVATE_YP_XN          (0xa << 4)
  39 #define TSC2007_SETUP                   (0xb << 4)
  40 #define TSC2007_MEASURE_X               (0xc << 4)
  41 #define TSC2007_MEASURE_Y               (0xd << 4)
  42 #define TSC2007_MEASURE_Z1              (0xe << 4)
  43 #define TSC2007_MEASURE_Z2              (0xf << 4)
  44
  45 #define TSC2007_POWER_OFF_IRQ_EN        (0x0 << 2)
  46 #define TSC2007_ADC_ON_IRQ_DIS0         (0x1 << 2)
  47 #define TSC2007_ADC_OFF_IRQ_EN          (0x2 << 2)
  48 #define TSC2007_ADC_ON_IRQ_DIS1         (0x3 << 2)
  49
  50 #define TSC2007_12BIT                   (0x0 << 1)
  51 #define TSC2007_8BIT                    (0x1 << 1)
  52
  53 #define MAX_12BIT                       ((1 << 12) - 1)
  54
  55 #define ADC_ON_12BIT    (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
  56
  57 #define READ_Y          (ADC_ON_12BIT | TSC2007_MEASURE_Y)
  58 #define READ_Z1         (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
  59 #define READ_Z2         (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
  60 #define READ_X          (ADC_ON_12BIT | TSC2007_MEASURE_X)
  61 #define PWRDOWN         (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
  62
  63 struct ts_event {
  64         u16     x;
  65         u16     y;
  66         u16     z1, z2;
  67 };
  68
  69 struct tsc2007 {
  70         struct input_dev        *input;
  71         char                    phys[32];
  72         struct delayed_work     work;
  73
  74         struct i2c_client       *client;
  75
  76         u16                     model;
  77         u16                     x_plate_ohms;
  78
  79         bool                    pendown;
  80         int                     irq;
  81
  82         int                     (*get_pendown_state)(void);
  83         void                    (*clear_penirq)(void);
  84 };
  85
  86 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  87 {
  88         s32 data;
  89         u16 val;
  90
  91         data = i2c_smbus_read_word_data(tsc->client, cmd);
  92         if (data < 0) {
  93                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
  94                 return data;
  95         }
  96
  97         /* The protocol and raw data format from i2c interface:
  98          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
  99          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
 100          */
 101         val = swab16(data) >> 4;
 102
 103         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
 104
 105         return val;
 106 }
 107
 108 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
 109 {
 110         /* y- still on; turn on only y+ (and ADC) */
 111         tc->y = tsc2007_xfer(tsc, READ_Y);
 112
 113         /* turn y- off, x+ on, then leave in lowpower */
 114         tc->x = tsc2007_xfer(tsc, READ_X);
 115
 116         /* turn y+ off, x- on; we'll use formula #1 */
 117         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
 118         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
 119
 120         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
 121         tsc2007_xfer(tsc, PWRDOWN);
 122 }
 123
 124 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
 125 {
 126         u32 rt = 0;
 127
 128         /* range filtering */
 129         if (tc->x == MAX_12BIT)
 130                 tc->x = 0;
 131
 132         if (likely(tc->x && tc->z1)) {
 133                 /* compute touch pressure resistance using equation #1 */
 134                 rt = tc->z2 - tc->z1;
 135                 rt *= tc->x;
 136                 rt *= tsc->x_plate_ohms;
 137                 rt /= tc->z1;
 138                 rt = (rt + 2047) >> 12;
 139         }
 140
 141         return rt;
 142 }
 143
 144 static void tsc2007_send_up_event(struct tsc2007 *tsc)
 145 {
 146         struct input_dev *input = tsc->input;
 147
 148         dev_dbg(&tsc->client->dev, "UP\n");
 149
 150         input_report_key(input, BTN_TOUCH, 0);
 151         input_report_abs(input, ABS_PRESSURE, 0);
 152         input_sync(input);
 153 }
 154
 155 static void tsc2007_work(struct work_struct *work)
 156 {
 157         struct tsc2007 *ts =
 158                 container_of(to_delayed_work(work), struct tsc2007, work);
 159         struct ts_event tc;
 160         u32 rt;
 161
 162         /*
 163          * NOTE: We can't rely on the pressure to determine the pen down
 164          * state, even though this controller has a pressure sensor.
 165          * The pressure value can fluctuate for quite a while after
 166          * lifting the pen and in some cases may not even settle at the
 167          * expected value.
 168          *
 169          * The only safe way to check for the pen up condition is in the
 170          * work function by reading the pen signal state (it's a GPIO
 171          * and IRQ). Unfortunately such callback is not always available,
 172          * in that case we have rely on the pressure anyway.
 173          */
 174         if (ts->get_pendown_state) {
 175                 if (unlikely(!ts->get_pendown_state())) {
 176                         tsc2007_send_up_event(ts);
 177                         ts->pendown = false;
 178                         goto out;
 179                 }
 180
 181                 dev_dbg(&ts->client->dev, "pen is still down\n");
 182         }
 183
 184         tsc2007_read_values(ts, &tc);
 185
 186         rt = tsc2007_calculate_pressure(ts, &tc);
 187         if (rt > MAX_12BIT) {
 188                 /*
 189                  * Sample found inconsistent by debouncing or pressure is
 190                  * beyond the maximum. Don't report it to user space,
 191                  * repeat at least once more the measurement.
 192                  */
 193                 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 194                 goto out;
 195
 196         }
 197
 198         if (rt) {
 199                 struct input_dev *input = ts->input;
 200
 201                 if (!ts->pendown) {
 202                         dev_dbg(&ts->client->dev, "DOWN\n");
 203
 204                         input_report_key(input, BTN_TOUCH, 1);
 205                         ts->pendown = true;
 206                 }
 207
 208                 input_report_abs(input, ABS_X, tc.x);
 209                 input_report_abs(input, ABS_Y, tc.y);
 210                 input_report_abs(input, ABS_PRESSURE, rt);
 211
 212                 input_sync(input);
 213
 214                 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
 215                         tc.x, tc.y, rt);
 216
 217         } else if (!ts->get_pendown_state && ts->pendown) {
 218                 /*
 219                  * We don't have callback to check pendown state, so we
 220                  * have to assume that since pressure reported is 0 the
 221                  * pen was lifted up.
 222                  */
 223                 tsc2007_send_up_event(ts);
 224                 ts->pendown = false;
 225         }
 226
 227  out:
 228         if (ts->pendown)
 229                 schedule_delayed_work(&ts->work,
 230                                       msecs_to_jiffies(TS_POLL_PERIOD));
 231         else
 232                 enable_irq(ts->irq);
 233 }
 234
 235 static irqreturn_t tsc2007_irq(int irq, void *handle)
 236 {
 237         struct tsc2007 *ts = handle;
 238
 239         if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
 240                 disable_irq_nosync(ts->irq);
 241                 schedule_delayed_work(&ts->work,
 242                                       msecs_to_jiffies(TS_POLL_DELAY));
 243         }
 244
 245         if (ts->clear_penirq)
 246                 ts->clear_penirq();
 247
 248         return IRQ_HANDLED;
 249 }
 250
 251 static void tsc2007_free_irq(struct tsc2007 *ts)
 252 {
 253         free_irq(ts->irq, ts);
 254         if (cancel_delayed_work_sync(&ts->work)) {
 255                 /*
 256                  * Work was pending, therefore we need to enable
 257                  * IRQ here to balance the disable_irq() done in the
 258                  * interrupt handler.
 259                  */
 260                 enable_irq(ts->irq);
 261         }
 262 }
 263
 264 static int __devinit tsc2007_probe(struct i2c_client *client,
 265                                    const struct i2c_device_id *id)
 266 {
 267         struct tsc2007 *ts;
 268         struct tsc2007_platform_data *pdata = client->dev.platform_data;
 269         struct input_dev *input_dev;
 270         int err;
 271
 272         if (!pdata) {
 273                 dev_err(&client->dev, "platform data is required!\n");
 274                 return -EINVAL;
 275         }
 276
 277         if (!i2c_check_functionality(client->adapter,
 278                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 279                 return -EIO;
 280
 281         ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
 282         input_dev = input_allocate_device();
 283         if (!ts || !input_dev) {
 284                 err = -ENOMEM;
 285                 goto err_free_mem;
 286         }
 287
 288         ts->client = client;
 289         ts->irq = client->irq;
 290         ts->input = input_dev;
 291         INIT_DELAYED_WORK(&ts->work, tsc2007_work);
 292
 293         ts->model             = pdata->model;
 294         ts->x_plate_ohms      = pdata->x_plate_ohms;
 295         ts->get_pendown_state = pdata->get_pendown_state;
 296         ts->clear_penirq      = pdata->clear_penirq;
 297
 298         snprintf(ts->phys, sizeof(ts->phys),
 299                  "%s/input0", dev_name(&client->dev));
 300
 301         input_dev->name = "TSC2007 Touchscreen";
 302         input_dev->phys = ts->phys;
 303         input_dev->id.bustype = BUS_I2C;
 304
 305         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 306         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 307
 308         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 309         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 310         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 311
 312         if (pdata->init_platform_hw)
 313                 pdata->init_platform_hw();
 314
 315         err = request_irq(ts->irq, tsc2007_irq, 0,
 316                         client->dev.driver->name, ts);
 317         if (err < 0) {
 318                 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
 319                 goto err_free_mem;
 320         }
 321
 322         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 323         err = tsc2007_xfer(ts, PWRDOWN);
 324         if (err < 0)
 325                 goto err_free_irq;
 326
 327         err = input_register_device(input_dev);
 328         if (err)
 329                 goto err_free_irq;
 330
 331         i2c_set_clientdata(client, ts);
 332
 333         return 0;
 334
 335  err_free_irq:
 336         tsc2007_free_irq(ts);
 337         if (pdata->exit_platform_hw)
 338                 pdata->exit_platform_hw();
 339  err_free_mem:
 340         input_free_device(input_dev);
 341         kfree(ts);
 342         return err;
 343 }
 344
 345 static int __devexit tsc2007_remove(struct i2c_client *client)
 346 {
 347         struct tsc2007  *ts = i2c_get_clientdata(client);
 348         struct tsc2007_platform_data *pdata = client->dev.platform_data;
 349
 350         tsc2007_free_irq(ts);
 351
 352         if (pdata->exit_platform_hw)
 353                 pdata->exit_platform_hw();
 354
 355         input_unregister_device(ts->input);
 356         kfree(ts);
 357
 358         return 0;
 359 }
 360
 361 static const struct i2c_device_id tsc2007_idtable[] = {
 362         { "tsc2007", 0 },
 363         { }
 364 };
 365
 366 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 367
 368 static struct i2c_driver tsc2007_driver = {
 369         .driver = {
 370                 .owner  = THIS_MODULE,
 371                 .name   = "tsc2007"
 372         },
 373         .id_table       = tsc2007_idtable,
 374         .probe          = tsc2007_probe,
 375         .remove         = __devexit_p(tsc2007_remove),
 376 };
 377
 378 static int __init tsc2007_init(void)
 379 {
 380         return i2c_add_driver(&tsc2007_driver);
 381 }
 382
 383 static void __exit tsc2007_exit(void)
 384 {
 385         i2c_del_driver(&tsc2007_driver);
 386 }
 387
 388 module_init(tsc2007_init);
 389 module_exit(tsc2007_exit);
 390
 391 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 392 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 393 MODULE_LICENSE("GPL");