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 #include <linux/of_device.h>
  30 #include <linux/of.h>
  31 #include <linux/of_gpio.h>
  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
  73         struct i2c_client       *client;
  74
  75         u16                     model;
  76         u16                     x_plate_ohms;
  77         u16                     max_rt;
  78         unsigned long           poll_period;
  79         int                     fuzzx;
  80         int                     fuzzy;
  81         int                     fuzzz;
  82
  83         unsigned                gpio;
  84         int                     irq;
  85
  86         wait_queue_head_t       wait;
  87         bool                    stopped;
  88
  89         int                     (*get_pendown_state)(struct device *);
  90         void                    (*clear_penirq)(void);
  91 };
  92
  93 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  94 {
  95         s32 data;
  96         u16 val;
  97
  98         data = i2c_smbus_read_word_data(tsc->client, cmd);
  99         if (data < 0) {
 100                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
 101                 return data;
 102         }
 103
 104         /* The protocol and raw data format from i2c interface:
 105          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
 106          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
 107          */
 108         val = swab16(data) >> 4;
 109
 110         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
 111
 112         return val;
 113 }
 114
 115 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
 116 {
 117         /* y- still on; turn on only y+ (and ADC) */
 118         tc->y = tsc2007_xfer(tsc, READ_Y);
 119
 120         /* turn y- off, x+ on, then leave in lowpower */
 121         tc->x = tsc2007_xfer(tsc, READ_X);
 122
 123         /* turn y+ off, x- on; we'll use formula #1 */
 124         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
 125         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
 126
 127         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
 128         tsc2007_xfer(tsc, PWRDOWN);
 129 }
 130
 131 static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
 132 {
 133         u32 rt = 0;
 134
 135         /* range filtering */
 136         if (tc->x == MAX_12BIT)
 137                 tc->x = 0;
 138
 139         if (likely(tc->x && tc->z1)) {
 140                 /* compute touch pressure resistance using equation #1 */
 141                 rt = tc->z2 - tc->z1;
 142                 rt *= tc->x;
 143                 rt *= tsc->x_plate_ohms;
 144                 rt /= tc->z1;
 145                 rt = (rt + 2047) >> 12;
 146         }
 147
 148         return rt;
 149 }
 150
 151 static bool tsc2007_is_pen_down(struct tsc2007 *ts)
 152 {
 153         /*
 154          * NOTE: We can't rely on the pressure to determine the pen down
 155          * state, even though this controller has a pressure sensor.
 156          * The pressure value can fluctuate for quite a while after
 157          * lifting the pen and in some cases may not even settle at the
 158          * expected value.
 159          *
 160          * The only safe way to check for the pen up condition is in the
 161          * work function by reading the pen signal state (it's a GPIO
 162          * and IRQ). Unfortunately such callback is not always available,
 163          * in that case we assume that the pen is down and expect caller
 164          * to fall back on the pressure reading.
 165          */
 166
 167         if (!ts->get_pendown_state)
 168                 return true;
 169
 170         return ts->get_pendown_state(&ts->client->dev);
 171 }
 172
 173 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 174 {
 175         struct tsc2007 *ts = handle;
 176         struct input_dev *input = ts->input;
 177         struct ts_event tc;
 178         u32 rt;
 179
 180         while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 181
 182                 /* pen is down, continue with the measurement */
 183                 tsc2007_read_values(ts, &tc);
 184
 185                 rt = tsc2007_calculate_pressure(ts, &tc);
 186
 187                 if (!rt && !ts->get_pendown_state) {
 188                         /*
 189                          * If pressure reported is 0 and we don't have
 190                          * callback to check pendown state, we have to
 191                          * assume that pen was lifted up.
 192                          */
 193                         break;
 194                 }
 195
 196                 if (rt <= ts->max_rt) {
 197                         dev_dbg(&ts->client->dev,
 198                                 "DOWN point(%4d,%4d), pressure (%4u)\n",
 199                                 tc.x, tc.y, rt);
 200
 201                         input_report_key(input, BTN_TOUCH, 1);
 202                         input_report_abs(input, ABS_X, tc.x);
 203                         input_report_abs(input, ABS_Y, tc.y);
 204                         input_report_abs(input, ABS_PRESSURE, rt);
 205
 206                         input_sync(input);
 207
 208                 } else {
 209                         /*
 210                          * Sample found inconsistent by debouncing or pressure is
 211                          * beyond the maximum. Don't report it to user space,
 212                          * repeat at least once more the measurement.
 213                          */
 214                         dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 215                 }
 216
 217                 wait_event_timeout(ts->wait, ts->stopped,
 218                                    msecs_to_jiffies(ts->poll_period));
 219         }
 220
 221         dev_dbg(&ts->client->dev, "UP\n");
 222
 223         input_report_key(input, BTN_TOUCH, 0);
 224         input_report_abs(input, ABS_PRESSURE, 0);
 225         input_sync(input);
 226
 227         if (ts->clear_penirq)
 228                 ts->clear_penirq();
 229
 230         return IRQ_HANDLED;
 231 }
 232
 233 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 234 {
 235         struct tsc2007 *ts = handle;
 236
 237         if (tsc2007_is_pen_down(ts))
 238                 return IRQ_WAKE_THREAD;
 239
 240         if (ts->clear_penirq)
 241                 ts->clear_penirq();
 242
 243         return IRQ_HANDLED;
 244 }
 245
 246 static void tsc2007_stop(struct tsc2007 *ts)
 247 {
 248         ts->stopped = true;
 249         mb();
 250         wake_up(&ts->wait);
 251
 252         disable_irq(ts->irq);
 253 }
 254
 255 static int tsc2007_open(struct input_dev *input_dev)
 256 {
 257         struct tsc2007 *ts = input_get_drvdata(input_dev);
 258         int err;
 259
 260         ts->stopped = false;
 261         mb();
 262
 263         enable_irq(ts->irq);
 264
 265         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 266         err = tsc2007_xfer(ts, PWRDOWN);
 267         if (err < 0) {
 268                 tsc2007_stop(ts);
 269                 return err;
 270         }
 271
 272         return 0;
 273 }
 274
 275 static void tsc2007_close(struct input_dev *input_dev)
 276 {
 277         struct tsc2007 *ts = input_get_drvdata(input_dev);
 278
 279         tsc2007_stop(ts);
 280 }
 281
 282 #ifdef CONFIG_OF
 283 static int tsc2007_get_pendown_state_gpio(struct device *dev)
 284 {
 285         struct i2c_client *client = to_i2c_client(dev);
 286         struct tsc2007 *ts = i2c_get_clientdata(client);
 287
 288         return !gpio_get_value(ts->gpio);
 289 }
 290
 291 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 292 {
 293         struct device_node *np = client->dev.of_node;
 294         u32 val32;
 295         u64 val64;
 296
 297         if (!np) {
 298                 dev_err(&client->dev, "missing device tree data\n");
 299                 return -EINVAL;
 300         }
 301
 302         if (!of_property_read_u32(np, "ti,max-rt", &val32))
 303                 ts->max_rt = val32;
 304         else
 305                 ts->max_rt = MAX_12BIT;
 306
 307         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
 308                 ts->fuzzx = val32;
 309
 310         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
 311                 ts->fuzzy = val32;
 312
 313         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
 314                 ts->fuzzz = val32;
 315
 316         if (!of_property_read_u64(np, "ti,poll-period", &val64))
 317                 ts->poll_period = val64;
 318         else
 319                 ts->poll_period = 1;
 320
 321         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
 322                 ts->x_plate_ohms = val32;
 323         } else {
 324                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
 325                 return -EINVAL;
 326         }
 327
 328         ts->gpio = of_get_gpio(np, 0);
 329         if (gpio_is_valid(ts->gpio))
 330                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 331         else
 332                 dev_warn(&client->dev,
 333                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
 334                          ts->gpio);
 335
 336         return 0;
 337 }
 338 #else
 339 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 340 {
 341         dev_err(&client->dev, "platform data is required!\n");
 342         return -EINVAL;
 343 }
 344 #endif
 345
 346 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
 347                               const struct tsc2007_platform_data *pdata,
 348                               const struct i2c_device_id *id)
 349 {
 350         ts->model             = pdata->model;
 351         ts->x_plate_ohms      = pdata->x_plate_ohms;
 352         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
 353         ts->poll_period       = pdata->poll_period ? : 1;
 354         ts->get_pendown_state = pdata->get_pendown_state;
 355         ts->clear_penirq      = pdata->clear_penirq;
 356         ts->fuzzx             = pdata->fuzzx;
 357         ts->fuzzy             = pdata->fuzzy;
 358         ts->fuzzz             = pdata->fuzzz;
 359
 360         if (pdata->x_plate_ohms == 0) {
 361                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
 362                 return -EINVAL;
 363         }
 364
 365         return 0;
 366 }
 367
 368 static void tsc2007_call_exit_platform_hw(void *data)
 369 {
 370         struct device *dev = data;
 371         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
 372
 373         pdata->exit_platform_hw();
 374 }
 375
 376 static int tsc2007_probe(struct i2c_client *client,
 377                          const struct i2c_device_id *id)
 378 {
 379         const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
 380         struct tsc2007 *ts;
 381         struct input_dev *input_dev;
 382         int err;
 383
 384         if (!i2c_check_functionality(client->adapter,
 385                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 386                 return -EIO;
 387
 388         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
 389         if (!ts)
 390                 return -ENOMEM;
 391
 392         if (pdata)
 393                 err = tsc2007_probe_pdev(client, ts, pdata, id);
 394         else
 395                 err = tsc2007_probe_dt(client, ts);
 396         if (err)
 397                 return err;
 398
 399         input_dev = devm_input_allocate_device(&client->dev);
 400         if (!input_dev)
 401                 return -ENOMEM;
 402
 403         i2c_set_clientdata(client, ts);
 404
 405         ts->client = client;
 406         ts->irq = client->irq;
 407         ts->input = input_dev;
 408         init_waitqueue_head(&ts->wait);
 409
 410         snprintf(ts->phys, sizeof(ts->phys),
 411                  "%s/input0", dev_name(&client->dev));
 412
 413         input_dev->name = "TSC2007 Touchscreen";
 414         input_dev->phys = ts->phys;
 415         input_dev->id.bustype = BUS_I2C;
 416
 417         input_dev->open = tsc2007_open;
 418         input_dev->close = tsc2007_close;
 419
 420         input_set_drvdata(input_dev, ts);
 421
 422         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 423         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 424
 425         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
 426         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
 427         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
 428                              ts->fuzzz, 0);
 429
 430         if (pdata) {
 431                 if (pdata->exit_platform_hw) {
 432                         err = devm_add_action(&client->dev,
 433                                               tsc2007_call_exit_platform_hw,
 434                                               &client->dev);
 435                         if (err) {
 436                                 dev_err(&client->dev,
 437                                         "Failed to register exit_platform_hw action, %d\n",
 438                                         err);
 439                                 return err;
 440                         }
 441                 }
 442
 443                 if (pdata->init_platform_hw)
 444                         pdata->init_platform_hw();
 445         }
 446
 447         err = devm_request_threaded_irq(&client->dev, ts->irq,
 448                                         tsc2007_hard_irq, tsc2007_soft_irq,
 449                                         IRQF_ONESHOT,
 450                                         client->dev.driver->name, ts);
 451         if (err) {
 452                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
 453                         ts->irq, err);
 454                 return err;
 455         }
 456
 457         tsc2007_stop(ts);
 458
 459         err = input_register_device(input_dev);
 460         if (err) {
 461                 dev_err(&client->dev,
 462                         "Failed to register input device: %d\n", err);
 463                 return err;
 464         }
 465
 466         return 0;
 467 }
 468
 469 static const struct i2c_device_id tsc2007_idtable[] = {
 470         { "tsc2007", 0 },
 471         { }
 472 };
 473
 474 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 475
 476 #ifdef CONFIG_OF
 477 static const struct of_device_id tsc2007_of_match[] = {
 478         { .compatible = "ti,tsc2007" },
 479         { /* sentinel */ }
 480 };
 481 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 482 #endif
 483
 484 static struct i2c_driver tsc2007_driver = {
 485         .driver = {
 486                 .owner  = THIS_MODULE,
 487                 .name   = "tsc2007",
 488                 .of_match_table = of_match_ptr(tsc2007_of_match),
 489         },
 490         .id_table       = tsc2007_idtable,
 491         .probe          = tsc2007_probe,
 492 };
 493
 494 module_i2c_driver(tsc2007_driver);
 495
 496 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 497 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 498 MODULE_LICENSE("GPL");