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; /* in jiffies */
  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, ts->poll_period);
 218         }
 219
 220         dev_dbg(&ts->client->dev, "UP\n");
 221
 222         input_report_key(input, BTN_TOUCH, 0);
 223         input_report_abs(input, ABS_PRESSURE, 0);
 224         input_sync(input);
 225
 226         if (ts->clear_penirq)
 227                 ts->clear_penirq();
 228
 229         return IRQ_HANDLED;
 230 }
 231
 232 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 233 {
 234         struct tsc2007 *ts = handle;
 235
 236         if (tsc2007_is_pen_down(ts))
 237                 return IRQ_WAKE_THREAD;
 238
 239         if (ts->clear_penirq)
 240                 ts->clear_penirq();
 241
 242         return IRQ_HANDLED;
 243 }
 244
 245 static void tsc2007_stop(struct tsc2007 *ts)
 246 {
 247         ts->stopped = true;
 248         mb();
 249         wake_up(&ts->wait);
 250
 251         disable_irq(ts->irq);
 252 }
 253
 254 static int tsc2007_open(struct input_dev *input_dev)
 255 {
 256         struct tsc2007 *ts = input_get_drvdata(input_dev);
 257         int err;
 258
 259         ts->stopped = false;
 260         mb();
 261
 262         enable_irq(ts->irq);
 263
 264         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 265         err = tsc2007_xfer(ts, PWRDOWN);
 266         if (err < 0) {
 267                 tsc2007_stop(ts);
 268                 return err;
 269         }
 270
 271         return 0;
 272 }
 273
 274 static void tsc2007_close(struct input_dev *input_dev)
 275 {
 276         struct tsc2007 *ts = input_get_drvdata(input_dev);
 277
 278         tsc2007_stop(ts);
 279 }
 280
 281 #ifdef CONFIG_OF
 282 static int tsc2007_get_pendown_state_gpio(struct device *dev)
 283 {
 284         struct i2c_client *client = to_i2c_client(dev);
 285         struct tsc2007 *ts = i2c_get_clientdata(client);
 286
 287         return !gpio_get_value(ts->gpio);
 288 }
 289
 290 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 291 {
 292         struct device_node *np = client->dev.of_node;
 293         u32 val32;
 294         u64 val64;
 295
 296         if (!np) {
 297                 dev_err(&client->dev, "missing device tree data\n");
 298                 return -EINVAL;
 299         }
 300
 301         if (!of_property_read_u32(np, "ti,max-rt", &val32))
 302                 ts->max_rt = val32;
 303         else
 304                 ts->max_rt = MAX_12BIT;
 305
 306         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
 307                 ts->fuzzx = val32;
 308
 309         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
 310                 ts->fuzzy = val32;
 311
 312         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
 313                 ts->fuzzz = val32;
 314
 315         if (!of_property_read_u64(np, "ti,poll-period", &val64))
 316                 ts->poll_period = msecs_to_jiffies(val64);
 317         else
 318                 ts->poll_period = msecs_to_jiffies(1);
 319
 320         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
 321                 ts->x_plate_ohms = val32;
 322         } else {
 323                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
 324                 return -EINVAL;
 325         }
 326
 327         ts->gpio = of_get_gpio(np, 0);
 328         if (gpio_is_valid(ts->gpio))
 329                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 330         else
 331                 dev_warn(&client->dev,
 332                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
 333                          ts->gpio);
 334
 335         return 0;
 336 }
 337 #else
 338 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 339 {
 340         dev_err(&client->dev, "platform data is required!\n");
 341         return -EINVAL;
 342 }
 343 #endif
 344
 345 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
 346                               const struct tsc2007_platform_data *pdata,
 347                               const struct i2c_device_id *id)
 348 {
 349         ts->model             = pdata->model;
 350         ts->x_plate_ohms      = pdata->x_plate_ohms;
 351         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
 352         ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
 353         ts->get_pendown_state = pdata->get_pendown_state;
 354         ts->clear_penirq      = pdata->clear_penirq;
 355         ts->fuzzx             = pdata->fuzzx;
 356         ts->fuzzy             = pdata->fuzzy;
 357         ts->fuzzz             = pdata->fuzzz;
 358
 359         if (pdata->x_plate_ohms == 0) {
 360                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
 361                 return -EINVAL;
 362         }
 363
 364         return 0;
 365 }
 366
 367 static void tsc2007_call_exit_platform_hw(void *data)
 368 {
 369         struct device *dev = data;
 370         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
 371
 372         pdata->exit_platform_hw();
 373 }
 374
 375 static int tsc2007_probe(struct i2c_client *client,
 376                          const struct i2c_device_id *id)
 377 {
 378         const struct tsc2007_platform_data *pdata = dev_get_platdata(&client->dev);
 379         struct tsc2007 *ts;
 380         struct input_dev *input_dev;
 381         int err;
 382
 383         if (!i2c_check_functionality(client->adapter,
 384                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 385                 return -EIO;
 386
 387         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
 388         if (!ts)
 389                 return -ENOMEM;
 390
 391         if (pdata)
 392                 err = tsc2007_probe_pdev(client, ts, pdata, id);
 393         else
 394                 err = tsc2007_probe_dt(client, ts);
 395         if (err)
 396                 return err;
 397
 398         input_dev = devm_input_allocate_device(&client->dev);
 399         if (!input_dev)
 400                 return -ENOMEM;
 401
 402         i2c_set_clientdata(client, ts);
 403
 404         ts->client = client;
 405         ts->irq = client->irq;
 406         ts->input = input_dev;
 407         init_waitqueue_head(&ts->wait);
 408
 409         snprintf(ts->phys, sizeof(ts->phys),
 410                  "%s/input0", dev_name(&client->dev));
 411
 412         input_dev->name = "TSC2007 Touchscreen";
 413         input_dev->phys = ts->phys;
 414         input_dev->id.bustype = BUS_I2C;
 415
 416         input_dev->open = tsc2007_open;
 417         input_dev->close = tsc2007_close;
 418
 419         input_set_drvdata(input_dev, ts);
 420
 421         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 422         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 423
 424         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
 425         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
 426         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
 427                              ts->fuzzz, 0);
 428
 429         if (pdata) {
 430                 if (pdata->exit_platform_hw) {
 431                         err = devm_add_action(&client->dev,
 432                                               tsc2007_call_exit_platform_hw,
 433                                               &client->dev);
 434                         if (err) {
 435                                 dev_err(&client->dev,
 436                                         "Failed to register exit_platform_hw action, %d\n",
 437                                         err);
 438                                 return err;
 439                         }
 440                 }
 441
 442                 if (pdata->init_platform_hw)
 443                         pdata->init_platform_hw();
 444         }
 445
 446         err = devm_request_threaded_irq(&client->dev, ts->irq,
 447                                         tsc2007_hard_irq, tsc2007_soft_irq,
 448                                         IRQF_ONESHOT,
 449                                         client->dev.driver->name, ts);
 450         if (err) {
 451                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
 452                         ts->irq, err);
 453                 return err;
 454         }
 455
 456         tsc2007_stop(ts);
 457
 458         /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
 459         err = tsc2007_xfer(ts, PWRDOWN);
 460         if (err < 0) {
 461                 dev_err(&client->dev,
 462                         "Failed to setup chip: %d\n", err);
 463                 return err;     /* usually, chip does not respond */
 464         }
 465
 466         err = input_register_device(input_dev);
 467         if (err) {
 468                 dev_err(&client->dev,
 469                         "Failed to register input device: %d\n", err);
 470                 return err;
 471         }
 472
 473         return 0;
 474 }
 475
 476 static const struct i2c_device_id tsc2007_idtable[] = {
 477         { "tsc2007", 0 },
 478         { }
 479 };
 480
 481 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 482
 483 #ifdef CONFIG_OF
 484 static const struct of_device_id tsc2007_of_match[] = {
 485         { .compatible = "ti,tsc2007" },
 486         { /* sentinel */ }
 487 };
 488 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 489 #endif
 490
 491 static struct i2c_driver tsc2007_driver = {
 492         .driver = {
 493                 .name   = "tsc2007",
 494                 .of_match_table = of_match_ptr(tsc2007_of_match),
 495         },
 496         .id_table       = tsc2007_idtable,
 497         .probe          = tsc2007_probe,
 498 };
 499
 500 module_i2c_driver(tsc2007_driver);
 501
 502 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 503 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 504 MODULE_LICENSE("GPL");