drivers/input/touchscreen/tsc2007_core.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_gpio.h>
  31 #include "tsc2007.h"
  32
  33 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  34 {
  35         s32 data;
  36         u16 val;
  37
  38         data = i2c_smbus_read_word_data(tsc->client, cmd);
  39         if (data < 0) {
  40                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
  41                 return data;
  42         }
  43
  44         /* The protocol and raw data format from i2c interface:
  45          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
  46          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
  47          */
  48         val = swab16(data) >> 4;
  49
  50         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
  51
  52         return val;
  53 }
  54
  55 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
  56 {
  57         /* y- still on; turn on only y+ (and ADC) */
  58         tc->y = tsc2007_xfer(tsc, READ_Y);
  59
  60         /* turn y- off, x+ on, then leave in lowpower */
  61         tc->x = tsc2007_xfer(tsc, READ_X);
  62
  63         /* turn y+ off, x- on; we'll use formula #1 */
  64         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
  65         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
  66
  67         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
  68         tsc2007_xfer(tsc, PWRDOWN);
  69 }
  70
  71 u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
  72 {
  73         u32 rt = 0;
  74
  75         /* range filtering */
  76         if (tc->x == MAX_12BIT)
  77                 tc->x = 0;
  78
  79         if (likely(tc->x && tc->z1)) {
  80                 /* compute touch pressure resistance using equation #1 */
  81                 rt = tc->z2 - tc->z1;
  82                 rt *= tc->x;
  83                 rt *= tsc->x_plate_ohms;
  84                 rt /= tc->z1;
  85                 rt = (rt + 2047) >> 12;
  86         }
  87
  88         return rt;
  89 }
  90
  91 bool tsc2007_is_pen_down(struct tsc2007 *ts)
  92 {
  93         /*
  94          * NOTE: We can't rely on the pressure to determine the pen down
  95          * state, even though this controller has a pressure sensor.
  96          * The pressure value can fluctuate for quite a while after
  97          * lifting the pen and in some cases may not even settle at the
  98          * expected value.
  99          *
 100          * The only safe way to check for the pen up condition is in the
 101          * work function by reading the pen signal state (it's a GPIO
 102          * and IRQ). Unfortunately such callback is not always available,
 103          * in that case we assume that the pen is down and expect caller
 104          * to fall back on the pressure reading.
 105          */
 106
 107         if (!ts->get_pendown_state)
 108                 return true;
 109
 110         return ts->get_pendown_state(&ts->client->dev);
 111 }
 112
 113 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 114 {
 115         struct tsc2007 *ts = handle;
 116         struct input_dev *input = ts->input;
 117         struct ts_event tc;
 118         u32 rt;
 119
 120         while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 121
 122                 /* pen is down, continue with the measurement */
 123
 124                 mutex_lock(&ts->mlock);
 125                 tsc2007_read_values(ts, &tc);
 126                 mutex_unlock(&ts->mlock);
 127
 128                 rt = tsc2007_calculate_pressure(ts, &tc);
 129
 130                 if (!rt && !ts->get_pendown_state) {
 131                         /*
 132                          * If pressure reported is 0 and we don't have
 133                          * callback to check pendown state, we have to
 134                          * assume that pen was lifted up.
 135                          */
 136                         break;
 137                 }
 138
 139                 if (rt <= ts->max_rt) {
 140                         dev_dbg(&ts->client->dev,
 141                                 "DOWN point(%4d,%4d), pressure (%4u)\n",
 142                                 tc.x, tc.y, rt);
 143
 144                         input_report_key(input, BTN_TOUCH, 1);
 145                         input_report_abs(input, ABS_X, tc.x);
 146                         input_report_abs(input, ABS_Y, tc.y);
 147                         input_report_abs(input, ABS_PRESSURE, rt);
 148
 149                         input_sync(input);
 150
 151                 } else {
 152                         /*
 153                          * Sample found inconsistent by debouncing or pressure is
 154                          * beyond the maximum. Don't report it to user space,
 155                          * repeat at least once more the measurement.
 156                          */
 157                         dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 158                 }
 159
 160                 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
 161         }
 162
 163         dev_dbg(&ts->client->dev, "UP\n");
 164
 165         input_report_key(input, BTN_TOUCH, 0);
 166         input_report_abs(input, ABS_PRESSURE, 0);
 167         input_sync(input);
 168
 169         if (ts->clear_penirq)
 170                 ts->clear_penirq();
 171
 172         return IRQ_HANDLED;
 173 }
 174
 175 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 176 {
 177         struct tsc2007 *ts = handle;
 178
 179         if (tsc2007_is_pen_down(ts))
 180                 return IRQ_WAKE_THREAD;
 181
 182         if (ts->clear_penirq)
 183                 ts->clear_penirq();
 184
 185         return IRQ_HANDLED;
 186 }
 187
 188 static void tsc2007_stop(struct tsc2007 *ts)
 189 {
 190         ts->stopped = true;
 191         mb();
 192         wake_up(&ts->wait);
 193
 194         disable_irq(ts->irq);
 195 }
 196
 197 static int tsc2007_open(struct input_dev *input_dev)
 198 {
 199         struct tsc2007 *ts = input_get_drvdata(input_dev);
 200         int err;
 201
 202         ts->stopped = false;
 203         mb();
 204
 205         enable_irq(ts->irq);
 206
 207         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 208         err = tsc2007_xfer(ts, PWRDOWN);
 209         if (err < 0) {
 210                 tsc2007_stop(ts);
 211                 return err;
 212         }
 213
 214         return 0;
 215 }
 216
 217 static void tsc2007_close(struct input_dev *input_dev)
 218 {
 219         struct tsc2007 *ts = input_get_drvdata(input_dev);
 220
 221         tsc2007_stop(ts);
 222 }
 223
 224 #ifdef CONFIG_OF
 225 static int tsc2007_get_pendown_state_gpio(struct device *dev)
 226 {
 227         struct i2c_client *client = to_i2c_client(dev);
 228         struct tsc2007 *ts = i2c_get_clientdata(client);
 229
 230         return !gpio_get_value(ts->gpio);
 231 }
 232
 233 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 234 {
 235         struct device_node *np = client->dev.of_node;
 236         u32 val32;
 237         u64 val64;
 238
 239         if (!np) {
 240                 dev_err(&client->dev, "missing device tree data\n");
 241                 return -EINVAL;
 242         }
 243
 244         if (!of_property_read_u32(np, "ti,max-rt", &val32))
 245                 ts->max_rt = val32;
 246         else
 247                 ts->max_rt = MAX_12BIT;
 248
 249         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
 250                 ts->fuzzx = val32;
 251
 252         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
 253                 ts->fuzzy = val32;
 254
 255         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
 256                 ts->fuzzz = val32;
 257
 258         if (!of_property_read_u64(np, "ti,poll-period", &val64))
 259                 ts->poll_period = msecs_to_jiffies(val64);
 260         else
 261                 ts->poll_period = msecs_to_jiffies(1);
 262
 263         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
 264                 ts->x_plate_ohms = val32;
 265         } else {
 266                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
 267                 return -EINVAL;
 268         }
 269
 270         ts->gpio = of_get_gpio(np, 0);
 271         if (gpio_is_valid(ts->gpio))
 272                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 273         else
 274                 dev_warn(&client->dev,
 275                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
 276                          ts->gpio);
 277
 278         return 0;
 279 }
 280 #else
 281 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 282 {
 283         dev_err(&client->dev, "platform data is required!\n");
 284         return -EINVAL;
 285 }
 286 #endif
 287
 288 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
 289                               const struct tsc2007_platform_data *pdata,
 290                               const struct i2c_device_id *id)
 291 {
 292         ts->model             = pdata->model;
 293         ts->x_plate_ohms      = pdata->x_plate_ohms;
 294         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
 295         ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
 296         ts->get_pendown_state = pdata->get_pendown_state;
 297         ts->clear_penirq      = pdata->clear_penirq;
 298         ts->fuzzx             = pdata->fuzzx;
 299         ts->fuzzy             = pdata->fuzzy;
 300         ts->fuzzz             = pdata->fuzzz;
 301
 302         if (pdata->x_plate_ohms == 0) {
 303                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
 304                 return -EINVAL;
 305         }
 306
 307         return 0;
 308 }
 309
 310 static void tsc2007_call_exit_platform_hw(void *data)
 311 {
 312         struct device *dev = data;
 313         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
 314
 315         pdata->exit_platform_hw();
 316 }
 317
 318 static int tsc2007_probe(struct i2c_client *client,
 319                          const struct i2c_device_id *id)
 320 {
 321         const struct tsc2007_platform_data *pdata =
 322                 dev_get_platdata(&client->dev);
 323         struct tsc2007 *ts;
 324         struct input_dev *input_dev;
 325         int err;
 326
 327         if (!i2c_check_functionality(client->adapter,
 328                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 329                 return -EIO;
 330
 331         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
 332         if (!ts)
 333                 return -ENOMEM;
 334
 335         if (pdata)
 336                 err = tsc2007_probe_pdev(client, ts, pdata, id);
 337         else
 338                 err = tsc2007_probe_dt(client, ts);
 339         if (err)
 340                 return err;
 341
 342         input_dev = devm_input_allocate_device(&client->dev);
 343         if (!input_dev)
 344                 return -ENOMEM;
 345
 346         i2c_set_clientdata(client, ts);
 347
 348         ts->client = client;
 349         ts->irq = client->irq;
 350         ts->input = input_dev;
 351
 352         init_waitqueue_head(&ts->wait);
 353         mutex_init(&ts->mlock);
 354
 355         snprintf(ts->phys, sizeof(ts->phys),
 356                  "%s/input0", dev_name(&client->dev));
 357
 358         input_dev->name = "TSC2007 Touchscreen";
 359         input_dev->phys = ts->phys;
 360         input_dev->id.bustype = BUS_I2C;
 361
 362         input_dev->open = tsc2007_open;
 363         input_dev->close = tsc2007_close;
 364
 365         input_set_drvdata(input_dev, ts);
 366
 367         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 368
 369         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
 370         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
 371         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
 372                              ts->fuzzz, 0);
 373
 374         if (pdata) {
 375                 if (pdata->exit_platform_hw) {
 376                         err = devm_add_action(&client->dev,
 377                                               tsc2007_call_exit_platform_hw,
 378                                               &client->dev);
 379                         if (err) {
 380                                 dev_err(&client->dev,
 381                                         "Failed to register exit_platform_hw action, %d\n",
 382                                         err);
 383                                 return err;
 384                         }
 385                 }
 386
 387                 if (pdata->init_platform_hw)
 388                         pdata->init_platform_hw();
 389         }
 390
 391         err = devm_request_threaded_irq(&client->dev, ts->irq,
 392                                         tsc2007_hard_irq, tsc2007_soft_irq,
 393                                         IRQF_ONESHOT,
 394                                         client->dev.driver->name, ts);
 395         if (err) {
 396                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
 397                         ts->irq, err);
 398                 return err;
 399         }
 400
 401         tsc2007_stop(ts);
 402
 403         /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
 404         err = tsc2007_xfer(ts, PWRDOWN);
 405         if (err < 0) {
 406                 dev_err(&client->dev,
 407                         "Failed to setup chip: %d\n", err);
 408                 return err;     /* chip does not respond */
 409         }
 410
 411         err = input_register_device(input_dev);
 412         if (err) {
 413                 dev_err(&client->dev,
 414                         "Failed to register input device: %d\n", err);
 415                 return err;
 416         }
 417
 418         err =  tsc2007_iio_configure(ts);
 419         if (err) {
 420                 dev_err(&client->dev,
 421                         "Failed to register with IIO: %d\n", err);
 422                 return err;
 423         }
 424
 425         return 0;
 426 }
 427
 428 static const struct i2c_device_id tsc2007_idtable[] = {
 429         { "tsc2007", 0 },
 430         { }
 431 };
 432
 433 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 434
 435 #ifdef CONFIG_OF
 436 static const struct of_device_id tsc2007_of_match[] = {
 437         { .compatible = "ti,tsc2007" },
 438         { /* sentinel */ }
 439 };
 440 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 441 #endif
 442
 443 static struct i2c_driver tsc2007_driver = {
 444         .driver = {
 445                 .name   = "tsc2007",
 446                 .of_match_table = of_match_ptr(tsc2007_of_match),
 447         },
 448         .id_table       = tsc2007_idtable,
 449         .probe          = tsc2007_probe,
 450 };
 451
 452 module_i2c_driver(tsc2007_driver);
 453
 454 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 455 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 456 MODULE_LICENSE("GPL");