drivers/input/touchscreen/tsc2007_core.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * drivers/input/touchscreen/tsc2007.c
   4  *
   5  * Copyright (c) 2008 MtekVision Co., Ltd.
   6  *      Kwangwoo Lee <kwlee@mtekvision.com>
   7  *
   8  * Using code from:
   9  *  - ads7846.c
  10  *      Copyright (c) 2005 David Brownell
  11  *      Copyright (c) 2006 Nokia Corporation
  12  *  - corgi_ts.c
  13  *      Copyright (C) 2004-2005 Richard Purdie
  14  *  - omap_ts.[hc], ads7846.h, ts_osk.c
  15  *      Copyright (C) 2002 MontaVista Software
  16  *      Copyright (C) 2004 Texas Instruments
  17  *      Copyright (C) 2005 Dirk Behme
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/slab.h>
  22 #include <linux/input.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/i2c.h>
  25 #include <linux/of_device.h>
  26 #include <linux/of_gpio.h>
  27 #include <linux/platform_data/tsc2007.h>
  28 #include "tsc2007.h"
  29
  30 int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  31 {
  32         s32 data;
  33         u16 val;
  34
  35         data = i2c_smbus_read_word_data(tsc->client, cmd);
  36         if (data < 0) {
  37                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
  38                 return data;
  39         }
  40
  41         /* The protocol and raw data format from i2c interface:
  42          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
  43          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
  44          */
  45         val = swab16(data) >> 4;
  46
  47         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
  48
  49         return val;
  50 }
  51
  52 static void tsc2007_read_values(struct tsc2007 *tsc, struct ts_event *tc)
  53 {
  54         /* y- still on; turn on only y+ (and ADC) */
  55         tc->y = tsc2007_xfer(tsc, READ_Y);
  56
  57         /* turn y- off, x+ on, then leave in lowpower */
  58         tc->x = tsc2007_xfer(tsc, READ_X);
  59
  60         /* turn y+ off, x- on; we'll use formula #1 */
  61         tc->z1 = tsc2007_xfer(tsc, READ_Z1);
  62         tc->z2 = tsc2007_xfer(tsc, READ_Z2);
  63
  64         /* Prepare for next touch reading - power down ADC, enable PENIRQ */
  65         tsc2007_xfer(tsc, PWRDOWN);
  66 }
  67
  68 u32 tsc2007_calculate_resistance(struct tsc2007 *tsc, struct ts_event *tc)
  69 {
  70         u32 rt = 0;
  71
  72         /* range filtering */
  73         if (tc->x == MAX_12BIT)
  74                 tc->x = 0;
  75
  76         if (likely(tc->x && tc->z1)) {
  77                 /* compute touch resistance using equation #1 */
  78                 rt = tc->z2 - tc->z1;
  79                 rt *= tc->x;
  80                 rt *= tsc->x_plate_ohms;
  81                 rt /= tc->z1;
  82                 rt = (rt + 2047) >> 12;
  83         }
  84
  85         return rt;
  86 }
  87
  88 bool tsc2007_is_pen_down(struct tsc2007 *ts)
  89 {
  90         /*
  91          * NOTE: We can't rely on the pressure to determine the pen down
  92          * state, even though this controller has a pressure sensor.
  93          * The pressure value can fluctuate for quite a while after
  94          * lifting the pen and in some cases may not even settle at the
  95          * expected value.
  96          *
  97          * The only safe way to check for the pen up condition is in the
  98          * work function by reading the pen signal state (it's a GPIO
  99          * and IRQ). Unfortunately such callback is not always available,
 100          * in that case we assume that the pen is down and expect caller
 101          * to fall back on the pressure reading.
 102          */
 103
 104         if (!ts->get_pendown_state)
 105                 return true;
 106
 107         return ts->get_pendown_state(&ts->client->dev);
 108 }
 109
 110 static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
 111 {
 112         struct tsc2007 *ts = handle;
 113         struct input_dev *input = ts->input;
 114         struct ts_event tc;
 115         u32 rt;
 116
 117         while (!ts->stopped && tsc2007_is_pen_down(ts)) {
 118
 119                 /* pen is down, continue with the measurement */
 120
 121                 mutex_lock(&ts->mlock);
 122                 tsc2007_read_values(ts, &tc);
 123                 mutex_unlock(&ts->mlock);
 124
 125                 rt = tsc2007_calculate_resistance(ts, &tc);
 126
 127                 if (!rt && !ts->get_pendown_state) {
 128                         /*
 129                          * If pressure reported is 0 and we don't have
 130                          * callback to check pendown state, we have to
 131                          * assume that pen was lifted up.
 132                          */
 133                         break;
 134                 }
 135
 136                 if (rt <= ts->max_rt) {
 137                         dev_dbg(&ts->client->dev,
 138                                 "DOWN point(%4d,%4d), resistance (%4u)\n",
 139                                 tc.x, tc.y, rt);
 140
 141                         rt = ts->max_rt - rt;
 142
 143                         input_report_key(input, BTN_TOUCH, 1);
 144                         input_report_abs(input, ABS_X, tc.x);
 145                         input_report_abs(input, ABS_Y, tc.y);
 146                         input_report_abs(input, ABS_PRESSURE, rt);
 147
 148                         input_sync(input);
 149
 150                 } else {
 151                         /*
 152                          * Sample found inconsistent by debouncing or pressure is
 153                          * beyond the maximum. Don't report it to user space,
 154                          * repeat at least once more the measurement.
 155                          */
 156                         dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 157                 }
 158
 159                 wait_event_timeout(ts->wait, ts->stopped, ts->poll_period);
 160         }
 161
 162         dev_dbg(&ts->client->dev, "UP\n");
 163
 164         input_report_key(input, BTN_TOUCH, 0);
 165         input_report_abs(input, ABS_PRESSURE, 0);
 166         input_sync(input);
 167
 168         if (ts->clear_penirq)
 169                 ts->clear_penirq();
 170
 171         return IRQ_HANDLED;
 172 }
 173
 174 static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 175 {
 176         struct tsc2007 *ts = handle;
 177
 178         if (tsc2007_is_pen_down(ts))
 179                 return IRQ_WAKE_THREAD;
 180
 181         if (ts->clear_penirq)
 182                 ts->clear_penirq();
 183
 184         return IRQ_HANDLED;
 185 }
 186
 187 static void tsc2007_stop(struct tsc2007 *ts)
 188 {
 189         ts->stopped = true;
 190         mb();
 191         wake_up(&ts->wait);
 192
 193         disable_irq(ts->irq);
 194 }
 195
 196 static int tsc2007_open(struct input_dev *input_dev)
 197 {
 198         struct tsc2007 *ts = input_get_drvdata(input_dev);
 199         int err;
 200
 201         ts->stopped = false;
 202         mb();
 203
 204         enable_irq(ts->irq);
 205
 206         /* Prepare for touch readings - power down ADC and enable PENIRQ */
 207         err = tsc2007_xfer(ts, PWRDOWN);
 208         if (err < 0) {
 209                 tsc2007_stop(ts);
 210                 return err;
 211         }
 212
 213         return 0;
 214 }
 215
 216 static void tsc2007_close(struct input_dev *input_dev)
 217 {
 218         struct tsc2007 *ts = input_get_drvdata(input_dev);
 219
 220         tsc2007_stop(ts);
 221 }
 222
 223 #ifdef CONFIG_OF
 224 static int tsc2007_get_pendown_state_gpio(struct device *dev)
 225 {
 226         struct i2c_client *client = to_i2c_client(dev);
 227         struct tsc2007 *ts = i2c_get_clientdata(client);
 228
 229         return !gpio_get_value(ts->gpio);
 230 }
 231
 232 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 233 {
 234         struct device_node *np = client->dev.of_node;
 235         u32 val32;
 236         u64 val64;
 237
 238         if (!np) {
 239                 dev_err(&client->dev, "missing device tree data\n");
 240                 return -EINVAL;
 241         }
 242
 243         if (!of_property_read_u32(np, "ti,max-rt", &val32))
 244                 ts->max_rt = val32;
 245         else
 246                 ts->max_rt = MAX_12BIT;
 247
 248         if (!of_property_read_u32(np, "ti,fuzzx", &val32))
 249                 ts->fuzzx = val32;
 250
 251         if (!of_property_read_u32(np, "ti,fuzzy", &val32))
 252                 ts->fuzzy = val32;
 253
 254         if (!of_property_read_u32(np, "ti,fuzzz", &val32))
 255                 ts->fuzzz = val32;
 256
 257         if (!of_property_read_u64(np, "ti,poll-period", &val64))
 258                 ts->poll_period = msecs_to_jiffies(val64);
 259         else
 260                 ts->poll_period = msecs_to_jiffies(1);
 261
 262         if (!of_property_read_u32(np, "ti,x-plate-ohms", &val32)) {
 263                 ts->x_plate_ohms = val32;
 264         } else {
 265                 dev_err(&client->dev, "missing ti,x-plate-ohms devicetree property.");
 266                 return -EINVAL;
 267         }
 268
 269         ts->gpio = of_get_gpio(np, 0);
 270         if (gpio_is_valid(ts->gpio))
 271                 ts->get_pendown_state = tsc2007_get_pendown_state_gpio;
 272         else
 273                 dev_warn(&client->dev,
 274                          "GPIO not specified in DT (of_get_gpio returned %d)\n",
 275                          ts->gpio);
 276
 277         return 0;
 278 }
 279 #else
 280 static int tsc2007_probe_dt(struct i2c_client *client, struct tsc2007 *ts)
 281 {
 282         dev_err(&client->dev, "platform data is required!\n");
 283         return -EINVAL;
 284 }
 285 #endif
 286
 287 static int tsc2007_probe_pdev(struct i2c_client *client, struct tsc2007 *ts,
 288                               const struct tsc2007_platform_data *pdata,
 289                               const struct i2c_device_id *id)
 290 {
 291         ts->model             = pdata->model;
 292         ts->x_plate_ohms      = pdata->x_plate_ohms;
 293         ts->max_rt            = pdata->max_rt ? : MAX_12BIT;
 294         ts->poll_period       = msecs_to_jiffies(pdata->poll_period ? : 1);
 295         ts->get_pendown_state = pdata->get_pendown_state;
 296         ts->clear_penirq      = pdata->clear_penirq;
 297         ts->fuzzx             = pdata->fuzzx;
 298         ts->fuzzy             = pdata->fuzzy;
 299         ts->fuzzz             = pdata->fuzzz;
 300
 301         if (pdata->x_plate_ohms == 0) {
 302                 dev_err(&client->dev, "x_plate_ohms is not set up in platform data");
 303                 return -EINVAL;
 304         }
 305
 306         return 0;
 307 }
 308
 309 static void tsc2007_call_exit_platform_hw(void *data)
 310 {
 311         struct device *dev = data;
 312         const struct tsc2007_platform_data *pdata = dev_get_platdata(dev);
 313
 314         pdata->exit_platform_hw();
 315 }
 316
 317 static int tsc2007_probe(struct i2c_client *client,
 318                          const struct i2c_device_id *id)
 319 {
 320         const struct tsc2007_platform_data *pdata =
 321                 dev_get_platdata(&client->dev);
 322         struct tsc2007 *ts;
 323         struct input_dev *input_dev;
 324         int err;
 325
 326         if (!i2c_check_functionality(client->adapter,
 327                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 328                 return -EIO;
 329
 330         ts = devm_kzalloc(&client->dev, sizeof(struct tsc2007), GFP_KERNEL);
 331         if (!ts)
 332                 return -ENOMEM;
 333
 334         if (pdata)
 335                 err = tsc2007_probe_pdev(client, ts, pdata, id);
 336         else
 337                 err = tsc2007_probe_dt(client, ts);
 338         if (err)
 339                 return err;
 340
 341         input_dev = devm_input_allocate_device(&client->dev);
 342         if (!input_dev)
 343                 return -ENOMEM;
 344
 345         i2c_set_clientdata(client, ts);
 346
 347         ts->client = client;
 348         ts->irq = client->irq;
 349         ts->input = input_dev;
 350
 351         init_waitqueue_head(&ts->wait);
 352         mutex_init(&ts->mlock);
 353
 354         snprintf(ts->phys, sizeof(ts->phys),
 355                  "%s/input0", dev_name(&client->dev));
 356
 357         input_dev->name = "TSC2007 Touchscreen";
 358         input_dev->phys = ts->phys;
 359         input_dev->id.bustype = BUS_I2C;
 360
 361         input_dev->open = tsc2007_open;
 362         input_dev->close = tsc2007_close;
 363
 364         input_set_drvdata(input_dev, ts);
 365
 366         input_set_capability(input_dev, EV_KEY, BTN_TOUCH);
 367
 368         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, ts->fuzzx, 0);
 369         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, ts->fuzzy, 0);
 370         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT,
 371                              ts->fuzzz, 0);
 372
 373         if (pdata) {
 374                 if (pdata->exit_platform_hw) {
 375                         err = devm_add_action(&client->dev,
 376                                               tsc2007_call_exit_platform_hw,
 377                                               &client->dev);
 378                         if (err) {
 379                                 dev_err(&client->dev,
 380                                         "Failed to register exit_platform_hw action, %d\n",
 381                                         err);
 382                                 return err;
 383                         }
 384                 }
 385
 386                 if (pdata->init_platform_hw)
 387                         pdata->init_platform_hw();
 388         }
 389
 390         err = devm_request_threaded_irq(&client->dev, ts->irq,
 391                                         tsc2007_hard_irq, tsc2007_soft_irq,
 392                                         IRQF_ONESHOT,
 393                                         client->dev.driver->name, ts);
 394         if (err) {
 395                 dev_err(&client->dev, "Failed to request irq %d: %d\n",
 396                         ts->irq, err);
 397                 return err;
 398         }
 399
 400         tsc2007_stop(ts);
 401
 402         /* power down the chip (TSC2007_SETUP does not ACK on I2C) */
 403         err = tsc2007_xfer(ts, PWRDOWN);
 404         if (err < 0) {
 405                 dev_err(&client->dev,
 406                         "Failed to setup chip: %d\n", err);
 407                 return err;     /* chip does not respond */
 408         }
 409
 410         err = input_register_device(input_dev);
 411         if (err) {
 412                 dev_err(&client->dev,
 413                         "Failed to register input device: %d\n", err);
 414                 return err;
 415         }
 416
 417         err =  tsc2007_iio_configure(ts);
 418         if (err) {
 419                 dev_err(&client->dev,
 420                         "Failed to register with IIO: %d\n", err);
 421                 return err;
 422         }
 423
 424         return 0;
 425 }
 426
 427 static const struct i2c_device_id tsc2007_idtable[] = {
 428         { "tsc2007", 0 },
 429         { }
 430 };
 431
 432 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 433
 434 #ifdef CONFIG_OF
 435 static const struct of_device_id tsc2007_of_match[] = {
 436         { .compatible = "ti,tsc2007" },
 437         { /* sentinel */ }
 438 };
 439 MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 440 #endif
 441
 442 static struct i2c_driver tsc2007_driver = {
 443         .driver = {
 444                 .name   = "tsc2007",
 445                 .of_match_table = of_match_ptr(tsc2007_of_match),
 446         },
 447         .id_table       = tsc2007_idtable,
 448         .probe          = tsc2007_probe,
 449 };
 450
 451 module_i2c_driver(tsc2007_driver);
 452
 453 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 454 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 455 MODULE_LICENSE("GPL");