linux/drivers/input/touchscreen/tsc2007.c
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   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
  63struct ts_event {
  64        u16     x;
  65        u16     y;
  66        u16     z1, z2;
  67};
  68
  69struct 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
  93static 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
 115static 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
 131static 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
 151static 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
 173static 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
 232static 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
 245static 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
 254static 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
 274static 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
 282static 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
 290static 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
 338static 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
 345static 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
 367static 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
 375static 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        err = input_register_device(input_dev);
 459        if (err) {
 460                dev_err(&client->dev,
 461                        "Failed to register input device: %d\n", err);
 462                return err;
 463        }
 464
 465        return 0;
 466}
 467
 468static const struct i2c_device_id tsc2007_idtable[] = {
 469        { "tsc2007", 0 },
 470        { }
 471};
 472
 473MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 474
 475#ifdef CONFIG_OF
 476static const struct of_device_id tsc2007_of_match[] = {
 477        { .compatible = "ti,tsc2007" },
 478        { /* sentinel */ }
 479};
 480MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 481#endif
 482
 483static struct i2c_driver tsc2007_driver = {
 484        .driver = {
 485                .name   = "tsc2007",
 486                .of_match_table = of_match_ptr(tsc2007_of_match),
 487        },
 488        .id_table       = tsc2007_idtable,
 489        .probe          = tsc2007_probe,
 490};
 491
 492module_i2c_driver(tsc2007_driver);
 493
 494MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 495MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 496MODULE_LICENSE("GPL");
 497
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