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;
  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,
 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
 233static 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
 246static 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
 255static 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
 275static 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
 283static 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
 291static 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
 339static 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
 346static 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
 368static 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
 376static 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
 469static const struct i2c_device_id tsc2007_idtable[] = {
 470        { "tsc2007", 0 },
 471        { }
 472};
 473
 474MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 475
 476#ifdef CONFIG_OF
 477static const struct of_device_id tsc2007_of_match[] = {
 478        { .compatible = "ti,tsc2007" },
 479        { /* sentinel */ }
 480};
 481MODULE_DEVICE_TABLE(of, tsc2007_of_match);
 482#endif
 483
 484static 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
 494module_i2c_driver(tsc2007_driver);
 495
 496MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 497MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 498MODULE_LICENSE("GPL");
 499
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