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
  30 #define TS_POLL_PERIOD  msecs_to_jiffies(1) /* ms delay between samples */
  31
  32 #define TSC2007_MEASURE_TEMP0           (0x0 << 4)
  33 #define TSC2007_MEASURE_AUX             (0x2 << 4)
  34 #define TSC2007_MEASURE_TEMP1           (0x4 << 4)
  35 #define TSC2007_ACTIVATE_XN             (0x8 << 4)
  36 #define TSC2007_ACTIVATE_YN             (0x9 << 4)
  37 #define TSC2007_ACTIVATE_YP_XN          (0xa << 4)
  38 #define TSC2007_SETUP                   (0xb << 4)
  39 #define TSC2007_MEASURE_X               (0xc << 4)
  40 #define TSC2007_MEASURE_Y               (0xd << 4)
  41 #define TSC2007_MEASURE_Z1              (0xe << 4)
  42 #define TSC2007_MEASURE_Z2              (0xf << 4)
  43
  44 #define TSC2007_POWER_OFF_IRQ_EN        (0x0 << 2)
  45 #define TSC2007_ADC_ON_IRQ_DIS0         (0x1 << 2)
  46 #define TSC2007_ADC_OFF_IRQ_EN          (0x2 << 2)
  47 #define TSC2007_ADC_ON_IRQ_DIS1         (0x3 << 2)
  48
  49 #define TSC2007_12BIT                   (0x0 << 1)
  50 #define TSC2007_8BIT                    (0x1 << 1)
  51
  52 #define MAX_12BIT                       ((1 << 12) - 1)
  53
  54 #define ADC_ON_12BIT    (TSC2007_12BIT | TSC2007_ADC_ON_IRQ_DIS0)
  55
  56 #define READ_Y          (ADC_ON_12BIT | TSC2007_MEASURE_Y)
  57 #define READ_Z1         (ADC_ON_12BIT | TSC2007_MEASURE_Z1)
  58 #define READ_Z2         (ADC_ON_12BIT | TSC2007_MEASURE_Z2)
  59 #define READ_X          (ADC_ON_12BIT | TSC2007_MEASURE_X)
  60 #define PWRDOWN         (TSC2007_12BIT | TSC2007_POWER_OFF_IRQ_EN)
  61
  62 struct ts_event {
  63         u16     x;
  64         u16     y;
  65         u16     z1, z2;
  66 };
  67
  68 struct tsc2007 {
  69         struct input_dev        *input;
  70         char                    phys[32];
  71         struct delayed_work     work;
  72         struct ts_event         tc;
  73
  74         struct i2c_client       *client;
  75
  76         u16                     model;
  77         u16                     x_plate_ohms;
  78
  79         unsigned                pendown;
  80         int                     irq;
  81
  82         int                     (*get_pendown_state)(void);
  83         void                    (*clear_penirq)(void);
  84 };
  85
  86 static inline int tsc2007_xfer(struct tsc2007 *tsc, u8 cmd)
  87 {
  88         s32 data;
  89         u16 val;
  90
  91         data = i2c_smbus_read_word_data(tsc->client, cmd);
  92         if (data < 0) {
  93                 dev_err(&tsc->client->dev, "i2c io error: %d\n", data);
  94                 return data;
  95         }
  96
  97         /* The protocol and raw data format from i2c interface:
  98          * S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P
  99          * Where DataLow has [D11-D4], DataHigh has [D3-D0 << 4 | Dummy 4bit].
 100          */
 101         val = swab16(data) >> 4;
 102
 103         dev_dbg(&tsc->client->dev, "data: 0x%x, val: 0x%x\n", data, val);
 104
 105         return val;
 106 }
 107
 108 static void tsc2007_send_event(void *tsc)
 109 {
 110         struct tsc2007  *ts = tsc;
 111         u32             rt;
 112         u16             x, y, z1, z2;
 113
 114         x = ts->tc.x;
 115         y = ts->tc.y;
 116         z1 = ts->tc.z1;
 117         z2 = ts->tc.z2;
 118
 119         /* range filtering */
 120         if (x == MAX_12BIT)
 121                 x = 0;
 122
 123         if (likely(x && z1)) {
 124                 /* compute touch pressure resistance using equation #1 */
 125                 rt = z2;
 126                 rt -= z1;
 127                 rt *= x;
 128                 rt *= ts->x_plate_ohms;
 129                 rt /= z1;
 130                 rt = (rt + 2047) >> 12;
 131         } else
 132                 rt = 0;
 133
 134         /* Sample found inconsistent by debouncing or pressure is beyond
 135          * the maximum. Don't report it to user space, repeat at least
 136          * once more the measurement
 137          */
 138         if (rt > MAX_12BIT) {
 139                 dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
 140
 141                 schedule_delayed_work(&ts->work, TS_POLL_PERIOD);
 142                 return;
 143         }
 144
 145         /* NOTE: We can't rely on the pressure to determine the pen down
 146          * state, even this controller has a pressure sensor.  The pressure
 147          * value can fluctuate for quite a while after lifting the pen and
 148          * in some cases may not even settle at the expected value.
 149          *
 150          * The only safe way to check for the pen up condition is in the
 151          * work function by reading the pen signal state (it's a GPIO and IRQ).
 152          */
 153         if (rt) {
 154                 struct input_dev *input = ts->input;
 155
 156                 if (!ts->pendown) {
 157                         dev_dbg(&ts->client->dev, "DOWN\n");
 158
 159                         input_report_key(input, BTN_TOUCH, 1);
 160                         ts->pendown = 1;
 161                 }
 162
 163                 input_report_abs(input, ABS_X, x);
 164                 input_report_abs(input, ABS_Y, y);
 165                 input_report_abs(input, ABS_PRESSURE, rt);
 166
 167                 input_sync(input);
 168
 169                 dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
 170                         x, y, rt);
 171         }
 172
 173         schedule_delayed_work(&ts->work, TS_POLL_PERIOD);
 174 }
 175
 176 static int tsc2007_read_values(struct tsc2007 *tsc)
 177 {
 178         /* y- still on; turn on only y+ (and ADC) */
 179         tsc->tc.y = tsc2007_xfer(tsc, READ_Y);
 180
 181         /* turn y- off, x+ on, then leave in lowpower */
 182         tsc->tc.x = tsc2007_xfer(tsc, READ_X);
 183
 184         /* turn y+ off, x- on; we'll use formula #1 */
 185         tsc->tc.z1 = tsc2007_xfer(tsc, READ_Z1);
 186         tsc->tc.z2 = tsc2007_xfer(tsc, READ_Z2);
 187
 188         /* power down */
 189         tsc2007_xfer(tsc, PWRDOWN);
 190
 191         return 0;
 192 }
 193
 194 static void tsc2007_work(struct work_struct *work)
 195 {
 196         struct tsc2007 *ts =
 197                 container_of(to_delayed_work(work), struct tsc2007, work);
 198         if (unlikely(!ts->get_pendown_state() && ts->pendown)) {
 199                 struct input_dev *input = ts->input;
 200
 201                 dev_dbg(&ts->client->dev, "UP\n");
 202
 203                 input_report_key(input, BTN_TOUCH, 0);
 204                 input_report_abs(input, ABS_PRESSURE, 0);
 205                 input_sync(input);
 206
 207                 ts->pendown = 0;
 208                 enable_irq(ts->irq);
 209         } else {
 210                 /* pen is still down, continue with the measurement */
 211                 dev_dbg(&ts->client->dev, "pen is still down\n");
 212
 213                 tsc2007_read_values(ts);
 214                 tsc2007_send_event(ts);
 215         }
 216 }
 217
 218 static irqreturn_t tsc2007_irq(int irq, void *handle)
 219 {
 220         struct tsc2007 *ts = handle;
 221
 222         if (likely(ts->get_pendown_state())) {
 223                 disable_irq_nosync(ts->irq);
 224                 schedule_delayed_work(&ts->work, 0);
 225         }
 226
 227         if (ts->clear_penirq)
 228                 ts->clear_penirq();
 229
 230         return IRQ_HANDLED;
 231 }
 232
 233 static int tsc2007_probe(struct i2c_client *client,
 234                         const struct i2c_device_id *id)
 235 {
 236         struct tsc2007 *ts;
 237         struct tsc2007_platform_data *pdata = pdata = client->dev.platform_data;
 238         struct input_dev *input_dev;
 239         int err;
 240
 241         if (!pdata || !pdata->get_pendown_state) {
 242                 dev_err(&client->dev, "platform data is required!\n");
 243                 return -EINVAL;
 244         }
 245
 246         if (!i2c_check_functionality(client->adapter,
 247                                      I2C_FUNC_SMBUS_READ_WORD_DATA))
 248                 return -EIO;
 249
 250         ts = kzalloc(sizeof(struct tsc2007), GFP_KERNEL);
 251         input_dev = input_allocate_device();
 252         if (!ts || !input_dev) {
 253                 err = -ENOMEM;
 254                 goto err_free_mem;
 255         }
 256
 257         ts->client = client;
 258         i2c_set_clientdata(client, ts);
 259
 260         ts->input = input_dev;
 261
 262         ts->model             = pdata->model;
 263         ts->x_plate_ohms      = pdata->x_plate_ohms;
 264         ts->get_pendown_state = pdata->get_pendown_state;
 265         ts->clear_penirq      = pdata->clear_penirq;
 266
 267         pdata->init_platform_hw();
 268
 269         snprintf(ts->phys, sizeof(ts->phys),
 270                  "%s/input0", dev_name(&client->dev));
 271
 272         input_dev->name = "TSC2007 Touchscreen";
 273         input_dev->phys = ts->phys;
 274         input_dev->id.bustype = BUS_I2C;
 275
 276         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 277         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 278
 279         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 280         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 281         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 282
 283         tsc2007_read_values(ts);
 284
 285         ts->irq = client->irq;
 286
 287         INIT_DELAYED_WORK(&ts->work, tsc2007_work);
 288
 289         err = request_irq(ts->irq, tsc2007_irq, 0,
 290                         client->dev.driver->name, ts);
 291         if (err < 0) {
 292                 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
 293                 goto err_free_mem;
 294         }
 295
 296         err = input_register_device(input_dev);
 297         if (err)
 298                 goto err_free_irq;
 299
 300         dev_info(&client->dev, "registered with irq (%d)\n", ts->irq);
 301
 302         return 0;
 303
 304  err_free_irq:
 305         free_irq(ts->irq, ts);
 306  err_free_mem:
 307         input_free_device(input_dev);
 308         kfree(ts);
 309         return err;
 310 }
 311
 312 static int tsc2007_remove(struct i2c_client *client)
 313 {
 314         struct tsc2007  *ts = i2c_get_clientdata(client);
 315         struct tsc2007_platform_data *pdata;
 316
 317         cancel_delayed_work_sync(&ts->work);
 318
 319         pdata = client->dev.platform_data;
 320         pdata->exit_platform_hw();
 321
 322         free_irq(ts->irq, ts);
 323         input_unregister_device(ts->input);
 324         kfree(ts);
 325
 326         return 0;
 327 }
 328
 329 static struct i2c_device_id tsc2007_idtable[] = {
 330         { "tsc2007", 0 },
 331         { }
 332 };
 333
 334 MODULE_DEVICE_TABLE(i2c, tsc2007_idtable);
 335
 336 static struct i2c_driver tsc2007_driver = {
 337         .driver = {
 338                 .owner  = THIS_MODULE,
 339                 .name   = "tsc2007"
 340         },
 341         .id_table       = tsc2007_idtable,
 342         .probe          = tsc2007_probe,
 343         .remove         = tsc2007_remove,
 344 };
 345
 346 static int __init tsc2007_init(void)
 347 {
 348         return i2c_add_driver(&tsc2007_driver);
 349 }
 350
 351 static void __exit tsc2007_exit(void)
 352 {
 353         i2c_del_driver(&tsc2007_driver);
 354 }
 355
 356 module_init(tsc2007_init);
 357 module_exit(tsc2007_exit);
 358
 359 MODULE_AUTHOR("Kwangwoo Lee <kwlee@mtekvision.com>");
 360 MODULE_DESCRIPTION("TSC2007 TouchScreen Driver");
 361 MODULE_LICENSE("GPL");