drivers/input/touchscreen/wm9713.c

   1 /*
   2  * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
   3  *
   4  * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
   5  * Author: Liam Girdwood <lrg@slimlogic.co.uk>
   6  * Parts Copyright : Ian Molton <spyro@f2s.com>
   7  *                   Andrew Zabolotny <zap@homelink.ru>
   8  *                   Russell King <rmk@arm.linux.org.uk>
   9  *
  10  *  This program is free software; you can redistribute  it and/or modify it
  11  *  under  the terms of  the GNU General  Public License as published by the
  12  *  Free Software Foundation;  either version 2 of the  License, or (at your
  13  *  option) any later version.
  14  *
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/moduleparam.h>
  19 #include <linux/version.h>
  20 #include <linux/kernel.h>
  21 #include <linux/input.h>
  22 #include <linux/delay.h>
  23 #include <linux/bitops.h>
  24 #include <linux/wm97xx.h>
  25
  26 #define TS_NAME                 "wm97xx"
  27 #define WM9713_VERSION          "1.00"
  28 #define DEFAULT_PRESSURE        0xb0c0
  29
  30 /*
  31  * Module parameters
  32  */
  33
  34 /*
  35  * Set internal pull up for pen detect.
  36  *
  37  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
  38  * i.e. pull up resistance = 64k Ohms / rpu.
  39  *
  40  * Adjust this value if you are having problems with pen detect not
  41  * detecting any down event.
  42  */
  43 static int rpu = 8;
  44 module_param(rpu, int, 0);
  45 MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");
  46
  47 /*
  48  * Set current used for pressure measurement.
  49  *
  50  * Set pil = 2 to use 400uA
  51  *     pil = 1 to use 200uA and
  52  *     pil = 0 to disable pressure measurement.
  53  *
  54  * This is used to increase the range of values returned by the adc
  55  * when measureing touchpanel pressure.
  56  */
  57 static int pil;
  58 module_param(pil, int, 0);
  59 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
  60
  61 /*
  62  * Set threshold for pressure measurement.
  63  *
  64  * Pen down pressure below threshold is ignored.
  65  */
  66 static int pressure = DEFAULT_PRESSURE & 0xfff;
  67 module_param(pressure, int, 0);
  68 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
  69
  70 /*
  71  * Set adc sample delay.
  72  *
  73  * For accurate touchpanel measurements, some settling time may be
  74  * required between the switch matrix applying a voltage across the
  75  * touchpanel plate and the ADC sampling the signal.
  76  *
  77  * This delay can be set by setting delay = n, where n is the array
  78  * position of the delay in the array delay_table below.
  79  * Long delays > 1ms are supported for completeness, but are not
  80  * recommended.
  81  */
  82 static int delay = 4;
  83 module_param(delay, int, 0);
  84 MODULE_PARM_DESC(delay, "Set adc sample delay.");
  85
  86 /*
  87  * Set five_wire = 1 to use a 5 wire touchscreen.
  88  *
  89  * NOTE: Five wire mode does not allow for readback of pressure.
  90  */
  91 static int five_wire;
  92 module_param(five_wire, int, 0);
  93 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
  94
  95 /*
  96  * Set adc mask function.
  97  *
  98  * Sources of glitch noise, such as signals driving an LCD display, may feed
  99  * through to the touch screen plates and affect measurement accuracy. In
 100  * order to minimise this, a signal may be applied to the MASK pin to delay or
 101  * synchronise the sampling.
 102  *
 103  * 0 = No delay or sync
 104  * 1 = High on pin stops conversions
 105  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 106  * 3 = Edge triggered, edge on pin starts conversion after delay param
 107  */
 108 static int mask;
 109 module_param(mask, int, 0);
 110 MODULE_PARM_DESC(mask, "Set adc mask function.");
 111
 112 /*
 113  * Coordinate Polling Enable.
 114  *
 115  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
 116  * for every poll.
 117  */
 118 static int coord;
 119 module_param(coord, int, 0);
 120 MODULE_PARM_DESC(coord, "Polling coordinate mode");
 121
 122 /*
 123  * ADC sample delay times in uS
 124  */
 125 static const int delay_table[] = {
 126         21,    /* 1 AC97 Link frames */
 127         42,    /* 2 */
 128         84,    /* 4 */
 129         167,   /* 8 */
 130         333,   /* 16 */
 131         667,   /* 32 */
 132         1000,  /* 48 */
 133         1333,  /* 64 */
 134         2000,  /* 96 */
 135         2667,  /* 128 */
 136         3333,  /* 160 */
 137         4000,  /* 192 */
 138         4667,  /* 224 */
 139         5333,  /* 256 */
 140         6000,  /* 288 */
 141         0      /* No delay, switch matrix always on */
 142 };
 143
 144 /*
 145  * Delay after issuing a POLL command.
 146  *
 147  * The delay is 3 AC97 link frames + the touchpanel settling delay
 148  */
 149 static inline void poll_delay(int d)
 150 {
 151         udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 152 }
 153
 154 /*
 155  * set up the physical settings of the WM9713
 156  */
 157 static void wm9713_phy_init(struct wm97xx *wm)
 158 {
 159         u16 dig1 = 0, dig2, dig3;
 160
 161         /* default values */
 162         dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
 163         dig3 = WM9712_RPU(1);
 164
 165         /* rpu */
 166         if (rpu) {
 167                 dig3 &= 0xffc0;
 168                 dig3 |= WM9712_RPU(rpu);
 169                 dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 170                          64000 / rpu);
 171         }
 172
 173         /* Five wire panel? */
 174         if (five_wire) {
 175                 dig3 |= WM9713_45W;
 176                 dev_info(wm->dev, "setting 5-wire touchscreen mode.");
 177
 178                 if (pil) {
 179                         dev_warn(wm->dev,
 180                                  "Pressure measurement not supported in 5 "
 181                                  "wire mode, disabling\n");
 182                         pil = 0;
 183                 }
 184         }
 185
 186         /* touchpanel pressure */
 187         if (pil == 2) {
 188                 dig3 |= WM9712_PIL;
 189                 dev_info(wm->dev,
 190                          "setting pressure measurement current to 400uA.");
 191         } else if (pil)
 192                 dev_info(wm->dev,
 193                          "setting pressure measurement current to 200uA.");
 194         if (!pil)
 195                 pressure = 0;
 196
 197         /* sample settling delay */
 198         if (delay < 0 || delay > 15) {
 199                 dev_info(wm->dev, "supplied delay out of range.");
 200                 delay = 4;
 201                 dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
 202                          delay_table[delay]);
 203         }
 204         dig2 &= 0xff0f;
 205         dig2 |= WM97XX_DELAY(delay);
 206
 207         /* mask */
 208         dig3 |= ((mask & 0x3) << 4);
 209         if (coord)
 210                 dig3 |= WM9713_WAIT;
 211
 212         wm->misc = wm97xx_reg_read(wm, 0x5a);
 213
 214         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 215         wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 216         wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 217         wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
 218 }
 219
 220 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
 221 {
 222         u16 val;
 223
 224         if (enable) {
 225                 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 226                 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
 227                 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
 228                                  WM97XX_PRP_DET_DIG);
 229                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 230         } else {
 231                 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
 232                                         ~WM97XX_PRP_DET_DIG);
 233                 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 234                 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
 235         }
 236 }
 237
 238 static void wm9713_dig_restore(struct wm97xx *wm)
 239 {
 240         wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
 241         wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
 242         wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
 243 }
 244
 245 static void wm9713_aux_prepare(struct wm97xx *wm)
 246 {
 247         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 248         wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
 249         wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
 250         wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
 251 }
 252
 253 static inline int is_pden(struct wm97xx *wm)
 254 {
 255         return wm->dig[2] & WM9713_PDEN;
 256 }
 257
 258 /*
 259  * Read a sample from the WM9713 adc in polling mode.
 260  */
 261 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 262 {
 263         u16 dig1;
 264         int timeout = 5 * delay;
 265
 266         if (!wm->pen_probably_down) {
 267                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 268                 if (!(data & WM97XX_PEN_DOWN))
 269                         return RC_PENUP;
 270                 wm->pen_probably_down = 1;
 271         }
 272
 273         /* set up digitiser */
 274         if (adcsel & 0x8000)
 275                 adcsel = 1 << ((adcsel & 0x7fff) + 3);
 276
 277         dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 278         dig1 &= ~WM9713_ADCSEL_MASK;
 279
 280         if (wm->mach_ops && wm->mach_ops->pre_sample)
 281                 wm->mach_ops->pre_sample(adcsel);
 282         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | adcsel | WM9713_POLL);
 283
 284         /* wait 3 AC97 time slots + delay for conversion */
 285         poll_delay(delay);
 286
 287         /* wait for POLL to go low */
 288         while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
 289                 timeout) {
 290                 udelay(AC97_LINK_FRAME);
 291                 timeout--;
 292         }
 293
 294         if (timeout <= 0) {
 295                 /* If PDEN is set, we can get a timeout when pen goes up */
 296                 if (is_pden(wm))
 297                         wm->pen_probably_down = 0;
 298                 else
 299                         dev_dbg(wm->dev, "adc sample timeout");
 300                 return RC_PENUP;
 301         }
 302
 303         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 304         if (wm->mach_ops && wm->mach_ops->post_sample)
 305                 wm->mach_ops->post_sample(adcsel);
 306
 307         /* check we have correct sample */
 308         if ((*sample & WM97XX_ADCSRC_MASK) != ffs(adcsel >> 1) << 12) {
 309                 dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 310                         *sample & WM97XX_ADCSRC_MASK);
 311                 return RC_PENUP;
 312         }
 313
 314         if (!(*sample & WM97XX_PEN_DOWN)) {
 315                 wm->pen_probably_down = 0;
 316                 return RC_PENUP;
 317         }
 318
 319         return RC_VALID;
 320 }
 321
 322 /*
 323  * Read a coordinate from the WM9713 adc in polling mode.
 324  */
 325 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 326 {
 327         u16 dig1;
 328         int timeout = 5 * delay;
 329
 330         if (!wm->pen_probably_down) {
 331                 u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 332                 if (!(val & WM97XX_PEN_DOWN))
 333                         return RC_PENUP;
 334                 wm->pen_probably_down = 1;
 335         }
 336
 337         /* set up digitiser */
 338         dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 339         dig1 &= ~WM9713_ADCSEL_MASK;
 340         if (pil)
 341                 dig1 |= WM9713_ADCSEL_PRES;
 342
 343         if (wm->mach_ops && wm->mach_ops->pre_sample)
 344                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 345         wm97xx_reg_write(wm, AC97_WM9713_DIG1,
 346                          dig1 | WM9713_POLL | WM9713_COO);
 347
 348         /* wait 3 AC97 time slots + delay for conversion */
 349         poll_delay(delay);
 350         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 351         /* wait for POLL to go low */
 352         while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
 353                && timeout) {
 354                 udelay(AC97_LINK_FRAME);
 355                 timeout--;
 356         }
 357
 358         if (timeout <= 0) {
 359                 /* If PDEN is set, we can get a timeout when pen goes up */
 360                 if (is_pden(wm))
 361                         wm->pen_probably_down = 0;
 362                 else
 363                         dev_dbg(wm->dev, "adc sample timeout");
 364                 return RC_PENUP;
 365         }
 366
 367         /* read back data */
 368         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 369         if (pil)
 370                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 371         else
 372                 data->p = DEFAULT_PRESSURE;
 373
 374         if (wm->mach_ops && wm->mach_ops->post_sample)
 375                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 376
 377         /* check we have correct sample */
 378         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 379                 goto err;
 380         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 381                 goto err;
 382
 383         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 384                 wm->pen_probably_down = 0;
 385                 return RC_PENUP;
 386         }
 387         return RC_VALID;
 388 err:
 389         return 0;
 390 }
 391
 392 /*
 393  * Sample the WM9713 touchscreen in polling mode
 394  */
 395 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 396 {
 397         int rc;
 398
 399         if (coord) {
 400                 rc = wm9713_poll_coord(wm, data);
 401                 if (rc != RC_VALID)
 402                         return rc;
 403         } else {
 404                 rc = wm9713_poll_sample(wm, WM9713_ADCSEL_X, &data->x);
 405                 if (rc != RC_VALID)
 406                         return rc;
 407                 rc = wm9713_poll_sample(wm, WM9713_ADCSEL_Y, &data->y);
 408                 if (rc != RC_VALID)
 409                         return rc;
 410                 if (pil) {
 411                         rc = wm9713_poll_sample(wm, WM9713_ADCSEL_PRES,
 412                                                 &data->p);
 413                         if (rc != RC_VALID)
 414                                 return rc;
 415                 } else
 416                         data->p = DEFAULT_PRESSURE;
 417         }
 418         return RC_VALID;
 419 }
 420
 421 /*
 422  * Enable WM9713 continuous mode, i.e. touch data is streamed across
 423  * an AC97 slot
 424  */
 425 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
 426 {
 427         u16 dig1, dig2, dig3;
 428         int ret = 0;
 429
 430         dig1 = wm->dig[0];
 431         dig2 = wm->dig[1];
 432         dig3 = wm->dig[2];
 433
 434         if (enable) {
 435                 /* continous mode */
 436                 if (wm->mach_ops->acc_startup &&
 437                         (ret = wm->mach_ops->acc_startup(wm)) < 0)
 438                         return ret;
 439
 440                 dig1 &= ~WM9713_ADCSEL_MASK;
 441                 dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
 442                         WM9713_ADCSEL_Y;
 443                 if (pil)
 444                         dig1 |= WM9713_ADCSEL_PRES;
 445                 dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
 446                         WM97XX_CM_RATE_MASK);
 447                 dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
 448                 WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
 449                 dig3 |= WM9713_PDEN;
 450         } else {
 451                 dig1 &= ~(WM9713_CTC | WM9713_COO);
 452                 dig2 &= ~WM97XX_SLEN;
 453                 dig3 &= ~WM9713_PDEN;
 454                 if (wm->mach_ops->acc_shutdown)
 455                         wm->mach_ops->acc_shutdown(wm);
 456         }
 457
 458         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 459         wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 460         wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 461
 462         return ret;
 463 }
 464
 465 struct wm97xx_codec_drv wm9713_codec = {
 466         .id = WM9713_ID2,
 467         .name = "wm9713",
 468         .poll_sample = wm9713_poll_sample,
 469         .poll_touch = wm9713_poll_touch,
 470         .acc_enable = wm9713_acc_enable,
 471         .phy_init = wm9713_phy_init,
 472         .dig_enable = wm9713_dig_enable,
 473         .dig_restore = wm9713_dig_restore,
 474         .aux_prepare = wm9713_aux_prepare,
 475 };
 476 EXPORT_SYMBOL_GPL(wm9713_codec);
 477
 478 /* Module information */
 479 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 480 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 481 MODULE_LICENSE("GPL");