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/kernel.h>
  20 #include <linux/input.h>
  21 #include <linux/delay.h>
  22 #include <linux/bitops.h>
  23 #include <linux/wm97xx.h>
  24
  25 #define TS_NAME                 "wm97xx"
  26 #define WM9713_VERSION          "1.00"
  27 #define DEFAULT_PRESSURE        0xb0c0
  28
  29 /*
  30  * Module parameters
  31  */
  32
  33 /*
  34  * Set internal pull up for pen detect.
  35  *
  36  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
  37  * i.e. pull up resistance = 64k Ohms / rpu.
  38  *
  39  * Adjust this value if you are having problems with pen detect not
  40  * detecting any down event.
  41  */
  42 static int rpu = 8;
  43 module_param(rpu, int, 0);
  44 MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect.");
  45
  46 /*
  47  * Set current used for pressure measurement.
  48  *
  49  * Set pil = 2 to use 400uA
  50  *     pil = 1 to use 200uA and
  51  *     pil = 0 to disable pressure measurement.
  52  *
  53  * This is used to increase the range of values returned by the adc
  54  * when measureing touchpanel pressure.
  55  */
  56 static int pil;
  57 module_param(pil, int, 0);
  58 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
  59
  60 /*
  61  * Set threshold for pressure measurement.
  62  *
  63  * Pen down pressure below threshold is ignored.
  64  */
  65 static int pressure = DEFAULT_PRESSURE & 0xfff;
  66 module_param(pressure, int, 0);
  67 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
  68
  69 /*
  70  * Set adc sample delay.
  71  *
  72  * For accurate touchpanel measurements, some settling time may be
  73  * required between the switch matrix applying a voltage across the
  74  * touchpanel plate and the ADC sampling the signal.
  75  *
  76  * This delay can be set by setting delay = n, where n is the array
  77  * position of the delay in the array delay_table below.
  78  * Long delays > 1ms are supported for completeness, but are not
  79  * recommended.
  80  */
  81 static int delay = 4;
  82 module_param(delay, int, 0);
  83 MODULE_PARM_DESC(delay, "Set adc sample delay.");
  84
  85 /*
  86  * Set five_wire = 1 to use a 5 wire touchscreen.
  87  *
  88  * NOTE: Five wire mode does not allow for readback of pressure.
  89  */
  90 static int five_wire;
  91 module_param(five_wire, int, 0);
  92 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
  93
  94 /*
  95  * Set adc mask function.
  96  *
  97  * Sources of glitch noise, such as signals driving an LCD display, may feed
  98  * through to the touch screen plates and affect measurement accuracy. In
  99  * order to minimise this, a signal may be applied to the MASK pin to delay or
 100  * synchronise the sampling.
 101  *
 102  * 0 = No delay or sync
 103  * 1 = High on pin stops conversions
 104  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 105  * 3 = Edge triggered, edge on pin starts conversion after delay param
 106  */
 107 static int mask;
 108 module_param(mask, int, 0);
 109 MODULE_PARM_DESC(mask, "Set adc mask function.");
 110
 111 /*
 112  * Coordinate Polling Enable.
 113  *
 114  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
 115  * for every poll.
 116  */
 117 static int coord;
 118 module_param(coord, int, 0);
 119 MODULE_PARM_DESC(coord, "Polling coordinate mode");
 120
 121 /*
 122  * ADC sample delay times in uS
 123  */
 124 static const int delay_table[] = {
 125         21,    /* 1 AC97 Link frames */
 126         42,    /* 2 */
 127         84,    /* 4 */
 128         167,   /* 8 */
 129         333,   /* 16 */
 130         667,   /* 32 */
 131         1000,  /* 48 */
 132         1333,  /* 64 */
 133         2000,  /* 96 */
 134         2667,  /* 128 */
 135         3333,  /* 160 */
 136         4000,  /* 192 */
 137         4667,  /* 224 */
 138         5333,  /* 256 */
 139         6000,  /* 288 */
 140         0      /* No delay, switch matrix always on */
 141 };
 142
 143 /*
 144  * Delay after issuing a POLL command.
 145  *
 146  * The delay is 3 AC97 link frames + the touchpanel settling delay
 147  */
 148 static inline void poll_delay(int d)
 149 {
 150         udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 151 }
 152
 153 /*
 154  * set up the physical settings of the WM9713
 155  */
 156 static void wm9713_phy_init(struct wm97xx *wm)
 157 {
 158         u16 dig1 = 0, dig2, dig3;
 159
 160         /* default values */
 161         dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
 162         dig3 = WM9712_RPU(1);
 163
 164         /* rpu */
 165         if (rpu) {
 166                 dig3 &= 0xffc0;
 167                 dig3 |= WM9712_RPU(rpu);
 168                 dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 169                          64000 / rpu);
 170         }
 171
 172         /* Five wire panel? */
 173         if (five_wire) {
 174                 dig3 |= WM9713_45W;
 175                 dev_info(wm->dev, "setting 5-wire touchscreen mode.");
 176
 177                 if (pil) {
 178                         dev_warn(wm->dev,
 179                                  "Pressure measurement not supported in 5 "
 180                                  "wire mode, disabling\n");
 181                         pil = 0;
 182                 }
 183         }
 184
 185         /* touchpanel pressure */
 186         if (pil == 2) {
 187                 dig3 |= WM9712_PIL;
 188                 dev_info(wm->dev,
 189                          "setting pressure measurement current to 400uA.");
 190         } else if (pil)
 191                 dev_info(wm->dev,
 192                          "setting pressure measurement current to 200uA.");
 193         if (!pil)
 194                 pressure = 0;
 195
 196         /* sample settling delay */
 197         if (delay < 0 || delay > 15) {
 198                 dev_info(wm->dev, "supplied delay out of range.");
 199                 delay = 4;
 200                 dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
 201                          delay_table[delay]);
 202         }
 203         dig2 &= 0xff0f;
 204         dig2 |= WM97XX_DELAY(delay);
 205
 206         /* mask */
 207         dig3 |= ((mask & 0x3) << 4);
 208         if (coord)
 209                 dig3 |= WM9713_WAIT;
 210
 211         wm->misc = wm97xx_reg_read(wm, 0x5a);
 212
 213         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 214         wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 215         wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 216         wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
 217 }
 218
 219 static void wm9713_dig_enable(struct wm97xx *wm, int enable)
 220 {
 221         u16 val;
 222
 223         if (enable) {
 224                 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 225                 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
 226                 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
 227                                  WM97XX_PRP_DET_DIG);
 228                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 229         } else {
 230                 wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
 231                                         ~WM97XX_PRP_DET_DIG);
 232                 val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 233                 wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
 234         }
 235 }
 236
 237 static void wm9713_dig_restore(struct wm97xx *wm)
 238 {
 239         wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
 240         wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
 241         wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
 242 }
 243
 244 static void wm9713_aux_prepare(struct wm97xx *wm)
 245 {
 246         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 247         wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
 248         wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
 249         wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
 250 }
 251
 252 static inline int is_pden(struct wm97xx *wm)
 253 {
 254         return wm->dig[2] & WM9713_PDEN;
 255 }
 256
 257 /*
 258  * Read a sample from the WM9713 adc in polling mode.
 259  */
 260 static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 261 {
 262         u16 dig1;
 263         int timeout = 5 * delay;
 264         bool wants_pen = adcsel & WM97XX_PEN_DOWN;
 265
 266         if (wants_pen && !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         dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 275         dig1 &= ~WM9713_ADCSEL_MASK;
 276         /* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
 277         dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
 278
 279         if (wm->mach_ops && wm->mach_ops->pre_sample)
 280                 wm->mach_ops->pre_sample(adcsel);
 281         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | WM9713_POLL);
 282
 283         /* wait 3 AC97 time slots + delay for conversion */
 284         poll_delay(delay);
 285
 286         /* wait for POLL to go low */
 287         while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
 288                 timeout) {
 289                 udelay(AC97_LINK_FRAME);
 290                 timeout--;
 291         }
 292
 293         if (timeout <= 0) {
 294                 /* If PDEN is set, we can get a timeout when pen goes up */
 295                 if (is_pden(wm))
 296                         wm->pen_probably_down = 0;
 297                 else
 298                         dev_dbg(wm->dev, "adc sample timeout");
 299                 return RC_PENUP;
 300         }
 301
 302         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 303         if (wm->mach_ops && wm->mach_ops->post_sample)
 304                 wm->mach_ops->post_sample(adcsel);
 305
 306         /* check we have correct sample */
 307         if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
 308                 dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
 309                         adcsel & WM97XX_ADCSEL_MASK,
 310                         *sample & WM97XX_ADCSEL_MASK);
 311                 return RC_PENUP;
 312         }
 313
 314         if (wants_pen && !(*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, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
 405                 if (rc != RC_VALID)
 406                         return rc;
 407                 rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
 408                 if (rc != RC_VALID)
 409                         return rc;
 410                 if (pil) {
 411                         rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
 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                 /* continuous 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");