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 resitor 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
 265         if (!wm->pen_probably_down) {
 266                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 267                 if (!(data & WM97XX_PEN_DOWN))
 268                         return RC_PENUP;
 269                 wm->pen_probably_down = 1;
 270         }
 271
 272         /* set up digitiser */
 273         if (adcsel & 0x8000)
 274                 adcsel = 1 << ((adcsel & 0x7fff) + 3);
 275
 276         dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 277         dig1 &= ~WM9713_ADCSEL_MASK;
 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 | adcsel | 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 & WM97XX_ADCSRC_MASK) != ffs(adcsel >> 1) << 12) {
 308                 dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 309                         *sample & WM97XX_ADCSRC_MASK);
 310                 return RC_PENUP;
 311         }
 312
 313         if (!(*sample & WM97XX_PEN_DOWN)) {
 314                 wm->pen_probably_down = 0;
 315                 return RC_PENUP;
 316         }
 317
 318         return RC_VALID;
 319 }
 320
 321 /*
 322  * Read a coordinate from the WM9713 adc in polling mode.
 323  */
 324 static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 325 {
 326         u16 dig1;
 327         int timeout = 5 * delay;
 328
 329         if (!wm->pen_probably_down) {
 330                 u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 331                 if (!(val & WM97XX_PEN_DOWN))
 332                         return RC_PENUP;
 333                 wm->pen_probably_down = 1;
 334         }
 335
 336         /* set up digitiser */
 337         dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 338         dig1 &= ~WM9713_ADCSEL_MASK;
 339         if (pil)
 340                 dig1 |= WM9713_ADCSEL_PRES;
 341
 342         if (wm->mach_ops && wm->mach_ops->pre_sample)
 343                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 344         wm97xx_reg_write(wm, AC97_WM9713_DIG1,
 345                          dig1 | WM9713_POLL | WM9713_COO);
 346
 347         /* wait 3 AC97 time slots + delay for conversion */
 348         poll_delay(delay);
 349         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 350         /* wait for POLL to go low */
 351         while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
 352                && timeout) {
 353                 udelay(AC97_LINK_FRAME);
 354                 timeout--;
 355         }
 356
 357         if (timeout <= 0) {
 358                 /* If PDEN is set, we can get a timeout when pen goes up */
 359                 if (is_pden(wm))
 360                         wm->pen_probably_down = 0;
 361                 else
 362                         dev_dbg(wm->dev, "adc sample timeout");
 363                 return RC_PENUP;
 364         }
 365
 366         /* read back data */
 367         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 368         if (pil)
 369                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 370         else
 371                 data->p = DEFAULT_PRESSURE;
 372
 373         if (wm->mach_ops && wm->mach_ops->post_sample)
 374                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 375
 376         /* check we have correct sample */
 377         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 378                 goto err;
 379         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 380                 goto err;
 381
 382         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 383                 wm->pen_probably_down = 0;
 384                 return RC_PENUP;
 385         }
 386         return RC_VALID;
 387 err:
 388         return 0;
 389 }
 390
 391 /*
 392  * Sample the WM9713 touchscreen in polling mode
 393  */
 394 static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 395 {
 396         int rc;
 397
 398         if (coord) {
 399                 rc = wm9713_poll_coord(wm, data);
 400                 if (rc != RC_VALID)
 401                         return rc;
 402         } else {
 403                 rc = wm9713_poll_sample(wm, WM9713_ADCSEL_X, &data->x);
 404                 if (rc != RC_VALID)
 405                         return rc;
 406                 rc = wm9713_poll_sample(wm, WM9713_ADCSEL_Y, &data->y);
 407                 if (rc != RC_VALID)
 408                         return rc;
 409                 if (pil) {
 410                         rc = wm9713_poll_sample(wm, WM9713_ADCSEL_PRES,
 411                                                 &data->p);
 412                         if (rc != RC_VALID)
 413                                 return rc;
 414                 } else
 415                         data->p = DEFAULT_PRESSURE;
 416         }
 417         return RC_VALID;
 418 }
 419
 420 /*
 421  * Enable WM9713 continuous mode, i.e. touch data is streamed across
 422  * an AC97 slot
 423  */
 424 static int wm9713_acc_enable(struct wm97xx *wm, int enable)
 425 {
 426         u16 dig1, dig2, dig3;
 427         int ret = 0;
 428
 429         dig1 = wm->dig[0];
 430         dig2 = wm->dig[1];
 431         dig3 = wm->dig[2];
 432
 433         if (enable) {
 434                 /* continous mode */
 435                 if (wm->mach_ops->acc_startup &&
 436                         (ret = wm->mach_ops->acc_startup(wm)) < 0)
 437                         return ret;
 438
 439                 dig1 &= ~WM9713_ADCSEL_MASK;
 440                 dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
 441                         WM9713_ADCSEL_Y;
 442                 if (pil)
 443                         dig1 |= WM9713_ADCSEL_PRES;
 444                 dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
 445                         WM97XX_CM_RATE_MASK);
 446                 dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
 447                 WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
 448                 dig3 |= WM9713_PDEN;
 449         } else {
 450                 dig1 &= ~(WM9713_CTC | WM9713_COO);
 451                 dig2 &= ~WM97XX_SLEN;
 452                 dig3 &= ~WM9713_PDEN;
 453                 if (wm->mach_ops->acc_shutdown)
 454                         wm->mach_ops->acc_shutdown(wm);
 455         }
 456
 457         wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 458         wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 459         wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 460
 461         return ret;
 462 }
 463
 464 struct wm97xx_codec_drv wm9713_codec = {
 465         .id = WM9713_ID2,
 466         .name = "wm9713",
 467         .poll_sample = wm9713_poll_sample,
 468         .poll_touch = wm9713_poll_touch,
 469         .acc_enable = wm9713_acc_enable,
 470         .phy_init = wm9713_phy_init,
 471         .dig_enable = wm9713_dig_enable,
 472         .dig_restore = wm9713_dig_restore,
 473         .aux_prepare = wm9713_aux_prepare,
 474 };
 475 EXPORT_SYMBOL_GPL(wm9713_codec);
 476
 477 /* Module information */
 478 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 479 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 480 MODULE_LICENSE("GPL");