drivers/input/touchscreen/wm9712.c

   1 /*
   2  * wm9712.c  --  Codec driver for Wolfson WM9712 AC97 Codecs.
   3  *
   4  * Copyright 2003, 2004, 2005, 2006, 2007 Wolfson Microelectronics PLC.
   5  * Author: Liam Girdwood
   6  *         liam.girdwood@wolfsonmicro.com or linux@wolfsonmicro.com
   7  * Parts Copyright : Ian Molton <spyro@f2s.com>
   8  *                   Andrew Zabolotny <zap@homelink.ru>
   9  *                   Russell King <rmk@arm.linux.org.uk>
  10  *
  11  *  This program is free software; you can redistribute  it and/or modify it
  12  *  under  the terms of  the GNU General  Public License as published by the
  13  *  Free Software Foundation;  either version 2 of the  License, or (at your
  14  *  option) any later version.
  15  *
  16  */
  17
  18 #include <linux/module.h>
  19 #include <linux/moduleparam.h>
  20 #include <linux/version.h>
  21 #include <linux/kernel.h>
  22 #include <linux/input.h>
  23 #include <linux/delay.h>
  24 #include <linux/bitops.h>
  25 #include <linux/wm97xx.h>
  26
  27 #define TS_NAME                 "wm97xx"
  28 #define WM9712_VERSION          "1.00"
  29 #define DEFAULT_PRESSURE        0xb0c0
  30
  31 /*
  32  * Module parameters
  33  */
  34
  35 /*
  36  * Set internal pull up for pen detect.
  37  *
  38  * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
  39  * i.e. pull up resistance = 64k Ohms / rpu.
  40  *
  41  * Adjust this value if you are having problems with pen detect not
  42  * detecting any down event.
  43  */
  44 static int rpu = 8;
  45 module_param(rpu, int, 0);
  46 MODULE_PARM_DESC(rpu, "Set internal pull up resitor for pen detect.");
  47
  48 /*
  49  * Set current used for pressure measurement.
  50  *
  51  * Set pil = 2 to use 400uA
  52  *     pil = 1 to use 200uA and
  53  *     pil = 0 to disable pressure measurement.
  54  *
  55  * This is used to increase the range of values returned by the adc
  56  * when measureing touchpanel pressure.
  57  */
  58 static int pil;
  59 module_param(pil, int, 0);
  60 MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
  61
  62 /*
  63  * Set threshold for pressure measurement.
  64  *
  65  * Pen down pressure below threshold is ignored.
  66  */
  67 static int pressure = DEFAULT_PRESSURE & 0xfff;
  68 module_param(pressure, int, 0);
  69 MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
  70
  71 /*
  72  * Set adc sample delay.
  73  *
  74  * For accurate touchpanel measurements, some settling time may be
  75  * required between the switch matrix applying a voltage across the
  76  * touchpanel plate and the ADC sampling the signal.
  77  *
  78  * This delay can be set by setting delay = n, where n is the array
  79  * position of the delay in the array delay_table below.
  80  * Long delays > 1ms are supported for completeness, but are not
  81  * recommended.
  82  */
  83 static int delay = 3;
  84 module_param(delay, int, 0);
  85 MODULE_PARM_DESC(delay, "Set adc sample delay.");
  86
  87 /*
  88  * Set five_wire = 1 to use a 5 wire touchscreen.
  89  *
  90  * NOTE: Five wire mode does not allow for readback of pressure.
  91  */
  92 static int five_wire;
  93 module_param(five_wire, int, 0);
  94 MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
  95
  96 /*
  97  * Set adc mask function.
  98  *
  99  * Sources of glitch noise, such as signals driving an LCD display, may feed
 100  * through to the touch screen plates and affect measurement accuracy. In
 101  * order to minimise this, a signal may be applied to the MASK pin to delay or
 102  * synchronise the sampling.
 103  *
 104  * 0 = No delay or sync
 105  * 1 = High on pin stops conversions
 106  * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 107  * 3 = Edge triggered, edge on pin starts conversion after delay param
 108  */
 109 static int mask;
 110 module_param(mask, int, 0);
 111 MODULE_PARM_DESC(mask, "Set adc mask function.");
 112
 113 /*
 114  * Coordinate Polling Enable.
 115  *
 116  * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
 117  * for every poll.
 118  */
 119 static int coord;
 120 module_param(coord, int, 0);
 121 MODULE_PARM_DESC(coord, "Polling coordinate mode");
 122
 123 /*
 124  * ADC sample delay times in uS
 125  */
 126 static const int delay_table[] = {
 127         21,    /* 1 AC97 Link frames */
 128         42,    /* 2 */
 129         84,    /* 4 */
 130         167,   /* 8 */
 131         333,   /* 16 */
 132         667,   /* 32 */
 133         1000,  /* 48 */
 134         1333,  /* 64 */
 135         2000,  /* 96 */
 136         2667,  /* 128 */
 137         3333,  /* 160 */
 138         4000,  /* 192 */
 139         4667,  /* 224 */
 140         5333,  /* 256 */
 141         6000,  /* 288 */
 142         0      /* No delay, switch matrix always on */
 143 };
 144
 145 /*
 146  * Delay after issuing a POLL command.
 147  *
 148  * The delay is 3 AC97 link frames + the touchpanel settling delay
 149  */
 150 static inline void poll_delay(int d)
 151 {
 152         udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 153 }
 154
 155 /*
 156  * set up the physical settings of the WM9712
 157  */
 158 static void wm9712_phy_init(struct wm97xx *wm)
 159 {
 160         u16 dig1 = 0;
 161         u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
 162
 163         /* WM9712 rpu */
 164         if (rpu) {
 165                 dig2 &= 0xffc0;
 166                 dig2 |= WM9712_RPU(rpu);
 167                 dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms",
 168                         64000 / rpu);
 169         }
 170
 171         /* WM9712 five wire */
 172         if (five_wire) {
 173                 dig2 |= WM9712_45W;
 174                 dev_dbg(wm->dev, "setting 5-wire touchscreen mode.");
 175
 176                 if (pil) {
 177                         dev_warn(wm->dev, "pressure measurement is not "
 178                                  "supported in 5-wire mode\n");
 179                         pil = 0;
 180                 }
 181         }
 182
 183         /* touchpanel pressure current*/
 184         if (pil == 2) {
 185                 dig2 |= WM9712_PIL;
 186                 dev_dbg(wm->dev,
 187                         "setting pressure measurement current to 400uA.");
 188         } else if (pil)
 189                 dev_dbg(wm->dev,
 190                         "setting pressure measurement current to 200uA.");
 191         if (!pil)
 192                 pressure = 0;
 193
 194         /* polling mode sample settling delay */
 195         if (delay < 0 || delay > 15) {
 196                 dev_dbg(wm->dev, "supplied delay out of range.");
 197                 delay = 4;
 198         }
 199         dig1 &= 0xff0f;
 200         dig1 |= WM97XX_DELAY(delay);
 201         dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
 202                 delay_table[delay]);
 203
 204         /* mask */
 205         dig2 |= ((mask & 0x3) << 6);
 206         if (mask) {
 207                 u16 reg;
 208                 /* Set GPIO4 as Mask Pin*/
 209                 reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
 210                 wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
 211                 reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
 212                 wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
 213         }
 214
 215         /* wait - coord mode */
 216         if (coord)
 217                 dig2 |= WM9712_WAIT;
 218
 219         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 220         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 221 }
 222
 223 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
 224 {
 225         u16 dig2 = wm->dig[2];
 226
 227         if (enable) {
 228                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 229                                  dig2 | WM97XX_PRP_DET_DIG);
 230                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 231         } else
 232                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 233                                  dig2 & ~WM97XX_PRP_DET_DIG);
 234 }
 235
 236 static void wm9712_aux_prepare(struct wm97xx *wm)
 237 {
 238         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 239         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
 240         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
 241 }
 242
 243 static void wm9712_dig_restore(struct wm97xx *wm)
 244 {
 245         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
 246         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
 247 }
 248
 249 static inline int is_pden(struct wm97xx *wm)
 250 {
 251         return wm->dig[2] & WM9712_PDEN;
 252 }
 253
 254 /*
 255  * Read a sample from the WM9712 adc in polling mode.
 256  */
 257 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 258 {
 259         int timeout = 5 * delay;
 260
 261         if (!wm->pen_probably_down) {
 262                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 263                 if (!(data & WM97XX_PEN_DOWN))
 264                         return RC_PENUP;
 265                 wm->pen_probably_down = 1;
 266         }
 267
 268         /* set up digitiser */
 269         if (adcsel & 0x8000)
 270                 adcsel = ((adcsel & 0x7fff) + 3) << 12;
 271
 272         if (wm->mach_ops && wm->mach_ops->pre_sample)
 273                 wm->mach_ops->pre_sample(adcsel);
 274         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 275                          adcsel | WM97XX_POLL | WM97XX_DELAY(delay));
 276
 277         /* wait 3 AC97 time slots + delay for conversion */
 278         poll_delay(delay);
 279
 280         /* wait for POLL to go low */
 281         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 282                && timeout) {
 283                 udelay(AC97_LINK_FRAME);
 284                 timeout--;
 285         }
 286
 287         if (timeout <= 0) {
 288                 /* If PDEN is set, we can get a timeout when pen goes up */
 289                 if (is_pden(wm))
 290                         wm->pen_probably_down = 0;
 291                 else
 292                         dev_dbg(wm->dev, "adc sample timeout");
 293                 return RC_PENUP;
 294         }
 295
 296         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 297         if (wm->mach_ops && wm->mach_ops->post_sample)
 298                 wm->mach_ops->post_sample(adcsel);
 299
 300         /* check we have correct sample */
 301         if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) {
 302                 dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 303                 *sample & WM97XX_ADCSEL_MASK);
 304                 return RC_PENUP;
 305         }
 306
 307         if (!(*sample & WM97XX_PEN_DOWN)) {
 308                 wm->pen_probably_down = 0;
 309                 return RC_PENUP;
 310         }
 311
 312         return RC_VALID;
 313 }
 314
 315 /*
 316  * Read a coord from the WM9712 adc in polling mode.
 317  */
 318 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 319 {
 320         int timeout = 5 * delay;
 321
 322         if (!wm->pen_probably_down) {
 323                 u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 324                 if (!(data_rd & WM97XX_PEN_DOWN))
 325                         return RC_PENUP;
 326                 wm->pen_probably_down = 1;
 327         }
 328
 329         /* set up digitiser */
 330         if (wm->mach_ops && wm->mach_ops->pre_sample)
 331                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 332
 333         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 334                 WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
 335
 336         /* wait 3 AC97 time slots + delay for conversion and read x */
 337         poll_delay(delay);
 338         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 339         /* wait for POLL to go low */
 340         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 341                && timeout) {
 342                 udelay(AC97_LINK_FRAME);
 343                 timeout--;
 344         }
 345
 346         if (timeout <= 0) {
 347                 /* If PDEN is set, we can get a timeout when pen goes up */
 348                 if (is_pden(wm))
 349                         wm->pen_probably_down = 0;
 350                 else
 351                         dev_dbg(wm->dev, "adc sample timeout");
 352                 return RC_PENUP;
 353         }
 354
 355         /* read back y data */
 356         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 357         if (pil)
 358                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 359         else
 360                 data->p = DEFAULT_PRESSURE;
 361
 362         if (wm->mach_ops && wm->mach_ops->post_sample)
 363                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 364
 365         /* check we have correct sample */
 366         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 367                 goto err;
 368         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 369                 goto err;
 370
 371         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 372                 wm->pen_probably_down = 0;
 373                 return RC_PENUP;
 374         }
 375         return RC_VALID;
 376 err:
 377         return 0;
 378 }
 379
 380 /*
 381  * Sample the WM9712 touchscreen in polling mode
 382  */
 383 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 384 {
 385         int rc;
 386
 387         if (coord) {
 388                 rc = wm9712_poll_coord(wm, data);
 389                 if (rc != RC_VALID)
 390                         return rc;
 391         } else {
 392                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
 393                 if (rc != RC_VALID)
 394                         return rc;
 395
 396                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
 397                 if (rc != RC_VALID)
 398                         return rc;
 399
 400                 if (pil && !five_wire) {
 401                         rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES,
 402                                                 &data->p);
 403                         if (rc != RC_VALID)
 404                                 return rc;
 405                 } else
 406                         data->p = DEFAULT_PRESSURE;
 407         }
 408         return RC_VALID;
 409 }
 410
 411 /*
 412  * Enable WM9712 continuous mode, i.e. touch data is streamed across
 413  * an AC97 slot
 414  */
 415 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
 416 {
 417         u16 dig1, dig2;
 418         int ret = 0;
 419
 420         dig1 = wm->dig[1];
 421         dig2 = wm->dig[2];
 422
 423         if (enable) {
 424                 /* continous mode */
 425                 if (wm->mach_ops->acc_startup) {
 426                         ret = wm->mach_ops->acc_startup(wm);
 427                         if (ret < 0)
 428                                 return ret;
 429                 }
 430                 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
 431                         WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
 432                 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
 433                         WM97XX_DELAY(delay) |
 434                         WM97XX_SLT(wm->acc_slot) |
 435                         WM97XX_RATE(wm->acc_rate);
 436                 if (pil)
 437                         dig1 |= WM97XX_ADCSEL_PRES;
 438                 dig2 |= WM9712_PDEN;
 439         } else {
 440                 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
 441                 dig2 &= ~WM9712_PDEN;
 442                 if (wm->mach_ops->acc_shutdown)
 443                         wm->mach_ops->acc_shutdown(wm);
 444         }
 445
 446         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 447         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 448
 449         return 0;
 450 }
 451
 452 struct wm97xx_codec_drv wm9712_codec = {
 453         .id = WM9712_ID2,
 454         .name = "wm9712",
 455         .poll_sample = wm9712_poll_sample,
 456         .poll_touch = wm9712_poll_touch,
 457         .acc_enable = wm9712_acc_enable,
 458         .phy_init = wm9712_phy_init,
 459         .dig_enable = wm9712_dig_enable,
 460         .dig_restore = wm9712_dig_restore,
 461         .aux_prepare = wm9712_aux_prepare,
 462 };
 463 EXPORT_SYMBOL_GPL(wm9712_codec);
 464
 465 /* Module information */
 466 MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
 467 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
 468 MODULE_LICENSE("GPL");