git.oblomov.eu Git - linux-2.6/blob - 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         /* touchpanel pressure current*/
 172         if (pil == 2) {
 173                 dig2 |= WM9712_PIL;
 174                 dev_dbg(wm->dev,
 175                         "setting pressure measurement current to 400uA.");
 176         } else if (pil)
 177                 dev_dbg(wm->dev,
 178                         "setting pressure measurement current to 200uA.");
 179         if (!pil)
 180                 pressure = 0;
 181
 182         /* WM9712 five wire */
 183         if (five_wire) {
 184                 dig2 |= WM9712_45W;
 185                 dev_dbg(wm->dev, "setting 5-wire touchscreen mode.");
 186         }
 187
 188         /* polling mode sample settling delay */
 189         if (delay < 0 || delay > 15) {
 190                 dev_dbg(wm->dev, "supplied delay out of range.");
 191                 delay = 4;
 192         }
 193         dig1 &= 0xff0f;
 194         dig1 |= WM97XX_DELAY(delay);
 195         dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
 196                 delay_table[delay]);
 197
 198         /* mask */
 199         dig2 |= ((mask & 0x3) << 6);
 200         if (mask) {
 201                 u16 reg;
 202                 /* Set GPIO4 as Mask Pin*/
 203                 reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
 204                 wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
 205                 reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
 206                 wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
 207         }
 208
 209         /* wait - coord mode */
 210         if (coord)
 211                 dig2 |= WM9712_WAIT;
 212
 213         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 214         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 215 }
 216
 217 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
 218 {
 219         u16 dig2 = wm->dig[2];
 220
 221         if (enable) {
 222                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 223                                  dig2 | WM97XX_PRP_DET_DIG);
 224                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 225         } else
 226                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 227                                  dig2 & ~WM97XX_PRP_DET_DIG);
 228 }
 229
 230 static void wm9712_aux_prepare(struct wm97xx *wm)
 231 {
 232         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 233         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
 234         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
 235 }
 236
 237 static void wm9712_dig_restore(struct wm97xx *wm)
 238 {
 239         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
 240         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
 241 }
 242
 243 static inline int is_pden(struct wm97xx *wm)
 244 {
 245         return wm->dig[2] & WM9712_PDEN;
 246 }
 247
 248 /*
 249  * Read a sample from the WM9712 adc in polling mode.
 250  */
 251 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 252 {
 253         int timeout = 5 * delay;
 254
 255         if (!wm->pen_probably_down) {
 256                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 257                 if (!(data & WM97XX_PEN_DOWN))
 258                         return RC_PENUP;
 259                 wm->pen_probably_down = 1;
 260         }
 261
 262         /* set up digitiser */
 263         if (adcsel & 0x8000)
 264                 adcsel = ((adcsel & 0x7fff) + 3) << 12;
 265
 266         if (wm->mach_ops && wm->mach_ops->pre_sample)
 267                 wm->mach_ops->pre_sample(adcsel);
 268         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 269                          adcsel | WM97XX_POLL | WM97XX_DELAY(delay));
 270
 271         /* wait 3 AC97 time slots + delay for conversion */
 272         poll_delay(delay);
 273
 274         /* wait for POLL to go low */
 275         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 276                && timeout) {
 277                 udelay(AC97_LINK_FRAME);
 278                 timeout--;
 279         }
 280
 281         if (timeout <= 0) {
 282                 /* If PDEN is set, we can get a timeout when pen goes up */
 283                 if (is_pden(wm))
 284                         wm->pen_probably_down = 0;
 285                 else
 286                         dev_dbg(wm->dev, "adc sample timeout");
 287                 return RC_PENUP;
 288         }
 289
 290         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 291         if (wm->mach_ops && wm->mach_ops->post_sample)
 292                 wm->mach_ops->post_sample(adcsel);
 293
 294         /* check we have correct sample */
 295         if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) {
 296                 dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 297                 *sample & WM97XX_ADCSEL_MASK);
 298                 return RC_PENUP;
 299         }
 300
 301         if (!(*sample & WM97XX_PEN_DOWN)) {
 302                 wm->pen_probably_down = 0;
 303                 return RC_PENUP;
 304         }
 305
 306         return RC_VALID;
 307 }
 308
 309 /*
 310  * Read a coord from the WM9712 adc in polling mode.
 311  */
 312 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 313 {
 314         int timeout = 5 * delay;
 315
 316         if (!wm->pen_probably_down) {
 317                 u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 318                 if (!(data_rd & WM97XX_PEN_DOWN))
 319                         return RC_PENUP;
 320                 wm->pen_probably_down = 1;
 321         }
 322
 323         /* set up digitiser */
 324         if (wm->mach_ops && wm->mach_ops->pre_sample)
 325                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 326
 327         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 328                 WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
 329
 330         /* wait 3 AC97 time slots + delay for conversion and read x */
 331         poll_delay(delay);
 332         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 333         /* wait for POLL to go low */
 334         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 335                && timeout) {
 336                 udelay(AC97_LINK_FRAME);
 337                 timeout--;
 338         }
 339
 340         if (timeout <= 0) {
 341                 /* If PDEN is set, we can get a timeout when pen goes up */
 342                 if (is_pden(wm))
 343                         wm->pen_probably_down = 0;
 344                 else
 345                         dev_dbg(wm->dev, "adc sample timeout");
 346                 return RC_PENUP;
 347         }
 348
 349         /* read back y data */
 350         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 351         if (pil)
 352                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 353         else
 354                 data->p = DEFAULT_PRESSURE;
 355
 356         if (wm->mach_ops && wm->mach_ops->post_sample)
 357                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 358
 359         /* check we have correct sample */
 360         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 361                 goto err;
 362         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 363                 goto err;
 364
 365         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 366                 wm->pen_probably_down = 0;
 367                 return RC_PENUP;
 368         }
 369         return RC_VALID;
 370 err:
 371         return 0;
 372 }
 373
 374 /*
 375  * Sample the WM9712 touchscreen in polling mode
 376  */
 377 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 378 {
 379         int rc;
 380
 381         if (coord) {
 382                 rc = wm9712_poll_coord(wm, data);
 383                 if (rc != RC_VALID)
 384                         return rc;
 385         } else {
 386                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
 387                 if (rc != RC_VALID)
 388                         return rc;
 389
 390                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
 391                 if (rc != RC_VALID)
 392                         return rc;
 393
 394                 if (pil && !five_wire) {
 395                         rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES,
 396                                                 &data->p);
 397                         if (rc != RC_VALID)
 398                                 return rc;
 399                 } else
 400                         data->p = DEFAULT_PRESSURE;
 401         }
 402         return RC_VALID;
 403 }
 404
 405 /*
 406  * Enable WM9712 continuous mode, i.e. touch data is streamed across
 407  * an AC97 slot
 408  */
 409 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
 410 {
 411         u16 dig1, dig2;
 412         int ret = 0;
 413
 414         dig1 = wm->dig[1];
 415         dig2 = wm->dig[2];
 416
 417         if (enable) {
 418                 /* continous mode */
 419                 if (wm->mach_ops->acc_startup) {
 420                         ret = wm->mach_ops->acc_startup(wm);
 421                         if (ret < 0)
 422                                 return ret;
 423                 }
 424                 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
 425                         WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
 426                 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
 427                         WM97XX_DELAY(delay) |
 428                         WM97XX_SLT(wm->acc_slot) |
 429                         WM97XX_RATE(wm->acc_rate);
 430                 if (pil)
 431                         dig1 |= WM97XX_ADCSEL_PRES;
 432                 dig2 |= WM9712_PDEN;
 433         } else {
 434                 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
 435                 dig2 &= ~WM9712_PDEN;
 436                 if (wm->mach_ops->acc_shutdown)
 437                         wm->mach_ops->acc_shutdown(wm);
 438         }
 439
 440         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 441         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 442
 443         return 0;
 444 }
 445
 446 struct wm97xx_codec_drv wm9712_codec = {
 447         .id = WM9712_ID2,
 448         .name = "wm9712",
 449         .poll_sample = wm9712_poll_sample,
 450         .poll_touch = wm9712_poll_touch,
 451         .acc_enable = wm9712_acc_enable,
 452         .phy_init = wm9712_phy_init,
 453         .dig_enable = wm9712_dig_enable,
 454         .dig_restore = wm9712_dig_restore,
 455         .aux_prepare = wm9712_aux_prepare,
 456 };
 457 EXPORT_SYMBOL_GPL(wm9712_codec);
 458
 459 /* Module information */
 460 MODULE_AUTHOR("Liam Girdwood <liam.girdwood@wolfsonmicro.com>");
 461 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
 462 MODULE_LICENSE("GPL");