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 <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 WM9712_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 = 3;
  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 WM9712
 155  */
 156 static void wm9712_phy_init(struct wm97xx *wm)
 157 {
 158         u16 dig1 = 0;
 159         u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
 160
 161         /* WM9712 rpu */
 162         if (rpu) {
 163                 dig2 &= 0xffc0;
 164                 dig2 |= WM9712_RPU(rpu);
 165                 dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 166                         64000 / rpu);
 167         }
 168
 169         /* WM9712 five wire */
 170         if (five_wire) {
 171                 dig2 |= WM9712_45W;
 172                 dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n");
 173
 174                 if (pil) {
 175                         dev_warn(wm->dev, "pressure measurement is not "
 176                                  "supported in 5-wire mode\n");
 177                         pil = 0;
 178                 }
 179         }
 180
 181         /* touchpanel pressure current*/
 182         if (pil == 2) {
 183                 dig2 |= WM9712_PIL;
 184                 dev_dbg(wm->dev,
 185                         "setting pressure measurement current to 400uA.\n");
 186         } else if (pil)
 187                 dev_dbg(wm->dev,
 188                         "setting pressure measurement current to 200uA.\n");
 189         if (!pil)
 190                 pressure = 0;
 191
 192         /* polling mode sample settling delay */
 193         if (delay < 0 || delay > 15) {
 194                 dev_dbg(wm->dev, "supplied delay out of range.\n");
 195                 delay = 4;
 196         }
 197         dig1 &= 0xff0f;
 198         dig1 |= WM97XX_DELAY(delay);
 199         dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n",
 200                 delay_table[delay]);
 201
 202         /* mask */
 203         dig2 |= ((mask & 0x3) << 6);
 204         if (mask) {
 205                 u16 reg;
 206                 /* Set GPIO4 as Mask Pin*/
 207                 reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
 208                 wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
 209                 reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
 210                 wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
 211         }
 212
 213         /* wait - coord mode */
 214         if (coord)
 215                 dig2 |= WM9712_WAIT;
 216
 217         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 218         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 219 }
 220
 221 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
 222 {
 223         u16 dig2 = wm->dig[2];
 224
 225         if (enable) {
 226                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 227                                  dig2 | WM97XX_PRP_DET_DIG);
 228                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 229         } else
 230                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 231                                  dig2 & ~WM97XX_PRP_DET_DIG);
 232 }
 233
 234 static void wm9712_aux_prepare(struct wm97xx *wm)
 235 {
 236         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 237         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
 238         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
 239 }
 240
 241 static void wm9712_dig_restore(struct wm97xx *wm)
 242 {
 243         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
 244         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
 245 }
 246
 247 static inline int is_pden(struct wm97xx *wm)
 248 {
 249         return wm->dig[2] & WM9712_PDEN;
 250 }
 251
 252 /*
 253  * Read a sample from the WM9712 adc in polling mode.
 254  */
 255 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 256 {
 257         int timeout = 5 * delay;
 258         bool wants_pen = adcsel & WM97XX_PEN_DOWN;
 259
 260         if (wants_pen && !wm->pen_probably_down) {
 261                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 262                 if (!(data & WM97XX_PEN_DOWN))
 263                         return RC_PENUP;
 264                 wm->pen_probably_down = 1;
 265         }
 266
 267         /* set up digitiser */
 268         if (wm->mach_ops && wm->mach_ops->pre_sample)
 269                 wm->mach_ops->pre_sample(adcsel);
 270         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
 271                                 | WM97XX_POLL | WM97XX_DELAY(delay));
 272
 273         /* wait 3 AC97 time slots + delay for conversion */
 274         poll_delay(delay);
 275
 276         /* wait for POLL to go low */
 277         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 278                && timeout) {
 279                 udelay(AC97_LINK_FRAME);
 280                 timeout--;
 281         }
 282
 283         if (timeout <= 0) {
 284                 /* If PDEN is set, we can get a timeout when pen goes up */
 285                 if (is_pden(wm))
 286                         wm->pen_probably_down = 0;
 287                 else
 288                         dev_dbg(wm->dev, "adc sample timeout\n");
 289                 return RC_PENUP;
 290         }
 291
 292         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 293         if (wm->mach_ops && wm->mach_ops->post_sample)
 294                 wm->mach_ops->post_sample(adcsel);
 295
 296         /* check we have correct sample */
 297         if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
 298                 dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x\n",
 299                         adcsel & WM97XX_ADCSEL_MASK,
 300                         *sample & WM97XX_ADCSEL_MASK);
 301                 return RC_AGAIN;
 302         }
 303
 304         if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
 305                 /* Sometimes it reads a wrong value the first time. */
 306                 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 307                 if (!(*sample & WM97XX_PEN_DOWN)) {
 308                         wm->pen_probably_down = 0;
 309                         return RC_PENUP;
 310                 }
 311         }
 312
 313         return RC_VALID;
 314 }
 315
 316 /*
 317  * Read a coord from the WM9712 adc in polling mode.
 318  */
 319 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 320 {
 321         int timeout = 5 * delay;
 322
 323         if (!wm->pen_probably_down) {
 324                 u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 325                 if (!(data_rd & WM97XX_PEN_DOWN))
 326                         return RC_PENUP;
 327                 wm->pen_probably_down = 1;
 328         }
 329
 330         /* set up digitiser */
 331         if (wm->mach_ops && wm->mach_ops->pre_sample)
 332                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 333
 334         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 335                 WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
 336
 337         /* wait 3 AC97 time slots + delay for conversion and read x */
 338         poll_delay(delay);
 339         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 340         /* wait for POLL to go low */
 341         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 342                && timeout) {
 343                 udelay(AC97_LINK_FRAME);
 344                 timeout--;
 345         }
 346
 347         if (timeout <= 0) {
 348                 /* If PDEN is set, we can get a timeout when pen goes up */
 349                 if (is_pden(wm))
 350                         wm->pen_probably_down = 0;
 351                 else
 352                         dev_dbg(wm->dev, "adc sample timeout\n");
 353                 return RC_PENUP;
 354         }
 355
 356         /* read back y data */
 357         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 358         if (pil)
 359                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 360         else
 361                 data->p = DEFAULT_PRESSURE;
 362
 363         if (wm->mach_ops && wm->mach_ops->post_sample)
 364                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 365
 366         /* check we have correct sample */
 367         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 368                 goto err;
 369         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 370                 goto err;
 371
 372         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 373                 wm->pen_probably_down = 0;
 374                 return RC_PENUP;
 375         }
 376         return RC_VALID;
 377 err:
 378         return 0;
 379 }
 380
 381 /*
 382  * Sample the WM9712 touchscreen in polling mode
 383  */
 384 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 385 {
 386         int rc;
 387
 388         if (coord) {
 389                 rc = wm9712_poll_coord(wm, data);
 390                 if (rc != RC_VALID)
 391                         return rc;
 392         } else {
 393                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN,
 394                                         &data->x);
 395                 if (rc != RC_VALID)
 396                         return rc;
 397
 398                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN,
 399                                         &data->y);
 400                 if (rc != RC_VALID)
 401                         return rc;
 402
 403                 if (pil && !five_wire) {
 404                         rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
 405                                                 &data->p);
 406                         if (rc != RC_VALID)
 407                                 return rc;
 408                 } else
 409                         data->p = DEFAULT_PRESSURE;
 410         }
 411         return RC_VALID;
 412 }
 413
 414 /*
 415  * Enable WM9712 continuous mode, i.e. touch data is streamed across
 416  * an AC97 slot
 417  */
 418 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
 419 {
 420         u16 dig1, dig2;
 421         int ret = 0;
 422
 423         dig1 = wm->dig[1];
 424         dig2 = wm->dig[2];
 425
 426         if (enable) {
 427                 /* continuous mode */
 428                 if (wm->mach_ops->acc_startup) {
 429                         ret = wm->mach_ops->acc_startup(wm);
 430                         if (ret < 0)
 431                                 return ret;
 432                 }
 433                 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
 434                         WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
 435                 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
 436                         WM97XX_DELAY(delay) |
 437                         WM97XX_SLT(wm->acc_slot) |
 438                         WM97XX_RATE(wm->acc_rate);
 439                 if (pil)
 440                         dig1 |= WM97XX_ADCSEL_PRES;
 441                 dig2 |= WM9712_PDEN;
 442         } else {
 443                 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
 444                 dig2 &= ~WM9712_PDEN;
 445                 if (wm->mach_ops->acc_shutdown)
 446                         wm->mach_ops->acc_shutdown(wm);
 447         }
 448
 449         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 450         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 451
 452         return 0;
 453 }
 454
 455 struct wm97xx_codec_drv wm9712_codec = {
 456         .id = WM9712_ID2,
 457         .name = "wm9712",
 458         .poll_sample = wm9712_poll_sample,
 459         .poll_touch = wm9712_poll_touch,
 460         .acc_enable = wm9712_acc_enable,
 461         .phy_init = wm9712_phy_init,
 462         .dig_enable = wm9712_dig_enable,
 463         .dig_restore = wm9712_dig_restore,
 464         .aux_prepare = wm9712_aux_prepare,
 465 };
 466 EXPORT_SYMBOL_GPL(wm9712_codec);
 467
 468 /* Module information */
 469 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 470 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
 471 MODULE_LICENSE("GPL");