LXR linux/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 */
  42static int rpu = 8;
  43module_param(rpu, int, 0);
  44MODULE_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 */
  56static int pil;
  57module_param(pil, int, 0);
  58MODULE_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 */
  65static int pressure = DEFAULT_PRESSURE & 0xfff;
  66module_param(pressure, int, 0);
  67MODULE_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 */
  81static int delay = 4;
  82module_param(delay, int, 0);
  83MODULE_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 */
  90static int five_wire;
  91module_param(five_wire, int, 0);
  92MODULE_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 */
 107static int mask;
 108module_param(mask, int, 0);
 109MODULE_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 */
 117static int coord;
 118module_param(coord, int, 0);
 119MODULE_PARM_DESC(coord, "Polling coordinate mode");
 120
 121/*
 122 * ADC sample delay times in uS
 123 */
 124static 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 */
 148static 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 */
 156static 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
 219static 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
 237static 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
 244static 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
 252static 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 */
 260static 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 */
 324static 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;
 387err:
 388        return 0;
 389}
 390
 391/*
 392 * Sample the WM9713 touchscreen in polling mode
 393 */
 394static 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 */
 424static 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
 464struct 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};
 475EXPORT_SYMBOL_GPL(wm9713_codec);
 476
 477/* Module information */
 478MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 479MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 480MODULE_LICENSE("GPL");
 481