LXR linux/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 */
  42static int rpu = 8;
  43module_param(rpu, int, 0);
  44MODULE_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 */
  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 = 3;
  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 WM9712
 155 */
 156static 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
 221static 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
 234static 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
 241static 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
 247static 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 */
 255static 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 */
 319static 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;
 377err:
 378        return 0;
 379}
 380
 381/*
 382 * Sample the WM9712 touchscreen in polling mode
 383 */
 384static 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 */
 418static 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
 455struct 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};
 466EXPORT_SYMBOL_GPL(wm9712_codec);
 467
 468/* Module information */
 469MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 470MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
 471MODULE_LICENSE("GPL");
 472