LXR linux/drivers/input/touchscreen/wm9705.c

   1/*
   2 * wm9705.c  --  Codec driver for Wolfson WM9705 AC97 Codec.
   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 WM9705_VERSION          "1.00"
  27#define DEFAULT_PRESSURE        0xb0c0
  28
  29/*
  30 * Module parameters
  31 */
  32
  33/*
  34 * Set current used for pressure measurement.
  35 *
  36 * Set pil = 2 to use 400uA
  37 *     pil = 1 to use 200uA and
  38 *     pil = 0 to disable pressure measurement.
  39 *
  40 * This is used to increase the range of values returned by the adc
  41 * when measureing touchpanel pressure.
  42 */
  43static int pil;
  44module_param(pil, int, 0);
  45MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
  46
  47/*
  48 * Set threshold for pressure measurement.
  49 *
  50 * Pen down pressure below threshold is ignored.
  51 */
  52static int pressure = DEFAULT_PRESSURE & 0xfff;
  53module_param(pressure, int, 0);
  54MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
  55
  56/*
  57 * Set adc sample delay.
  58 *
  59 * For accurate touchpanel measurements, some settling time may be
  60 * required between the switch matrix applying a voltage across the
  61 * touchpanel plate and the ADC sampling the signal.
  62 *
  63 * This delay can be set by setting delay = n, where n is the array
  64 * position of the delay in the array delay_table below.
  65 * Long delays > 1ms are supported for completeness, but are not
  66 * recommended.
  67 */
  68static int delay = 4;
  69module_param(delay, int, 0);
  70MODULE_PARM_DESC(delay, "Set adc sample delay.");
  71
  72/*
  73 * Pen detect comparator threshold.
  74 *
  75 * 0 to Vmid in 15 steps, 0 = use zero power comparator with Vmid threshold
  76 * i.e. 1 =  Vmid/15 threshold
  77 *      15 =  Vmid/1 threshold
  78 *
  79 * Adjust this value if you are having problems with pen detect not
  80 * detecting any down events.
  81 */
  82static int pdd = 8;
  83module_param(pdd, int, 0);
  84MODULE_PARM_DESC(pdd, "Set pen detect comparator threshold");
  85
  86/*
  87 * Set adc mask function.
  88 *
  89 * Sources of glitch noise, such as signals driving an LCD display, may feed
  90 * through to the touch screen plates and affect measurement accuracy. In
  91 * order to minimise this, a signal may be applied to the MASK pin to delay or
  92 * synchronise the sampling.
  93 *
  94 * 0 = No delay or sync
  95 * 1 = High on pin stops conversions
  96 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
  97 * 3 = Edge triggered, edge on pin starts conversion after delay param
  98 */
  99static int mask;
 100module_param(mask, int, 0);
 101MODULE_PARM_DESC(mask, "Set adc mask function.");
 102
 103/*
 104 * ADC sample delay times in uS
 105 */
 106static const int delay_table[] = {
 107        21,    /* 1 AC97 Link frames */
 108        42,    /* 2                  */
 109        84,    /* 4                  */
 110        167,   /* 8                  */
 111        333,   /* 16                 */
 112        667,   /* 32                 */
 113        1000,  /* 48                 */
 114        1333,  /* 64                 */
 115        2000,  /* 96                 */
 116        2667,  /* 128                */
 117        3333,  /* 160                */
 118        4000,  /* 192                */
 119        4667,  /* 224                */
 120        5333,  /* 256                */
 121        6000,  /* 288                */
 122        0      /* No delay, switch matrix always on */
 123};
 124
 125/*
 126 * Delay after issuing a POLL command.
 127 *
 128 * The delay is 3 AC97 link frames + the touchpanel settling delay
 129 */
 130static inline void poll_delay(int d)
 131{
 132        udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 133}
 134
 135/*
 136 * set up the physical settings of the WM9705
 137 */
 138static void wm9705_phy_init(struct wm97xx *wm)
 139{
 140        u16 dig1 = 0, dig2 = WM97XX_RPR;
 141
 142        /*
 143        * mute VIDEO and AUX as they share X and Y touchscreen
 144        * inputs on the WM9705
 145        */
 146        wm97xx_reg_write(wm, AC97_AUX, 0x8000);
 147        wm97xx_reg_write(wm, AC97_VIDEO, 0x8000);
 148
 149        /* touchpanel pressure current*/
 150        if (pil == 2) {
 151                dig2 |= WM9705_PIL;
 152                dev_dbg(wm->dev,
 153                        "setting pressure measurement current to 400uA.");
 154        } else if (pil)
 155                dev_dbg(wm->dev,
 156                        "setting pressure measurement current to 200uA.");
 157        if (!pil)
 158                pressure = 0;
 159
 160        /* polling mode sample settling delay */
 161        if (delay != 4) {
 162                if (delay < 0 || delay > 15) {
 163                        dev_dbg(wm->dev, "supplied delay out of range.");
 164                        delay = 4;
 165                }
 166        }
 167        dig1 &= 0xff0f;
 168        dig1 |= WM97XX_DELAY(delay);
 169        dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.",
 170                delay_table[delay]);
 171
 172        /* WM9705 pdd */
 173        dig2 |= (pdd & 0x000f);
 174        dev_dbg(wm->dev, "setting pdd to Vmid/%d", 1 - (pdd & 0x000f));
 175
 176        /* mask */
 177        dig2 |= ((mask & 0x3) << 4);
 178
 179        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 180        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 181}
 182
 183static void wm9705_dig_enable(struct wm97xx *wm, int enable)
 184{
 185        if (enable) {
 186                wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 187                                 wm->dig[2] | WM97XX_PRP_DET_DIG);
 188                wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 189        } else
 190                wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 191                                 wm->dig[2] & ~WM97XX_PRP_DET_DIG);
 192}
 193
 194static void wm9705_aux_prepare(struct wm97xx *wm)
 195{
 196        memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 197        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
 198        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
 199}
 200
 201static void wm9705_dig_restore(struct wm97xx *wm)
 202{
 203        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
 204        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
 205}
 206
 207static inline int is_pden(struct wm97xx *wm)
 208{
 209        return wm->dig[2] & WM9705_PDEN;
 210}
 211
 212/*
 213 * Read a sample from the WM9705 adc in polling mode.
 214 */
 215static int wm9705_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 216{
 217        int timeout = 5 * delay;
 218
 219        if (!wm->pen_probably_down) {
 220                u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 221                if (!(data & WM97XX_PEN_DOWN))
 222                        return RC_PENUP;
 223                wm->pen_probably_down = 1;
 224        }
 225
 226        /* set up digitiser */
 227        if (adcsel & 0x8000)
 228                adcsel = ((adcsel & 0x7fff) + 3) << 12;
 229
 230        if (wm->mach_ops && wm->mach_ops->pre_sample)
 231                wm->mach_ops->pre_sample(adcsel);
 232        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 233                         adcsel | WM97XX_POLL | WM97XX_DELAY(delay));
 234
 235        /* wait 3 AC97 time slots + delay for conversion */
 236        poll_delay(delay);
 237
 238        /* wait for POLL to go low */
 239        while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 240               && timeout) {
 241                udelay(AC97_LINK_FRAME);
 242                timeout--;
 243        }
 244
 245        if (timeout == 0) {
 246                /* If PDEN is set, we can get a timeout when pen goes up */
 247                if (is_pden(wm))
 248                        wm->pen_probably_down = 0;
 249                else
 250                        dev_dbg(wm->dev, "adc sample timeout");
 251                return RC_PENUP;
 252        }
 253
 254        *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 255        if (wm->mach_ops && wm->mach_ops->post_sample)
 256                wm->mach_ops->post_sample(adcsel);
 257
 258        /* check we have correct sample */
 259        if ((*sample & WM97XX_ADCSEL_MASK) != adcsel) {
 260                dev_dbg(wm->dev, "adc wrong sample, read %x got %x", adcsel,
 261                *sample & WM97XX_ADCSEL_MASK);
 262                return RC_PENUP;
 263        }
 264
 265        if (!(*sample & WM97XX_PEN_DOWN)) {
 266                wm->pen_probably_down = 0;
 267                return RC_PENUP;
 268        }
 269
 270        return RC_VALID;
 271}
 272
 273/*
 274 * Sample the WM9705 touchscreen in polling mode
 275 */
 276static int wm9705_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 277{
 278        int rc;
 279
 280        rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_X, &data->x);
 281        if (rc != RC_VALID)
 282                return rc;
 283        rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_Y, &data->y);
 284        if (rc != RC_VALID)
 285                return rc;
 286        if (pil) {
 287                rc = wm9705_poll_sample(wm, WM97XX_ADCSEL_PRES, &data->p);
 288                if (rc != RC_VALID)
 289                        return rc;
 290        } else
 291                data->p = DEFAULT_PRESSURE;
 292
 293        return RC_VALID;
 294}
 295
 296/*
 297 * Enable WM9705 continuous mode, i.e. touch data is streamed across
 298 * an AC97 slot
 299 */
 300static int wm9705_acc_enable(struct wm97xx *wm, int enable)
 301{
 302        u16 dig1, dig2;
 303        int ret = 0;
 304
 305        dig1 = wm->dig[1];
 306        dig2 = wm->dig[2];
 307
 308        if (enable) {
 309                /* continous mode */
 310                if (wm->mach_ops->acc_startup &&
 311                    (ret = wm->mach_ops->acc_startup(wm)) < 0)
 312                        return ret;
 313                dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
 314                          WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
 315                dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
 316                        WM97XX_DELAY(delay) |
 317                        WM97XX_SLT(wm->acc_slot) |
 318                        WM97XX_RATE(wm->acc_rate);
 319                if (pil)
 320                        dig1 |= WM97XX_ADCSEL_PRES;
 321                dig2 |= WM9705_PDEN;
 322        } else {
 323                dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
 324                dig2 &= ~WM9705_PDEN;
 325                if (wm->mach_ops->acc_shutdown)
 326                        wm->mach_ops->acc_shutdown(wm);
 327        }
 328
 329        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 330        wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 331
 332        return ret;
 333}
 334
 335struct wm97xx_codec_drv wm9705_codec = {
 336        .id = WM9705_ID2,
 337        .name = "wm9705",
 338        .poll_sample = wm9705_poll_sample,
 339        .poll_touch = wm9705_poll_touch,
 340        .acc_enable = wm9705_acc_enable,
 341        .phy_init = wm9705_phy_init,
 342        .dig_enable = wm9705_dig_enable,
 343        .dig_restore = wm9705_dig_restore,
 344        .aux_prepare = wm9705_aux_prepare,
 345};
 346EXPORT_SYMBOL_GPL(wm9705_codec);
 347
 348/* Module information */
 349MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 350MODULE_DESCRIPTION("WM9705 Touch Screen Driver");
 351MODULE_LICENSE("GPL");
 352