LXR linux/drivers/input/touchscreen/wm9713.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * wm9713.c  --  Codec touch driver for Wolfson WM9713 AC97 Codec.
   4 *
   5 * Copyright 2003, 2004, 2005, 2006, 2007, 2008 Wolfson Microelectronics PLC.
   6 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
   7 * Parts Copyright : Ian Molton <spyro@f2s.com>
   8 *                   Andrew Zabolotny <zap@homelink.ru>
   9 *                   Russell King <rmk@arm.linux.org.uk>
  10 */
  11
  12#include <linux/module.h>
  13#include <linux/moduleparam.h>
  14#include <linux/kernel.h>
  15#include <linux/input.h>
  16#include <linux/delay.h>
  17#include <linux/bitops.h>
  18#include <linux/wm97xx.h>
  19
  20#define TS_NAME                 "wm97xx"
  21#define WM9713_VERSION          "1.00"
  22#define DEFAULT_PRESSURE        0xb0c0
  23
  24/*
  25 * Module parameters
  26 */
  27
  28/*
  29 * Set internal pull up for pen detect.
  30 *
  31 * Pull up is in the range 1.02k (least sensitive) to 64k (most sensitive)
  32 * i.e. pull up resistance = 64k Ohms / rpu.
  33 *
  34 * Adjust this value if you are having problems with pen detect not
  35 * detecting any down event.
  36 */
  37static int rpu = 8;
  38module_param(rpu, int, 0);
  39MODULE_PARM_DESC(rpu, "Set internal pull up resistor for pen detect.");
  40
  41/*
  42 * Set current used for pressure measurement.
  43 *
  44 * Set pil = 2 to use 400uA
  45 *     pil = 1 to use 200uA and
  46 *     pil = 0 to disable pressure measurement.
  47 *
  48 * This is used to increase the range of values returned by the adc
  49 * when measureing touchpanel pressure.
  50 */
  51static int pil;
  52module_param(pil, int, 0);
  53MODULE_PARM_DESC(pil, "Set current used for pressure measurement.");
  54
  55/*
  56 * Set threshold for pressure measurement.
  57 *
  58 * Pen down pressure below threshold is ignored.
  59 */
  60static int pressure = DEFAULT_PRESSURE & 0xfff;
  61module_param(pressure, int, 0);
  62MODULE_PARM_DESC(pressure, "Set threshold for pressure measurement.");
  63
  64/*
  65 * Set adc sample delay.
  66 *
  67 * For accurate touchpanel measurements, some settling time may be
  68 * required between the switch matrix applying a voltage across the
  69 * touchpanel plate and the ADC sampling the signal.
  70 *
  71 * This delay can be set by setting delay = n, where n is the array
  72 * position of the delay in the array delay_table below.
  73 * Long delays > 1ms are supported for completeness, but are not
  74 * recommended.
  75 */
  76static int delay = 4;
  77module_param(delay, int, 0);
  78MODULE_PARM_DESC(delay, "Set adc sample delay.");
  79
  80/*
  81 * Set five_wire = 1 to use a 5 wire touchscreen.
  82 *
  83 * NOTE: Five wire mode does not allow for readback of pressure.
  84 */
  85static int five_wire;
  86module_param(five_wire, int, 0);
  87MODULE_PARM_DESC(five_wire, "Set to '1' to use 5-wire touchscreen.");
  88
  89/*
  90 * Set adc mask function.
  91 *
  92 * Sources of glitch noise, such as signals driving an LCD display, may feed
  93 * through to the touch screen plates and affect measurement accuracy. In
  94 * order to minimise this, a signal may be applied to the MASK pin to delay or
  95 * synchronise the sampling.
  96 *
  97 * 0 = No delay or sync
  98 * 1 = High on pin stops conversions
  99 * 2 = Edge triggered, edge on pin delays conversion by delay param (above)
 100 * 3 = Edge triggered, edge on pin starts conversion after delay param
 101 */
 102static int mask;
 103module_param(mask, int, 0);
 104MODULE_PARM_DESC(mask, "Set adc mask function.");
 105
 106/*
 107 * Coordinate Polling Enable.
 108 *
 109 * Set to 1 to enable coordinate polling. e.g. x,y[,p] is sampled together
 110 * for every poll.
 111 */
 112static int coord;
 113module_param(coord, int, 0);
 114MODULE_PARM_DESC(coord, "Polling coordinate mode");
 115
 116/*
 117 * ADC sample delay times in uS
 118 */
 119static const int delay_table[] = {
 120        21,    /* 1 AC97 Link frames */
 121        42,    /* 2 */
 122        84,    /* 4 */
 123        167,   /* 8 */
 124        333,   /* 16 */
 125        667,   /* 32 */
 126        1000,  /* 48 */
 127        1333,  /* 64 */
 128        2000,  /* 96 */
 129        2667,  /* 128 */
 130        3333,  /* 160 */
 131        4000,  /* 192 */
 132        4667,  /* 224 */
 133        5333,  /* 256 */
 134        6000,  /* 288 */
 135        0      /* No delay, switch matrix always on */
 136};
 137
 138/*
 139 * Delay after issuing a POLL command.
 140 *
 141 * The delay is 3 AC97 link frames + the touchpanel settling delay
 142 */
 143static inline void poll_delay(int d)
 144{
 145        udelay(3 * AC97_LINK_FRAME + delay_table[d]);
 146}
 147
 148/*
 149 * set up the physical settings of the WM9713
 150 */
 151static void wm9713_phy_init(struct wm97xx *wm)
 152{
 153        u16 dig1 = 0, dig2, dig3;
 154
 155        /* default values */
 156        dig2 = WM97XX_DELAY(4) | WM97XX_SLT(5);
 157        dig3 = WM9712_RPU(1);
 158
 159        /* rpu */
 160        if (rpu) {
 161                dig3 &= 0xffc0;
 162                dig3 |= WM9712_RPU(rpu);
 163                dev_info(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 164                         64000 / rpu);
 165        }
 166
 167        /* Five wire panel? */
 168        if (five_wire) {
 169                dig3 |= WM9713_45W;
 170                dev_info(wm->dev, "setting 5-wire touchscreen mode.");
 171
 172                if (pil) {
 173                        dev_warn(wm->dev,
 174                                 "Pressure measurement not supported in 5 "
 175                                 "wire mode, disabling\n");
 176                        pil = 0;
 177                }
 178        }
 179
 180        /* touchpanel pressure */
 181        if (pil == 2) {
 182                dig3 |= WM9712_PIL;
 183                dev_info(wm->dev,
 184                         "setting pressure measurement current to 400uA.");
 185        } else if (pil)
 186                dev_info(wm->dev,
 187                         "setting pressure measurement current to 200uA.");
 188        if (!pil)
 189                pressure = 0;
 190
 191        /* sample settling delay */
 192        if (delay < 0 || delay > 15) {
 193                dev_info(wm->dev, "supplied delay out of range.");
 194                delay = 4;
 195                dev_info(wm->dev, "setting adc sample delay to %d u Secs.",
 196                         delay_table[delay]);
 197        }
 198        dig2 &= 0xff0f;
 199        dig2 |= WM97XX_DELAY(delay);
 200
 201        /* mask */
 202        dig3 |= ((mask & 0x3) << 4);
 203        if (coord)
 204                dig3 |= WM9713_WAIT;
 205
 206        wm->misc = wm97xx_reg_read(wm, 0x5a);
 207
 208        wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 209        wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 210        wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 211        wm97xx_reg_write(wm, AC97_GPIO_STICKY, 0x0);
 212}
 213
 214static void wm9713_dig_enable(struct wm97xx *wm, int enable)
 215{
 216        u16 val;
 217
 218        if (enable) {
 219                val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 220                wm97xx_reg_write(wm, AC97_EXTENDED_MID, val & 0x7fff);
 221                wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] |
 222                                 WM97XX_PRP_DET_DIG);
 223                wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 224        } else {
 225                wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig[2] &
 226                                        ~WM97XX_PRP_DET_DIG);
 227                val = wm97xx_reg_read(wm, AC97_EXTENDED_MID);
 228                wm97xx_reg_write(wm, AC97_EXTENDED_MID, val | 0x8000);
 229        }
 230}
 231
 232static void wm9713_dig_restore(struct wm97xx *wm)
 233{
 234        wm97xx_reg_write(wm, AC97_WM9713_DIG1, wm->dig_save[0]);
 235        wm97xx_reg_write(wm, AC97_WM9713_DIG2, wm->dig_save[1]);
 236        wm97xx_reg_write(wm, AC97_WM9713_DIG3, wm->dig_save[2]);
 237}
 238
 239static void wm9713_aux_prepare(struct wm97xx *wm)
 240{
 241        memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 242        wm97xx_reg_write(wm, AC97_WM9713_DIG1, 0);
 243        wm97xx_reg_write(wm, AC97_WM9713_DIG2, 0);
 244        wm97xx_reg_write(wm, AC97_WM9713_DIG3, WM97XX_PRP_DET_DIG);
 245}
 246
 247static inline int is_pden(struct wm97xx *wm)
 248{
 249        return wm->dig[2] & WM9713_PDEN;
 250}
 251
 252/*
 253 * Read a sample from the WM9713 adc in polling mode.
 254 */
 255static int wm9713_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 256{
 257        u16 dig1;
 258        int timeout = 5 * delay;
 259        bool wants_pen = adcsel & WM97XX_PEN_DOWN;
 260
 261        if (wants_pen && !wm->pen_probably_down) {
 262                u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 263                if (!(data & WM97XX_PEN_DOWN))
 264                        return RC_PENUP;
 265                wm->pen_probably_down = 1;
 266        }
 267
 268        /* set up digitiser */
 269        dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 270        dig1 &= ~WM9713_ADCSEL_MASK;
 271        /* WM97XX_ADCSEL_* channels need to be converted to WM9713 format */
 272        dig1 |= 1 << ((adcsel & WM97XX_ADCSEL_MASK) >> 12);
 273
 274        if (wm->mach_ops && wm->mach_ops->pre_sample)
 275                wm->mach_ops->pre_sample(adcsel);
 276        wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1 | WM9713_POLL);
 277
 278        /* wait 3 AC97 time slots + delay for conversion */
 279        poll_delay(delay);
 280
 281        /* wait for POLL to go low */
 282        while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL) &&
 283                timeout) {
 284                udelay(AC97_LINK_FRAME);
 285                timeout--;
 286        }
 287
 288        if (timeout <= 0) {
 289                /* If PDEN is set, we can get a timeout when pen goes up */
 290                if (is_pden(wm))
 291                        wm->pen_probably_down = 0;
 292                else
 293                        dev_dbg(wm->dev, "adc sample timeout");
 294                return RC_PENUP;
 295        }
 296
 297        *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 298        if (wm->mach_ops && wm->mach_ops->post_sample)
 299                wm->mach_ops->post_sample(adcsel);
 300
 301        /* check we have correct sample */
 302        if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
 303                dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x",
 304                        adcsel & WM97XX_ADCSEL_MASK,
 305                        *sample & WM97XX_ADCSEL_MASK);
 306                return RC_PENUP;
 307        }
 308
 309        if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
 310                wm->pen_probably_down = 0;
 311                return RC_PENUP;
 312        }
 313
 314        return RC_VALID;
 315}
 316
 317/*
 318 * Read a coordinate from the WM9713 adc in polling mode.
 319 */
 320static int wm9713_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 321{
 322        u16 dig1;
 323        int timeout = 5 * delay;
 324
 325        if (!wm->pen_probably_down) {
 326                u16 val = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 327                if (!(val & WM97XX_PEN_DOWN))
 328                        return RC_PENUP;
 329                wm->pen_probably_down = 1;
 330        }
 331
 332        /* set up digitiser */
 333        dig1 = wm97xx_reg_read(wm, AC97_WM9713_DIG1);
 334        dig1 &= ~WM9713_ADCSEL_MASK;
 335        if (pil)
 336                dig1 |= WM9713_ADCSEL_PRES;
 337
 338        if (wm->mach_ops && wm->mach_ops->pre_sample)
 339                wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 340        wm97xx_reg_write(wm, AC97_WM9713_DIG1,
 341                         dig1 | WM9713_POLL | WM9713_COO);
 342
 343        /* wait 3 AC97 time slots + delay for conversion */
 344        poll_delay(delay);
 345        data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 346        /* wait for POLL to go low */
 347        while ((wm97xx_reg_read(wm, AC97_WM9713_DIG1) & WM9713_POLL)
 348               && timeout) {
 349                udelay(AC97_LINK_FRAME);
 350                timeout--;
 351        }
 352
 353        if (timeout <= 0) {
 354                /* If PDEN is set, we can get a timeout when pen goes up */
 355                if (is_pden(wm))
 356                        wm->pen_probably_down = 0;
 357                else
 358                        dev_dbg(wm->dev, "adc sample timeout");
 359                return RC_PENUP;
 360        }
 361
 362        /* read back data */
 363        data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 364        if (pil)
 365                data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 366        else
 367                data->p = DEFAULT_PRESSURE;
 368
 369        if (wm->mach_ops && wm->mach_ops->post_sample)
 370                wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 371
 372        /* check we have correct sample */
 373        if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 374                goto err;
 375        if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 376                goto err;
 377
 378        if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 379                wm->pen_probably_down = 0;
 380                return RC_PENUP;
 381        }
 382        return RC_VALID;
 383err:
 384        return 0;
 385}
 386
 387/*
 388 * Sample the WM9713 touchscreen in polling mode
 389 */
 390static int wm9713_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 391{
 392        int rc;
 393
 394        if (coord) {
 395                rc = wm9713_poll_coord(wm, data);
 396                if (rc != RC_VALID)
 397                        return rc;
 398        } else {
 399                rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN, &data->x);
 400                if (rc != RC_VALID)
 401                        return rc;
 402                rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN, &data->y);
 403                if (rc != RC_VALID)
 404                        return rc;
 405                if (pil) {
 406                        rc = wm9713_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
 407                                                &data->p);
 408                        if (rc != RC_VALID)
 409                                return rc;
 410                } else
 411                        data->p = DEFAULT_PRESSURE;
 412        }
 413        return RC_VALID;
 414}
 415
 416/*
 417 * Enable WM9713 continuous mode, i.e. touch data is streamed across
 418 * an AC97 slot
 419 */
 420static int wm9713_acc_enable(struct wm97xx *wm, int enable)
 421{
 422        u16 dig1, dig2, dig3;
 423        int ret = 0;
 424
 425        dig1 = wm->dig[0];
 426        dig2 = wm->dig[1];
 427        dig3 = wm->dig[2];
 428
 429        if (enable) {
 430                /* continuous mode */
 431                if (wm->mach_ops->acc_startup &&
 432                        (ret = wm->mach_ops->acc_startup(wm)) < 0)
 433                        return ret;
 434
 435                dig1 &= ~WM9713_ADCSEL_MASK;
 436                dig1 |= WM9713_CTC | WM9713_COO | WM9713_ADCSEL_X |
 437                        WM9713_ADCSEL_Y;
 438                if (pil)
 439                        dig1 |= WM9713_ADCSEL_PRES;
 440                dig2 &= ~(WM97XX_DELAY_MASK | WM97XX_SLT_MASK  |
 441                        WM97XX_CM_RATE_MASK);
 442                dig2 |= WM97XX_SLEN | WM97XX_DELAY(delay) |
 443                WM97XX_SLT(wm->acc_slot) | WM97XX_RATE(wm->acc_rate);
 444                dig3 |= WM9713_PDEN;
 445        } else {
 446                dig1 &= ~(WM9713_CTC | WM9713_COO);
 447                dig2 &= ~WM97XX_SLEN;
 448                dig3 &= ~WM9713_PDEN;
 449                if (wm->mach_ops->acc_shutdown)
 450                        wm->mach_ops->acc_shutdown(wm);
 451        }
 452
 453        wm97xx_reg_write(wm, AC97_WM9713_DIG1, dig1);
 454        wm97xx_reg_write(wm, AC97_WM9713_DIG2, dig2);
 455        wm97xx_reg_write(wm, AC97_WM9713_DIG3, dig3);
 456
 457        return ret;
 458}
 459
 460struct wm97xx_codec_drv wm9713_codec = {
 461        .id = WM9713_ID2,
 462        .name = "wm9713",
 463        .poll_sample = wm9713_poll_sample,
 464        .poll_touch = wm9713_poll_touch,
 465        .acc_enable = wm9713_acc_enable,
 466        .phy_init = wm9713_phy_init,
 467        .dig_enable = wm9713_dig_enable,
 468        .dig_restore = wm9713_dig_restore,
 469        .aux_prepare = wm9713_aux_prepare,
 470};
 471EXPORT_SYMBOL_GPL(wm9713_codec);
 472
 473/* Module information */
 474MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 475MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 476MODULE_LICENSE("GPL");
 477