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  */
  37 static int rpu = 8;
  38 module_param(rpu, int, 0);
  39 MODULE_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  */
  51 static int pil;
  52 module_param(pil, int, 0);
  53 MODULE_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  */
  60 static int pressure = DEFAULT_PRESSURE & 0xfff;
  61 module_param(pressure, int, 0);
  62 MODULE_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  */
  76 static int delay = 4;
  77 module_param(delay, int, 0);
  78 MODULE_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  */
  85 static int five_wire;
  86 module_param(five_wire, int, 0);
  87 MODULE_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  */
 102 static int mask;
 103 module_param(mask, int, 0);
 104 MODULE_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  */
 112 static int coord;
 113 module_param(coord, int, 0);
 114 MODULE_PARM_DESC(coord, "Polling coordinate mode");
 115
 116 /*
 117  * ADC sample delay times in uS
 118  */
 119 static 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  */
 143 static 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  */
 151 static 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
 214 static 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
 232 static 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
 239 static 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
 247 static 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  */
 255 static 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  */
 320 static 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;
 383 err:
 384         return 0;
 385 }
 386
 387 /*
 388  * Sample the WM9713 touchscreen in polling mode
 389  */
 390 static 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  */
 420 static 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
 460 struct 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 };
 471 EXPORT_SYMBOL_GPL(wm9713_codec);
 472
 473 /* Module information */
 474 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 475 MODULE_DESCRIPTION("WM9713 Touch Screen Driver");
 476 MODULE_LICENSE("GPL");