drivers/input/touchscreen/wm9712.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * wm9712.c  --  Codec driver for Wolfson WM9712 AC97 Codecs.
   4  *
   5  * Copyright 2003, 2004, 2005, 2006, 2007 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 WM9712_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 = 3;
  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 WM9712
 150  */
 151 static void wm9712_phy_init(struct wm97xx *wm)
 152 {
 153         u16 dig1 = 0;
 154         u16 dig2 = WM97XX_RPR | WM9712_RPU(1);
 155
 156         /* WM9712 rpu */
 157         if (rpu) {
 158                 dig2 &= 0xffc0;
 159                 dig2 |= WM9712_RPU(rpu);
 160                 dev_dbg(wm->dev, "setting pen detect pull-up to %d Ohms\n",
 161                         64000 / rpu);
 162         }
 163
 164         /* WM9712 five wire */
 165         if (five_wire) {
 166                 dig2 |= WM9712_45W;
 167                 dev_dbg(wm->dev, "setting 5-wire touchscreen mode.\n");
 168
 169                 if (pil) {
 170                         dev_warn(wm->dev, "pressure measurement is not "
 171                                  "supported in 5-wire mode\n");
 172                         pil = 0;
 173                 }
 174         }
 175
 176         /* touchpanel pressure current*/
 177         if (pil == 2) {
 178                 dig2 |= WM9712_PIL;
 179                 dev_dbg(wm->dev,
 180                         "setting pressure measurement current to 400uA.\n");
 181         } else if (pil)
 182                 dev_dbg(wm->dev,
 183                         "setting pressure measurement current to 200uA.\n");
 184         if (!pil)
 185                 pressure = 0;
 186
 187         /* polling mode sample settling delay */
 188         if (delay < 0 || delay > 15) {
 189                 dev_dbg(wm->dev, "supplied delay out of range.\n");
 190                 delay = 4;
 191         }
 192         dig1 &= 0xff0f;
 193         dig1 |= WM97XX_DELAY(delay);
 194         dev_dbg(wm->dev, "setting adc sample delay to %d u Secs.\n",
 195                 delay_table[delay]);
 196
 197         /* mask */
 198         dig2 |= ((mask & 0x3) << 6);
 199         if (mask) {
 200                 u16 reg;
 201                 /* Set GPIO4 as Mask Pin*/
 202                 reg = wm97xx_reg_read(wm, AC97_MISC_AFE);
 203                 wm97xx_reg_write(wm, AC97_MISC_AFE, reg | WM97XX_GPIO_4);
 204                 reg = wm97xx_reg_read(wm, AC97_GPIO_CFG);
 205                 wm97xx_reg_write(wm, AC97_GPIO_CFG, reg | WM97XX_GPIO_4);
 206         }
 207
 208         /* wait - coord mode */
 209         if (coord)
 210                 dig2 |= WM9712_WAIT;
 211
 212         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 213         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 214 }
 215
 216 static void wm9712_dig_enable(struct wm97xx *wm, int enable)
 217 {
 218         u16 dig2 = wm->dig[2];
 219
 220         if (enable) {
 221                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 222                                  dig2 | WM97XX_PRP_DET_DIG);
 223                 wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD); /* dummy read */
 224         } else
 225                 wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2,
 226                                  dig2 & ~WM97XX_PRP_DET_DIG);
 227 }
 228
 229 static void wm9712_aux_prepare(struct wm97xx *wm)
 230 {
 231         memcpy(wm->dig_save, wm->dig, sizeof(wm->dig));
 232         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, 0);
 233         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, WM97XX_PRP_DET_DIG);
 234 }
 235
 236 static void wm9712_dig_restore(struct wm97xx *wm)
 237 {
 238         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, wm->dig_save[1]);
 239         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, wm->dig_save[2]);
 240 }
 241
 242 static inline int is_pden(struct wm97xx *wm)
 243 {
 244         return wm->dig[2] & WM9712_PDEN;
 245 }
 246
 247 /*
 248  * Read a sample from the WM9712 adc in polling mode.
 249  */
 250 static int wm9712_poll_sample(struct wm97xx *wm, int adcsel, int *sample)
 251 {
 252         int timeout = 5 * delay;
 253         bool wants_pen = adcsel & WM97XX_PEN_DOWN;
 254
 255         if (wants_pen && !wm->pen_probably_down) {
 256                 u16 data = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 257                 if (!(data & WM97XX_PEN_DOWN))
 258                         return RC_PENUP;
 259                 wm->pen_probably_down = 1;
 260         }
 261
 262         /* set up digitiser */
 263         if (wm->mach_ops && wm->mach_ops->pre_sample)
 264                 wm->mach_ops->pre_sample(adcsel);
 265         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, (adcsel & WM97XX_ADCSEL_MASK)
 266                                 | WM97XX_POLL | WM97XX_DELAY(delay));
 267
 268         /* wait 3 AC97 time slots + delay for conversion */
 269         poll_delay(delay);
 270
 271         /* wait for POLL to go low */
 272         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 273                && timeout) {
 274                 udelay(AC97_LINK_FRAME);
 275                 timeout--;
 276         }
 277
 278         if (timeout <= 0) {
 279                 /* If PDEN is set, we can get a timeout when pen goes up */
 280                 if (is_pden(wm))
 281                         wm->pen_probably_down = 0;
 282                 else
 283                         dev_dbg(wm->dev, "adc sample timeout\n");
 284                 return RC_PENUP;
 285         }
 286
 287         *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 288         if (wm->mach_ops && wm->mach_ops->post_sample)
 289                 wm->mach_ops->post_sample(adcsel);
 290
 291         /* check we have correct sample */
 292         if ((*sample ^ adcsel) & WM97XX_ADCSEL_MASK) {
 293                 dev_dbg(wm->dev, "adc wrong sample, wanted %x got %x\n",
 294                         adcsel & WM97XX_ADCSEL_MASK,
 295                         *sample & WM97XX_ADCSEL_MASK);
 296                 return RC_AGAIN;
 297         }
 298
 299         if (wants_pen && !(*sample & WM97XX_PEN_DOWN)) {
 300                 /* Sometimes it reads a wrong value the first time. */
 301                 *sample = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 302                 if (!(*sample & WM97XX_PEN_DOWN)) {
 303                         wm->pen_probably_down = 0;
 304                         return RC_PENUP;
 305                 }
 306         }
 307
 308         return RC_VALID;
 309 }
 310
 311 /*
 312  * Read a coord from the WM9712 adc in polling mode.
 313  */
 314 static int wm9712_poll_coord(struct wm97xx *wm, struct wm97xx_data *data)
 315 {
 316         int timeout = 5 * delay;
 317
 318         if (!wm->pen_probably_down) {
 319                 u16 data_rd = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 320                 if (!(data_rd & WM97XX_PEN_DOWN))
 321                         return RC_PENUP;
 322                 wm->pen_probably_down = 1;
 323         }
 324
 325         /* set up digitiser */
 326         if (wm->mach_ops && wm->mach_ops->pre_sample)
 327                 wm->mach_ops->pre_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 328
 329         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1,
 330                 WM97XX_COO | WM97XX_POLL | WM97XX_DELAY(delay));
 331
 332         /* wait 3 AC97 time slots + delay for conversion and read x */
 333         poll_delay(delay);
 334         data->x = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 335         /* wait for POLL to go low */
 336         while ((wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER1) & WM97XX_POLL)
 337                && timeout) {
 338                 udelay(AC97_LINK_FRAME);
 339                 timeout--;
 340         }
 341
 342         if (timeout <= 0) {
 343                 /* If PDEN is set, we can get a timeout when pen goes up */
 344                 if (is_pden(wm))
 345                         wm->pen_probably_down = 0;
 346                 else
 347                         dev_dbg(wm->dev, "adc sample timeout\n");
 348                 return RC_PENUP;
 349         }
 350
 351         /* read back y data */
 352         data->y = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 353         if (pil)
 354                 data->p = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER_RD);
 355         else
 356                 data->p = DEFAULT_PRESSURE;
 357
 358         if (wm->mach_ops && wm->mach_ops->post_sample)
 359                 wm->mach_ops->post_sample(WM97XX_ADCSEL_X | WM97XX_ADCSEL_Y);
 360
 361         /* check we have correct sample */
 362         if (!(data->x & WM97XX_ADCSEL_X) || !(data->y & WM97XX_ADCSEL_Y))
 363                 goto err;
 364         if (pil && !(data->p & WM97XX_ADCSEL_PRES))
 365                 goto err;
 366
 367         if (!(data->x & WM97XX_PEN_DOWN) || !(data->y & WM97XX_PEN_DOWN)) {
 368                 wm->pen_probably_down = 0;
 369                 return RC_PENUP;
 370         }
 371         return RC_VALID;
 372 err:
 373         return 0;
 374 }
 375
 376 /*
 377  * Sample the WM9712 touchscreen in polling mode
 378  */
 379 static int wm9712_poll_touch(struct wm97xx *wm, struct wm97xx_data *data)
 380 {
 381         int rc;
 382
 383         if (coord) {
 384                 rc = wm9712_poll_coord(wm, data);
 385                 if (rc != RC_VALID)
 386                         return rc;
 387         } else {
 388                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_X | WM97XX_PEN_DOWN,
 389                                         &data->x);
 390                 if (rc != RC_VALID)
 391                         return rc;
 392
 393                 rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_Y | WM97XX_PEN_DOWN,
 394                                         &data->y);
 395                 if (rc != RC_VALID)
 396                         return rc;
 397
 398                 if (pil && !five_wire) {
 399                         rc = wm9712_poll_sample(wm, WM97XX_ADCSEL_PRES | WM97XX_PEN_DOWN,
 400                                                 &data->p);
 401                         if (rc != RC_VALID)
 402                                 return rc;
 403                 } else
 404                         data->p = DEFAULT_PRESSURE;
 405         }
 406         return RC_VALID;
 407 }
 408
 409 /*
 410  * Enable WM9712 continuous mode, i.e. touch data is streamed across
 411  * an AC97 slot
 412  */
 413 static int wm9712_acc_enable(struct wm97xx *wm, int enable)
 414 {
 415         u16 dig1, dig2;
 416         int ret = 0;
 417
 418         dig1 = wm->dig[1];
 419         dig2 = wm->dig[2];
 420
 421         if (enable) {
 422                 /* continuous mode */
 423                 if (wm->mach_ops->acc_startup) {
 424                         ret = wm->mach_ops->acc_startup(wm);
 425                         if (ret < 0)
 426                                 return ret;
 427                 }
 428                 dig1 &= ~(WM97XX_CM_RATE_MASK | WM97XX_ADCSEL_MASK |
 429                         WM97XX_DELAY_MASK | WM97XX_SLT_MASK);
 430                 dig1 |= WM97XX_CTC | WM97XX_COO | WM97XX_SLEN |
 431                         WM97XX_DELAY(delay) |
 432                         WM97XX_SLT(wm->acc_slot) |
 433                         WM97XX_RATE(wm->acc_rate);
 434                 if (pil)
 435                         dig1 |= WM97XX_ADCSEL_PRES;
 436                 dig2 |= WM9712_PDEN;
 437         } else {
 438                 dig1 &= ~(WM97XX_CTC | WM97XX_COO | WM97XX_SLEN);
 439                 dig2 &= ~WM9712_PDEN;
 440                 if (wm->mach_ops->acc_shutdown)
 441                         wm->mach_ops->acc_shutdown(wm);
 442         }
 443
 444         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER1, dig1);
 445         wm97xx_reg_write(wm, AC97_WM97XX_DIGITISER2, dig2);
 446
 447         return 0;
 448 }
 449
 450 struct wm97xx_codec_drv wm9712_codec = {
 451         .id = WM9712_ID2,
 452         .name = "wm9712",
 453         .poll_sample = wm9712_poll_sample,
 454         .poll_touch = wm9712_poll_touch,
 455         .acc_enable = wm9712_acc_enable,
 456         .phy_init = wm9712_phy_init,
 457         .dig_enable = wm9712_dig_enable,
 458         .dig_restore = wm9712_dig_restore,
 459         .aux_prepare = wm9712_aux_prepare,
 460 };
 461 EXPORT_SYMBOL_GPL(wm9712_codec);
 462
 463 /* Module information */
 464 MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
 465 MODULE_DESCRIPTION("WM9712 Touch Screen Driver");
 466 MODULE_LICENSE("GPL");