drivers/input/touchscreen/ti_am335x_tsc.c

   1 /*
   2  * TI Touch Screen driver
   3  *
   4  * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation version 2.
   9  *
  10  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11  * kind, whether express or implied; without even the implied warranty
  12  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16
  17 #include <linux/kernel.h>
  18 #include <linux/err.h>
  19 #include <linux/module.h>
  20 #include <linux/input.h>
  21 #include <linux/slab.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/clk.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/io.h>
  26 #include <linux/delay.h>
  27 #include <linux/of.h>
  28 #include <linux/of_device.h>
  29 #include <linux/sort.h>
  30
  31 #include <linux/mfd/ti_am335x_tscadc.h>
  32
  33 #define ADCFSM_STEPID           0x10
  34 #define SEQ_SETTLE              275
  35 #define MAX_12BIT               ((1 << 12) - 1)
  36
  37 static const int config_pins[] = {
  38         STEPCONFIG_XPP,
  39         STEPCONFIG_XNN,
  40         STEPCONFIG_YPP,
  41         STEPCONFIG_YNN,
  42 };
  43
  44 struct titsc {
  45         struct input_dev        *input;
  46         struct ti_tscadc_dev    *mfd_tscadc;
  47         unsigned int            irq;
  48         unsigned int            wires;
  49         unsigned int            x_plate_resistance;
  50         bool                    pen_down;
  51         int                     coordinate_readouts;
  52         u32                     config_inp[4];
  53         u32                     bit_xp, bit_xn, bit_yp, bit_yn;
  54         u32                     inp_xp, inp_xn, inp_yp, inp_yn;
  55         u32                     step_mask;
  56         u32                     charge_delay;
  57 };
  58
  59 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
  60 {
  61         return readl(ts->mfd_tscadc->tscadc_base + reg);
  62 }
  63
  64 static void titsc_writel(struct titsc *tsc, unsigned int reg,
  65                                         unsigned int val)
  66 {
  67         writel(val, tsc->mfd_tscadc->tscadc_base + reg);
  68 }
  69
  70 static int titsc_config_wires(struct titsc *ts_dev)
  71 {
  72         u32 analog_line[4];
  73         u32 wire_order[4];
  74         int i, bit_cfg;
  75
  76         for (i = 0; i < 4; i++) {
  77                 /*
  78                  * Get the order in which TSC wires are attached
  79                  * w.r.t. each of the analog input lines on the EVM.
  80                  */
  81                 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
  82                 wire_order[i] = ts_dev->config_inp[i] & 0x0F;
  83                 if (WARN_ON(analog_line[i] > 7))
  84                         return -EINVAL;
  85                 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
  86                         return -EINVAL;
  87         }
  88
  89         for (i = 0; i < 4; i++) {
  90                 int an_line;
  91                 int wi_order;
  92
  93                 an_line = analog_line[i];
  94                 wi_order = wire_order[i];
  95                 bit_cfg = config_pins[wi_order];
  96                 if (bit_cfg == 0)
  97                         return -EINVAL;
  98                 switch (wi_order) {
  99                 case 0:
 100                         ts_dev->bit_xp = bit_cfg;
 101                         ts_dev->inp_xp = an_line;
 102                         break;
 103
 104                 case 1:
 105                         ts_dev->bit_xn = bit_cfg;
 106                         ts_dev->inp_xn = an_line;
 107                         break;
 108
 109                 case 2:
 110                         ts_dev->bit_yp = bit_cfg;
 111                         ts_dev->inp_yp = an_line;
 112                         break;
 113                 case 3:
 114                         ts_dev->bit_yn = bit_cfg;
 115                         ts_dev->inp_yn = an_line;
 116                         break;
 117                 }
 118         }
 119         return 0;
 120 }
 121
 122 static void titsc_step_config(struct titsc *ts_dev)
 123 {
 124         unsigned int    config;
 125         int i;
 126         int end_step, first_step, tsc_steps;
 127         u32 stepenable;
 128
 129         config = STEPCONFIG_MODE_HWSYNC |
 130                         STEPCONFIG_AVG_16 | ts_dev->bit_xp;
 131         switch (ts_dev->wires) {
 132         case 4:
 133                 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
 134                 break;
 135         case 5:
 136                 config |= ts_dev->bit_yn |
 137                                 STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
 138                                 ts_dev->bit_yp;
 139                 break;
 140         case 8:
 141                 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
 142                 break;
 143         }
 144
 145         tsc_steps = ts_dev->coordinate_readouts * 2 + 2;
 146         first_step = TOTAL_STEPS - tsc_steps;
 147         /* Steps 16 to 16-coordinate_readouts is for X */
 148         end_step = first_step + tsc_steps;
 149         for (i = end_step - ts_dev->coordinate_readouts; i < end_step; i++) {
 150                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
 151                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 152         }
 153
 154         config = 0;
 155         config = STEPCONFIG_MODE_HWSYNC |
 156                         STEPCONFIG_AVG_16 | ts_dev->bit_yn |
 157                         STEPCONFIG_INM_ADCREFM;
 158         switch (ts_dev->wires) {
 159         case 4:
 160                 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
 161                 break;
 162         case 5:
 163                 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
 164                                 ts_dev->bit_xn | ts_dev->bit_yp;
 165                 break;
 166         case 8:
 167                 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
 168                 break;
 169         }
 170
 171         /* 1 ... coordinate_readouts is for Y */
 172         end_step = first_step + ts_dev->coordinate_readouts;
 173         for (i = first_step; i < end_step; i++) {
 174                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
 175                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 176         }
 177
 178         /* Make CHARGECONFIG same as IDLECONFIG */
 179
 180         config = titsc_readl(ts_dev, REG_IDLECONFIG);
 181         titsc_writel(ts_dev, REG_CHARGECONFIG, config);
 182         titsc_writel(ts_dev, REG_CHARGEDELAY, ts_dev->charge_delay);
 183
 184         /* coordinate_readouts + 1 ... coordinate_readouts + 2 is for Z */
 185         config = STEPCONFIG_MODE_HWSYNC |
 186                         STEPCONFIG_AVG_16 | ts_dev->bit_yp |
 187                         ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
 188                         STEPCONFIG_INP(ts_dev->inp_xp);
 189         titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
 190         titsc_writel(ts_dev, REG_STEPDELAY(end_step),
 191                         STEPCONFIG_OPENDLY);
 192
 193         end_step++;
 194         config |= STEPCONFIG_INP(ts_dev->inp_yn);
 195         titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
 196         titsc_writel(ts_dev, REG_STEPDELAY(end_step),
 197                         STEPCONFIG_OPENDLY);
 198
 199         /* The steps end ... end - readouts * 2 + 2 and bit 0 for TS_Charge */
 200         stepenable = 1;
 201         for (i = 0; i < tsc_steps; i++)
 202                 stepenable |= 1 << (first_step + i + 1);
 203
 204         ts_dev->step_mask = stepenable;
 205         am335x_tsc_se_set_cache(ts_dev->mfd_tscadc, ts_dev->step_mask);
 206 }
 207
 208 static int titsc_cmp_coord(const void *a, const void *b)
 209 {
 210         return *(int *)a - *(int *)b;
 211 }
 212
 213 static void titsc_read_coordinates(struct titsc *ts_dev,
 214                 u32 *x, u32 *y, u32 *z1, u32 *z2)
 215 {
 216         unsigned int yvals[7], xvals[7];
 217         unsigned int i, xsum = 0, ysum = 0;
 218         unsigned int creads = ts_dev->coordinate_readouts;
 219
 220         for (i = 0; i < creads; i++) {
 221                 yvals[i] = titsc_readl(ts_dev, REG_FIFO0);
 222                 yvals[i] &= 0xfff;
 223         }
 224
 225         *z1 = titsc_readl(ts_dev, REG_FIFO0);
 226         *z1 &= 0xfff;
 227         *z2 = titsc_readl(ts_dev, REG_FIFO0);
 228         *z2 &= 0xfff;
 229
 230         for (i = 0; i < creads; i++) {
 231                 xvals[i] = titsc_readl(ts_dev, REG_FIFO0);
 232                 xvals[i] &= 0xfff;
 233         }
 234
 235         /*
 236          * If co-ordinates readouts is less than 4 then
 237          * report the average. In case of 4 or more
 238          * readouts, sort the co-ordinate samples, drop
 239          * min and max values and report the average of
 240          * remaining values.
 241          */
 242         if (creads <=  3) {
 243                 for (i = 0; i < creads; i++) {
 244                         ysum += yvals[i];
 245                         xsum += xvals[i];
 246                 }
 247                 ysum /= creads;
 248                 xsum /= creads;
 249         } else {
 250                 sort(yvals, creads, sizeof(unsigned int),
 251                      titsc_cmp_coord, NULL);
 252                 sort(xvals, creads, sizeof(unsigned int),
 253                      titsc_cmp_coord, NULL);
 254                 for (i = 1; i < creads - 1; i++) {
 255                         ysum += yvals[i];
 256                         xsum += xvals[i];
 257                 }
 258                 ysum /= creads - 2;
 259                 xsum /= creads - 2;
 260         }
 261         *y = ysum;
 262         *x = xsum;
 263 }
 264
 265 static irqreturn_t titsc_irq(int irq, void *dev)
 266 {
 267         struct titsc *ts_dev = dev;
 268         struct input_dev *input_dev = ts_dev->input;
 269         unsigned int fsm, status, irqclr = 0;
 270         unsigned int x = 0, y = 0;
 271         unsigned int z1, z2, z;
 272
 273         status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
 274         if (status & IRQENB_HW_PEN) {
 275                 ts_dev->pen_down = true;
 276                 titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
 277                 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
 278                 irqclr |= IRQENB_HW_PEN;
 279         }
 280
 281         if (status & IRQENB_PENUP) {
 282                 fsm = titsc_readl(ts_dev, REG_ADCFSM);
 283                 if (fsm == ADCFSM_STEPID) {
 284                         ts_dev->pen_down = false;
 285                         input_report_key(input_dev, BTN_TOUCH, 0);
 286                         input_report_abs(input_dev, ABS_PRESSURE, 0);
 287                         input_sync(input_dev);
 288                 } else {
 289                         ts_dev->pen_down = true;
 290                 }
 291                 irqclr |= IRQENB_PENUP;
 292         }
 293
 294         if (status & IRQENB_EOS)
 295                 irqclr |= IRQENB_EOS;
 296
 297         /*
 298          * ADC and touchscreen share the IRQ line.
 299          * FIFO1 interrupts are used by ADC. Handle FIFO0 IRQs here only
 300          */
 301         if (status & IRQENB_FIFO0THRES) {
 302
 303                 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
 304
 305                 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
 306                         /*
 307                          * Calculate pressure using formula
 308                          * Resistance(touch) = x plate resistance *
 309                          * x postion/4096 * ((z2 / z1) - 1)
 310                          */
 311                         z = z1 - z2;
 312                         z *= x;
 313                         z *= ts_dev->x_plate_resistance;
 314                         z /= z2;
 315                         z = (z + 2047) >> 12;
 316
 317                         if (z <= MAX_12BIT) {
 318                                 input_report_abs(input_dev, ABS_X, x);
 319                                 input_report_abs(input_dev, ABS_Y, y);
 320                                 input_report_abs(input_dev, ABS_PRESSURE, z);
 321                                 input_report_key(input_dev, BTN_TOUCH, 1);
 322                                 input_sync(input_dev);
 323                         }
 324                 }
 325                 irqclr |= IRQENB_FIFO0THRES;
 326         }
 327         if (irqclr) {
 328                 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
 329                 if (status & IRQENB_EOS)
 330                         am335x_tsc_se_set_cache(ts_dev->mfd_tscadc,
 331                                                 ts_dev->step_mask);
 332                 return IRQ_HANDLED;
 333         }
 334         return IRQ_NONE;
 335 }
 336
 337 static int titsc_parse_dt(struct platform_device *pdev,
 338                                         struct titsc *ts_dev)
 339 {
 340         struct device_node *node = pdev->dev.of_node;
 341         int err;
 342
 343         if (!node)
 344                 return -EINVAL;
 345
 346         err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
 347         if (err < 0)
 348                 return err;
 349         switch (ts_dev->wires) {
 350         case 4:
 351         case 5:
 352         case 8:
 353                 break;
 354         default:
 355                 return -EINVAL;
 356         }
 357
 358         err = of_property_read_u32(node, "ti,x-plate-resistance",
 359                         &ts_dev->x_plate_resistance);
 360         if (err < 0)
 361                 return err;
 362
 363         /*
 364          * Try with the new binding first. If it fails, try again with
 365          * bogus, miss-spelled version.
 366          */
 367         err = of_property_read_u32(node, "ti,coordinate-readouts",
 368                         &ts_dev->coordinate_readouts);
 369         if (err < 0) {
 370                 dev_warn(&pdev->dev, "please use 'ti,coordinate-readouts' instead\n");
 371                 err = of_property_read_u32(node, "ti,coordiante-readouts",
 372                                 &ts_dev->coordinate_readouts);
 373         }
 374
 375         if (err < 0)
 376                 return err;
 377
 378         if (ts_dev->coordinate_readouts <= 0) {
 379                 dev_warn(&pdev->dev,
 380                          "invalid co-ordinate readouts, resetting it to 5\n");
 381                 ts_dev->coordinate_readouts = 5;
 382         }
 383
 384         err = of_property_read_u32(node, "ti,charge-delay",
 385                                    &ts_dev->charge_delay);
 386         /*
 387          * If ti,charge-delay value is not specified, then use
 388          * CHARGEDLY_OPENDLY as the default value.
 389          */
 390         if (err < 0) {
 391                 ts_dev->charge_delay = CHARGEDLY_OPENDLY;
 392                 dev_warn(&pdev->dev, "ti,charge-delay not specified\n");
 393         }
 394
 395         return of_property_read_u32_array(node, "ti,wire-config",
 396                         ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
 397 }
 398
 399 /*
 400  * The functions for inserting/removing driver as a module.
 401  */
 402
 403 static int titsc_probe(struct platform_device *pdev)
 404 {
 405         struct titsc *ts_dev;
 406         struct input_dev *input_dev;
 407         struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
 408         int err;
 409
 410         /* Allocate memory for device */
 411         ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
 412         input_dev = input_allocate_device();
 413         if (!ts_dev || !input_dev) {
 414                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 415                 err = -ENOMEM;
 416                 goto err_free_mem;
 417         }
 418
 419         tscadc_dev->tsc = ts_dev;
 420         ts_dev->mfd_tscadc = tscadc_dev;
 421         ts_dev->input = input_dev;
 422         ts_dev->irq = tscadc_dev->irq;
 423
 424         err = titsc_parse_dt(pdev, ts_dev);
 425         if (err) {
 426                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 427                 goto err_free_mem;
 428         }
 429
 430         err = request_irq(ts_dev->irq, titsc_irq,
 431                           IRQF_SHARED, pdev->dev.driver->name, ts_dev);
 432         if (err) {
 433                 dev_err(&pdev->dev, "failed to allocate irq.\n");
 434                 goto err_free_mem;
 435         }
 436
 437         titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
 438         titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_EOS);
 439         err = titsc_config_wires(ts_dev);
 440         if (err) {
 441                 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
 442                 goto err_free_irq;
 443         }
 444         titsc_step_config(ts_dev);
 445         titsc_writel(ts_dev, REG_FIFO0THR,
 446                         ts_dev->coordinate_readouts * 2 + 2 - 1);
 447
 448         input_dev->name = "ti-tsc";
 449         input_dev->dev.parent = &pdev->dev;
 450
 451         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 452         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 453
 454         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 455         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 456         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 457
 458         /* register to the input system */
 459         err = input_register_device(input_dev);
 460         if (err)
 461                 goto err_free_irq;
 462
 463         platform_set_drvdata(pdev, ts_dev);
 464         return 0;
 465
 466 err_free_irq:
 467         free_irq(ts_dev->irq, ts_dev);
 468 err_free_mem:
 469         input_free_device(input_dev);
 470         kfree(ts_dev);
 471         return err;
 472 }
 473
 474 static int titsc_remove(struct platform_device *pdev)
 475 {
 476         struct titsc *ts_dev = platform_get_drvdata(pdev);
 477         u32 steps;
 478
 479         free_irq(ts_dev->irq, ts_dev);
 480
 481         /* total steps followed by the enable mask */
 482         steps = 2 * ts_dev->coordinate_readouts + 2;
 483         steps = (1 << steps) - 1;
 484         am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
 485
 486         input_unregister_device(ts_dev->input);
 487
 488         kfree(ts_dev);
 489         return 0;
 490 }
 491
 492 #ifdef CONFIG_PM
 493 static int titsc_suspend(struct device *dev)
 494 {
 495         struct titsc *ts_dev = dev_get_drvdata(dev);
 496         struct ti_tscadc_dev *tscadc_dev;
 497         unsigned int idle;
 498
 499         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 500         if (device_may_wakeup(tscadc_dev->dev)) {
 501                 idle = titsc_readl(ts_dev, REG_IRQENABLE);
 502                 titsc_writel(ts_dev, REG_IRQENABLE,
 503                                 (idle | IRQENB_HW_PEN));
 504                 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
 505         }
 506         return 0;
 507 }
 508
 509 static int titsc_resume(struct device *dev)
 510 {
 511         struct titsc *ts_dev = dev_get_drvdata(dev);
 512         struct ti_tscadc_dev *tscadc_dev;
 513
 514         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 515         if (device_may_wakeup(tscadc_dev->dev)) {
 516                 titsc_writel(ts_dev, REG_IRQWAKEUP,
 517                                 0x00);
 518                 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
 519         }
 520         titsc_step_config(ts_dev);
 521         titsc_writel(ts_dev, REG_FIFO0THR,
 522                         ts_dev->coordinate_readouts * 2 + 2 - 1);
 523         return 0;
 524 }
 525
 526 static const struct dev_pm_ops titsc_pm_ops = {
 527         .suspend = titsc_suspend,
 528         .resume  = titsc_resume,
 529 };
 530 #define TITSC_PM_OPS (&titsc_pm_ops)
 531 #else
 532 #define TITSC_PM_OPS NULL
 533 #endif
 534
 535 static const struct of_device_id ti_tsc_dt_ids[] = {
 536         { .compatible = "ti,am3359-tsc", },
 537         { }
 538 };
 539 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
 540
 541 static struct platform_driver ti_tsc_driver = {
 542         .probe  = titsc_probe,
 543         .remove = titsc_remove,
 544         .driver = {
 545                 .name   = "TI-am335x-tsc",
 546                 .pm     = TITSC_PM_OPS,
 547                 .of_match_table = ti_tsc_dt_ids,
 548         },
 549 };
 550 module_platform_driver(ti_tsc_driver);
 551
 552 MODULE_DESCRIPTION("TI touchscreen controller driver");
 553 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 554 MODULE_LICENSE("GPL");