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/init.h>
  18 #include <linux/kernel.h>
  19 #include <linux/err.h>
  20 #include <linux/module.h>
  21 #include <linux/input.h>
  22 #include <linux/slab.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/clk.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/io.h>
  27 #include <linux/delay.h>
  28 #include <linux/of.h>
  29 #include <linux/of_device.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 };
  56
  57 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
  58 {
  59         return readl(ts->mfd_tscadc->tscadc_base + reg);
  60 }
  61
  62 static void titsc_writel(struct titsc *tsc, unsigned int reg,
  63                                         unsigned int val)
  64 {
  65         writel(val, tsc->mfd_tscadc->tscadc_base + reg);
  66 }
  67
  68 static int titsc_config_wires(struct titsc *ts_dev)
  69 {
  70         u32 analog_line[4];
  71         u32 wire_order[4];
  72         int i, bit_cfg;
  73
  74         for (i = 0; i < 4; i++) {
  75                 /*
  76                  * Get the order in which TSC wires are attached
  77                  * w.r.t. each of the analog input lines on the EVM.
  78                  */
  79                 analog_line[i] = (ts_dev->config_inp[i] & 0xF0) >> 4;
  80                 wire_order[i] = ts_dev->config_inp[i] & 0x0F;
  81                 if (WARN_ON(analog_line[i] > 7))
  82                         return -EINVAL;
  83                 if (WARN_ON(wire_order[i] > ARRAY_SIZE(config_pins)))
  84                         return -EINVAL;
  85         }
  86
  87         for (i = 0; i < 4; i++) {
  88                 int an_line;
  89                 int wi_order;
  90
  91                 an_line = analog_line[i];
  92                 wi_order = wire_order[i];
  93                 bit_cfg = config_pins[wi_order];
  94                 if (bit_cfg == 0)
  95                         return -EINVAL;
  96                 switch (wi_order) {
  97                 case 0:
  98                         ts_dev->bit_xp = bit_cfg;
  99                         ts_dev->inp_xp = an_line;
 100                         break;
 101
 102                 case 1:
 103                         ts_dev->bit_xn = bit_cfg;
 104                         ts_dev->inp_xn = an_line;
 105                         break;
 106
 107                 case 2:
 108                         ts_dev->bit_yp = bit_cfg;
 109                         ts_dev->inp_yp = an_line;
 110                         break;
 111                 case 3:
 112                         ts_dev->bit_yn = bit_cfg;
 113                         ts_dev->inp_yn = an_line;
 114                         break;
 115                 }
 116         }
 117         return 0;
 118 }
 119
 120 static void titsc_step_config(struct titsc *ts_dev)
 121 {
 122         unsigned int    config;
 123         int i;
 124         int end_step;
 125         u32 stepenable;
 126
 127         config = STEPCONFIG_MODE_HWSYNC |
 128                         STEPCONFIG_AVG_16 | ts_dev->bit_xp;
 129         switch (ts_dev->wires) {
 130         case 4:
 131                 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
 132                 break;
 133         case 5:
 134                 config |= ts_dev->bit_yn |
 135                                 STEPCONFIG_INP_AN4 | ts_dev->bit_xn |
 136                                 ts_dev->bit_yp;
 137                 break;
 138         case 8:
 139                 config |= STEPCONFIG_INP(ts_dev->inp_yp) | ts_dev->bit_xn;
 140                 break;
 141         }
 142
 143         /* 1 … coordinate_readouts is for X */
 144         end_step = ts_dev->coordinate_readouts;
 145         for (i = 0; i < end_step; i++) {
 146                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
 147                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 148         }
 149
 150         config = 0;
 151         config = STEPCONFIG_MODE_HWSYNC |
 152                         STEPCONFIG_AVG_16 | ts_dev->bit_yn |
 153                         STEPCONFIG_INM_ADCREFM;
 154         switch (ts_dev->wires) {
 155         case 4:
 156                 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
 157                 break;
 158         case 5:
 159                 config |= ts_dev->bit_xp | STEPCONFIG_INP_AN4 |
 160                                 ts_dev->bit_xn | ts_dev->bit_yp;
 161                 break;
 162         case 8:
 163                 config |= ts_dev->bit_yp | STEPCONFIG_INP(ts_dev->inp_xp);
 164                 break;
 165         }
 166
 167         /* coordinate_readouts … coordinate_readouts * 2 is for Y */
 168         end_step = ts_dev->coordinate_readouts * 2;
 169         for (i = ts_dev->coordinate_readouts; i < end_step; i++) {
 170                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
 171                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 172         }
 173
 174         /* Charge step configuration */
 175         config = ts_dev->bit_xp | ts_dev->bit_yn |
 176                         STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
 177                         STEPCHARGE_INM_AN1 | STEPCHARGE_INP(ts_dev->inp_yp);
 178
 179         titsc_writel(ts_dev, REG_CHARGECONFIG, config);
 180         titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
 181
 182         /* coordinate_readouts * 2 … coordinate_readouts * 2 + 2 is for Z */
 183         config = STEPCONFIG_MODE_HWSYNC |
 184                         STEPCONFIG_AVG_16 | ts_dev->bit_yp |
 185                         ts_dev->bit_xn | STEPCONFIG_INM_ADCREFM |
 186                         STEPCONFIG_INP(ts_dev->inp_xp);
 187         titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
 188         titsc_writel(ts_dev, REG_STEPDELAY(end_step),
 189                         STEPCONFIG_OPENDLY);
 190
 191         end_step++;
 192         config |= STEPCONFIG_INP(ts_dev->inp_yn);
 193         titsc_writel(ts_dev, REG_STEPCONFIG(end_step), config);
 194         titsc_writel(ts_dev, REG_STEPDELAY(end_step),
 195                         STEPCONFIG_OPENDLY);
 196
 197         /* The steps1 … end and bit 0 for TS_Charge */
 198         stepenable = (1 << (end_step + 2)) - 1;
 199         am335x_tsc_se_set(ts_dev->mfd_tscadc, stepenable);
 200 }
 201
 202 static void titsc_read_coordinates(struct titsc *ts_dev,
 203                 u32 *x, u32 *y, u32 *z1, u32 *z2)
 204 {
 205         unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
 206         unsigned int prev_val_x = ~0, prev_val_y = ~0;
 207         unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
 208         unsigned int read, diff;
 209         unsigned int i, channel;
 210         unsigned int creads = ts_dev->coordinate_readouts;
 211
 212         *z1 = *z2 = 0;
 213         if (fifocount % (creads * 2 + 2))
 214                 fifocount -= fifocount % (creads * 2 + 2);
 215         /*
 216          * Delta filter is used to remove large variations in sampled
 217          * values from ADC. The filter tries to predict where the next
 218          * coordinate could be. This is done by taking a previous
 219          * coordinate and subtracting it form current one. Further the
 220          * algorithm compares the difference with that of a present value,
 221          * if true the value is reported to the sub system.
 222          */
 223         for (i = 0; i < fifocount; i++) {
 224                 read = titsc_readl(ts_dev, REG_FIFO0);
 225
 226                 channel = (read & 0xf0000) >> 16;
 227                 read &= 0xfff;
 228                 if (channel < creads) {
 229                         diff = abs(read - prev_val_x);
 230                         if (diff < prev_diff_x) {
 231                                 prev_diff_x = diff;
 232                                 *x = read;
 233                         }
 234                         prev_val_x = read;
 235
 236                 } else if (channel < creads * 2) {
 237                         diff = abs(read - prev_val_y);
 238                         if (diff < prev_diff_y) {
 239                                 prev_diff_y = diff;
 240                                 *y = read;
 241                         }
 242                         prev_val_y = read;
 243
 244                 } else if (channel < creads * 2 + 1) {
 245                         *z1 = read;
 246
 247                 } else if (channel < creads * 2 + 2) {
 248                         *z2 = read;
 249                 }
 250         }
 251 }
 252
 253 static irqreturn_t titsc_irq(int irq, void *dev)
 254 {
 255         struct titsc *ts_dev = dev;
 256         struct input_dev *input_dev = ts_dev->input;
 257         unsigned int status, irqclr = 0;
 258         unsigned int x = 0, y = 0;
 259         unsigned int z1, z2, z;
 260         unsigned int fsm;
 261
 262         status = titsc_readl(ts_dev, REG_IRQSTATUS);
 263         if (status & IRQENB_FIFO0THRES) {
 264
 265                 titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
 266
 267                 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
 268                         /*
 269                          * Calculate pressure using formula
 270                          * Resistance(touch) = x plate resistance *
 271                          * x postion/4096 * ((z2 / z1) - 1)
 272                          */
 273                         z = z1 - z2;
 274                         z *= x;
 275                         z *= ts_dev->x_plate_resistance;
 276                         z /= z2;
 277                         z = (z + 2047) >> 12;
 278
 279                         if (z <= MAX_12BIT) {
 280                                 input_report_abs(input_dev, ABS_X, x);
 281                                 input_report_abs(input_dev, ABS_Y, y);
 282                                 input_report_abs(input_dev, ABS_PRESSURE, z);
 283                                 input_report_key(input_dev, BTN_TOUCH, 1);
 284                                 input_sync(input_dev);
 285                         }
 286                 }
 287                 irqclr |= IRQENB_FIFO0THRES;
 288         }
 289
 290         /*
 291          * Time for sequencer to settle, to read
 292          * correct state of the sequencer.
 293          */
 294         udelay(SEQ_SETTLE);
 295
 296         status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
 297         if (status & IRQENB_PENUP) {
 298                 /* Pen up event */
 299                 fsm = titsc_readl(ts_dev, REG_ADCFSM);
 300                 if (fsm == ADCFSM_STEPID) {
 301                         ts_dev->pen_down = false;
 302                         input_report_key(input_dev, BTN_TOUCH, 0);
 303                         input_report_abs(input_dev, ABS_PRESSURE, 0);
 304                         input_sync(input_dev);
 305                 } else {
 306                         ts_dev->pen_down = true;
 307                 }
 308                 irqclr |= IRQENB_PENUP;
 309         }
 310
 311         if (status & IRQENB_HW_PEN) {
 312
 313                 titsc_writel(ts_dev, REG_IRQWAKEUP, 0x00);
 314                 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
 315         }
 316
 317         if (irqclr) {
 318                 titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
 319                 am335x_tsc_se_update(ts_dev->mfd_tscadc);
 320                 return IRQ_HANDLED;
 321         }
 322         return IRQ_NONE;
 323 }
 324
 325 static int titsc_parse_dt(struct platform_device *pdev,
 326                                         struct titsc *ts_dev)
 327 {
 328         struct device_node *node = pdev->dev.of_node;
 329         int err;
 330
 331         if (!node)
 332                 return -EINVAL;
 333
 334         err = of_property_read_u32(node, "ti,wires", &ts_dev->wires);
 335         if (err < 0)
 336                 return err;
 337         switch (ts_dev->wires) {
 338         case 4:
 339         case 5:
 340         case 8:
 341                 break;
 342         default:
 343                 return -EINVAL;
 344         }
 345
 346         err = of_property_read_u32(node, "ti,x-plate-resistance",
 347                         &ts_dev->x_plate_resistance);
 348         if (err < 0)
 349                 return err;
 350
 351         err = of_property_read_u32(node, "ti,coordiante-readouts",
 352                         &ts_dev->coordinate_readouts);
 353         if (err < 0)
 354                 return err;
 355
 356         return of_property_read_u32_array(node, "ti,wire-config",
 357                         ts_dev->config_inp, ARRAY_SIZE(ts_dev->config_inp));
 358 }
 359
 360 /*
 361  * The functions for inserting/removing driver as a module.
 362  */
 363
 364 static int titsc_probe(struct platform_device *pdev)
 365 {
 366         struct titsc *ts_dev;
 367         struct input_dev *input_dev;
 368         struct ti_tscadc_dev *tscadc_dev = ti_tscadc_dev_get(pdev);
 369         int err;
 370
 371         /* Allocate memory for device */
 372         ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
 373         input_dev = input_allocate_device();
 374         if (!ts_dev || !input_dev) {
 375                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 376                 err = -ENOMEM;
 377                 goto err_free_mem;
 378         }
 379
 380         tscadc_dev->tsc = ts_dev;
 381         ts_dev->mfd_tscadc = tscadc_dev;
 382         ts_dev->input = input_dev;
 383         ts_dev->irq = tscadc_dev->irq;
 384
 385         err = titsc_parse_dt(pdev, ts_dev);
 386         if (err) {
 387                 dev_err(&pdev->dev, "Could not find valid DT data.\n");
 388                 goto err_free_mem;
 389         }
 390
 391         err = request_irq(ts_dev->irq, titsc_irq,
 392                           0, pdev->dev.driver->name, ts_dev);
 393         if (err) {
 394                 dev_err(&pdev->dev, "failed to allocate irq.\n");
 395                 goto err_free_mem;
 396         }
 397
 398         titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
 399         err = titsc_config_wires(ts_dev);
 400         if (err) {
 401                 dev_err(&pdev->dev, "wrong i/p wire configuration\n");
 402                 goto err_free_irq;
 403         }
 404         titsc_step_config(ts_dev);
 405         titsc_writel(ts_dev, REG_FIFO0THR,
 406                         ts_dev->coordinate_readouts * 2 + 2 - 1);
 407
 408         input_dev->name = "ti-tsc";
 409         input_dev->dev.parent = &pdev->dev;
 410
 411         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 412         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 413
 414         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 415         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 416         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 417
 418         /* register to the input system */
 419         err = input_register_device(input_dev);
 420         if (err)
 421                 goto err_free_irq;
 422
 423         platform_set_drvdata(pdev, ts_dev);
 424         return 0;
 425
 426 err_free_irq:
 427         free_irq(ts_dev->irq, ts_dev);
 428 err_free_mem:
 429         input_free_device(input_dev);
 430         kfree(ts_dev);
 431         return err;
 432 }
 433
 434 static int titsc_remove(struct platform_device *pdev)
 435 {
 436         struct titsc *ts_dev = platform_get_drvdata(pdev);
 437         u32 steps;
 438
 439         free_irq(ts_dev->irq, ts_dev);
 440
 441         /* total steps followed by the enable mask */
 442         steps = 2 * ts_dev->coordinate_readouts + 2;
 443         steps = (1 << steps) - 1;
 444         am335x_tsc_se_clr(ts_dev->mfd_tscadc, steps);
 445
 446         input_unregister_device(ts_dev->input);
 447
 448         platform_set_drvdata(pdev, NULL);
 449         kfree(ts_dev);
 450         return 0;
 451 }
 452
 453 #ifdef CONFIG_PM
 454 static int titsc_suspend(struct device *dev)
 455 {
 456         struct titsc *ts_dev = dev_get_drvdata(dev);
 457         struct ti_tscadc_dev *tscadc_dev;
 458         unsigned int idle;
 459
 460         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 461         if (device_may_wakeup(tscadc_dev->dev)) {
 462                 idle = titsc_readl(ts_dev, REG_IRQENABLE);
 463                 titsc_writel(ts_dev, REG_IRQENABLE,
 464                                 (idle | IRQENB_HW_PEN));
 465                 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
 466         }
 467         return 0;
 468 }
 469
 470 static int titsc_resume(struct device *dev)
 471 {
 472         struct titsc *ts_dev = dev_get_drvdata(dev);
 473         struct ti_tscadc_dev *tscadc_dev;
 474
 475         tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev));
 476         if (device_may_wakeup(tscadc_dev->dev)) {
 477                 titsc_writel(ts_dev, REG_IRQWAKEUP,
 478                                 0x00);
 479                 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
 480         }
 481         titsc_step_config(ts_dev);
 482         titsc_writel(ts_dev, REG_FIFO0THR,
 483                         ts_dev->coordinate_readouts * 2 + 2 - 1);
 484         return 0;
 485 }
 486
 487 static const struct dev_pm_ops titsc_pm_ops = {
 488         .suspend = titsc_suspend,
 489         .resume  = titsc_resume,
 490 };
 491 #define TITSC_PM_OPS (&titsc_pm_ops)
 492 #else
 493 #define TITSC_PM_OPS NULL
 494 #endif
 495
 496 static const struct of_device_id ti_tsc_dt_ids[] = {
 497         { .compatible = "ti,am3359-tsc", },
 498         { }
 499 };
 500 MODULE_DEVICE_TABLE(of, ti_tsc_dt_ids);
 501
 502 static struct platform_driver ti_tsc_driver = {
 503         .probe  = titsc_probe,
 504         .remove = titsc_remove,
 505         .driver = {
 506                 .name   = "TI-am335x-tsc",
 507                 .owner  = THIS_MODULE,
 508                 .pm     = TITSC_PM_OPS,
 509                 .of_match_table = of_match_ptr(ti_tsc_dt_ids),
 510         },
 511 };
 512 module_platform_driver(ti_tsc_driver);
 513
 514 MODULE_DESCRIPTION("TI touchscreen controller driver");
 515 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 516 MODULE_LICENSE("GPL");