drivers/input/touchscreen/ti_tscadc.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/input/ti_tscadc.h>
  28 #include <linux/delay.h>
  29
  30 #define REG_IRQEOI              0x020
  31 #define REG_RAWIRQSTATUS        0x024
  32 #define REG_IRQSTATUS           0x028
  33 #define REG_IRQENABLE           0x02C
  34 #define REG_IRQWAKEUP           0x034
  35 #define REG_CTRL                0x040
  36 #define REG_ADCFSM              0x044
  37 #define REG_CLKDIV              0x04C
  38 #define REG_SE                  0x054
  39 #define REG_IDLECONFIG          0x058
  40 #define REG_CHARGECONFIG        0x05C
  41 #define REG_CHARGEDELAY         0x060
  42 #define REG_STEPCONFIG(n)       (0x64 + ((n - 1) * 8))
  43 #define REG_STEPDELAY(n)        (0x68 + ((n - 1) * 8))
  44 #define REG_STEPCONFIG13        0x0C4
  45 #define REG_STEPDELAY13         0x0C8
  46 #define REG_STEPCONFIG14        0x0CC
  47 #define REG_STEPDELAY14         0x0D0
  48 #define REG_FIFO0CNT            0xE4
  49 #define REG_FIFO1THR            0xF4
  50 #define REG_FIFO0               0x100
  51 #define REG_FIFO1               0x200
  52
  53 /*      Register Bitfields      */
  54 #define IRQWKUP_ENB             BIT(0)
  55 #define STPENB_STEPENB          0x7FFF
  56 #define IRQENB_FIFO1THRES       BIT(5)
  57 #define IRQENB_PENUP            BIT(9)
  58 #define STEPCONFIG_MODE_HWSYNC  0x2
  59 #define STEPCONFIG_SAMPLES_AVG  (1 << 4)
  60 #define STEPCONFIG_XPP          (1 << 5)
  61 #define STEPCONFIG_XNN          (1 << 6)
  62 #define STEPCONFIG_YPP          (1 << 7)
  63 #define STEPCONFIG_YNN          (1 << 8)
  64 #define STEPCONFIG_XNP          (1 << 9)
  65 #define STEPCONFIG_YPN          (1 << 10)
  66 #define STEPCONFIG_INM          (1 << 18)
  67 #define STEPCONFIG_INP          (1 << 20)
  68 #define STEPCONFIG_INP_5        (1 << 21)
  69 #define STEPCONFIG_FIFO1        (1 << 26)
  70 #define STEPCONFIG_OPENDLY      0xff
  71 #define STEPCONFIG_Z1           (3 << 19)
  72 #define STEPIDLE_INP            (1 << 22)
  73 #define STEPCHARGE_RFP          (1 << 12)
  74 #define STEPCHARGE_INM          (1 << 15)
  75 #define STEPCHARGE_INP          (1 << 19)
  76 #define STEPCHARGE_RFM          (1 << 23)
  77 #define STEPCHARGE_DELAY        0x1
  78 #define CNTRLREG_TSCSSENB       (1 << 0)
  79 #define CNTRLREG_STEPID         (1 << 1)
  80 #define CNTRLREG_STEPCONFIGWRT  (1 << 2)
  81 #define CNTRLREG_4WIRE          (1 << 5)
  82 #define CNTRLREG_5WIRE          (1 << 6)
  83 #define CNTRLREG_8WIRE          (3 << 5)
  84 #define CNTRLREG_TSCENB         (1 << 7)
  85 #define ADCFSM_STEPID           0x10
  86
  87 #define SEQ_SETTLE              275
  88 #define ADC_CLK                 3000000
  89 #define MAX_12BIT               ((1 << 12) - 1)
  90 #define TSCADC_DELTA_X          15
  91 #define TSCADC_DELTA_Y          15
  92
  93 struct tscadc {
  94         struct input_dev        *input;
  95         struct clk              *tsc_ick;
  96         void __iomem            *tsc_base;
  97         unsigned int            irq;
  98         unsigned int            wires;
  99         unsigned int            x_plate_resistance;
 100         bool                    pen_down;
 101 };
 102
 103 static unsigned int tscadc_readl(struct tscadc *ts, unsigned int reg)
 104 {
 105         return readl(ts->tsc_base + reg);
 106 }
 107
 108 static void tscadc_writel(struct tscadc *tsc, unsigned int reg,
 109                                         unsigned int val)
 110 {
 111         writel(val, tsc->tsc_base + reg);
 112 }
 113
 114 static void tscadc_step_config(struct tscadc *ts_dev)
 115 {
 116         unsigned int    config;
 117         int i;
 118
 119         /* Configure the Step registers */
 120
 121         config = STEPCONFIG_MODE_HWSYNC |
 122                         STEPCONFIG_SAMPLES_AVG | STEPCONFIG_XPP;
 123         switch (ts_dev->wires) {
 124         case 4:
 125                 config |= STEPCONFIG_INP | STEPCONFIG_XNN;
 126                 break;
 127         case 5:
 128                 config |= STEPCONFIG_YNN |
 129                                 STEPCONFIG_INP_5 | STEPCONFIG_XNN |
 130                                 STEPCONFIG_YPP;
 131                 break;
 132         case 8:
 133                 config |= STEPCONFIG_INP | STEPCONFIG_XNN;
 134                 break;
 135         }
 136
 137         for (i = 1; i < 7; i++) {
 138                 tscadc_writel(ts_dev, REG_STEPCONFIG(i), config);
 139                 tscadc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 140         }
 141
 142         config = 0;
 143         config = STEPCONFIG_MODE_HWSYNC |
 144                         STEPCONFIG_SAMPLES_AVG | STEPCONFIG_YNN |
 145                         STEPCONFIG_INM | STEPCONFIG_FIFO1;
 146         switch (ts_dev->wires) {
 147         case 4:
 148                 config |= STEPCONFIG_YPP;
 149                 break;
 150         case 5:
 151                 config |= STEPCONFIG_XPP | STEPCONFIG_INP_5 |
 152                                 STEPCONFIG_XNP | STEPCONFIG_YPN;
 153                 break;
 154         case 8:
 155                 config |= STEPCONFIG_YPP;
 156                 break;
 157         }
 158
 159         for (i = 7; i < 13; i++) {
 160                 tscadc_writel(ts_dev, REG_STEPCONFIG(i), config);
 161                 tscadc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 162         }
 163
 164         config = 0;
 165         /* Charge step configuration */
 166         config = STEPCONFIG_XPP | STEPCONFIG_YNN |
 167                         STEPCHARGE_RFP | STEPCHARGE_RFM |
 168                         STEPCHARGE_INM | STEPCHARGE_INP;
 169
 170         tscadc_writel(ts_dev, REG_CHARGECONFIG, config);
 171         tscadc_writel(ts_dev, REG_CHARGEDELAY, STEPCHARGE_DELAY);
 172
 173         config = 0;
 174         /* Configure to calculate pressure */
 175         config = STEPCONFIG_MODE_HWSYNC |
 176                         STEPCONFIG_SAMPLES_AVG | STEPCONFIG_YPP |
 177                         STEPCONFIG_XNN | STEPCONFIG_INM;
 178         tscadc_writel(ts_dev, REG_STEPCONFIG13, config);
 179         tscadc_writel(ts_dev, REG_STEPDELAY13, STEPCONFIG_OPENDLY);
 180
 181         config |= STEPCONFIG_Z1 | STEPCONFIG_FIFO1;
 182         tscadc_writel(ts_dev, REG_STEPCONFIG14, config);
 183         tscadc_writel(ts_dev, REG_STEPDELAY14, STEPCONFIG_OPENDLY);
 184
 185         tscadc_writel(ts_dev, REG_SE, STPENB_STEPENB);
 186 }
 187
 188 static void tscadc_idle_config(struct tscadc *ts_config)
 189 {
 190         unsigned int idleconfig;
 191
 192         idleconfig = STEPCONFIG_YNN |
 193                         STEPCONFIG_INM |
 194                         STEPCONFIG_YPN | STEPIDLE_INP;
 195         tscadc_writel(ts_config, REG_IDLECONFIG, idleconfig);
 196 }
 197
 198 static void tscadc_read_coordinates(struct tscadc *ts_dev,
 199                                     unsigned int *x, unsigned int *y)
 200 {
 201         unsigned int fifocount = tscadc_readl(ts_dev, REG_FIFO0CNT);
 202         unsigned int prev_val_x = ~0, prev_val_y = ~0;
 203         unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
 204         unsigned int read, diff;
 205         unsigned int i;
 206
 207         /*
 208          * Delta filter is used to remove large variations in sampled
 209          * values from ADC. The filter tries to predict where the next
 210          * coordinate could be. This is done by taking a previous
 211          * coordinate and subtracting it form current one. Further the
 212          * algorithm compares the difference with that of a present value,
 213          * if true the value is reported to the sub system.
 214          */
 215         for (i = 0; i < fifocount - 1; i++) {
 216                 read = tscadc_readl(ts_dev, REG_FIFO0) & 0xfff;
 217                 diff = abs(read - prev_val_x);
 218                 if (diff < prev_diff_x) {
 219                         prev_diff_x = diff;
 220                         *x = read;
 221                 }
 222                 prev_val_x = read;
 223
 224                 read = tscadc_readl(ts_dev, REG_FIFO1) & 0xfff;
 225                 diff = abs(read - prev_val_y);
 226                 if (diff < prev_diff_y) {
 227                         prev_diff_y = diff;
 228                         *y = read;
 229                 }
 230                 prev_val_y = read;
 231         }
 232 }
 233
 234 static irqreturn_t tscadc_irq(int irq, void *dev)
 235 {
 236         struct tscadc *ts_dev = dev;
 237         struct input_dev *input_dev = ts_dev->input;
 238         unsigned int status, irqclr = 0;
 239         unsigned int x = 0, y = 0;
 240         unsigned int z1, z2, z;
 241         unsigned int fsm;
 242
 243         status = tscadc_readl(ts_dev, REG_IRQSTATUS);
 244         if (status & IRQENB_FIFO1THRES) {
 245                 tscadc_read_coordinates(ts_dev, &x, &y);
 246
 247                 z1 = tscadc_readl(ts_dev, REG_FIFO0) & 0xfff;
 248                 z2 = tscadc_readl(ts_dev, REG_FIFO1) & 0xfff;
 249
 250                 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
 251                         /*
 252                          * Calculate pressure using formula
 253                          * Resistance(touch) = x plate resistance *
 254                          * x postion/4096 * ((z2 / z1) - 1)
 255                          */
 256                         z = z2 - z1;
 257                         z *= x;
 258                         z *= ts_dev->x_plate_resistance;
 259                         z /= z1;
 260                         z = (z + 2047) >> 12;
 261
 262                         if (z <= MAX_12BIT) {
 263                                 input_report_abs(input_dev, ABS_X, x);
 264                                 input_report_abs(input_dev, ABS_Y, y);
 265                                 input_report_abs(input_dev, ABS_PRESSURE, z);
 266                                 input_report_key(input_dev, BTN_TOUCH, 1);
 267                                 input_sync(input_dev);
 268                         }
 269                 }
 270                 irqclr |= IRQENB_FIFO1THRES;
 271         }
 272
 273         /*
 274          * Time for sequencer to settle, to read
 275          * correct state of the sequencer.
 276          */
 277         udelay(SEQ_SETTLE);
 278
 279         status = tscadc_readl(ts_dev, REG_RAWIRQSTATUS);
 280         if (status & IRQENB_PENUP) {
 281                 /* Pen up event */
 282                 fsm = tscadc_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         tscadc_writel(ts_dev, REG_IRQSTATUS, irqclr);
 295         /* check pending interrupts */
 296         tscadc_writel(ts_dev, REG_IRQEOI, 0x0);
 297
 298         tscadc_writel(ts_dev, REG_SE, STPENB_STEPENB);
 299         return IRQ_HANDLED;
 300 }
 301
 302 /*
 303  * The functions for inserting/removing driver as a module.
 304  */
 305
 306 static int __devinit tscadc_probe(struct platform_device *pdev)
 307 {
 308         const struct tsc_data *pdata = pdev->dev.platform_data;
 309         struct resource *res;
 310         struct tscadc *ts_dev;
 311         struct input_dev *input_dev;
 312         struct clk *clk;
 313         int err;
 314         int clk_value, ctrl, irq;
 315
 316         if (!pdata) {
 317                 dev_err(&pdev->dev, "missing platform data.\n");
 318                 return -EINVAL;
 319         }
 320
 321         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 322         if (!res) {
 323                 dev_err(&pdev->dev, "no memory resource defined.\n");
 324                 return -EINVAL;
 325         }
 326
 327         irq = platform_get_irq(pdev, 0);
 328         if (irq < 0) {
 329                 dev_err(&pdev->dev, "no irq ID is specified.\n");
 330                 return -EINVAL;
 331         }
 332
 333         /* Allocate memory for device */
 334         ts_dev = kzalloc(sizeof(struct tscadc), GFP_KERNEL);
 335         input_dev = input_allocate_device();
 336         if (!ts_dev || !input_dev) {
 337                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 338                 err = -ENOMEM;
 339                 goto err_free_mem;
 340         }
 341
 342         ts_dev->input = input_dev;
 343         ts_dev->irq = irq;
 344         ts_dev->wires = pdata->wires;
 345         ts_dev->x_plate_resistance = pdata->x_plate_resistance;
 346
 347         res = request_mem_region(res->start, resource_size(res), pdev->name);
 348         if (!res) {
 349                 dev_err(&pdev->dev, "failed to reserve registers.\n");
 350                 err = -EBUSY;
 351                 goto err_free_mem;
 352         }
 353
 354         ts_dev->tsc_base = ioremap(res->start, resource_size(res));
 355         if (!ts_dev->tsc_base) {
 356                 dev_err(&pdev->dev, "failed to map registers.\n");
 357                 err = -ENOMEM;
 358                 goto err_release_mem_region;
 359         }
 360
 361         err = request_irq(ts_dev->irq, tscadc_irq,
 362                           0, pdev->dev.driver->name, ts_dev);
 363         if (err) {
 364                 dev_err(&pdev->dev, "failed to allocate irq.\n");
 365                 goto err_unmap_regs;
 366         }
 367
 368         ts_dev->tsc_ick = clk_get(&pdev->dev, "adc_tsc_ick");
 369         if (IS_ERR(ts_dev->tsc_ick)) {
 370                 dev_err(&pdev->dev, "failed to get TSC ick\n");
 371                 goto err_free_irq;
 372         }
 373         clk_enable(ts_dev->tsc_ick);
 374
 375         clk = clk_get(&pdev->dev, "adc_tsc_fck");
 376         if (IS_ERR(clk)) {
 377                 dev_err(&pdev->dev, "failed to get TSC fck\n");
 378                 err = PTR_ERR(clk);
 379                 goto err_disable_clk;
 380         }
 381
 382         clk_value = clk_get_rate(clk) / ADC_CLK;
 383         clk_put(clk);
 384
 385         if (clk_value < 7) {
 386                 dev_err(&pdev->dev, "clock input less than min clock requirement\n");
 387                 goto err_disable_clk;
 388         }
 389         /* CLKDIV needs to be configured to the value minus 1 */
 390         tscadc_writel(ts_dev, REG_CLKDIV, clk_value - 1);
 391
 392          /* Enable wake-up of the SoC using touchscreen */
 393         tscadc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
 394
 395         ctrl = CNTRLREG_STEPCONFIGWRT |
 396                         CNTRLREG_TSCENB |
 397                         CNTRLREG_STEPID;
 398         switch (ts_dev->wires) {
 399         case 4:
 400                 ctrl |= CNTRLREG_4WIRE;
 401                 break;
 402         case 5:
 403                 ctrl |= CNTRLREG_5WIRE;
 404                 break;
 405         case 8:
 406                 ctrl |= CNTRLREG_8WIRE;
 407                 break;
 408         }
 409         tscadc_writel(ts_dev, REG_CTRL, ctrl);
 410
 411         tscadc_idle_config(ts_dev);
 412         tscadc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO1THRES);
 413         tscadc_step_config(ts_dev);
 414         tscadc_writel(ts_dev, REG_FIFO1THR, 6);
 415
 416         ctrl |= CNTRLREG_TSCSSENB;
 417         tscadc_writel(ts_dev, REG_CTRL, ctrl);
 418
 419         input_dev->name = "ti-tsc-adc";
 420         input_dev->dev.parent = &pdev->dev;
 421
 422         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 423         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 424
 425         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 426         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 427         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 428
 429         /* register to the input system */
 430         err = input_register_device(input_dev);
 431         if (err)
 432                 goto err_disable_clk;
 433
 434         platform_set_drvdata(pdev, ts_dev);
 435         return 0;
 436
 437 err_disable_clk:
 438         clk_disable(ts_dev->tsc_ick);
 439         clk_put(ts_dev->tsc_ick);
 440 err_free_irq:
 441         free_irq(ts_dev->irq, ts_dev);
 442 err_unmap_regs:
 443         iounmap(ts_dev->tsc_base);
 444 err_release_mem_region:
 445         release_mem_region(res->start, resource_size(res));
 446 err_free_mem:
 447         input_free_device(input_dev);
 448         kfree(ts_dev);
 449         return err;
 450 }
 451
 452 static int __devexit tscadc_remove(struct platform_device *pdev)
 453 {
 454         struct tscadc *ts_dev = platform_get_drvdata(pdev);
 455         struct resource *res;
 456
 457         free_irq(ts_dev->irq, ts_dev);
 458
 459         input_unregister_device(ts_dev->input);
 460
 461         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 462         iounmap(ts_dev->tsc_base);
 463         release_mem_region(res->start, resource_size(res));
 464
 465         clk_disable(ts_dev->tsc_ick);
 466         clk_put(ts_dev->tsc_ick);
 467
 468         kfree(ts_dev);
 469
 470         platform_set_drvdata(pdev, NULL);
 471         return 0;
 472 }
 473
 474 static struct platform_driver ti_tsc_driver = {
 475         .probe  = tscadc_probe,
 476         .remove = __devexit_p(tscadc_remove),
 477         .driver = {
 478                 .name   = "tsc",
 479                 .owner  = THIS_MODULE,
 480         },
 481 };
 482 module_platform_driver(ti_tsc_driver);
 483
 484 MODULE_DESCRIPTION("TI touchscreen controller driver");
 485 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 486 MODULE_LICENSE("GPL");