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/input/ti_am335x_tsc.h>
  28 #include <linux/delay.h>
  29
  30 #include <linux/mfd/ti_am335x_tscadc.h>
  31
  32 #define ADCFSM_STEPID           0x10
  33 #define SEQ_SETTLE              275
  34 #define MAX_12BIT               ((1 << 12) - 1)
  35
  36 struct titsc {
  37         struct input_dev        *input;
  38         struct ti_tscadc_dev    *mfd_tscadc;
  39         unsigned int            irq;
  40         unsigned int            wires;
  41         unsigned int            x_plate_resistance;
  42         bool                    pen_down;
  43         int                     steps_to_configure;
  44 };
  45
  46 static unsigned int titsc_readl(struct titsc *ts, unsigned int reg)
  47 {
  48         return readl(ts->mfd_tscadc->tscadc_base + reg);
  49 }
  50
  51 static void titsc_writel(struct titsc *tsc, unsigned int reg,
  52                                         unsigned int val)
  53 {
  54         writel(val, tsc->mfd_tscadc->tscadc_base + reg);
  55 }
  56
  57 static void titsc_step_config(struct titsc *ts_dev)
  58 {
  59         unsigned int    config;
  60         int i, total_steps;
  61
  62         /* Configure the Step registers */
  63         total_steps = 2 * ts_dev->steps_to_configure;
  64
  65         config = STEPCONFIG_MODE_HWSYNC |
  66                         STEPCONFIG_AVG_16 | STEPCONFIG_XPP;
  67         switch (ts_dev->wires) {
  68         case 4:
  69                 config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
  70                 break;
  71         case 5:
  72                 config |= STEPCONFIG_YNN |
  73                                 STEPCONFIG_INP_AN4 | STEPCONFIG_XNN |
  74                                 STEPCONFIG_YPP;
  75                 break;
  76         case 8:
  77                 config |= STEPCONFIG_INP_AN2 | STEPCONFIG_XNN;
  78                 break;
  79         }
  80
  81         for (i = 1; i <= ts_dev->steps_to_configure; i++) {
  82                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
  83                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
  84         }
  85
  86         config = 0;
  87         config = STEPCONFIG_MODE_HWSYNC |
  88                         STEPCONFIG_AVG_16 | STEPCONFIG_YNN |
  89                         STEPCONFIG_INM_ADCREFM | STEPCONFIG_FIFO1;
  90         switch (ts_dev->wires) {
  91         case 4:
  92                 config |= STEPCONFIG_YPP;
  93                 break;
  94         case 5:
  95                 config |= STEPCONFIG_XPP | STEPCONFIG_INP_AN4 |
  96                                 STEPCONFIG_XNP | STEPCONFIG_YPN;
  97                 break;
  98         case 8:
  99                 config |= STEPCONFIG_YPP;
 100                 break;
 101         }
 102
 103         for (i = (ts_dev->steps_to_configure + 1); i <= total_steps; i++) {
 104                 titsc_writel(ts_dev, REG_STEPCONFIG(i), config);
 105                 titsc_writel(ts_dev, REG_STEPDELAY(i), STEPCONFIG_OPENDLY);
 106         }
 107
 108         config = 0;
 109         /* Charge step configuration */
 110         config = STEPCONFIG_XPP | STEPCONFIG_YNN |
 111                         STEPCHARGE_RFP_XPUL | STEPCHARGE_RFM_XNUR |
 112                         STEPCHARGE_INM_AN1 | STEPCHARGE_INP_AN1;
 113
 114         titsc_writel(ts_dev, REG_CHARGECONFIG, config);
 115         titsc_writel(ts_dev, REG_CHARGEDELAY, CHARGEDLY_OPENDLY);
 116
 117         config = 0;
 118         /* Configure to calculate pressure */
 119         config = STEPCONFIG_MODE_HWSYNC |
 120                         STEPCONFIG_AVG_16 | STEPCONFIG_YPP |
 121                         STEPCONFIG_XNN | STEPCONFIG_INM_ADCREFM;
 122         titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 1), config);
 123         titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 1),
 124                         STEPCONFIG_OPENDLY);
 125
 126         config |= STEPCONFIG_INP_AN3 | STEPCONFIG_FIFO1;
 127         titsc_writel(ts_dev, REG_STEPCONFIG(total_steps + 2), config);
 128         titsc_writel(ts_dev, REG_STEPDELAY(total_steps + 2),
 129                         STEPCONFIG_OPENDLY);
 130
 131         titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
 132 }
 133
 134 static void titsc_read_coordinates(struct titsc *ts_dev,
 135                                     unsigned int *x, unsigned int *y)
 136 {
 137         unsigned int fifocount = titsc_readl(ts_dev, REG_FIFO0CNT);
 138         unsigned int prev_val_x = ~0, prev_val_y = ~0;
 139         unsigned int prev_diff_x = ~0, prev_diff_y = ~0;
 140         unsigned int read, diff;
 141         unsigned int i, channel;
 142
 143         /*
 144          * Delta filter is used to remove large variations in sampled
 145          * values from ADC. The filter tries to predict where the next
 146          * coordinate could be. This is done by taking a previous
 147          * coordinate and subtracting it form current one. Further the
 148          * algorithm compares the difference with that of a present value,
 149          * if true the value is reported to the sub system.
 150          */
 151         for (i = 0; i < fifocount - 1; i++) {
 152                 read = titsc_readl(ts_dev, REG_FIFO0);
 153                 channel = read & 0xf0000;
 154                 channel = channel >> 0x10;
 155                 if ((channel >= 0) && (channel < ts_dev->steps_to_configure)) {
 156                         read &= 0xfff;
 157                         diff = abs(read - prev_val_x);
 158                         if (diff < prev_diff_x) {
 159                                 prev_diff_x = diff;
 160                                 *x = read;
 161                         }
 162                         prev_val_x = read;
 163                 }
 164
 165                 read = titsc_readl(ts_dev, REG_FIFO1);
 166                 channel = read & 0xf0000;
 167                 channel = channel >> 0x10;
 168                 if ((channel >= ts_dev->steps_to_configure) &&
 169                         (channel < (2 * ts_dev->steps_to_configure - 1))) {
 170                         read &= 0xfff;
 171                         diff = abs(read - prev_val_y);
 172                         if (diff < prev_diff_y) {
 173                                 prev_diff_y = diff;
 174                                 *y = read;
 175                         }
 176                         prev_val_y = read;
 177                 }
 178         }
 179 }
 180
 181 static irqreturn_t titsc_irq(int irq, void *dev)
 182 {
 183         struct titsc *ts_dev = dev;
 184         struct input_dev *input_dev = ts_dev->input;
 185         unsigned int status, irqclr = 0;
 186         unsigned int x = 0, y = 0;
 187         unsigned int z1, z2, z;
 188         unsigned int fsm;
 189         unsigned int fifo1count, fifo0count;
 190         int i;
 191
 192         status = titsc_readl(ts_dev, REG_IRQSTATUS);
 193         if (status & IRQENB_FIFO0THRES) {
 194                 titsc_read_coordinates(ts_dev, &x, &y);
 195
 196                 z1 = titsc_readl(ts_dev, REG_FIFO0) & 0xfff;
 197                 z2 = titsc_readl(ts_dev, REG_FIFO1) & 0xfff;
 198
 199                 fifo1count = titsc_readl(ts_dev, REG_FIFO1CNT);
 200                 for (i = 0; i < fifo1count; i++)
 201                         titsc_readl(ts_dev, REG_FIFO1);
 202
 203                 fifo0count = titsc_readl(ts_dev, REG_FIFO0CNT);
 204                 for (i = 0; i < fifo0count; i++)
 205                         titsc_readl(ts_dev, REG_FIFO0);
 206
 207                 if (ts_dev->pen_down && z1 != 0 && z2 != 0) {
 208                         /*
 209                          * Calculate pressure using formula
 210                          * Resistance(touch) = x plate resistance *
 211                          * x postion/4096 * ((z2 / z1) - 1)
 212                          */
 213                         z = z2 - z1;
 214                         z *= x;
 215                         z *= ts_dev->x_plate_resistance;
 216                         z /= z1;
 217                         z = (z + 2047) >> 12;
 218
 219                         if (z <= MAX_12BIT) {
 220                                 input_report_abs(input_dev, ABS_X, x);
 221                                 input_report_abs(input_dev, ABS_Y, y);
 222                                 input_report_abs(input_dev, ABS_PRESSURE, z);
 223                                 input_report_key(input_dev, BTN_TOUCH, 1);
 224                                 input_sync(input_dev);
 225                         }
 226                 }
 227                 irqclr |= IRQENB_FIFO0THRES;
 228         }
 229
 230         /*
 231          * Time for sequencer to settle, to read
 232          * correct state of the sequencer.
 233          */
 234         udelay(SEQ_SETTLE);
 235
 236         status = titsc_readl(ts_dev, REG_RAWIRQSTATUS);
 237         if (status & IRQENB_PENUP) {
 238                 /* Pen up event */
 239                 fsm = titsc_readl(ts_dev, REG_ADCFSM);
 240                 if (fsm == ADCFSM_STEPID) {
 241                         ts_dev->pen_down = false;
 242                         input_report_key(input_dev, BTN_TOUCH, 0);
 243                         input_report_abs(input_dev, ABS_PRESSURE, 0);
 244                         input_sync(input_dev);
 245                 } else {
 246                         ts_dev->pen_down = true;
 247                 }
 248                 irqclr |= IRQENB_PENUP;
 249         }
 250
 251         titsc_writel(ts_dev, REG_IRQSTATUS, irqclr);
 252
 253         titsc_writel(ts_dev, REG_SE, STPENB_STEPENB_TC);
 254         return IRQ_HANDLED;
 255 }
 256
 257 /*
 258  * The functions for inserting/removing driver as a module.
 259  */
 260
 261 static int titsc_probe(struct platform_device *pdev)
 262 {
 263         struct titsc *ts_dev;
 264         struct input_dev *input_dev;
 265         struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
 266         struct mfd_tscadc_board *pdata;
 267         int err;
 268
 269         pdata = tscadc_dev->dev->platform_data;
 270
 271         if (!pdata) {
 272                 dev_err(&pdev->dev, "Could not find platform data\n");
 273                 return -EINVAL;
 274         }
 275
 276         /* Allocate memory for device */
 277         ts_dev = kzalloc(sizeof(struct titsc), GFP_KERNEL);
 278         input_dev = input_allocate_device();
 279         if (!ts_dev || !input_dev) {
 280                 dev_err(&pdev->dev, "failed to allocate memory.\n");
 281                 err = -ENOMEM;
 282                 goto err_free_mem;
 283         }
 284
 285         tscadc_dev->tsc = ts_dev;
 286         ts_dev->mfd_tscadc = tscadc_dev;
 287         ts_dev->input = input_dev;
 288         ts_dev->irq = tscadc_dev->irq;
 289         ts_dev->wires = pdata->tsc_init->wires;
 290         ts_dev->x_plate_resistance = pdata->tsc_init->x_plate_resistance;
 291         ts_dev->steps_to_configure = pdata->tsc_init->steps_to_configure;
 292
 293         err = request_irq(ts_dev->irq, titsc_irq,
 294                           0, pdev->dev.driver->name, ts_dev);
 295         if (err) {
 296                 dev_err(&pdev->dev, "failed to allocate irq.\n");
 297                 goto err_free_mem;
 298         }
 299
 300         titsc_writel(ts_dev, REG_IRQENABLE, IRQENB_FIFO0THRES);
 301         titsc_step_config(ts_dev);
 302         titsc_writel(ts_dev, REG_FIFO0THR, ts_dev->steps_to_configure);
 303
 304         input_dev->name = "ti-tsc";
 305         input_dev->dev.parent = &pdev->dev;
 306
 307         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 308         input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 309
 310         input_set_abs_params(input_dev, ABS_X, 0, MAX_12BIT, 0, 0);
 311         input_set_abs_params(input_dev, ABS_Y, 0, MAX_12BIT, 0, 0);
 312         input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_12BIT, 0, 0);
 313
 314         /* register to the input system */
 315         err = input_register_device(input_dev);
 316         if (err)
 317                 goto err_free_irq;
 318
 319         platform_set_drvdata(pdev, ts_dev);
 320         return 0;
 321
 322 err_free_irq:
 323         free_irq(ts_dev->irq, ts_dev);
 324 err_free_mem:
 325         input_free_device(input_dev);
 326         kfree(ts_dev);
 327         return err;
 328 }
 329
 330 static int titsc_remove(struct platform_device *pdev)
 331 {
 332         struct ti_tscadc_dev *tscadc_dev = pdev->dev.platform_data;
 333         struct titsc *ts_dev = tscadc_dev->tsc;
 334
 335         free_irq(ts_dev->irq, ts_dev);
 336
 337         input_unregister_device(ts_dev->input);
 338
 339         kfree(ts_dev);
 340         return 0;
 341 }
 342
 343 #ifdef CONFIG_PM
 344 static int titsc_suspend(struct device *dev)
 345 {
 346         struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
 347         struct titsc *ts_dev = tscadc_dev->tsc;
 348         unsigned int idle;
 349
 350         if (device_may_wakeup(tscadc_dev->dev)) {
 351                 idle = titsc_readl(ts_dev, REG_IRQENABLE);
 352                 titsc_writel(ts_dev, REG_IRQENABLE,
 353                                 (idle | IRQENB_HW_PEN));
 354                 titsc_writel(ts_dev, REG_IRQWAKEUP, IRQWKUP_ENB);
 355         }
 356         return 0;
 357 }
 358
 359 static int titsc_resume(struct device *dev)
 360 {
 361         struct ti_tscadc_dev *tscadc_dev = dev->platform_data;
 362         struct titsc *ts_dev = tscadc_dev->tsc;
 363
 364         if (device_may_wakeup(tscadc_dev->dev)) {
 365                 titsc_writel(ts_dev, REG_IRQWAKEUP,
 366                                 0x00);
 367                 titsc_writel(ts_dev, REG_IRQCLR, IRQENB_HW_PEN);
 368         }
 369         titsc_step_config(ts_dev);
 370         titsc_writel(ts_dev, REG_FIFO0THR,
 371                         ts_dev->steps_to_configure);
 372         return 0;
 373 }
 374
 375 static const struct dev_pm_ops titsc_pm_ops = {
 376         .suspend = titsc_suspend,
 377         .resume  = titsc_resume,
 378 };
 379 #define TITSC_PM_OPS (&titsc_pm_ops)
 380 #else
 381 #define TITSC_PM_OPS NULL
 382 #endif
 383
 384 static struct platform_driver ti_tsc_driver = {
 385         .probe  = titsc_probe,
 386         .remove = titsc_remove,
 387         .driver = {
 388                 .name   = "tsc",
 389                 .owner  = THIS_MODULE,
 390                 .pm     = TITSC_PM_OPS,
 391         },
 392 };
 393 module_platform_driver(ti_tsc_driver);
 394
 395 MODULE_DESCRIPTION("TI touchscreen controller driver");
 396 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
 397 MODULE_LICENSE("GPL");