drivers/input/touchscreen/stmpe-ts.c

   1 /*
   2  * STMicroelectronics STMPE811 Touchscreen Driver
   3  *
   4  * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
   5  * All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute  it and/or modify it
   8  *  under  the terms of  the GNU General  Public License as published by the
   9  *  Free Software Foundation;  either version 2 of the  License, or (at your
  10  *  option) any later version.
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/device.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/input.h>
  22 #include <linux/slab.h>
  23 #include <linux/delay.h>
  24 #include <linux/i2c.h>
  25 #include <linux/workqueue.h>
  26
  27 #include <linux/mfd/stmpe.h>
  28
  29 /* Register layouts and functionalities are identical on all stmpexxx variants
  30  * with touchscreen controller
  31  */
  32 #define STMPE_REG_INT_STA               0x0B
  33 #define STMPE_REG_ADC_CTRL1             0x20
  34 #define STMPE_REG_ADC_CTRL2             0x21
  35 #define STMPE_REG_TSC_CTRL              0x40
  36 #define STMPE_REG_TSC_CFG               0x41
  37 #define STMPE_REG_FIFO_TH               0x4A
  38 #define STMPE_REG_FIFO_STA              0x4B
  39 #define STMPE_REG_FIFO_SIZE             0x4C
  40 #define STMPE_REG_TSC_DATA_XYZ          0x52
  41 #define STMPE_REG_TSC_FRACTION_Z        0x56
  42 #define STMPE_REG_TSC_I_DRIVE           0x58
  43
  44 #define OP_MOD_XYZ                      0
  45
  46 #define STMPE_TSC_CTRL_TSC_EN           (1<<0)
  47
  48 #define STMPE_FIFO_STA_RESET            (1<<0)
  49
  50 #define STMPE_IRQ_TOUCH_DET             0
  51
  52 #define SAMPLE_TIME(x)                  ((x & 0xf) << 4)
  53 #define MOD_12B(x)                      ((x & 0x1) << 3)
  54 #define REF_SEL(x)                      ((x & 0x1) << 1)
  55 #define ADC_FREQ(x)                     (x & 0x3)
  56 #define AVE_CTRL(x)                     ((x & 0x3) << 6)
  57 #define DET_DELAY(x)                    ((x & 0x7) << 3)
  58 #define SETTLING(x)                     (x & 0x7)
  59 #define FRACTION_Z(x)                   (x & 0x7)
  60 #define I_DRIVE(x)                      (x & 0x1)
  61 #define OP_MODE(x)                      ((x & 0x7) << 1)
  62
  63 #define STMPE_TS_NAME                   "stmpe-ts"
  64 #define XY_MASK                         0xfff
  65
  66 /**
  67  * struct stmpe_touch - stmpe811 touch screen controller state
  68  * @stmpe: pointer back to STMPE MFD container
  69  * @idev: registered input device
  70  * @work: a work item used to scan the device
  71  * @dev: a pointer back to the MFD cell struct device*
  72  * @sample_time: ADC converstion time in number of clock.
  73  * (0 -> 36 clocks, 1 -> 44 clocks, 2 -> 56 clocks, 3 -> 64 clocks,
  74  * 4 -> 80 clocks, 5 -> 96 clocks, 6 -> 144 clocks),
  75  * recommended is 4.
  76  * @mod_12b: ADC Bit mode (0 -> 10bit ADC, 1 -> 12bit ADC)
  77  * @ref_sel: ADC reference source
  78  * (0 -> internal reference, 1 -> external reference)
  79  * @adc_freq: ADC Clock speed
  80  * (0 -> 1.625 MHz, 1 -> 3.25 MHz, 2 || 3 -> 6.5 MHz)
  81  * @ave_ctrl: Sample average control
  82  * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
  83  * @touch_det_delay: Touch detect interrupt delay
  84  * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
  85  * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
  86  * recommended is 3
  87  * @settling: Panel driver settling time
  88  * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
  89  * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
  90  * recommended is 2
  91  * @fraction_z: Length of the fractional part in z
  92  * (fraction_z ([0..7]) = Count of the fractional part)
  93  * recommended is 7
  94  * @i_drive: current limit value of the touchscreen drivers
  95  * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
  96  */
  97 struct stmpe_touch {
  98         struct stmpe *stmpe;
  99         struct input_dev *idev;
 100         struct delayed_work work;
 101         struct device *dev;
 102         u8 sample_time;
 103         u8 mod_12b;
 104         u8 ref_sel;
 105         u8 adc_freq;
 106         u8 ave_ctrl;
 107         u8 touch_det_delay;
 108         u8 settling;
 109         u8 fraction_z;
 110         u8 i_drive;
 111 };
 112
 113 static int __stmpe_reset_fifo(struct stmpe *stmpe)
 114 {
 115         int ret;
 116
 117         ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
 118                         STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
 119         if (ret)
 120                 return ret;
 121
 122         return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
 123                         STMPE_FIFO_STA_RESET, 0);
 124 }
 125
 126 static void stmpe_work(struct work_struct *work)
 127 {
 128         int int_sta;
 129         u32 timeout = 40;
 130
 131         struct stmpe_touch *ts =
 132             container_of(work, struct stmpe_touch, work.work);
 133
 134         int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 135
 136         /*
 137          * touch_det sometimes get desasserted or just get stuck. This appears
 138          * to be a silicon bug, We still have to clearify this with the
 139          * manufacture. As a workaround We release the key anyway if the
 140          * touch_det keeps coming in after 4ms, while the FIFO contains no value
 141          * during the whole time.
 142          */
 143         while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
 144                 timeout--;
 145                 int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 146                 udelay(100);
 147         }
 148
 149         /* reset the FIFO before we report release event */
 150         __stmpe_reset_fifo(ts->stmpe);
 151
 152         input_report_abs(ts->idev, ABS_PRESSURE, 0);
 153         input_report_key(ts->idev, BTN_TOUCH, 0);
 154         input_sync(ts->idev);
 155 }
 156
 157 static irqreturn_t stmpe_ts_handler(int irq, void *data)
 158 {
 159         u8 data_set[4];
 160         int x, y, z;
 161         struct stmpe_touch *ts = data;
 162
 163         /*
 164          * Cancel scheduled polling for release if we have new value
 165          * available. Wait if the polling is already running.
 166          */
 167         cancel_delayed_work_sync(&ts->work);
 168
 169         /*
 170          * The FIFO sometimes just crashes and stops generating interrupts. This
 171          * appears to be a silicon bug. We still have to clearify this with
 172          * the manufacture. As a workaround we disable the TSC while we are
 173          * collecting data and flush the FIFO after reading
 174          */
 175         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 176                                 STMPE_TSC_CTRL_TSC_EN, 0);
 177
 178         stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
 179
 180         x = (data_set[0] << 4) | (data_set[1] >> 4);
 181         y = ((data_set[1] & 0xf) << 8) | data_set[2];
 182         z = data_set[3];
 183
 184         input_report_abs(ts->idev, ABS_X, x);
 185         input_report_abs(ts->idev, ABS_Y, y);
 186         input_report_abs(ts->idev, ABS_PRESSURE, z);
 187         input_report_key(ts->idev, BTN_TOUCH, 1);
 188         input_sync(ts->idev);
 189
 190        /* flush the FIFO after we have read out our values. */
 191         __stmpe_reset_fifo(ts->stmpe);
 192
 193         /* reenable the tsc */
 194         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 195                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 196
 197         /* start polling for touch_det to detect release */
 198         schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
 199
 200         return IRQ_HANDLED;
 201 }
 202
 203 static int stmpe_init_hw(struct stmpe_touch *ts)
 204 {
 205         int ret;
 206         u8 adc_ctrl1, adc_ctrl1_mask, tsc_cfg, tsc_cfg_mask;
 207         struct stmpe *stmpe = ts->stmpe;
 208         struct device *dev = ts->dev;
 209
 210         ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
 211         if (ret) {
 212                 dev_err(dev, "Could not enable clock for ADC and TS\n");
 213                 return ret;
 214         }
 215
 216         adc_ctrl1 = SAMPLE_TIME(ts->sample_time) | MOD_12B(ts->mod_12b) |
 217                 REF_SEL(ts->ref_sel);
 218         adc_ctrl1_mask = SAMPLE_TIME(0xff) | MOD_12B(0xff) | REF_SEL(0xff);
 219
 220         ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL1,
 221                         adc_ctrl1_mask, adc_ctrl1);
 222         if (ret) {
 223                 dev_err(dev, "Could not setup ADC\n");
 224                 return ret;
 225         }
 226
 227         ret = stmpe_set_bits(stmpe, STMPE_REG_ADC_CTRL2,
 228                         ADC_FREQ(0xff), ADC_FREQ(ts->adc_freq));
 229         if (ret) {
 230                 dev_err(dev, "Could not setup ADC\n");
 231                 return ret;
 232         }
 233
 234         tsc_cfg = AVE_CTRL(ts->ave_ctrl) | DET_DELAY(ts->touch_det_delay) |
 235                         SETTLING(ts->settling);
 236         tsc_cfg_mask = AVE_CTRL(0xff) | DET_DELAY(0xff) | SETTLING(0xff);
 237
 238         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
 239         if (ret) {
 240                 dev_err(dev, "Could not config touch\n");
 241                 return ret;
 242         }
 243
 244         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
 245                         FRACTION_Z(0xff), FRACTION_Z(ts->fraction_z));
 246         if (ret) {
 247                 dev_err(dev, "Could not config touch\n");
 248                 return ret;
 249         }
 250
 251         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
 252                         I_DRIVE(0xff), I_DRIVE(ts->i_drive));
 253         if (ret) {
 254                 dev_err(dev, "Could not config touch\n");
 255                 return ret;
 256         }
 257
 258         /* set FIFO to 1 for single point reading */
 259         ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
 260         if (ret) {
 261                 dev_err(dev, "Could not set FIFO\n");
 262                 return ret;
 263         }
 264
 265         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
 266                         OP_MODE(0xff), OP_MODE(OP_MOD_XYZ));
 267         if (ret) {
 268                 dev_err(dev, "Could not set mode\n");
 269                 return ret;
 270         }
 271
 272         return 0;
 273 }
 274
 275 static int stmpe_ts_open(struct input_dev *dev)
 276 {
 277         struct stmpe_touch *ts = input_get_drvdata(dev);
 278         int ret = 0;
 279
 280         ret = __stmpe_reset_fifo(ts->stmpe);
 281         if (ret)
 282                 return ret;
 283
 284         return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 285                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 286 }
 287
 288 static void stmpe_ts_close(struct input_dev *dev)
 289 {
 290         struct stmpe_touch *ts = input_get_drvdata(dev);
 291
 292         cancel_delayed_work_sync(&ts->work);
 293
 294         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 295                         STMPE_TSC_CTRL_TSC_EN, 0);
 296 }
 297
 298 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
 299                                         struct stmpe_touch *ts)
 300 {
 301         struct device_node *np = pdev->dev.of_node;
 302         u32 val;
 303
 304         if (np) {
 305                 if (!of_property_read_u32(np, "st,sample-time", &val))
 306                         ts->sample_time = val;
 307                 if (!of_property_read_u32(np, "st,mod-12b", &val))
 308                         ts->mod_12b = val;
 309                 if (!of_property_read_u32(np, "st,ref-sel", &val))
 310                         ts->ref_sel = val;
 311                 if (!of_property_read_u32(np, "st,adc-freq", &val))
 312                         ts->adc_freq = val;
 313                 if (!of_property_read_u32(np, "st,ave-ctrl", &val))
 314                         ts->ave_ctrl = val;
 315                 if (!of_property_read_u32(np, "st,touch-det-delay", &val))
 316                         ts->touch_det_delay = val;
 317                 if (!of_property_read_u32(np, "st,settling", &val))
 318                         ts->settling = val;
 319                 if (!of_property_read_u32(np, "st,fraction-z", &val))
 320                         ts->fraction_z = val;
 321                 if (!of_property_read_u32(np, "st,i-drive", &val))
 322                         ts->i_drive = val;
 323         }
 324 }
 325
 326 static int stmpe_input_probe(struct platform_device *pdev)
 327 {
 328         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
 329         struct stmpe_touch *ts;
 330         struct input_dev *idev;
 331         int error;
 332         int ts_irq;
 333
 334         ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
 335         if (ts_irq < 0)
 336                 return ts_irq;
 337
 338         ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
 339         if (!ts)
 340                 return -ENOMEM;
 341
 342         idev = devm_input_allocate_device(&pdev->dev);
 343         if (!idev)
 344                 return -ENOMEM;
 345
 346         platform_set_drvdata(pdev, ts);
 347         ts->stmpe = stmpe;
 348         ts->idev = idev;
 349         ts->dev = &pdev->dev;
 350
 351         stmpe_ts_get_platform_info(pdev, ts);
 352
 353         INIT_DELAYED_WORK(&ts->work, stmpe_work);
 354
 355         error = devm_request_threaded_irq(&pdev->dev, ts_irq,
 356                                           NULL, stmpe_ts_handler,
 357                                           IRQF_ONESHOT, STMPE_TS_NAME, ts);
 358         if (error) {
 359                 dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
 360                 return error;
 361         }
 362
 363         error = stmpe_init_hw(ts);
 364         if (error)
 365                 return error;
 366
 367         idev->name = STMPE_TS_NAME;
 368         idev->phys = STMPE_TS_NAME"/input0";
 369         idev->id.bustype = BUS_I2C;
 370
 371         idev->open = stmpe_ts_open;
 372         idev->close = stmpe_ts_close;
 373
 374         input_set_drvdata(idev, ts);
 375
 376         input_set_capability(idev, EV_KEY, BTN_TOUCH);
 377         input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
 378         input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
 379         input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
 380
 381         error = input_register_device(idev);
 382         if (error) {
 383                 dev_err(&pdev->dev, "Could not register input device\n");
 384                 return error;
 385         }
 386
 387         return 0;
 388 }
 389
 390 static int stmpe_ts_remove(struct platform_device *pdev)
 391 {
 392         struct stmpe_touch *ts = platform_get_drvdata(pdev);
 393
 394         stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
 395
 396         return 0;
 397 }
 398
 399 static struct platform_driver stmpe_ts_driver = {
 400         .driver = {
 401                 .name = STMPE_TS_NAME,
 402         },
 403         .probe = stmpe_input_probe,
 404         .remove = stmpe_ts_remove,
 405 };
 406 module_platform_driver(stmpe_ts_driver);
 407
 408 static const struct of_device_id stmpe_ts_ids[] = {
 409         { .compatible = "st,stmpe-ts", },
 410         { },
 411 };
 412 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
 413
 414 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
 415 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
 416 MODULE_LICENSE("GPL");