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_TSC_CTRL              0x40
  34 #define STMPE_REG_TSC_CFG               0x41
  35 #define STMPE_REG_FIFO_TH               0x4A
  36 #define STMPE_REG_FIFO_STA              0x4B
  37 #define STMPE_REG_FIFO_SIZE             0x4C
  38 #define STMPE_REG_TSC_DATA_XYZ          0x52
  39 #define STMPE_REG_TSC_FRACTION_Z        0x56
  40 #define STMPE_REG_TSC_I_DRIVE           0x58
  41
  42 #define OP_MOD_XYZ                      0
  43
  44 #define STMPE_TSC_CTRL_TSC_EN           (1<<0)
  45
  46 #define STMPE_FIFO_STA_RESET            (1<<0)
  47
  48 #define STMPE_IRQ_TOUCH_DET             0
  49
  50 #define STMPE_TS_NAME                   "stmpe-ts"
  51 #define XY_MASK                         0xfff
  52
  53 /**
  54  * struct stmpe_touch - stmpe811 touch screen controller state
  55  * @stmpe: pointer back to STMPE MFD container
  56  * @idev: registered input device
  57  * @work: a work item used to scan the device
  58  * @dev: a pointer back to the MFD cell struct device*
  59  * @ave_ctrl: Sample average control
  60  * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
  61  * @touch_det_delay: Touch detect interrupt delay
  62  * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
  63  * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
  64  * recommended is 3
  65  * @settling: Panel driver settling time
  66  * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
  67  * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
  68  * recommended is 2
  69  * @fraction_z: Length of the fractional part in z
  70  * (fraction_z ([0..7]) = Count of the fractional part)
  71  * recommended is 7
  72  * @i_drive: current limit value of the touchscreen drivers
  73  * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
  74  */
  75 struct stmpe_touch {
  76         struct stmpe *stmpe;
  77         struct input_dev *idev;
  78         struct delayed_work work;
  79         struct device *dev;
  80         u8 ave_ctrl;
  81         u8 touch_det_delay;
  82         u8 settling;
  83         u8 fraction_z;
  84         u8 i_drive;
  85 };
  86
  87 static int __stmpe_reset_fifo(struct stmpe *stmpe)
  88 {
  89         int ret;
  90
  91         ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
  92                         STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
  93         if (ret)
  94                 return ret;
  95
  96         return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
  97                         STMPE_FIFO_STA_RESET, 0);
  98 }
  99
 100 static void stmpe_work(struct work_struct *work)
 101 {
 102         int int_sta;
 103         u32 timeout = 40;
 104
 105         struct stmpe_touch *ts =
 106             container_of(work, struct stmpe_touch, work.work);
 107
 108         int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 109
 110         /*
 111          * touch_det sometimes get desasserted or just get stuck. This appears
 112          * to be a silicon bug, We still have to clearify this with the
 113          * manufacture. As a workaround We release the key anyway if the
 114          * touch_det keeps coming in after 4ms, while the FIFO contains no value
 115          * during the whole time.
 116          */
 117         while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
 118                 timeout--;
 119                 int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 120                 udelay(100);
 121         }
 122
 123         /* reset the FIFO before we report release event */
 124         __stmpe_reset_fifo(ts->stmpe);
 125
 126         input_report_abs(ts->idev, ABS_PRESSURE, 0);
 127         input_report_key(ts->idev, BTN_TOUCH, 0);
 128         input_sync(ts->idev);
 129 }
 130
 131 static irqreturn_t stmpe_ts_handler(int irq, void *data)
 132 {
 133         u8 data_set[4];
 134         int x, y, z;
 135         struct stmpe_touch *ts = data;
 136
 137         /*
 138          * Cancel scheduled polling for release if we have new value
 139          * available. Wait if the polling is already running.
 140          */
 141         cancel_delayed_work_sync(&ts->work);
 142
 143         /*
 144          * The FIFO sometimes just crashes and stops generating interrupts. This
 145          * appears to be a silicon bug. We still have to clearify this with
 146          * the manufacture. As a workaround we disable the TSC while we are
 147          * collecting data and flush the FIFO after reading
 148          */
 149         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 150                                 STMPE_TSC_CTRL_TSC_EN, 0);
 151
 152         stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
 153
 154         x = (data_set[0] << 4) | (data_set[1] >> 4);
 155         y = ((data_set[1] & 0xf) << 8) | data_set[2];
 156         z = data_set[3];
 157
 158         input_report_abs(ts->idev, ABS_X, x);
 159         input_report_abs(ts->idev, ABS_Y, y);
 160         input_report_abs(ts->idev, ABS_PRESSURE, z);
 161         input_report_key(ts->idev, BTN_TOUCH, 1);
 162         input_sync(ts->idev);
 163
 164        /* flush the FIFO after we have read out our values. */
 165         __stmpe_reset_fifo(ts->stmpe);
 166
 167         /* reenable the tsc */
 168         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 169                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 170
 171         /* start polling for touch_det to detect release */
 172         schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
 173
 174         return IRQ_HANDLED;
 175 }
 176
 177 static int stmpe_init_hw(struct stmpe_touch *ts)
 178 {
 179         int ret;
 180         u8 tsc_cfg, tsc_cfg_mask;
 181         struct stmpe *stmpe = ts->stmpe;
 182         struct device *dev = ts->dev;
 183
 184         ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
 185         if (ret) {
 186                 dev_err(dev, "Could not enable clock for ADC and TS\n");
 187                 return ret;
 188         }
 189
 190         ret = stmpe811_adc_common_init(stmpe);
 191         if (ret) {
 192                 stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
 193                 return ret;
 194         }
 195
 196         tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
 197                   STMPE_DET_DELAY(ts->touch_det_delay) |
 198                   STMPE_SETTLING(ts->settling);
 199         tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
 200                        STMPE_SETTLING(0xff);
 201
 202         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
 203         if (ret) {
 204                 dev_err(dev, "Could not config touch\n");
 205                 return ret;
 206         }
 207
 208         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
 209                         STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
 210         if (ret) {
 211                 dev_err(dev, "Could not config touch\n");
 212                 return ret;
 213         }
 214
 215         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
 216                         STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
 217         if (ret) {
 218                 dev_err(dev, "Could not config touch\n");
 219                 return ret;
 220         }
 221
 222         /* set FIFO to 1 for single point reading */
 223         ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
 224         if (ret) {
 225                 dev_err(dev, "Could not set FIFO\n");
 226                 return ret;
 227         }
 228
 229         ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
 230                         STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
 231         if (ret) {
 232                 dev_err(dev, "Could not set mode\n");
 233                 return ret;
 234         }
 235
 236         return 0;
 237 }
 238
 239 static int stmpe_ts_open(struct input_dev *dev)
 240 {
 241         struct stmpe_touch *ts = input_get_drvdata(dev);
 242         int ret = 0;
 243
 244         ret = __stmpe_reset_fifo(ts->stmpe);
 245         if (ret)
 246                 return ret;
 247
 248         return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 249                         STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 250 }
 251
 252 static void stmpe_ts_close(struct input_dev *dev)
 253 {
 254         struct stmpe_touch *ts = input_get_drvdata(dev);
 255
 256         cancel_delayed_work_sync(&ts->work);
 257
 258         stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 259                         STMPE_TSC_CTRL_TSC_EN, 0);
 260 }
 261
 262 static void stmpe_ts_get_platform_info(struct platform_device *pdev,
 263                                         struct stmpe_touch *ts)
 264 {
 265         struct device_node *np = pdev->dev.of_node;
 266         u32 val;
 267
 268         if (np) {
 269                 if (!of_property_read_u32(np, "st,sample-time", &val))
 270                         ts->stmpe->sample_time = val;
 271                 if (!of_property_read_u32(np, "st,mod-12b", &val))
 272                         ts->stmpe->mod_12b = val;
 273                 if (!of_property_read_u32(np, "st,ref-sel", &val))
 274                         ts->stmpe->ref_sel = val;
 275                 if (!of_property_read_u32(np, "st,adc-freq", &val))
 276                         ts->stmpe->adc_freq = val;
 277                 if (!of_property_read_u32(np, "st,ave-ctrl", &val))
 278                         ts->ave_ctrl = val;
 279                 if (!of_property_read_u32(np, "st,touch-det-delay", &val))
 280                         ts->touch_det_delay = val;
 281                 if (!of_property_read_u32(np, "st,settling", &val))
 282                         ts->settling = val;
 283                 if (!of_property_read_u32(np, "st,fraction-z", &val))
 284                         ts->fraction_z = val;
 285                 if (!of_property_read_u32(np, "st,i-drive", &val))
 286                         ts->i_drive = val;
 287         }
 288 }
 289
 290 static int stmpe_input_probe(struct platform_device *pdev)
 291 {
 292         struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
 293         struct stmpe_touch *ts;
 294         struct input_dev *idev;
 295         int error;
 296         int ts_irq;
 297
 298         ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
 299         if (ts_irq < 0)
 300                 return ts_irq;
 301
 302         ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
 303         if (!ts)
 304                 return -ENOMEM;
 305
 306         idev = devm_input_allocate_device(&pdev->dev);
 307         if (!idev)
 308                 return -ENOMEM;
 309
 310         platform_set_drvdata(pdev, ts);
 311         ts->stmpe = stmpe;
 312         ts->idev = idev;
 313         ts->dev = &pdev->dev;
 314
 315         stmpe_ts_get_platform_info(pdev, ts);
 316
 317         INIT_DELAYED_WORK(&ts->work, stmpe_work);
 318
 319         error = devm_request_threaded_irq(&pdev->dev, ts_irq,
 320                                           NULL, stmpe_ts_handler,
 321                                           IRQF_ONESHOT, STMPE_TS_NAME, ts);
 322         if (error) {
 323                 dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
 324                 return error;
 325         }
 326
 327         error = stmpe_init_hw(ts);
 328         if (error)
 329                 return error;
 330
 331         idev->name = STMPE_TS_NAME;
 332         idev->phys = STMPE_TS_NAME"/input0";
 333         idev->id.bustype = BUS_I2C;
 334
 335         idev->open = stmpe_ts_open;
 336         idev->close = stmpe_ts_close;
 337
 338         input_set_drvdata(idev, ts);
 339
 340         input_set_capability(idev, EV_KEY, BTN_TOUCH);
 341         input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
 342         input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
 343         input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
 344
 345         error = input_register_device(idev);
 346         if (error) {
 347                 dev_err(&pdev->dev, "Could not register input device\n");
 348                 return error;
 349         }
 350
 351         return 0;
 352 }
 353
 354 static int stmpe_ts_remove(struct platform_device *pdev)
 355 {
 356         struct stmpe_touch *ts = platform_get_drvdata(pdev);
 357
 358         stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
 359
 360         return 0;
 361 }
 362
 363 static struct platform_driver stmpe_ts_driver = {
 364         .driver = {
 365                 .name = STMPE_TS_NAME,
 366         },
 367         .probe = stmpe_input_probe,
 368         .remove = stmpe_ts_remove,
 369 };
 370 module_platform_driver(stmpe_ts_driver);
 371
 372 static const struct of_device_id stmpe_ts_ids[] = {
 373         { .compatible = "st,stmpe-ts", },
 374         { },
 375 };
 376 MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
 377
 378 MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
 379 MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
 380 MODULE_LICENSE("GPL");