LXR linux/drivers/input/touchscreen/stmpe-ts.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * STMicroelectronics STMPE811 Touchscreen Driver
   4 *
   5 * (C) 2010 Luotao Fu <l.fu@pengutronix.de>
   6 * All rights reserved.
   7 */
   8
   9#include <linux/kernel.h>
  10#include <linux/module.h>
  11#include <linux/sched.h>
  12#include <linux/interrupt.h>
  13#include <linux/device.h>
  14#include <linux/of.h>
  15#include <linux/platform_device.h>
  16#include <linux/input.h>
  17#include <linux/slab.h>
  18#include <linux/delay.h>
  19#include <linux/i2c.h>
  20#include <linux/workqueue.h>
  21
  22#include <linux/mfd/stmpe.h>
  23
  24/* Register layouts and functionalities are identical on all stmpexxx variants
  25 * with touchscreen controller
  26 */
  27#define STMPE_REG_INT_STA               0x0B
  28#define STMPE_REG_TSC_CTRL              0x40
  29#define STMPE_REG_TSC_CFG               0x41
  30#define STMPE_REG_FIFO_TH               0x4A
  31#define STMPE_REG_FIFO_STA              0x4B
  32#define STMPE_REG_FIFO_SIZE             0x4C
  33#define STMPE_REG_TSC_DATA_XYZ          0x52
  34#define STMPE_REG_TSC_FRACTION_Z        0x56
  35#define STMPE_REG_TSC_I_DRIVE           0x58
  36
  37#define OP_MOD_XYZ                      0
  38
  39#define STMPE_TSC_CTRL_TSC_EN           (1<<0)
  40
  41#define STMPE_FIFO_STA_RESET            (1<<0)
  42
  43#define STMPE_IRQ_TOUCH_DET             0
  44
  45#define STMPE_TS_NAME                   "stmpe-ts"
  46#define XY_MASK                         0xfff
  47
  48/**
  49 * struct stmpe_touch - stmpe811 touch screen controller state
  50 * @stmpe: pointer back to STMPE MFD container
  51 * @idev: registered input device
  52 * @work: a work item used to scan the device
  53 * @dev: a pointer back to the MFD cell struct device*
  54 * @ave_ctrl: Sample average control
  55 * (0 -> 1 sample, 1 -> 2 samples, 2 -> 4 samples, 3 -> 8 samples)
  56 * @touch_det_delay: Touch detect interrupt delay
  57 * (0 -> 10 us, 1 -> 50 us, 2 -> 100 us, 3 -> 500 us,
  58 * 4-> 1 ms, 5 -> 5 ms, 6 -> 10 ms, 7 -> 50 ms)
  59 * recommended is 3
  60 * @settling: Panel driver settling time
  61 * (0 -> 10 us, 1 -> 100 us, 2 -> 500 us, 3 -> 1 ms,
  62 * 4 -> 5 ms, 5 -> 10 ms, 6 for 50 ms, 7 -> 100 ms)
  63 * recommended is 2
  64 * @fraction_z: Length of the fractional part in z
  65 * (fraction_z ([0..7]) = Count of the fractional part)
  66 * recommended is 7
  67 * @i_drive: current limit value of the touchscreen drivers
  68 * (0 -> 20 mA typical 35 mA max, 1 -> 50 mA typical 80 mA max)
  69 */
  70struct stmpe_touch {
  71        struct stmpe *stmpe;
  72        struct input_dev *idev;
  73        struct delayed_work work;
  74        struct device *dev;
  75        u8 ave_ctrl;
  76        u8 touch_det_delay;
  77        u8 settling;
  78        u8 fraction_z;
  79        u8 i_drive;
  80};
  81
  82static int __stmpe_reset_fifo(struct stmpe *stmpe)
  83{
  84        int ret;
  85
  86        ret = stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
  87                        STMPE_FIFO_STA_RESET, STMPE_FIFO_STA_RESET);
  88        if (ret)
  89                return ret;
  90
  91        return stmpe_set_bits(stmpe, STMPE_REG_FIFO_STA,
  92                        STMPE_FIFO_STA_RESET, 0);
  93}
  94
  95static void stmpe_work(struct work_struct *work)
  96{
  97        int int_sta;
  98        u32 timeout = 40;
  99
 100        struct stmpe_touch *ts =
 101            container_of(work, struct stmpe_touch, work.work);
 102
 103        int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 104
 105        /*
 106         * touch_det sometimes get desasserted or just get stuck. This appears
 107         * to be a silicon bug, We still have to clearify this with the
 108         * manufacture. As a workaround We release the key anyway if the
 109         * touch_det keeps coming in after 4ms, while the FIFO contains no value
 110         * during the whole time.
 111         */
 112        while ((int_sta & (1 << STMPE_IRQ_TOUCH_DET)) && (timeout > 0)) {
 113                timeout--;
 114                int_sta = stmpe_reg_read(ts->stmpe, STMPE_REG_INT_STA);
 115                udelay(100);
 116        }
 117
 118        /* reset the FIFO before we report release event */
 119        __stmpe_reset_fifo(ts->stmpe);
 120
 121        input_report_abs(ts->idev, ABS_PRESSURE, 0);
 122        input_report_key(ts->idev, BTN_TOUCH, 0);
 123        input_sync(ts->idev);
 124}
 125
 126static irqreturn_t stmpe_ts_handler(int irq, void *data)
 127{
 128        u8 data_set[4];
 129        int x, y, z;
 130        struct stmpe_touch *ts = data;
 131
 132        /*
 133         * Cancel scheduled polling for release if we have new value
 134         * available. Wait if the polling is already running.
 135         */
 136        cancel_delayed_work_sync(&ts->work);
 137
 138        /*
 139         * The FIFO sometimes just crashes and stops generating interrupts. This
 140         * appears to be a silicon bug. We still have to clearify this with
 141         * the manufacture. As a workaround we disable the TSC while we are
 142         * collecting data and flush the FIFO after reading
 143         */
 144        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 145                                STMPE_TSC_CTRL_TSC_EN, 0);
 146
 147        stmpe_block_read(ts->stmpe, STMPE_REG_TSC_DATA_XYZ, 4, data_set);
 148
 149        x = (data_set[0] << 4) | (data_set[1] >> 4);
 150        y = ((data_set[1] & 0xf) << 8) | data_set[2];
 151        z = data_set[3];
 152
 153        input_report_abs(ts->idev, ABS_X, x);
 154        input_report_abs(ts->idev, ABS_Y, y);
 155        input_report_abs(ts->idev, ABS_PRESSURE, z);
 156        input_report_key(ts->idev, BTN_TOUCH, 1);
 157        input_sync(ts->idev);
 158
 159       /* flush the FIFO after we have read out our values. */
 160        __stmpe_reset_fifo(ts->stmpe);
 161
 162        /* reenable the tsc */
 163        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 164                        STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 165
 166        /* start polling for touch_det to detect release */
 167        schedule_delayed_work(&ts->work, msecs_to_jiffies(50));
 168
 169        return IRQ_HANDLED;
 170}
 171
 172static int stmpe_init_hw(struct stmpe_touch *ts)
 173{
 174        int ret;
 175        u8 tsc_cfg, tsc_cfg_mask;
 176        struct stmpe *stmpe = ts->stmpe;
 177        struct device *dev = ts->dev;
 178
 179        ret = stmpe_enable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
 180        if (ret) {
 181                dev_err(dev, "Could not enable clock for ADC and TS\n");
 182                return ret;
 183        }
 184
 185        ret = stmpe811_adc_common_init(stmpe);
 186        if (ret) {
 187                stmpe_disable(stmpe, STMPE_BLOCK_TOUCHSCREEN | STMPE_BLOCK_ADC);
 188                return ret;
 189        }
 190
 191        tsc_cfg = STMPE_AVE_CTRL(ts->ave_ctrl) |
 192                  STMPE_DET_DELAY(ts->touch_det_delay) |
 193                  STMPE_SETTLING(ts->settling);
 194        tsc_cfg_mask = STMPE_AVE_CTRL(0xff) | STMPE_DET_DELAY(0xff) |
 195                       STMPE_SETTLING(0xff);
 196
 197        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CFG, tsc_cfg_mask, tsc_cfg);
 198        if (ret) {
 199                dev_err(dev, "Could not config touch\n");
 200                return ret;
 201        }
 202
 203        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_FRACTION_Z,
 204                        STMPE_FRACTION_Z(0xff), STMPE_FRACTION_Z(ts->fraction_z));
 205        if (ret) {
 206                dev_err(dev, "Could not config touch\n");
 207                return ret;
 208        }
 209
 210        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_I_DRIVE,
 211                        STMPE_I_DRIVE(0xff), STMPE_I_DRIVE(ts->i_drive));
 212        if (ret) {
 213                dev_err(dev, "Could not config touch\n");
 214                return ret;
 215        }
 216
 217        /* set FIFO to 1 for single point reading */
 218        ret = stmpe_reg_write(stmpe, STMPE_REG_FIFO_TH, 1);
 219        if (ret) {
 220                dev_err(dev, "Could not set FIFO\n");
 221                return ret;
 222        }
 223
 224        ret = stmpe_set_bits(stmpe, STMPE_REG_TSC_CTRL,
 225                        STMPE_OP_MODE(0xff), STMPE_OP_MODE(OP_MOD_XYZ));
 226        if (ret) {
 227                dev_err(dev, "Could not set mode\n");
 228                return ret;
 229        }
 230
 231        return 0;
 232}
 233
 234static int stmpe_ts_open(struct input_dev *dev)
 235{
 236        struct stmpe_touch *ts = input_get_drvdata(dev);
 237        int ret = 0;
 238
 239        ret = __stmpe_reset_fifo(ts->stmpe);
 240        if (ret)
 241                return ret;
 242
 243        return stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 244                        STMPE_TSC_CTRL_TSC_EN, STMPE_TSC_CTRL_TSC_EN);
 245}
 246
 247static void stmpe_ts_close(struct input_dev *dev)
 248{
 249        struct stmpe_touch *ts = input_get_drvdata(dev);
 250
 251        cancel_delayed_work_sync(&ts->work);
 252
 253        stmpe_set_bits(ts->stmpe, STMPE_REG_TSC_CTRL,
 254                        STMPE_TSC_CTRL_TSC_EN, 0);
 255}
 256
 257static void stmpe_ts_get_platform_info(struct platform_device *pdev,
 258                                        struct stmpe_touch *ts)
 259{
 260        struct device_node *np = pdev->dev.of_node;
 261        u32 val;
 262
 263        if (np) {
 264                if (!of_property_read_u32(np, "st,sample-time", &val))
 265                        ts->stmpe->sample_time = val;
 266                if (!of_property_read_u32(np, "st,mod-12b", &val))
 267                        ts->stmpe->mod_12b = val;
 268                if (!of_property_read_u32(np, "st,ref-sel", &val))
 269                        ts->stmpe->ref_sel = val;
 270                if (!of_property_read_u32(np, "st,adc-freq", &val))
 271                        ts->stmpe->adc_freq = val;
 272                if (!of_property_read_u32(np, "st,ave-ctrl", &val))
 273                        ts->ave_ctrl = val;
 274                if (!of_property_read_u32(np, "st,touch-det-delay", &val))
 275                        ts->touch_det_delay = val;
 276                if (!of_property_read_u32(np, "st,settling", &val))
 277                        ts->settling = val;
 278                if (!of_property_read_u32(np, "st,fraction-z", &val))
 279                        ts->fraction_z = val;
 280                if (!of_property_read_u32(np, "st,i-drive", &val))
 281                        ts->i_drive = val;
 282        }
 283}
 284
 285static int stmpe_input_probe(struct platform_device *pdev)
 286{
 287        struct stmpe *stmpe = dev_get_drvdata(pdev->dev.parent);
 288        struct stmpe_touch *ts;
 289        struct input_dev *idev;
 290        int error;
 291        int ts_irq;
 292
 293        ts_irq = platform_get_irq_byname(pdev, "FIFO_TH");
 294        if (ts_irq < 0)
 295                return ts_irq;
 296
 297        ts = devm_kzalloc(&pdev->dev, sizeof(*ts), GFP_KERNEL);
 298        if (!ts)
 299                return -ENOMEM;
 300
 301        idev = devm_input_allocate_device(&pdev->dev);
 302        if (!idev)
 303                return -ENOMEM;
 304
 305        platform_set_drvdata(pdev, ts);
 306        ts->stmpe = stmpe;
 307        ts->idev = idev;
 308        ts->dev = &pdev->dev;
 309
 310        stmpe_ts_get_platform_info(pdev, ts);
 311
 312        INIT_DELAYED_WORK(&ts->work, stmpe_work);
 313
 314        error = devm_request_threaded_irq(&pdev->dev, ts_irq,
 315                                          NULL, stmpe_ts_handler,
 316                                          IRQF_ONESHOT, STMPE_TS_NAME, ts);
 317        if (error) {
 318                dev_err(&pdev->dev, "Failed to request IRQ %d\n", ts_irq);
 319                return error;
 320        }
 321
 322        error = stmpe_init_hw(ts);
 323        if (error)
 324                return error;
 325
 326        idev->name = STMPE_TS_NAME;
 327        idev->phys = STMPE_TS_NAME"/input0";
 328        idev->id.bustype = BUS_I2C;
 329
 330        idev->open = stmpe_ts_open;
 331        idev->close = stmpe_ts_close;
 332
 333        input_set_drvdata(idev, ts);
 334
 335        input_set_capability(idev, EV_KEY, BTN_TOUCH);
 336        input_set_abs_params(idev, ABS_X, 0, XY_MASK, 0, 0);
 337        input_set_abs_params(idev, ABS_Y, 0, XY_MASK, 0, 0);
 338        input_set_abs_params(idev, ABS_PRESSURE, 0x0, 0xff, 0, 0);
 339
 340        error = input_register_device(idev);
 341        if (error) {
 342                dev_err(&pdev->dev, "Could not register input device\n");
 343                return error;
 344        }
 345
 346        return 0;
 347}
 348
 349static int stmpe_ts_remove(struct platform_device *pdev)
 350{
 351        struct stmpe_touch *ts = platform_get_drvdata(pdev);
 352
 353        stmpe_disable(ts->stmpe, STMPE_BLOCK_TOUCHSCREEN);
 354
 355        return 0;
 356}
 357
 358static struct platform_driver stmpe_ts_driver = {
 359        .driver = {
 360                .name = STMPE_TS_NAME,
 361        },
 362        .probe = stmpe_input_probe,
 363        .remove = stmpe_ts_remove,
 364};
 365module_platform_driver(stmpe_ts_driver);
 366
 367static const struct of_device_id stmpe_ts_ids[] = {
 368        { .compatible = "st,stmpe-ts", },
 369        { },
 370};
 371MODULE_DEVICE_TABLE(of, stmpe_ts_ids);
 372
 373MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
 374MODULE_DESCRIPTION("STMPEXXX touchscreen driver");
 375MODULE_LICENSE("GPL");
 376