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