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