drivers/input/touchscreen/ektf2127.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for ELAN eKTF2127 i2c touchscreen controller
   4  *
   5  * For this driver the layout of the Chipone icn8318 i2c
   6  * touchscreencontroller is used.
   7  *
   8  * Author:
   9  * Michel Verlaan <michel.verl@gmail.com>
  10  * Siebren Vroegindeweij <siebren.vroegindeweij@hotmail.com>
  11  *
  12  * Original chipone_icn8318 driver:
  13  * Hans de Goede <hdegoede@redhat.com>
  14  */
  15
  16 #include <linux/gpio/consumer.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/i2c.h>
  19 #include <linux/input.h>
  20 #include <linux/input/mt.h>
  21 #include <linux/input/touchscreen.h>
  22 #include <linux/module.h>
  23 #include <linux/of.h>
  24 #include <linux/delay.h>
  25
  26 /* Packet header defines (first byte of data send / received) */
  27 #define EKTF2127_NOISE                  0x40
  28 #define EKTF2127_RESPONSE               0x52
  29 #define EKTF2127_REQUEST                0x53
  30 #define EKTF2127_HELLO                  0x55
  31 #define EKTF2127_REPORT                 0x5d
  32 #define EKTF2127_CALIB_DONE             0x66
  33
  34 /* Register defines (second byte of data send / received) */
  35 #define EKTF2127_ENV_NOISY              0x41
  36 #define EKTF2127_HEIGHT                 0x60
  37 #define EKTF2127_WIDTH                  0x63
  38
  39 /* 2 bytes header + 5 * 3 bytes coordinates + 3 bytes pressure info + footer */
  40 #define EKTF2127_TOUCH_REPORT_SIZE      21
  41 #define EKTF2127_MAX_TOUCHES            5
  42
  43 struct ektf2127_ts {
  44         struct i2c_client *client;
  45         struct input_dev *input;
  46         struct gpio_desc *power_gpios;
  47         struct touchscreen_properties prop;
  48 };
  49
  50 static void ektf2127_parse_coordinates(const u8 *buf, unsigned int touch_count,
  51                                        struct input_mt_pos *touches)
  52 {
  53         int index = 0;
  54         int i;
  55
  56         for (i = 0; i < touch_count; i++) {
  57                 index = 2 + i * 3;
  58
  59                 touches[i].x = (buf[index] & 0x0f);
  60                 touches[i].x <<= 8;
  61                 touches[i].x |= buf[index + 2];
  62
  63                 touches[i].y = (buf[index] & 0xf0);
  64                 touches[i].y <<= 4;
  65                 touches[i].y |= buf[index + 1];
  66         }
  67 }
  68
  69 static void ektf2127_report_event(struct ektf2127_ts *ts, const u8 *buf)
  70 {
  71         struct input_mt_pos touches[EKTF2127_MAX_TOUCHES];
  72         int slots[EKTF2127_MAX_TOUCHES];
  73         unsigned int touch_count, i;
  74
  75         touch_count = buf[1] & 0x07;
  76         if (touch_count > EKTF2127_MAX_TOUCHES) {
  77                 dev_err(&ts->client->dev,
  78                         "Too many touches %d > %d\n",
  79                         touch_count, EKTF2127_MAX_TOUCHES);
  80                 touch_count = EKTF2127_MAX_TOUCHES;
  81         }
  82
  83         ektf2127_parse_coordinates(buf, touch_count, touches);
  84         input_mt_assign_slots(ts->input, slots, touches,
  85                               touch_count, 0);
  86
  87         for (i = 0; i < touch_count; i++) {
  88                 input_mt_slot(ts->input, slots[i]);
  89                 input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
  90                 touchscreen_report_pos(ts->input, &ts->prop,
  91                                        touches[i].x, touches[i].y, true);
  92         }
  93
  94         input_mt_sync_frame(ts->input);
  95         input_sync(ts->input);
  96 }
  97
  98 static irqreturn_t ektf2127_irq(int irq, void *dev_id)
  99 {
 100         struct ektf2127_ts *ts = dev_id;
 101         struct device *dev = &ts->client->dev;
 102         char buf[EKTF2127_TOUCH_REPORT_SIZE];
 103         int ret;
 104
 105         ret = i2c_master_recv(ts->client, buf, EKTF2127_TOUCH_REPORT_SIZE);
 106         if (ret != EKTF2127_TOUCH_REPORT_SIZE) {
 107                 dev_err(dev, "Error reading touch data: %d\n", ret);
 108                 goto out;
 109         }
 110
 111         switch (buf[0]) {
 112         case EKTF2127_REPORT:
 113                 ektf2127_report_event(ts, buf);
 114                 break;
 115
 116         case EKTF2127_NOISE:
 117                 if (buf[1] == EKTF2127_ENV_NOISY)
 118                         dev_dbg(dev, "Environment is electrically noisy\n");
 119                 break;
 120
 121         case EKTF2127_HELLO:
 122         case EKTF2127_CALIB_DONE:
 123                 break;
 124
 125         default:
 126                 dev_err(dev, "Unexpected packet header byte %#02x\n", buf[0]);
 127                 break;
 128         }
 129
 130 out:
 131         return IRQ_HANDLED;
 132 }
 133
 134 static int ektf2127_start(struct input_dev *dev)
 135 {
 136         struct ektf2127_ts *ts = input_get_drvdata(dev);
 137
 138         enable_irq(ts->client->irq);
 139         gpiod_set_value_cansleep(ts->power_gpios, 1);
 140
 141         return 0;
 142 }
 143
 144 static void ektf2127_stop(struct input_dev *dev)
 145 {
 146         struct ektf2127_ts *ts = input_get_drvdata(dev);
 147
 148         disable_irq(ts->client->irq);
 149         gpiod_set_value_cansleep(ts->power_gpios, 0);
 150 }
 151
 152 static int __maybe_unused ektf2127_suspend(struct device *dev)
 153 {
 154         struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
 155
 156         mutex_lock(&ts->input->mutex);
 157         if (ts->input->users)
 158                 ektf2127_stop(ts->input);
 159         mutex_unlock(&ts->input->mutex);
 160
 161         return 0;
 162 }
 163
 164 static int __maybe_unused ektf2127_resume(struct device *dev)
 165 {
 166         struct ektf2127_ts *ts = i2c_get_clientdata(to_i2c_client(dev));
 167
 168         mutex_lock(&ts->input->mutex);
 169         if (ts->input->users)
 170                 ektf2127_start(ts->input);
 171         mutex_unlock(&ts->input->mutex);
 172
 173         return 0;
 174 }
 175
 176 static SIMPLE_DEV_PM_OPS(ektf2127_pm_ops, ektf2127_suspend,
 177                          ektf2127_resume);
 178
 179 static int ektf2127_query_dimension(struct i2c_client *client, bool width)
 180 {
 181         struct device *dev = &client->dev;
 182         const char *what = width ? "width" : "height";
 183         u8 what_code = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
 184         u8 buf[4];
 185         int ret;
 186         int error;
 187
 188         /* Request dimension */
 189         buf[0] = EKTF2127_REQUEST;
 190         buf[1] = width ? EKTF2127_WIDTH : EKTF2127_HEIGHT;
 191         buf[2] = 0x00;
 192         buf[3] = 0x00;
 193         ret = i2c_master_send(client, buf, sizeof(buf));
 194         if (ret != sizeof(buf)) {
 195                 error = ret < 0 ? ret : -EIO;
 196                 dev_err(dev, "Failed to request %s: %d\n", what, error);
 197                 return error;
 198         }
 199
 200         msleep(20);
 201
 202         /* Read response */
 203         ret = i2c_master_recv(client, buf, sizeof(buf));
 204         if (ret != sizeof(buf)) {
 205                 error = ret < 0 ? ret : -EIO;
 206                 dev_err(dev, "Failed to receive %s data: %d\n", what, error);
 207                 return error;
 208         }
 209
 210         if (buf[0] != EKTF2127_RESPONSE || buf[1] != what_code) {
 211                 dev_err(dev, "Unexpected %s data: %#02x %#02x\n",
 212                         what, buf[0], buf[1]);
 213                 return -EIO;
 214         }
 215
 216         return (((buf[3] & 0xf0) << 4) | buf[2]) - 1;
 217 }
 218
 219 static int ektf2127_probe(struct i2c_client *client,
 220                           const struct i2c_device_id *id)
 221 {
 222         struct device *dev = &client->dev;
 223         struct ektf2127_ts *ts;
 224         struct input_dev *input;
 225         u8 buf[4];
 226         int max_x, max_y;
 227         int error;
 228
 229         if (!client->irq) {
 230                 dev_err(dev, "Error no irq specified\n");
 231                 return -EINVAL;
 232         }
 233
 234         ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
 235         if (!ts)
 236                 return -ENOMEM;
 237
 238         /* This requests the gpio *and* turns on the touchscreen controller */
 239         ts->power_gpios = devm_gpiod_get(dev, "power", GPIOD_OUT_HIGH);
 240         if (IS_ERR(ts->power_gpios)) {
 241                 error = PTR_ERR(ts->power_gpios);
 242                 if (error != -EPROBE_DEFER)
 243                         dev_err(dev, "Error getting power gpio: %d\n", error);
 244                 return error;
 245         }
 246
 247         input = devm_input_allocate_device(dev);
 248         if (!input)
 249                 return -ENOMEM;
 250
 251         input->name = client->name;
 252         input->id.bustype = BUS_I2C;
 253         input->open = ektf2127_start;
 254         input->close = ektf2127_stop;
 255
 256         ts->client = client;
 257
 258         /* Read hello (ignore result, depends on initial power state) */
 259         msleep(20);
 260         i2c_master_recv(ts->client, buf, sizeof(buf));
 261
 262         /* Read resolution from chip */
 263         max_x = ektf2127_query_dimension(client, true);
 264         if (max_x < 0)
 265                 return max_x;
 266
 267         max_y = ektf2127_query_dimension(client, false);
 268         if (max_y < 0)
 269                 return max_y;
 270
 271         input_set_abs_params(input, ABS_MT_POSITION_X, 0, max_x, 0, 0);
 272         input_set_abs_params(input, ABS_MT_POSITION_Y, 0, max_y, 0, 0);
 273         touchscreen_parse_properties(input, true, &ts->prop);
 274
 275         error = input_mt_init_slots(input, EKTF2127_MAX_TOUCHES,
 276                                     INPUT_MT_DIRECT |
 277                                         INPUT_MT_DROP_UNUSED |
 278                                         INPUT_MT_TRACK);
 279         if (error)
 280                 return error;
 281
 282         ts->input = input;
 283         input_set_drvdata(input, ts);
 284
 285         error = devm_request_threaded_irq(dev, client->irq,
 286                                           NULL, ektf2127_irq,
 287                                           IRQF_ONESHOT, client->name, ts);
 288         if (error) {
 289                 dev_err(dev, "Error requesting irq: %d\n", error);
 290                 return error;
 291         }
 292
 293         /* Stop device till opened */
 294         ektf2127_stop(ts->input);
 295
 296         error = input_register_device(input);
 297         if (error)
 298                 return error;
 299
 300         i2c_set_clientdata(client, ts);
 301
 302         return 0;
 303 }
 304
 305 #ifdef CONFIG_OF
 306 static const struct of_device_id ektf2127_of_match[] = {
 307         { .compatible = "elan,ektf2127" },
 308         {}
 309 };
 310 MODULE_DEVICE_TABLE(of, ektf2127_of_match);
 311 #endif
 312
 313 static const struct i2c_device_id ektf2127_i2c_id[] = {
 314         { "ektf2127", 0 },
 315         {}
 316 };
 317 MODULE_DEVICE_TABLE(i2c, ektf2127_i2c_id);
 318
 319 static struct i2c_driver ektf2127_driver = {
 320         .driver = {
 321                 .name   = "elan_ektf2127",
 322                 .pm     = &ektf2127_pm_ops,
 323                 .of_match_table = of_match_ptr(ektf2127_of_match),
 324         },
 325         .probe = ektf2127_probe,
 326         .id_table = ektf2127_i2c_id,
 327 };
 328 module_i2c_driver(ektf2127_driver);
 329
 330 MODULE_DESCRIPTION("ELAN eKTF2127 I2C Touchscreen Driver");
 331 MODULE_AUTHOR("Michel Verlaan, Siebren Vroegindeweij");
 332 MODULE_LICENSE("GPL");