drivers/input/touchscreen/eeti_ts.c

   1 /*
   2  * Touch Screen driver for EETI's I2C connected touch screen panels
   3  *   Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org>
   4  *
   5  * See EETI's software guide for the protocol specification:
   6  *   http://home.eeti.com.tw/documentation.html
   7  *
   8  * Based on migor_ts.c
   9  *   Copyright (c) 2008 Magnus Damm
  10  *   Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com>
  11  *
  12  * This file is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU  General Public
  14  * License as published by the Free Software Foundation; either
  15  * version 2 of the License, or (at your option) any later version.
  16  *
  17  * This file is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20  *  General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public
  23  * License along with this library; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  */
  26
  27 #include <linux/module.h>
  28 #include <linux/kernel.h>
  29 #include <linux/input.h>
  30 #include <linux/input/touchscreen.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/i2c.h>
  33 #include <linux/timer.h>
  34 #include <linux/gpio/consumer.h>
  35 #include <linux/of.h>
  36 #include <linux/slab.h>
  37 #include <asm/unaligned.h>
  38
  39 struct eeti_ts {
  40         struct i2c_client *client;
  41         struct input_dev *input;
  42         struct gpio_desc *attn_gpio;
  43         struct touchscreen_properties props;
  44         bool running;
  45 };
  46
  47 #define EETI_TS_BITDEPTH        (11)
  48 #define EETI_MAXVAL             ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
  49
  50 #define REPORT_BIT_PRESSED      BIT(0)
  51 #define REPORT_BIT_AD0          BIT(1)
  52 #define REPORT_BIT_AD1          BIT(2)
  53 #define REPORT_BIT_HAS_PRESSURE BIT(6)
  54 #define REPORT_RES_BITS(v)      (((v) >> 1) + EETI_TS_BITDEPTH)
  55
  56 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
  57 {
  58         unsigned int res;
  59         u16 x, y;
  60
  61         res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
  62
  63         x = get_unaligned_be16(&buf[1]);
  64         y = get_unaligned_be16(&buf[3]);
  65
  66         /* fix the range to 11 bits */
  67         x >>= res - EETI_TS_BITDEPTH;
  68         y >>= res - EETI_TS_BITDEPTH;
  69
  70         if (buf[0] & REPORT_BIT_HAS_PRESSURE)
  71                 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]);
  72
  73         touchscreen_report_pos(eeti->input, &eeti->props, x, y, false);
  74         input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
  75         input_sync(eeti->input);
  76 }
  77
  78 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
  79 {
  80         struct eeti_ts *eeti = dev_id;
  81         int len;
  82         int error;
  83         char buf[6];
  84
  85         do {
  86                 len = i2c_master_recv(eeti->client, buf, sizeof(buf));
  87                 if (len != sizeof(buf)) {
  88                         error = len < 0 ? len : -EIO;
  89                         dev_err(&eeti->client->dev,
  90                                 "failed to read touchscreen data: %d\n",
  91                                 error);
  92                         break;
  93                 }
  94
  95                 if (buf[0] & 0x80) {
  96                         /* Motion packet */
  97                         eeti_ts_report_event(eeti, buf);
  98                 }
  99         } while (eeti->running &&
 100                  eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio));
 101
 102         return IRQ_HANDLED;
 103 }
 104
 105 static void eeti_ts_start(struct eeti_ts *eeti)
 106 {
 107         eeti->running = true;
 108         wmb();
 109         enable_irq(eeti->client->irq);
 110 }
 111
 112 static void eeti_ts_stop(struct eeti_ts *eeti)
 113 {
 114         eeti->running = false;
 115         wmb();
 116         disable_irq(eeti->client->irq);
 117 }
 118
 119 static int eeti_ts_open(struct input_dev *dev)
 120 {
 121         struct eeti_ts *eeti = input_get_drvdata(dev);
 122
 123         eeti_ts_start(eeti);
 124
 125         return 0;
 126 }
 127
 128 static void eeti_ts_close(struct input_dev *dev)
 129 {
 130         struct eeti_ts *eeti = input_get_drvdata(dev);
 131
 132         eeti_ts_stop(eeti);
 133 }
 134
 135 static int eeti_ts_probe(struct i2c_client *client,
 136                          const struct i2c_device_id *idp)
 137 {
 138         struct device *dev = &client->dev;
 139         struct eeti_ts *eeti;
 140         struct input_dev *input;
 141         int error;
 142
 143         /*
 144          * In contrast to what's described in the datasheet, there seems
 145          * to be no way of probing the presence of that device using I2C
 146          * commands. So we need to blindly believe it is there, and wait
 147          * for interrupts to occur.
 148          */
 149
 150         eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
 151         if (!eeti) {
 152                 dev_err(dev, "failed to allocate driver data\n");
 153                 return -ENOMEM;
 154         }
 155
 156         input = devm_input_allocate_device(dev);
 157         if (!input) {
 158                 dev_err(dev, "Failed to allocate input device.\n");
 159                 return -ENOMEM;
 160         }
 161
 162         input_set_capability(input, EV_KEY, BTN_TOUCH);
 163
 164         input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
 165         input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
 166         input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
 167
 168         touchscreen_parse_properties(input, false, &eeti->props);
 169
 170         input->name = client->name;
 171         input->id.bustype = BUS_I2C;
 172         input->open = eeti_ts_open;
 173         input->close = eeti_ts_close;
 174
 175         eeti->client = client;
 176         eeti->input = input;
 177
 178         eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
 179         if (IS_ERR(eeti->attn_gpio))
 180                 return PTR_ERR(eeti->attn_gpio);
 181
 182         i2c_set_clientdata(client, eeti);
 183         input_set_drvdata(input, eeti);
 184
 185         error = devm_request_threaded_irq(dev, client->irq,
 186                                           NULL, eeti_ts_isr,
 187                                           IRQF_ONESHOT,
 188                                           client->name, eeti);
 189         if (error) {
 190                 dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
 191                         error);
 192                 return error;
 193         }
 194
 195         /*
 196          * Disable the device for now. It will be enabled once the
 197          * input device is opened.
 198          */
 199         eeti_ts_stop(eeti);
 200
 201         error = input_register_device(input);
 202         if (error)
 203                 return error;
 204
 205         return 0;
 206 }
 207
 208 static int __maybe_unused eeti_ts_suspend(struct device *dev)
 209 {
 210         struct i2c_client *client = to_i2c_client(dev);
 211         struct eeti_ts *eeti = i2c_get_clientdata(client);
 212         struct input_dev *input_dev = eeti->input;
 213
 214         mutex_lock(&input_dev->mutex);
 215
 216         if (input_dev->users)
 217                 eeti_ts_stop(eeti);
 218
 219         mutex_unlock(&input_dev->mutex);
 220
 221         if (device_may_wakeup(&client->dev))
 222                 enable_irq_wake(client->irq);
 223
 224         return 0;
 225 }
 226
 227 static int __maybe_unused eeti_ts_resume(struct device *dev)
 228 {
 229         struct i2c_client *client = to_i2c_client(dev);
 230         struct eeti_ts *eeti = i2c_get_clientdata(client);
 231         struct input_dev *input_dev = eeti->input;
 232
 233         if (device_may_wakeup(&client->dev))
 234                 disable_irq_wake(client->irq);
 235
 236         mutex_lock(&input_dev->mutex);
 237
 238         if (input_dev->users)
 239                 eeti_ts_start(eeti);
 240
 241         mutex_unlock(&input_dev->mutex);
 242
 243         return 0;
 244 }
 245
 246 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
 247
 248 static const struct i2c_device_id eeti_ts_id[] = {
 249         { "eeti_ts", 0 },
 250         { }
 251 };
 252 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
 253
 254 #ifdef CONFIG_OF
 255 static const struct of_device_id of_eeti_ts_match[] = {
 256         { .compatible = "eeti,exc3000-i2c", },
 257         { }
 258 };
 259 #endif
 260
 261 static struct i2c_driver eeti_ts_driver = {
 262         .driver = {
 263                 .name = "eeti_ts",
 264                 .pm = &eeti_ts_pm,
 265                 .of_match_table = of_match_ptr(of_eeti_ts_match),
 266         },
 267         .probe = eeti_ts_probe,
 268         .id_table = eeti_ts_id,
 269 };
 270
 271 module_i2c_driver(eeti_ts_driver);
 272
 273 MODULE_DESCRIPTION("EETI Touchscreen driver");
 274 MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>");
 275 MODULE_LICENSE("GPL");