drivers/input/touchscreen/eeti_ts.c

   1 /*
   2  * Touch Screen driver for EETI's I2C connected touch screen panels
   3  *   Copyright (c) 2009 Daniel Mack <daniel@caiaq.de>
   4  *
   5  * See EETI's software guide for the protocol specification:
   6  *   http://home.eeti.com.tw/web20/eg/guide.htm
   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/moduleparam.h>
  29 #include <linux/kernel.h>
  30 #include <linux/input.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/slab.h>
  36 #include <asm/unaligned.h>
  37
  38 static bool flip_x;
  39 module_param(flip_x, bool, 0644);
  40 MODULE_PARM_DESC(flip_x, "flip x coordinate");
  41
  42 static bool flip_y;
  43 module_param(flip_y, bool, 0644);
  44 MODULE_PARM_DESC(flip_y, "flip y coordinate");
  45
  46 struct eeti_ts {
  47         struct i2c_client *client;
  48         struct input_dev *input;
  49         struct gpio_desc *attn_gpio;
  50         bool running;
  51 };
  52
  53 #define EETI_TS_BITDEPTH        (11)
  54 #define EETI_MAXVAL             ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
  55
  56 #define REPORT_BIT_PRESSED      BIT(0)
  57 #define REPORT_BIT_AD0          BIT(1)
  58 #define REPORT_BIT_AD1          BIT(2)
  59 #define REPORT_BIT_HAS_PRESSURE BIT(6)
  60 #define REPORT_RES_BITS(v)      (((v) >> 1) + EETI_TS_BITDEPTH)
  61
  62 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
  63 {
  64         unsigned int res;
  65         u16 x, y;
  66
  67         res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
  68
  69         x = get_unaligned_be16(&buf[1]);
  70         y = get_unaligned_be16(&buf[3]);
  71
  72         /* fix the range to 11 bits */
  73         x >>= res - EETI_TS_BITDEPTH;
  74         y >>= res - EETI_TS_BITDEPTH;
  75
  76         if (flip_x)
  77                 x = EETI_MAXVAL - x;
  78
  79         if (flip_y)
  80                 y = EETI_MAXVAL - y;
  81
  82         if (buf[0] & REPORT_BIT_HAS_PRESSURE)
  83                 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]);
  84
  85         input_report_abs(eeti->input, ABS_X, x);
  86         input_report_abs(eeti->input, ABS_Y, y);
  87         input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
  88         input_sync(eeti->input);
  89 }
  90
  91 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
  92 {
  93         struct eeti_ts *eeti = dev_id;
  94         int len;
  95         int error;
  96         char buf[6];
  97
  98         do {
  99                 len = i2c_master_recv(eeti->client, buf, sizeof(buf));
 100                 if (len != sizeof(buf)) {
 101                         error = len < 0 ? len : -EIO;
 102                         dev_err(&eeti->client->dev,
 103                                 "failed to read touchscreen data: %d\n",
 104                                 error);
 105                         break;
 106                 }
 107
 108                 if (buf[0] & 0x80) {
 109                         /* Motion packet */
 110                         eeti_ts_report_event(eeti, buf);
 111                 }
 112         } while (eeti->running &&
 113                  eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio));
 114
 115         return IRQ_HANDLED;
 116 }
 117
 118 static void eeti_ts_start(struct eeti_ts *eeti)
 119 {
 120         eeti->running = true;
 121         wmb();
 122         enable_irq(eeti->client->irq);
 123 }
 124
 125 static void eeti_ts_stop(struct eeti_ts *eeti)
 126 {
 127         eeti->running = false;
 128         wmb();
 129         disable_irq(eeti->client->irq);
 130 }
 131
 132 static int eeti_ts_open(struct input_dev *dev)
 133 {
 134         struct eeti_ts *eeti = input_get_drvdata(dev);
 135
 136         eeti_ts_start(eeti);
 137
 138         return 0;
 139 }
 140
 141 static void eeti_ts_close(struct input_dev *dev)
 142 {
 143         struct eeti_ts *eeti = input_get_drvdata(dev);
 144
 145         eeti_ts_stop(eeti);
 146 }
 147
 148 static int eeti_ts_probe(struct i2c_client *client,
 149                          const struct i2c_device_id *idp)
 150 {
 151         struct device *dev = &client->dev;
 152         struct eeti_ts *eeti;
 153         struct input_dev *input;
 154         int error;
 155
 156         /*
 157          * In contrast to what's described in the datasheet, there seems
 158          * to be no way of probing the presence of that device using I2C
 159          * commands. So we need to blindly believe it is there, and wait
 160          * for interrupts to occur.
 161          */
 162
 163         eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL);
 164         if (!eeti) {
 165                 dev_err(dev, "failed to allocate driver data\n");
 166                 return -ENOMEM;
 167         }
 168
 169         input = devm_input_allocate_device(dev);
 170         if (!input) {
 171                 dev_err(dev, "Failed to allocate input device.\n");
 172                 return -ENOMEM;
 173         }
 174
 175         input_set_capability(input, EV_KEY, BTN_TOUCH);
 176
 177         input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
 178         input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
 179         input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
 180
 181         input->name = client->name;
 182         input->id.bustype = BUS_I2C;
 183         input->open = eeti_ts_open;
 184         input->close = eeti_ts_close;
 185
 186         eeti->client = client;
 187         eeti->input = input;
 188
 189         eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN);
 190         if (IS_ERR(eeti->attn_gpio))
 191                 return PTR_ERR(eeti->attn_gpio);
 192
 193         i2c_set_clientdata(client, eeti);
 194         input_set_drvdata(input, eeti);
 195
 196         error = devm_request_threaded_irq(dev, client->irq,
 197                                           NULL, eeti_ts_isr,
 198                                           IRQF_ONESHOT,
 199                                           client->name, eeti);
 200         if (error) {
 201                 dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
 202                         error);
 203                 return error;
 204         }
 205
 206         /*
 207          * Disable the device for now. It will be enabled once the
 208          * input device is opened.
 209          */
 210         eeti_ts_stop(eeti);
 211
 212         error = input_register_device(input);
 213         if (error)
 214                 return error;
 215
 216         return 0;
 217 }
 218
 219 static int __maybe_unused eeti_ts_suspend(struct device *dev)
 220 {
 221         struct i2c_client *client = to_i2c_client(dev);
 222         struct eeti_ts *eeti = i2c_get_clientdata(client);
 223         struct input_dev *input_dev = eeti->input;
 224
 225         mutex_lock(&input_dev->mutex);
 226
 227         if (input_dev->users)
 228                 eeti_ts_stop(eeti);
 229
 230         mutex_unlock(&input_dev->mutex);
 231
 232         if (device_may_wakeup(&client->dev))
 233                 enable_irq_wake(client->irq);
 234
 235         return 0;
 236 }
 237
 238 static int __maybe_unused eeti_ts_resume(struct device *dev)
 239 {
 240         struct i2c_client *client = to_i2c_client(dev);
 241         struct eeti_ts *eeti = i2c_get_clientdata(client);
 242         struct input_dev *input_dev = eeti->input;
 243
 244         if (device_may_wakeup(&client->dev))
 245                 disable_irq_wake(client->irq);
 246
 247         mutex_lock(&input_dev->mutex);
 248
 249         if (input_dev->users)
 250                 eeti_ts_start(eeti);
 251
 252         mutex_unlock(&input_dev->mutex);
 253
 254         return 0;
 255 }
 256
 257 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
 258
 259 static const struct i2c_device_id eeti_ts_id[] = {
 260         { "eeti_ts", 0 },
 261         { }
 262 };
 263 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
 264
 265 static struct i2c_driver eeti_ts_driver = {
 266         .driver = {
 267                 .name = "eeti_ts",
 268                 .pm = &eeti_ts_pm,
 269         },
 270         .probe = eeti_ts_probe,
 271         .id_table = eeti_ts_id,
 272 };
 273
 274 module_i2c_driver(eeti_ts_driver);
 275
 276 MODULE_DESCRIPTION("EETI Touchscreen driver");
 277 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 278 MODULE_LICENSE("GPL");