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.h>
  35
  36 static int flip_x;
  37 module_param(flip_x, bool, 0644);
  38 MODULE_PARM_DESC(flip_x, "flip x coordinate");
  39
  40 static int flip_y;
  41 module_param(flip_y, bool, 0644);
  42 MODULE_PARM_DESC(flip_y, "flip y coordinate");
  43
  44 struct eeti_ts_priv {
  45         struct i2c_client *client;
  46         struct input_dev *input;
  47         struct work_struct work;
  48         struct mutex mutex;
  49         int irq;
  50 };
  51
  52 #define EETI_TS_BITDEPTH        (11)
  53 #define EETI_MAXVAL             ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
  54
  55 #define REPORT_BIT_PRESSED      (1 << 0)
  56 #define REPORT_BIT_AD0          (1 << 1)
  57 #define REPORT_BIT_AD1          (1 << 2)
  58 #define REPORT_BIT_HAS_PRESSURE (1 << 6)
  59 #define REPORT_RES_BITS(v)      (((v) >> 1) + EETI_TS_BITDEPTH)
  60
  61 static void eeti_ts_read(struct work_struct *work)
  62 {
  63         char buf[6];
  64         unsigned int x, y, res, pressed, to = 100;
  65         struct eeti_ts_priv *priv =
  66                 container_of(work, struct eeti_ts_priv, work);
  67
  68         mutex_lock(&priv->mutex);
  69
  70         while (!gpio_get_value(irq_to_gpio(priv->irq)) && --to)
  71                 i2c_master_recv(priv->client, buf, sizeof(buf));
  72
  73         if (!to) {
  74                 dev_err(&priv->client->dev,
  75                         "unable to clear IRQ - line stuck?\n");
  76                 goto out;
  77         }
  78
  79         /* drop non-report packets */
  80         if (!(buf[0] & 0x80))
  81                 goto out;
  82
  83         pressed = buf[0] & REPORT_BIT_PRESSED;
  84         res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
  85         x = buf[2] | (buf[1] << 8);
  86         y = buf[4] | (buf[3] << 8);
  87
  88         /* fix the range to 11 bits */
  89         x >>= res - EETI_TS_BITDEPTH;
  90         y >>= res - EETI_TS_BITDEPTH;
  91
  92         if (flip_x)
  93                 x = EETI_MAXVAL - x;
  94
  95         if (flip_y)
  96                 y = EETI_MAXVAL - y;
  97
  98         if (buf[0] & REPORT_BIT_HAS_PRESSURE)
  99                 input_report_abs(priv->input, ABS_PRESSURE, buf[5]);
 100
 101         input_report_abs(priv->input, ABS_X, x);
 102         input_report_abs(priv->input, ABS_Y, y);
 103         input_report_key(priv->input, BTN_TOUCH, !!pressed);
 104         input_sync(priv->input);
 105
 106 out:
 107         mutex_unlock(&priv->mutex);
 108 }
 109
 110 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
 111 {
 112         struct eeti_ts_priv *priv = dev_id;
 113
 114          /* postpone I2C transactions as we are atomic */
 115         schedule_work(&priv->work);
 116
 117         return IRQ_HANDLED;
 118 }
 119
 120 static int eeti_ts_open(struct input_dev *dev)
 121 {
 122         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 123
 124         enable_irq(priv->irq);
 125
 126         /* Read the events once to arm the IRQ */
 127         eeti_ts_read(&priv->work);
 128
 129         return 0;
 130 }
 131
 132 static void eeti_ts_close(struct input_dev *dev)
 133 {
 134         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 135
 136         disable_irq(priv->irq);
 137         cancel_work_sync(&priv->work);
 138 }
 139
 140 static int __devinit eeti_ts_probe(struct i2c_client *client,
 141                                    const struct i2c_device_id *idp)
 142 {
 143         struct eeti_ts_priv *priv;
 144         struct input_dev *input;
 145         int err = -ENOMEM;
 146
 147         /* In contrast to what's described in the datasheet, there seems
 148          * to be no way of probing the presence of that device using I2C
 149          * commands. So we need to blindly believe it is there, and wait
 150          * for interrupts to occur. */
 151
 152         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 153         if (!priv) {
 154                 dev_err(&client->dev, "failed to allocate driver data\n");
 155                 goto err0;
 156         }
 157
 158         mutex_init(&priv->mutex);
 159         input = input_allocate_device();
 160
 161         if (!input) {
 162                 dev_err(&client->dev, "Failed to allocate input device.\n");
 163                 goto err1;
 164         }
 165
 166         input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 167         input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 168
 169         input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
 170         input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
 171         input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
 172
 173         input->name = client->name;
 174         input->id.bustype = BUS_I2C;
 175         input->dev.parent = &client->dev;
 176         input->open = eeti_ts_open;
 177         input->close = eeti_ts_close;
 178
 179         priv->client = client;
 180         priv->input = input;
 181         priv->irq = client->irq;
 182
 183         INIT_WORK(&priv->work, eeti_ts_read);
 184         i2c_set_clientdata(client, priv);
 185         input_set_drvdata(input, priv);
 186
 187         err = input_register_device(input);
 188         if (err)
 189                 goto err1;
 190
 191         err = request_irq(priv->irq, eeti_ts_isr, IRQF_TRIGGER_FALLING,
 192                           client->name, priv);
 193         if (err) {
 194                 dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
 195                 goto err2;
 196         }
 197
 198         /* Disable the irq for now. It will be enabled once the input device
 199          * is opened. */
 200         disable_irq(priv->irq);
 201
 202         device_init_wakeup(&client->dev, 0);
 203         return 0;
 204
 205 err2:
 206         input_unregister_device(input);
 207         input = NULL; /* so we dont try to free it below */
 208 err1:
 209         input_free_device(input);
 210         i2c_set_clientdata(client, NULL);
 211         kfree(priv);
 212 err0:
 213         return err;
 214 }
 215
 216 static int __devexit eeti_ts_remove(struct i2c_client *client)
 217 {
 218         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 219
 220         free_irq(priv->irq, priv);
 221         input_unregister_device(priv->input);
 222         i2c_set_clientdata(client, NULL);
 223         kfree(priv);
 224
 225         return 0;
 226 }
 227
 228 #ifdef CONFIG_PM
 229 static int eeti_ts_suspend(struct i2c_client *client, pm_message_t mesg)
 230 {
 231         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 232
 233         if (device_may_wakeup(&client->dev))
 234                 enable_irq_wake(priv->irq);
 235
 236         return 0;
 237 }
 238
 239 static int eeti_ts_resume(struct i2c_client *client)
 240 {
 241         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 242
 243         if (device_may_wakeup(&client->dev))
 244                 disable_irq_wake(priv->irq);
 245
 246         return 0;
 247 }
 248 #else
 249 #define eeti_ts_suspend NULL
 250 #define eeti_ts_resume NULL
 251 #endif
 252
 253 static const struct i2c_device_id eeti_ts_id[] = {
 254         { "eeti_ts", 0 },
 255         { }
 256 };
 257 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
 258
 259 static struct i2c_driver eeti_ts_driver = {
 260         .driver = {
 261                 .name = "eeti_ts",
 262         },
 263         .probe = eeti_ts_probe,
 264         .remove = __devexit_p(eeti_ts_remove),
 265         .suspend = eeti_ts_suspend,
 266         .resume = eeti_ts_resume,
 267         .id_table = eeti_ts_id,
 268 };
 269
 270 static int __init eeti_ts_init(void)
 271 {
 272         return i2c_add_driver(&eeti_ts_driver);
 273 }
 274
 275 static void __exit eeti_ts_exit(void)
 276 {
 277         i2c_del_driver(&eeti_ts_driver);
 278 }
 279
 280 MODULE_DESCRIPTION("EETI Touchscreen driver");
 281 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 282 MODULE_LICENSE("GPL");
 283
 284 module_init(eeti_ts_init);
 285 module_exit(eeti_ts_exit);
 286