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 #include <linux/input/eeti_ts.h>
  36
  37 static int flip_x;
  38 module_param(flip_x, bool, 0644);
  39 MODULE_PARM_DESC(flip_x, "flip x coordinate");
  40
  41 static int flip_y;
  42 module_param(flip_y, bool, 0644);
  43 MODULE_PARM_DESC(flip_y, "flip y coordinate");
  44
  45 struct eeti_ts_priv {
  46         struct i2c_client *client;
  47         struct input_dev *input;
  48         struct work_struct work;
  49         struct mutex mutex;
  50         int irq, irq_active_high;
  51 };
  52
  53 #define EETI_TS_BITDEPTH        (11)
  54 #define EETI_MAXVAL             ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
  55
  56 #define REPORT_BIT_PRESSED      (1 << 0)
  57 #define REPORT_BIT_AD0          (1 << 1)
  58 #define REPORT_BIT_AD1          (1 << 2)
  59 #define REPORT_BIT_HAS_PRESSURE (1 << 6)
  60 #define REPORT_RES_BITS(v)      (((v) >> 1) + EETI_TS_BITDEPTH)
  61
  62 static inline int eeti_ts_irq_active(struct eeti_ts_priv *priv)
  63 {
  64         return gpio_get_value(irq_to_gpio(priv->irq)) == priv->irq_active_high;
  65 }
  66
  67 static void eeti_ts_read(struct work_struct *work)
  68 {
  69         char buf[6];
  70         unsigned int x, y, res, pressed, to = 100;
  71         struct eeti_ts_priv *priv =
  72                 container_of(work, struct eeti_ts_priv, work);
  73
  74         mutex_lock(&priv->mutex);
  75
  76         while (eeti_ts_irq_active(priv) && --to)
  77                 i2c_master_recv(priv->client, buf, sizeof(buf));
  78
  79         if (!to) {
  80                 dev_err(&priv->client->dev,
  81                         "unable to clear IRQ - line stuck?\n");
  82                 goto out;
  83         }
  84
  85         /* drop non-report packets */
  86         if (!(buf[0] & 0x80))
  87                 goto out;
  88
  89         pressed = buf[0] & REPORT_BIT_PRESSED;
  90         res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
  91         x = buf[2] | (buf[1] << 8);
  92         y = buf[4] | (buf[3] << 8);
  93
  94         /* fix the range to 11 bits */
  95         x >>= res - EETI_TS_BITDEPTH;
  96         y >>= res - EETI_TS_BITDEPTH;
  97
  98         if (flip_x)
  99                 x = EETI_MAXVAL - x;
 100
 101         if (flip_y)
 102                 y = EETI_MAXVAL - y;
 103
 104         if (buf[0] & REPORT_BIT_HAS_PRESSURE)
 105                 input_report_abs(priv->input, ABS_PRESSURE, buf[5]);
 106
 107         input_report_abs(priv->input, ABS_X, x);
 108         input_report_abs(priv->input, ABS_Y, y);
 109         input_report_key(priv->input, BTN_TOUCH, !!pressed);
 110         input_sync(priv->input);
 111
 112 out:
 113         mutex_unlock(&priv->mutex);
 114 }
 115
 116 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
 117 {
 118         struct eeti_ts_priv *priv = dev_id;
 119
 120          /* postpone I2C transactions as we are atomic */
 121         schedule_work(&priv->work);
 122
 123         return IRQ_HANDLED;
 124 }
 125
 126 static int eeti_ts_open(struct input_dev *dev)
 127 {
 128         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 129
 130         enable_irq(priv->irq);
 131
 132         /* Read the events once to arm the IRQ */
 133         eeti_ts_read(&priv->work);
 134
 135         return 0;
 136 }
 137
 138 static void eeti_ts_close(struct input_dev *dev)
 139 {
 140         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 141
 142         disable_irq(priv->irq);
 143         cancel_work_sync(&priv->work);
 144 }
 145
 146 static int __devinit eeti_ts_probe(struct i2c_client *client,
 147                                    const struct i2c_device_id *idp)
 148 {
 149         struct eeti_ts_platform_data *pdata;
 150         struct eeti_ts_priv *priv;
 151         struct input_dev *input;
 152         unsigned int irq_flags;
 153         int err = -ENOMEM;
 154
 155         /* In contrast to what's described in the datasheet, there seems
 156          * to be no way of probing the presence of that device using I2C
 157          * commands. So we need to blindly believe it is there, and wait
 158          * for interrupts to occur. */
 159
 160         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 161         if (!priv) {
 162                 dev_err(&client->dev, "failed to allocate driver data\n");
 163                 goto err0;
 164         }
 165
 166         mutex_init(&priv->mutex);
 167         input = input_allocate_device();
 168
 169         if (!input) {
 170                 dev_err(&client->dev, "Failed to allocate input device.\n");
 171                 goto err1;
 172         }
 173
 174         input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 175         input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(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->dev.parent = &client->dev;
 184         input->open = eeti_ts_open;
 185         input->close = eeti_ts_close;
 186
 187         priv->client = client;
 188         priv->input = input;
 189         priv->irq = client->irq;
 190
 191         pdata = client->dev.platform_data;
 192
 193         if (pdata)
 194                 priv->irq_active_high = pdata->irq_active_high;
 195
 196         irq_flags = priv->irq_active_high ?
 197                 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
 198
 199         INIT_WORK(&priv->work, eeti_ts_read);
 200         i2c_set_clientdata(client, priv);
 201         input_set_drvdata(input, priv);
 202
 203         err = input_register_device(input);
 204         if (err)
 205                 goto err1;
 206
 207         err = request_irq(priv->irq, eeti_ts_isr, irq_flags,
 208                           client->name, priv);
 209         if (err) {
 210                 dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
 211                 goto err2;
 212         }
 213
 214         /* Disable the irq for now. It will be enabled once the input device
 215          * is opened. */
 216         disable_irq(priv->irq);
 217
 218         device_init_wakeup(&client->dev, 0);
 219         return 0;
 220
 221 err2:
 222         input_unregister_device(input);
 223         input = NULL; /* so we dont try to free it below */
 224 err1:
 225         input_free_device(input);
 226         i2c_set_clientdata(client, NULL);
 227         kfree(priv);
 228 err0:
 229         return err;
 230 }
 231
 232 static int __devexit eeti_ts_remove(struct i2c_client *client)
 233 {
 234         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 235
 236         free_irq(priv->irq, priv);
 237         input_unregister_device(priv->input);
 238         i2c_set_clientdata(client, NULL);
 239         kfree(priv);
 240
 241         return 0;
 242 }
 243
 244 #ifdef CONFIG_PM
 245 static int eeti_ts_suspend(struct i2c_client *client, pm_message_t mesg)
 246 {
 247         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 248
 249         if (device_may_wakeup(&client->dev))
 250                 enable_irq_wake(priv->irq);
 251
 252         return 0;
 253 }
 254
 255 static int eeti_ts_resume(struct i2c_client *client)
 256 {
 257         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 258
 259         if (device_may_wakeup(&client->dev))
 260                 disable_irq_wake(priv->irq);
 261
 262         return 0;
 263 }
 264 #else
 265 #define eeti_ts_suspend NULL
 266 #define eeti_ts_resume NULL
 267 #endif
 268
 269 static const struct i2c_device_id eeti_ts_id[] = {
 270         { "eeti_ts", 0 },
 271         { }
 272 };
 273 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
 274
 275 static struct i2c_driver eeti_ts_driver = {
 276         .driver = {
 277                 .name = "eeti_ts",
 278         },
 279         .probe = eeti_ts_probe,
 280         .remove = __devexit_p(eeti_ts_remove),
 281         .suspend = eeti_ts_suspend,
 282         .resume = eeti_ts_resume,
 283         .id_table = eeti_ts_id,
 284 };
 285
 286 static int __init eeti_ts_init(void)
 287 {
 288         return i2c_add_driver(&eeti_ts_driver);
 289 }
 290
 291 static void __exit eeti_ts_exit(void)
 292 {
 293         i2c_del_driver(&eeti_ts_driver);
 294 }
 295
 296 MODULE_DESCRIPTION("EETI Touchscreen driver");
 297 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 298 MODULE_LICENSE("GPL");
 299
 300 module_init(eeti_ts_init);
 301 module_exit(eeti_ts_exit);
 302