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 #include <linux/slab.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_priv {
  47         struct i2c_client *client;
  48         struct input_dev *input;
  49         struct work_struct work;
  50         struct mutex mutex;
  51         int irq_gpio, irq, irq_active_high;
  52 };
  53
  54 #define EETI_TS_BITDEPTH        (11)
  55 #define EETI_MAXVAL             ((1 << (EETI_TS_BITDEPTH + 1)) - 1)
  56
  57 #define REPORT_BIT_PRESSED      (1 << 0)
  58 #define REPORT_BIT_AD0          (1 << 1)
  59 #define REPORT_BIT_AD1          (1 << 2)
  60 #define REPORT_BIT_HAS_PRESSURE (1 << 6)
  61 #define REPORT_RES_BITS(v)      (((v) >> 1) + EETI_TS_BITDEPTH)
  62
  63 static inline int eeti_ts_irq_active(struct eeti_ts_priv *priv)
  64 {
  65         return gpio_get_value(priv->irq_gpio) == priv->irq_active_high;
  66 }
  67
  68 static void eeti_ts_read(struct work_struct *work)
  69 {
  70         char buf[6];
  71         unsigned int x, y, res, pressed, to = 100;
  72         struct eeti_ts_priv *priv =
  73                 container_of(work, struct eeti_ts_priv, work);
  74
  75         mutex_lock(&priv->mutex);
  76
  77         while (eeti_ts_irq_active(priv) && --to)
  78                 i2c_master_recv(priv->client, buf, sizeof(buf));
  79
  80         if (!to) {
  81                 dev_err(&priv->client->dev,
  82                         "unable to clear IRQ - line stuck?\n");
  83                 goto out;
  84         }
  85
  86         /* drop non-report packets */
  87         if (!(buf[0] & 0x80))
  88                 goto out;
  89
  90         pressed = buf[0] & REPORT_BIT_PRESSED;
  91         res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
  92         x = buf[2] | (buf[1] << 8);
  93         y = buf[4] | (buf[3] << 8);
  94
  95         /* fix the range to 11 bits */
  96         x >>= res - EETI_TS_BITDEPTH;
  97         y >>= res - EETI_TS_BITDEPTH;
  98
  99         if (flip_x)
 100                 x = EETI_MAXVAL - x;
 101
 102         if (flip_y)
 103                 y = EETI_MAXVAL - y;
 104
 105         if (buf[0] & REPORT_BIT_HAS_PRESSURE)
 106                 input_report_abs(priv->input, ABS_PRESSURE, buf[5]);
 107
 108         input_report_abs(priv->input, ABS_X, x);
 109         input_report_abs(priv->input, ABS_Y, y);
 110         input_report_key(priv->input, BTN_TOUCH, !!pressed);
 111         input_sync(priv->input);
 112
 113 out:
 114         mutex_unlock(&priv->mutex);
 115 }
 116
 117 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
 118 {
 119         struct eeti_ts_priv *priv = dev_id;
 120
 121          /* postpone I2C transactions as we are atomic */
 122         schedule_work(&priv->work);
 123
 124         return IRQ_HANDLED;
 125 }
 126
 127 static void eeti_ts_start(struct eeti_ts_priv *priv)
 128 {
 129         enable_irq(priv->irq);
 130
 131         /* Read the events once to arm the IRQ */
 132         eeti_ts_read(&priv->work);
 133 }
 134
 135 static void eeti_ts_stop(struct eeti_ts_priv *priv)
 136 {
 137         disable_irq(priv->irq);
 138         cancel_work_sync(&priv->work);
 139 }
 140
 141 static int eeti_ts_open(struct input_dev *dev)
 142 {
 143         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 144
 145         eeti_ts_start(priv);
 146
 147         return 0;
 148 }
 149
 150 static void eeti_ts_close(struct input_dev *dev)
 151 {
 152         struct eeti_ts_priv *priv = input_get_drvdata(dev);
 153
 154         eeti_ts_stop(priv);
 155 }
 156
 157 static int eeti_ts_probe(struct i2c_client *client,
 158                                    const struct i2c_device_id *idp)
 159 {
 160         struct eeti_ts_platform_data *pdata = dev_get_platdata(&client->dev);
 161         struct eeti_ts_priv *priv;
 162         struct input_dev *input;
 163         unsigned int irq_flags;
 164         int err = -ENOMEM;
 165
 166         /*
 167          * In contrast to what's described in the datasheet, there seems
 168          * to be no way of probing the presence of that device using I2C
 169          * commands. So we need to blindly believe it is there, and wait
 170          * for interrupts to occur.
 171          */
 172
 173         priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 174         if (!priv) {
 175                 dev_err(&client->dev, "failed to allocate driver data\n");
 176                 return -ENOMEM;
 177         }
 178
 179         mutex_init(&priv->mutex);
 180         input = input_allocate_device();
 181         if (!input) {
 182                 dev_err(&client->dev, "Failed to allocate input device.\n");
 183                 goto err1;
 184         }
 185
 186         input->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
 187         input->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
 188
 189         input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0);
 190         input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0);
 191         input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0);
 192
 193         input->name = client->name;
 194         input->id.bustype = BUS_I2C;
 195         input->dev.parent = &client->dev;
 196         input->open = eeti_ts_open;
 197         input->close = eeti_ts_close;
 198
 199         priv->client = client;
 200         priv->input = input;
 201         priv->irq_gpio = pdata->irq_gpio;
 202         priv->irq = gpio_to_irq(pdata->irq_gpio);
 203
 204         err = gpio_request_one(pdata->irq_gpio, GPIOF_IN, client->name);
 205         if (err < 0)
 206                 goto err1;
 207
 208         priv->irq_active_high = pdata->irq_active_high;
 209
 210         irq_flags = priv->irq_active_high ?
 211                 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
 212
 213         INIT_WORK(&priv->work, eeti_ts_read);
 214         i2c_set_clientdata(client, priv);
 215         input_set_drvdata(input, priv);
 216
 217         err = input_register_device(input);
 218         if (err)
 219                 goto err2;
 220
 221         err = request_irq(priv->irq, eeti_ts_isr, irq_flags,
 222                           client->name, priv);
 223         if (err) {
 224                 dev_err(&client->dev, "Unable to request touchscreen IRQ.\n");
 225                 goto err3;
 226         }
 227
 228         /*
 229          * Disable the device for now. It will be enabled once the
 230          * input device is opened.
 231          */
 232         eeti_ts_stop(priv);
 233
 234         return 0;
 235
 236 err3:
 237         input_unregister_device(input);
 238         input = NULL; /* so we dont try to free it below */
 239 err2:
 240         gpio_free(pdata->irq_gpio);
 241 err1:
 242         input_free_device(input);
 243         kfree(priv);
 244         return err;
 245 }
 246
 247 static int eeti_ts_remove(struct i2c_client *client)
 248 {
 249         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 250
 251         free_irq(priv->irq, priv);
 252         /*
 253          * eeti_ts_stop() leaves IRQ disabled. We need to re-enable it
 254          * so that device still works if we reload the driver.
 255          */
 256         enable_irq(priv->irq);
 257
 258         input_unregister_device(priv->input);
 259         kfree(priv);
 260
 261         return 0;
 262 }
 263
 264 static int __maybe_unused eeti_ts_suspend(struct device *dev)
 265 {
 266         struct i2c_client *client = to_i2c_client(dev);
 267         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 268         struct input_dev *input_dev = priv->input;
 269
 270         mutex_lock(&input_dev->mutex);
 271
 272         if (input_dev->users)
 273                 eeti_ts_stop(priv);
 274
 275         mutex_unlock(&input_dev->mutex);
 276
 277         if (device_may_wakeup(&client->dev))
 278                 enable_irq_wake(priv->irq);
 279
 280         return 0;
 281 }
 282
 283 static int __maybe_unused eeti_ts_resume(struct device *dev)
 284 {
 285         struct i2c_client *client = to_i2c_client(dev);
 286         struct eeti_ts_priv *priv = i2c_get_clientdata(client);
 287         struct input_dev *input_dev = priv->input;
 288
 289         if (device_may_wakeup(&client->dev))
 290                 disable_irq_wake(priv->irq);
 291
 292         mutex_lock(&input_dev->mutex);
 293
 294         if (input_dev->users)
 295                 eeti_ts_start(priv);
 296
 297         mutex_unlock(&input_dev->mutex);
 298
 299         return 0;
 300 }
 301
 302 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume);
 303
 304 static const struct i2c_device_id eeti_ts_id[] = {
 305         { "eeti_ts", 0 },
 306         { }
 307 };
 308 MODULE_DEVICE_TABLE(i2c, eeti_ts_id);
 309
 310 static struct i2c_driver eeti_ts_driver = {
 311         .driver = {
 312                 .name = "eeti_ts",
 313                 .pm = &eeti_ts_pm,
 314         },
 315         .probe = eeti_ts_probe,
 316         .remove = eeti_ts_remove,
 317         .id_table = eeti_ts_id,
 318 };
 319
 320 module_i2c_driver(eeti_ts_driver);
 321
 322 MODULE_DESCRIPTION("EETI Touchscreen driver");
 323 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
 324 MODULE_LICENSE("GPL");