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 void eeti_ts_start(struct eeti_ts_priv *priv) 127 { 128 enable_irq(priv->irq); 129 130 /* Read the events once to arm the IRQ */ 131 eeti_ts_read(&priv->work); 132 } 133 134 static void eeti_ts_stop(struct eeti_ts_priv *priv) 135 { 136 disable_irq(priv->irq); 137 cancel_work_sync(&priv->work); 138 } 139 140 static int eeti_ts_open(struct input_dev *dev) 141 { 142 struct eeti_ts_priv *priv = input_get_drvdata(dev); 143 144 eeti_ts_start(priv); 145 146 return 0; 147 } 148 149 static void eeti_ts_close(struct input_dev *dev) 150 { 151 struct eeti_ts_priv *priv = input_get_drvdata(dev); 152 153 eeti_ts_stop(priv); 154 } 155 156 static int __devinit eeti_ts_probe(struct i2c_client *client, 157 const struct i2c_device_id *idp) 158 { 159 struct eeti_ts_platform_data *pdata; 160 struct eeti_ts_priv *priv; 161 struct input_dev *input; 162 unsigned int irq_flags; 163 int err = -ENOMEM; 164 165 /* 166 * In contrast to what's described in the datasheet, there seems 167 * to be no way of probing the presence of that device using I2C 168 * commands. So we need to blindly believe it is there, and wait 169 * for interrupts to occur. 170 */ 171 172 priv = kzalloc(sizeof(*priv), GFP_KERNEL); 173 if (!priv) { 174 dev_err(&client->dev, "failed to allocate driver data\n"); 175 goto err0; 176 } 177 178 mutex_init(&priv->mutex); 179 input = input_allocate_device(); 180 181 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 = client->irq; 202 203 pdata = client->dev.platform_data; 204 205 if (pdata) 206 priv->irq_active_high = pdata->irq_active_high; 207 208 irq_flags = priv->irq_active_high ? 209 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 210 211 INIT_WORK(&priv->work, eeti_ts_read); 212 i2c_set_clientdata(client, priv); 213 input_set_drvdata(input, priv); 214 215 err = input_register_device(input); 216 if (err) 217 goto err1; 218 219 err = request_irq(priv->irq, eeti_ts_isr, irq_flags, 220 client->name, priv); 221 if (err) { 222 dev_err(&client->dev, "Unable to request touchscreen IRQ.\n"); 223 goto err2; 224 } 225 226 /* 227 * Disable the device for now. It will be enabled once the 228 * input device is opened. 229 */ 230 eeti_ts_stop(priv); 231 232 device_init_wakeup(&client->dev, 0); 233 return 0; 234 235 err2: 236 input_unregister_device(input); 237 input = NULL; /* so we dont try to free it below */ 238 err1: 239 input_free_device(input); 240 i2c_set_clientdata(client, NULL); 241 kfree(priv); 242 err0: 243 return err; 244 } 245 246 static int __devexit eeti_ts_remove(struct i2c_client *client) 247 { 248 struct eeti_ts_priv *priv = i2c_get_clientdata(client); 249 250 free_irq(priv->irq, priv); 251 /* 252 * eeti_ts_stop() leaves IRQ disabled. We need to re-enable it 253 * so that device still works if we reload the driver. 254 */ 255 enable_irq(priv->irq); 256 257 input_unregister_device(priv->input); 258 i2c_set_clientdata(client, NULL); 259 kfree(priv); 260 261 return 0; 262 } 263 264 #ifdef CONFIG_PM 265 static int eeti_ts_suspend(struct i2c_client *client, pm_message_t mesg) 266 { 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 eeti_ts_resume(struct i2c_client *client) 284 { 285 struct eeti_ts_priv *priv = i2c_get_clientdata(client); 286 struct input_dev *input_dev = priv->input; 287 288 if (device_may_wakeup(&client->dev)) 289 disable_irq_wake(priv->irq); 290 291 mutex_lock(&input_dev->mutex); 292 293 if (input_dev->users) 294 eeti_ts_start(priv); 295 296 mutex_unlock(&input_dev->mutex); 297 298 return 0; 299 } 300 #else 301 #define eeti_ts_suspend NULL 302 #define eeti_ts_resume NULL 303 #endif 304 305 static const struct i2c_device_id eeti_ts_id[] = { 306 { "eeti_ts", 0 }, 307 { } 308 }; 309 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 310 311 static struct i2c_driver eeti_ts_driver = { 312 .driver = { 313 .name = "eeti_ts", 314 }, 315 .probe = eeti_ts_probe, 316 .remove = __devexit_p(eeti_ts_remove), 317 .suspend = eeti_ts_suspend, 318 .resume = eeti_ts_resume, 319 .id_table = eeti_ts_id, 320 }; 321 322 static int __init eeti_ts_init(void) 323 { 324 return i2c_add_driver(&eeti_ts_driver); 325 } 326 327 static void __exit eeti_ts_exit(void) 328 { 329 i2c_del_driver(&eeti_ts_driver); 330 } 331 332 MODULE_DESCRIPTION("EETI Touchscreen driver"); 333 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); 334 MODULE_LICENSE("GPL"); 335 336 module_init(eeti_ts_init); 337 module_exit(eeti_ts_exit); 338 339