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 #include <asm/unaligned.h> 38 39 static bool flip_x; 40 module_param(flip_x, bool, 0644); 41 MODULE_PARM_DESC(flip_x, "flip x coordinate"); 42 43 static bool flip_y; 44 module_param(flip_y, bool, 0644); 45 MODULE_PARM_DESC(flip_y, "flip y coordinate"); 46 47 struct eeti_ts { 48 struct i2c_client *client; 49 struct input_dev *input; 50 struct work_struct work; 51 struct mutex mutex; 52 int irq_gpio, irq_active_high; 53 }; 54 55 #define EETI_TS_BITDEPTH (11) 56 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1) 57 58 #define REPORT_BIT_PRESSED BIT(0) 59 #define REPORT_BIT_AD0 BIT(1) 60 #define REPORT_BIT_AD1 BIT(2) 61 #define REPORT_BIT_HAS_PRESSURE BIT(6) 62 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH) 63 64 static inline int eeti_ts_irq_active(struct eeti_ts *eeti) 65 { 66 return gpio_get_value_cansleep(eeti->irq_gpio) == eeti->irq_active_high; 67 } 68 69 static void eeti_ts_read(struct work_struct *work) 70 { 71 char buf[6]; 72 unsigned int x, y, res, pressed, to = 100; 73 struct eeti_ts *eeti = 74 container_of(work, struct eeti_ts, work); 75 76 mutex_lock(&eeti->mutex); 77 78 while (eeti_ts_irq_active(eeti) && --to) 79 i2c_master_recv(eeti->client, buf, sizeof(buf)); 80 81 if (!to) { 82 dev_err(&eeti->client->dev, 83 "unable to clear IRQ - line stuck?\n"); 84 goto out; 85 } 86 87 /* drop non-report packets */ 88 if (!(buf[0] & 0x80)) 89 goto out; 90 91 pressed = buf[0] & REPORT_BIT_PRESSED; 92 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1)); 93 94 x = get_unaligned_be16(&buf[1]); 95 y = get_unaligned_be16(&buf[3]); 96 97 /* fix the range to 11 bits */ 98 x >>= res - EETI_TS_BITDEPTH; 99 y >>= res - EETI_TS_BITDEPTH; 100 101 if (flip_x) 102 x = EETI_MAXVAL - x; 103 104 if (flip_y) 105 y = EETI_MAXVAL - y; 106 107 if (buf[0] & REPORT_BIT_HAS_PRESSURE) 108 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]); 109 110 input_report_abs(eeti->input, ABS_X, x); 111 input_report_abs(eeti->input, ABS_Y, y); 112 input_report_key(eeti->input, BTN_TOUCH, !!pressed); 113 input_sync(eeti->input); 114 115 out: 116 mutex_unlock(&eeti->mutex); 117 } 118 119 static irqreturn_t eeti_ts_isr(int irq, void *dev_id) 120 { 121 struct eeti_ts *eeti = dev_id; 122 123 /* postpone I2C transactions as we are atomic */ 124 schedule_work(&eeti->work); 125 126 return IRQ_HANDLED; 127 } 128 129 static void eeti_ts_start(struct eeti_ts *eeti) 130 { 131 enable_irq(eeti->client->irq); 132 133 /* Read the events once to arm the IRQ */ 134 eeti_ts_read(&eeti->work); 135 } 136 137 static void eeti_ts_stop(struct eeti_ts *eeti) 138 { 139 disable_irq(eeti->client->irq); 140 cancel_work_sync(&eeti->work); 141 } 142 143 static int eeti_ts_open(struct input_dev *dev) 144 { 145 struct eeti_ts *eeti = input_get_drvdata(dev); 146 147 eeti_ts_start(eeti); 148 149 return 0; 150 } 151 152 static void eeti_ts_close(struct input_dev *dev) 153 { 154 struct eeti_ts *eeti = input_get_drvdata(dev); 155 156 eeti_ts_stop(eeti); 157 } 158 159 static int eeti_ts_probe(struct i2c_client *client, 160 const struct i2c_device_id *idp) 161 { 162 struct device *dev = &client->dev; 163 struct eeti_ts_platform_data *pdata = dev_get_platdata(dev); 164 struct eeti_ts *eeti; 165 struct input_dev *input; 166 unsigned int irq_flags; 167 int error; 168 169 /* 170 * In contrast to what's described in the datasheet, there seems 171 * to be no way of probing the presence of that device using I2C 172 * commands. So we need to blindly believe it is there, and wait 173 * for interrupts to occur. 174 */ 175 176 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL); 177 if (!eeti) { 178 dev_err(dev, "failed to allocate driver data\n"); 179 return -ENOMEM; 180 } 181 182 mutex_init(&eeti->mutex); 183 184 input = devm_input_allocate_device(dev); 185 if (!input) { 186 dev_err(dev, "Failed to allocate input device.\n"); 187 return -ENOMEM; 188 } 189 190 input_set_capability(input, EV_KEY, BTN_TOUCH); 191 192 input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0); 193 input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0); 194 input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0); 195 196 input->name = client->name; 197 input->id.bustype = BUS_I2C; 198 input->open = eeti_ts_open; 199 input->close = eeti_ts_close; 200 201 eeti->client = client; 202 eeti->input = input; 203 eeti->irq_gpio = pdata->irq_gpio; 204 205 error = devm_gpio_request_one(dev, pdata->irq_gpio, GPIOF_IN, 206 client->name); 207 if (error) 208 return error; 209 210 eeti->irq_active_high = pdata->irq_active_high; 211 212 irq_flags = eeti->irq_active_high ? 213 IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING; 214 215 INIT_WORK(&eeti->work, eeti_ts_read); 216 i2c_set_clientdata(client, eeti); 217 input_set_drvdata(input, eeti); 218 219 error = input_register_device(input); 220 if (error) 221 return error; 222 223 error = devm_request_irq(dev, client->irq, eeti_ts_isr, irq_flags, 224 client->name, eeti); 225 if (error) { 226 dev_err(dev, "Unable to request touchscreen IRQ: %d\n", 227 error); 228 return error; 229 } 230 231 /* 232 * Disable the device for now. It will be enabled once the 233 * input device is opened. 234 */ 235 eeti_ts_stop(eeti); 236 237 return 0; 238 } 239 240 static int __maybe_unused eeti_ts_suspend(struct device *dev) 241 { 242 struct i2c_client *client = to_i2c_client(dev); 243 struct eeti_ts *eeti = i2c_get_clientdata(client); 244 struct input_dev *input_dev = eeti->input; 245 246 mutex_lock(&input_dev->mutex); 247 248 if (input_dev->users) 249 eeti_ts_stop(eeti); 250 251 mutex_unlock(&input_dev->mutex); 252 253 if (device_may_wakeup(&client->dev)) 254 enable_irq_wake(client->irq); 255 256 return 0; 257 } 258 259 static int __maybe_unused eeti_ts_resume(struct device *dev) 260 { 261 struct i2c_client *client = to_i2c_client(dev); 262 struct eeti_ts *eeti = i2c_get_clientdata(client); 263 struct input_dev *input_dev = eeti->input; 264 265 if (device_may_wakeup(&client->dev)) 266 disable_irq_wake(client->irq); 267 268 mutex_lock(&input_dev->mutex); 269 270 if (input_dev->users) 271 eeti_ts_start(eeti); 272 273 mutex_unlock(&input_dev->mutex); 274 275 return 0; 276 } 277 278 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume); 279 280 static const struct i2c_device_id eeti_ts_id[] = { 281 { "eeti_ts", 0 }, 282 { } 283 }; 284 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 285 286 static struct i2c_driver eeti_ts_driver = { 287 .driver = { 288 .name = "eeti_ts", 289 .pm = &eeti_ts_pm, 290 }, 291 .probe = eeti_ts_probe, 292 .id_table = eeti_ts_id, 293 }; 294 295 module_i2c_driver(eeti_ts_driver); 296 297 MODULE_DESCRIPTION("EETI Touchscreen driver"); 298 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); 299 MODULE_LICENSE("GPL"); 300