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/consumer.h> 35 #include <linux/slab.h> 36 #include <asm/unaligned.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 { 47 struct i2c_client *client; 48 struct input_dev *input; 49 struct gpio_desc *attn_gpio; 50 bool running; 51 }; 52 53 #define EETI_TS_BITDEPTH (11) 54 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1) 55 56 #define REPORT_BIT_PRESSED BIT(0) 57 #define REPORT_BIT_AD0 BIT(1) 58 #define REPORT_BIT_AD1 BIT(2) 59 #define REPORT_BIT_HAS_PRESSURE BIT(6) 60 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH) 61 62 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf) 63 { 64 unsigned int res; 65 u16 x, y; 66 67 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1)); 68 69 x = get_unaligned_be16(&buf[1]); 70 y = get_unaligned_be16(&buf[3]); 71 72 /* fix the range to 11 bits */ 73 x >>= res - EETI_TS_BITDEPTH; 74 y >>= res - EETI_TS_BITDEPTH; 75 76 if (flip_x) 77 x = EETI_MAXVAL - x; 78 79 if (flip_y) 80 y = EETI_MAXVAL - y; 81 82 if (buf[0] & REPORT_BIT_HAS_PRESSURE) 83 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]); 84 85 input_report_abs(eeti->input, ABS_X, x); 86 input_report_abs(eeti->input, ABS_Y, y); 87 input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED); 88 input_sync(eeti->input); 89 } 90 91 static irqreturn_t eeti_ts_isr(int irq, void *dev_id) 92 { 93 struct eeti_ts *eeti = dev_id; 94 int len; 95 int error; 96 char buf[6]; 97 98 do { 99 len = i2c_master_recv(eeti->client, buf, sizeof(buf)); 100 if (len != sizeof(buf)) { 101 error = len < 0 ? len : -EIO; 102 dev_err(&eeti->client->dev, 103 "failed to read touchscreen data: %d\n", 104 error); 105 break; 106 } 107 108 if (buf[0] & 0x80) { 109 /* Motion packet */ 110 eeti_ts_report_event(eeti, buf); 111 } 112 } while (eeti->running && 113 eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio)); 114 115 return IRQ_HANDLED; 116 } 117 118 static void eeti_ts_start(struct eeti_ts *eeti) 119 { 120 eeti->running = true; 121 wmb(); 122 enable_irq(eeti->client->irq); 123 } 124 125 static void eeti_ts_stop(struct eeti_ts *eeti) 126 { 127 eeti->running = false; 128 wmb(); 129 disable_irq(eeti->client->irq); 130 } 131 132 static int eeti_ts_open(struct input_dev *dev) 133 { 134 struct eeti_ts *eeti = input_get_drvdata(dev); 135 136 eeti_ts_start(eeti); 137 138 return 0; 139 } 140 141 static void eeti_ts_close(struct input_dev *dev) 142 { 143 struct eeti_ts *eeti = input_get_drvdata(dev); 144 145 eeti_ts_stop(eeti); 146 } 147 148 static int eeti_ts_probe(struct i2c_client *client, 149 const struct i2c_device_id *idp) 150 { 151 struct device *dev = &client->dev; 152 struct eeti_ts *eeti; 153 struct input_dev *input; 154 int error; 155 156 /* 157 * In contrast to what's described in the datasheet, there seems 158 * to be no way of probing the presence of that device using I2C 159 * commands. So we need to blindly believe it is there, and wait 160 * for interrupts to occur. 161 */ 162 163 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL); 164 if (!eeti) { 165 dev_err(dev, "failed to allocate driver data\n"); 166 return -ENOMEM; 167 } 168 169 input = devm_input_allocate_device(dev); 170 if (!input) { 171 dev_err(dev, "Failed to allocate input device.\n"); 172 return -ENOMEM; 173 } 174 175 input_set_capability(input, EV_KEY, 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->open = eeti_ts_open; 184 input->close = eeti_ts_close; 185 186 eeti->client = client; 187 eeti->input = input; 188 189 eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN); 190 if (IS_ERR(eeti->attn_gpio)) 191 return PTR_ERR(eeti->attn_gpio); 192 193 i2c_set_clientdata(client, eeti); 194 input_set_drvdata(input, eeti); 195 196 error = devm_request_threaded_irq(dev, client->irq, 197 NULL, eeti_ts_isr, 198 IRQF_ONESHOT, 199 client->name, eeti); 200 if (error) { 201 dev_err(dev, "Unable to request touchscreen IRQ: %d\n", 202 error); 203 return error; 204 } 205 206 /* 207 * Disable the device for now. It will be enabled once the 208 * input device is opened. 209 */ 210 eeti_ts_stop(eeti); 211 212 error = input_register_device(input); 213 if (error) 214 return error; 215 216 return 0; 217 } 218 219 static int __maybe_unused eeti_ts_suspend(struct device *dev) 220 { 221 struct i2c_client *client = to_i2c_client(dev); 222 struct eeti_ts *eeti = i2c_get_clientdata(client); 223 struct input_dev *input_dev = eeti->input; 224 225 mutex_lock(&input_dev->mutex); 226 227 if (input_dev->users) 228 eeti_ts_stop(eeti); 229 230 mutex_unlock(&input_dev->mutex); 231 232 if (device_may_wakeup(&client->dev)) 233 enable_irq_wake(client->irq); 234 235 return 0; 236 } 237 238 static int __maybe_unused eeti_ts_resume(struct device *dev) 239 { 240 struct i2c_client *client = to_i2c_client(dev); 241 struct eeti_ts *eeti = i2c_get_clientdata(client); 242 struct input_dev *input_dev = eeti->input; 243 244 if (device_may_wakeup(&client->dev)) 245 disable_irq_wake(client->irq); 246 247 mutex_lock(&input_dev->mutex); 248 249 if (input_dev->users) 250 eeti_ts_start(eeti); 251 252 mutex_unlock(&input_dev->mutex); 253 254 return 0; 255 } 256 257 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume); 258 259 static const struct i2c_device_id eeti_ts_id[] = { 260 { "eeti_ts", 0 }, 261 { } 262 }; 263 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 264 265 static struct i2c_driver eeti_ts_driver = { 266 .driver = { 267 .name = "eeti_ts", 268 .pm = &eeti_ts_pm, 269 }, 270 .probe = eeti_ts_probe, 271 .id_table = eeti_ts_id, 272 }; 273 274 module_i2c_driver(eeti_ts_driver); 275 276 MODULE_DESCRIPTION("EETI Touchscreen driver"); 277 MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>"); 278 MODULE_LICENSE("GPL"); 279