1 /* 2 * Touch Screen driver for EETI's I2C connected touch screen panels 3 * Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org> 4 * 5 * See EETI's software guide for the protocol specification: 6 * http://home.eeti.com.tw/documentation.html 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/kernel.h> 29 #include <linux/input.h> 30 #include <linux/input/touchscreen.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/of.h> 36 #include <linux/slab.h> 37 #include <asm/unaligned.h> 38 39 struct eeti_ts { 40 struct i2c_client *client; 41 struct input_dev *input; 42 struct gpio_desc *attn_gpio; 43 struct touchscreen_properties props; 44 struct mutex mutex; 45 bool running; 46 }; 47 48 #define EETI_TS_BITDEPTH (11) 49 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1) 50 51 #define REPORT_BIT_PRESSED BIT(0) 52 #define REPORT_BIT_AD0 BIT(1) 53 #define REPORT_BIT_AD1 BIT(2) 54 #define REPORT_BIT_HAS_PRESSURE BIT(6) 55 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH) 56 57 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf) 58 { 59 unsigned int res; 60 u16 x, y; 61 62 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1)); 63 64 x = get_unaligned_be16(&buf[1]); 65 y = get_unaligned_be16(&buf[3]); 66 67 /* fix the range to 11 bits */ 68 x >>= res - EETI_TS_BITDEPTH; 69 y >>= res - EETI_TS_BITDEPTH; 70 71 if (buf[0] & REPORT_BIT_HAS_PRESSURE) 72 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]); 73 74 touchscreen_report_pos(eeti->input, &eeti->props, x, y, false); 75 input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED); 76 input_sync(eeti->input); 77 } 78 79 static int eeti_ts_read(struct eeti_ts *eeti) 80 { 81 int len, error; 82 char buf[6]; 83 84 len = i2c_master_recv(eeti->client, buf, sizeof(buf)); 85 if (len != sizeof(buf)) { 86 error = len < 0 ? len : -EIO; 87 dev_err(&eeti->client->dev, 88 "failed to read touchscreen data: %d\n", 89 error); 90 return error; 91 } 92 93 /* Motion packet */ 94 if (buf[0] & 0x80) 95 eeti_ts_report_event(eeti, buf); 96 97 return 0; 98 } 99 100 static irqreturn_t eeti_ts_isr(int irq, void *dev_id) 101 { 102 struct eeti_ts *eeti = dev_id; 103 int error; 104 105 mutex_lock(&eeti->mutex); 106 107 do { 108 /* 109 * If we have attention GPIO, trust it. Otherwise we'll read 110 * once and exit. We assume that in this case we are using 111 * level triggered interrupt and it will get raised again 112 * if/when there is more data. 113 */ 114 if (eeti->attn_gpio && 115 !gpiod_get_value_cansleep(eeti->attn_gpio)) { 116 break; 117 } 118 119 error = eeti_ts_read(eeti); 120 if (error) 121 break; 122 123 } while (eeti->running && eeti->attn_gpio); 124 125 mutex_unlock(&eeti->mutex); 126 return IRQ_HANDLED; 127 } 128 129 static void eeti_ts_start(struct eeti_ts *eeti) 130 { 131 mutex_lock(&eeti->mutex); 132 133 eeti->running = true; 134 enable_irq(eeti->client->irq); 135 136 /* 137 * Kick the controller in case we are using edge interrupt and 138 * we missed our edge while interrupt was disabled. We expect 139 * the attention GPIO to be wired in this case. 140 */ 141 if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio)) 142 eeti_ts_read(eeti); 143 144 mutex_unlock(&eeti->mutex); 145 } 146 147 static void eeti_ts_stop(struct eeti_ts *eeti) 148 { 149 /* 150 * Not locking here, just setting a flag and expect that the 151 * interrupt thread will notice the flag eventually. 152 */ 153 eeti->running = false; 154 wmb(); 155 disable_irq(eeti->client->irq); 156 } 157 158 static int eeti_ts_open(struct input_dev *dev) 159 { 160 struct eeti_ts *eeti = input_get_drvdata(dev); 161 162 eeti_ts_start(eeti); 163 164 return 0; 165 } 166 167 static void eeti_ts_close(struct input_dev *dev) 168 { 169 struct eeti_ts *eeti = input_get_drvdata(dev); 170 171 eeti_ts_stop(eeti); 172 } 173 174 static int eeti_ts_probe(struct i2c_client *client, 175 const struct i2c_device_id *idp) 176 { 177 struct device *dev = &client->dev; 178 struct eeti_ts *eeti; 179 struct input_dev *input; 180 int error; 181 182 /* 183 * In contrast to what's described in the datasheet, there seems 184 * to be no way of probing the presence of that device using I2C 185 * commands. So we need to blindly believe it is there, and wait 186 * for interrupts to occur. 187 */ 188 189 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL); 190 if (!eeti) { 191 dev_err(dev, "failed to allocate driver data\n"); 192 return -ENOMEM; 193 } 194 195 mutex_init(&eeti->mutex); 196 197 input = devm_input_allocate_device(dev); 198 if (!input) { 199 dev_err(dev, "Failed to allocate input device.\n"); 200 return -ENOMEM; 201 } 202 203 input_set_capability(input, EV_KEY, BTN_TOUCH); 204 205 input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0); 206 input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0); 207 input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0); 208 209 touchscreen_parse_properties(input, false, &eeti->props); 210 211 input->name = client->name; 212 input->id.bustype = BUS_I2C; 213 input->open = eeti_ts_open; 214 input->close = eeti_ts_close; 215 216 eeti->client = client; 217 eeti->input = input; 218 219 eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN); 220 if (IS_ERR(eeti->attn_gpio)) 221 return PTR_ERR(eeti->attn_gpio); 222 223 i2c_set_clientdata(client, eeti); 224 input_set_drvdata(input, eeti); 225 226 error = devm_request_threaded_irq(dev, client->irq, 227 NULL, eeti_ts_isr, 228 IRQF_ONESHOT, 229 client->name, eeti); 230 if (error) { 231 dev_err(dev, "Unable to request touchscreen IRQ: %d\n", 232 error); 233 return error; 234 } 235 236 /* 237 * Disable the device for now. It will be enabled once the 238 * input device is opened. 239 */ 240 eeti_ts_stop(eeti); 241 242 error = input_register_device(input); 243 if (error) 244 return error; 245 246 return 0; 247 } 248 249 static int __maybe_unused eeti_ts_suspend(struct device *dev) 250 { 251 struct i2c_client *client = to_i2c_client(dev); 252 struct eeti_ts *eeti = i2c_get_clientdata(client); 253 struct input_dev *input_dev = eeti->input; 254 255 mutex_lock(&input_dev->mutex); 256 257 if (input_dev->users) 258 eeti_ts_stop(eeti); 259 260 mutex_unlock(&input_dev->mutex); 261 262 if (device_may_wakeup(&client->dev)) 263 enable_irq_wake(client->irq); 264 265 return 0; 266 } 267 268 static int __maybe_unused eeti_ts_resume(struct device *dev) 269 { 270 struct i2c_client *client = to_i2c_client(dev); 271 struct eeti_ts *eeti = i2c_get_clientdata(client); 272 struct input_dev *input_dev = eeti->input; 273 274 if (device_may_wakeup(&client->dev)) 275 disable_irq_wake(client->irq); 276 277 mutex_lock(&input_dev->mutex); 278 279 if (input_dev->users) 280 eeti_ts_start(eeti); 281 282 mutex_unlock(&input_dev->mutex); 283 284 return 0; 285 } 286 287 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume); 288 289 static const struct i2c_device_id eeti_ts_id[] = { 290 { "eeti_ts", 0 }, 291 { } 292 }; 293 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 294 295 #ifdef CONFIG_OF 296 static const struct of_device_id of_eeti_ts_match[] = { 297 { .compatible = "eeti,exc3000-i2c", }, 298 { } 299 }; 300 #endif 301 302 static struct i2c_driver eeti_ts_driver = { 303 .driver = { 304 .name = "eeti_ts", 305 .pm = &eeti_ts_pm, 306 .of_match_table = of_match_ptr(of_eeti_ts_match), 307 }, 308 .probe = eeti_ts_probe, 309 .id_table = eeti_ts_id, 310 }; 311 312 module_i2c_driver(eeti_ts_driver); 313 314 MODULE_DESCRIPTION("EETI Touchscreen driver"); 315 MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>"); 316 MODULE_LICENSE("GPL"); 317