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 bool running; 45 }; 46 47 #define EETI_TS_BITDEPTH (11) 48 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1) 49 50 #define REPORT_BIT_PRESSED BIT(0) 51 #define REPORT_BIT_AD0 BIT(1) 52 #define REPORT_BIT_AD1 BIT(2) 53 #define REPORT_BIT_HAS_PRESSURE BIT(6) 54 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH) 55 56 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf) 57 { 58 unsigned int res; 59 u16 x, y; 60 61 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1)); 62 63 x = get_unaligned_be16(&buf[1]); 64 y = get_unaligned_be16(&buf[3]); 65 66 /* fix the range to 11 bits */ 67 x >>= res - EETI_TS_BITDEPTH; 68 y >>= res - EETI_TS_BITDEPTH; 69 70 if (buf[0] & REPORT_BIT_HAS_PRESSURE) 71 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]); 72 73 touchscreen_report_pos(eeti->input, &eeti->props, x, y, false); 74 input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED); 75 input_sync(eeti->input); 76 } 77 78 static irqreturn_t eeti_ts_isr(int irq, void *dev_id) 79 { 80 struct eeti_ts *eeti = dev_id; 81 int len; 82 int error; 83 char buf[6]; 84 85 do { 86 len = i2c_master_recv(eeti->client, buf, sizeof(buf)); 87 if (len != sizeof(buf)) { 88 error = len < 0 ? len : -EIO; 89 dev_err(&eeti->client->dev, 90 "failed to read touchscreen data: %d\n", 91 error); 92 break; 93 } 94 95 if (buf[0] & 0x80) { 96 /* Motion packet */ 97 eeti_ts_report_event(eeti, buf); 98 } 99 } while (eeti->running && 100 eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio)); 101 102 return IRQ_HANDLED; 103 } 104 105 static void eeti_ts_start(struct eeti_ts *eeti) 106 { 107 eeti->running = true; 108 wmb(); 109 enable_irq(eeti->client->irq); 110 } 111 112 static void eeti_ts_stop(struct eeti_ts *eeti) 113 { 114 eeti->running = false; 115 wmb(); 116 disable_irq(eeti->client->irq); 117 } 118 119 static int eeti_ts_open(struct input_dev *dev) 120 { 121 struct eeti_ts *eeti = input_get_drvdata(dev); 122 123 eeti_ts_start(eeti); 124 125 return 0; 126 } 127 128 static void eeti_ts_close(struct input_dev *dev) 129 { 130 struct eeti_ts *eeti = input_get_drvdata(dev); 131 132 eeti_ts_stop(eeti); 133 } 134 135 static int eeti_ts_probe(struct i2c_client *client, 136 const struct i2c_device_id *idp) 137 { 138 struct device *dev = &client->dev; 139 struct eeti_ts *eeti; 140 struct input_dev *input; 141 int error; 142 143 /* 144 * In contrast to what's described in the datasheet, there seems 145 * to be no way of probing the presence of that device using I2C 146 * commands. So we need to blindly believe it is there, and wait 147 * for interrupts to occur. 148 */ 149 150 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL); 151 if (!eeti) { 152 dev_err(dev, "failed to allocate driver data\n"); 153 return -ENOMEM; 154 } 155 156 input = devm_input_allocate_device(dev); 157 if (!input) { 158 dev_err(dev, "Failed to allocate input device.\n"); 159 return -ENOMEM; 160 } 161 162 input_set_capability(input, EV_KEY, BTN_TOUCH); 163 164 input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0); 165 input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0); 166 input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0); 167 168 touchscreen_parse_properties(input, false, &eeti->props); 169 170 input->name = client->name; 171 input->id.bustype = BUS_I2C; 172 input->open = eeti_ts_open; 173 input->close = eeti_ts_close; 174 175 eeti->client = client; 176 eeti->input = input; 177 178 eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN); 179 if (IS_ERR(eeti->attn_gpio)) 180 return PTR_ERR(eeti->attn_gpio); 181 182 i2c_set_clientdata(client, eeti); 183 input_set_drvdata(input, eeti); 184 185 error = devm_request_threaded_irq(dev, client->irq, 186 NULL, eeti_ts_isr, 187 IRQF_ONESHOT, 188 client->name, eeti); 189 if (error) { 190 dev_err(dev, "Unable to request touchscreen IRQ: %d\n", 191 error); 192 return error; 193 } 194 195 /* 196 * Disable the device for now. It will be enabled once the 197 * input device is opened. 198 */ 199 eeti_ts_stop(eeti); 200 201 error = input_register_device(input); 202 if (error) 203 return error; 204 205 return 0; 206 } 207 208 static int __maybe_unused eeti_ts_suspend(struct device *dev) 209 { 210 struct i2c_client *client = to_i2c_client(dev); 211 struct eeti_ts *eeti = i2c_get_clientdata(client); 212 struct input_dev *input_dev = eeti->input; 213 214 mutex_lock(&input_dev->mutex); 215 216 if (input_dev->users) 217 eeti_ts_stop(eeti); 218 219 mutex_unlock(&input_dev->mutex); 220 221 if (device_may_wakeup(&client->dev)) 222 enable_irq_wake(client->irq); 223 224 return 0; 225 } 226 227 static int __maybe_unused eeti_ts_resume(struct device *dev) 228 { 229 struct i2c_client *client = to_i2c_client(dev); 230 struct eeti_ts *eeti = i2c_get_clientdata(client); 231 struct input_dev *input_dev = eeti->input; 232 233 if (device_may_wakeup(&client->dev)) 234 disable_irq_wake(client->irq); 235 236 mutex_lock(&input_dev->mutex); 237 238 if (input_dev->users) 239 eeti_ts_start(eeti); 240 241 mutex_unlock(&input_dev->mutex); 242 243 return 0; 244 } 245 246 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume); 247 248 static const struct i2c_device_id eeti_ts_id[] = { 249 { "eeti_ts", 0 }, 250 { } 251 }; 252 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 253 254 #ifdef CONFIG_OF 255 static const struct of_device_id of_eeti_ts_match[] = { 256 { .compatible = "eeti,exc3000-i2c", }, 257 { } 258 }; 259 #endif 260 261 static struct i2c_driver eeti_ts_driver = { 262 .driver = { 263 .name = "eeti_ts", 264 .pm = &eeti_ts_pm, 265 .of_match_table = of_match_ptr(of_eeti_ts_match), 266 }, 267 .probe = eeti_ts_probe, 268 .id_table = eeti_ts_id, 269 }; 270 271 module_i2c_driver(eeti_ts_driver); 272 273 MODULE_DESCRIPTION("EETI Touchscreen driver"); 274 MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>"); 275 MODULE_LICENSE("GPL"); 276