1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Touch Screen driver for EETI's I2C connected touch screen panels 4 * Copyright (c) 2009,2018 Daniel Mack <daniel@zonque.org> 5 * 6 * See EETI's software guide for the protocol specification: 7 * http://home.eeti.com.tw/documentation.html 8 * 9 * Based on migor_ts.c 10 * Copyright (c) 2008 Magnus Damm 11 * Copyright (c) 2007 Ujjwal Pande <ujjwal@kenati.com> 12 */ 13 14 #include <linux/module.h> 15 #include <linux/kernel.h> 16 #include <linux/input.h> 17 #include <linux/input/touchscreen.h> 18 #include <linux/interrupt.h> 19 #include <linux/i2c.h> 20 #include <linux/timer.h> 21 #include <linux/gpio/consumer.h> 22 #include <linux/of.h> 23 #include <linux/slab.h> 24 #include <asm/unaligned.h> 25 26 struct eeti_ts { 27 struct i2c_client *client; 28 struct input_dev *input; 29 struct gpio_desc *attn_gpio; 30 struct touchscreen_properties props; 31 struct mutex mutex; 32 bool running; 33 }; 34 35 #define EETI_TS_BITDEPTH (11) 36 #define EETI_MAXVAL ((1 << (EETI_TS_BITDEPTH + 1)) - 1) 37 38 #define REPORT_BIT_PRESSED BIT(0) 39 #define REPORT_BIT_AD0 BIT(1) 40 #define REPORT_BIT_AD1 BIT(2) 41 #define REPORT_BIT_HAS_PRESSURE BIT(6) 42 #define REPORT_RES_BITS(v) (((v) >> 1) + EETI_TS_BITDEPTH) 43 44 static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf) 45 { 46 unsigned int res; 47 u16 x, y; 48 49 res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1)); 50 51 x = get_unaligned_be16(&buf[1]); 52 y = get_unaligned_be16(&buf[3]); 53 54 /* fix the range to 11 bits */ 55 x >>= res - EETI_TS_BITDEPTH; 56 y >>= res - EETI_TS_BITDEPTH; 57 58 if (buf[0] & REPORT_BIT_HAS_PRESSURE) 59 input_report_abs(eeti->input, ABS_PRESSURE, buf[5]); 60 61 touchscreen_report_pos(eeti->input, &eeti->props, x, y, false); 62 input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED); 63 input_sync(eeti->input); 64 } 65 66 static int eeti_ts_read(struct eeti_ts *eeti) 67 { 68 int len, error; 69 char buf[6]; 70 71 len = i2c_master_recv(eeti->client, buf, sizeof(buf)); 72 if (len != sizeof(buf)) { 73 error = len < 0 ? len : -EIO; 74 dev_err(&eeti->client->dev, 75 "failed to read touchscreen data: %d\n", 76 error); 77 return error; 78 } 79 80 /* Motion packet */ 81 if (buf[0] & 0x80) 82 eeti_ts_report_event(eeti, buf); 83 84 return 0; 85 } 86 87 static irqreturn_t eeti_ts_isr(int irq, void *dev_id) 88 { 89 struct eeti_ts *eeti = dev_id; 90 int error; 91 92 mutex_lock(&eeti->mutex); 93 94 do { 95 /* 96 * If we have attention GPIO, trust it. Otherwise we'll read 97 * once and exit. We assume that in this case we are using 98 * level triggered interrupt and it will get raised again 99 * if/when there is more data. 100 */ 101 if (eeti->attn_gpio && 102 !gpiod_get_value_cansleep(eeti->attn_gpio)) { 103 break; 104 } 105 106 error = eeti_ts_read(eeti); 107 if (error) 108 break; 109 110 } while (eeti->running && eeti->attn_gpio); 111 112 mutex_unlock(&eeti->mutex); 113 return IRQ_HANDLED; 114 } 115 116 static void eeti_ts_start(struct eeti_ts *eeti) 117 { 118 mutex_lock(&eeti->mutex); 119 120 eeti->running = true; 121 enable_irq(eeti->client->irq); 122 123 /* 124 * Kick the controller in case we are using edge interrupt and 125 * we missed our edge while interrupt was disabled. We expect 126 * the attention GPIO to be wired in this case. 127 */ 128 if (eeti->attn_gpio && gpiod_get_value_cansleep(eeti->attn_gpio)) 129 eeti_ts_read(eeti); 130 131 mutex_unlock(&eeti->mutex); 132 } 133 134 static void eeti_ts_stop(struct eeti_ts *eeti) 135 { 136 /* 137 * Not locking here, just setting a flag and expect that the 138 * interrupt thread will notice the flag eventually. 139 */ 140 eeti->running = false; 141 wmb(); 142 disable_irq(eeti->client->irq); 143 } 144 145 static int eeti_ts_open(struct input_dev *dev) 146 { 147 struct eeti_ts *eeti = input_get_drvdata(dev); 148 149 eeti_ts_start(eeti); 150 151 return 0; 152 } 153 154 static void eeti_ts_close(struct input_dev *dev) 155 { 156 struct eeti_ts *eeti = input_get_drvdata(dev); 157 158 eeti_ts_stop(eeti); 159 } 160 161 static int eeti_ts_probe(struct i2c_client *client) 162 { 163 struct device *dev = &client->dev; 164 struct eeti_ts *eeti; 165 struct input_dev *input; 166 int error; 167 168 /* 169 * In contrast to what's described in the datasheet, there seems 170 * to be no way of probing the presence of that device using I2C 171 * commands. So we need to blindly believe it is there, and wait 172 * for interrupts to occur. 173 */ 174 175 eeti = devm_kzalloc(dev, sizeof(*eeti), GFP_KERNEL); 176 if (!eeti) { 177 dev_err(dev, "failed to allocate driver data\n"); 178 return -ENOMEM; 179 } 180 181 mutex_init(&eeti->mutex); 182 183 input = devm_input_allocate_device(dev); 184 if (!input) { 185 dev_err(dev, "Failed to allocate input device.\n"); 186 return -ENOMEM; 187 } 188 189 input_set_capability(input, EV_KEY, BTN_TOUCH); 190 191 input_set_abs_params(input, ABS_X, 0, EETI_MAXVAL, 0, 0); 192 input_set_abs_params(input, ABS_Y, 0, EETI_MAXVAL, 0, 0); 193 input_set_abs_params(input, ABS_PRESSURE, 0, 0xff, 0, 0); 194 195 touchscreen_parse_properties(input, false, &eeti->props); 196 197 input->name = client->name; 198 input->id.bustype = BUS_I2C; 199 input->open = eeti_ts_open; 200 input->close = eeti_ts_close; 201 202 eeti->client = client; 203 eeti->input = input; 204 205 eeti->attn_gpio = devm_gpiod_get_optional(dev, "attn", GPIOD_IN); 206 if (IS_ERR(eeti->attn_gpio)) 207 return PTR_ERR(eeti->attn_gpio); 208 209 i2c_set_clientdata(client, eeti); 210 input_set_drvdata(input, eeti); 211 212 error = devm_request_threaded_irq(dev, client->irq, 213 NULL, eeti_ts_isr, 214 IRQF_ONESHOT, 215 client->name, eeti); 216 if (error) { 217 dev_err(dev, "Unable to request touchscreen IRQ: %d\n", 218 error); 219 return error; 220 } 221 222 /* 223 * Disable the device for now. It will be enabled once the 224 * input device is opened. 225 */ 226 eeti_ts_stop(eeti); 227 228 error = input_register_device(input); 229 if (error) 230 return error; 231 232 return 0; 233 } 234 235 static int __maybe_unused eeti_ts_suspend(struct device *dev) 236 { 237 struct i2c_client *client = to_i2c_client(dev); 238 struct eeti_ts *eeti = i2c_get_clientdata(client); 239 struct input_dev *input_dev = eeti->input; 240 241 mutex_lock(&input_dev->mutex); 242 243 if (input_device_enabled(input_dev)) 244 eeti_ts_stop(eeti); 245 246 mutex_unlock(&input_dev->mutex); 247 248 if (device_may_wakeup(&client->dev)) 249 enable_irq_wake(client->irq); 250 251 return 0; 252 } 253 254 static int __maybe_unused eeti_ts_resume(struct device *dev) 255 { 256 struct i2c_client *client = to_i2c_client(dev); 257 struct eeti_ts *eeti = i2c_get_clientdata(client); 258 struct input_dev *input_dev = eeti->input; 259 260 if (device_may_wakeup(&client->dev)) 261 disable_irq_wake(client->irq); 262 263 mutex_lock(&input_dev->mutex); 264 265 if (input_device_enabled(input_dev)) 266 eeti_ts_start(eeti); 267 268 mutex_unlock(&input_dev->mutex); 269 270 return 0; 271 } 272 273 static SIMPLE_DEV_PM_OPS(eeti_ts_pm, eeti_ts_suspend, eeti_ts_resume); 274 275 static const struct i2c_device_id eeti_ts_id[] = { 276 { "eeti_ts", 0 }, 277 { } 278 }; 279 MODULE_DEVICE_TABLE(i2c, eeti_ts_id); 280 281 #ifdef CONFIG_OF 282 static const struct of_device_id of_eeti_ts_match[] = { 283 { .compatible = "eeti,exc3000-i2c", }, 284 { } 285 }; 286 #endif 287 288 static struct i2c_driver eeti_ts_driver = { 289 .driver = { 290 .name = "eeti_ts", 291 .pm = &eeti_ts_pm, 292 .of_match_table = of_match_ptr(of_eeti_ts_match), 293 }, 294 .probe_new = eeti_ts_probe, 295 .id_table = eeti_ts_id, 296 }; 297 298 module_i2c_driver(eeti_ts_driver); 299 300 MODULE_DESCRIPTION("EETI Touchscreen driver"); 301 MODULE_AUTHOR("Daniel Mack <daniel@zonque.org>"); 302 MODULE_LICENSE("GPL"); 303