1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Sahara TouchIT-213 serial touchscreen driver 4 * 5 * Copyright (c) 2007-2008 Claudio Nieder <private@claudio.ch> 6 * 7 * Based on Touchright driver (drivers/input/touchscreen/touchright.c) 8 * Copyright (c) 2006 Rick Koch <n1gp@hotmail.com> 9 * Copyright (c) 2004 Vojtech Pavlik 10 * and Dan Streetman <ddstreet@ieee.org> 11 */ 12 13 14 #include <linux/errno.h> 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/slab.h> 18 #include <linux/input.h> 19 #include <linux/serio.h> 20 21 #define DRIVER_DESC "Sahara TouchIT-213 serial touchscreen driver" 22 23 MODULE_AUTHOR("Claudio Nieder <private@claudio.ch>"); 24 MODULE_DESCRIPTION(DRIVER_DESC); 25 MODULE_LICENSE("GPL"); 26 27 /* 28 * Definitions & global arrays. 29 */ 30 31 /* 32 * Data is received through COM1 at 9600bit/s,8bit,no parity in packets 33 * of 5 byte each. 34 * 35 * +--------+ +--------+ +--------+ +--------+ +--------+ 36 * |1000000p| |0xxxxxxx| |0xxxxxxx| |0yyyyyyy| |0yyyyyyy| 37 * +--------+ +--------+ +--------+ +--------+ +--------+ 38 * MSB LSB MSB LSB 39 * 40 * The value of p is 1 as long as the screen is touched and 0 when 41 * reporting the location where touching stopped, e.g. where the pen was 42 * lifted from the screen. 43 * 44 * When holding the screen in landscape mode as the BIOS text output is 45 * presented, x is the horizontal axis with values growing from left to 46 * right and y is the vertical axis with values growing from top to 47 * bottom. 48 * 49 * When holding the screen in portrait mode with the Sahara logo in its 50 * correct position, x ist the vertical axis with values growing from 51 * top to bottom and y is the horizontal axis with values growing from 52 * right to left. 53 */ 54 55 #define T213_FORMAT_TOUCH_BIT 0x01 56 #define T213_FORMAT_STATUS_BYTE 0x80 57 #define T213_FORMAT_STATUS_MASK ~T213_FORMAT_TOUCH_BIT 58 59 /* 60 * On my Sahara Touch-IT 213 I have observed x values from 0 to 0x7f0 61 * and y values from 0x1d to 0x7e9, so the actual measurement is 62 * probably done with an 11 bit precision. 63 */ 64 #define T213_MIN_XC 0 65 #define T213_MAX_XC 0x07ff 66 #define T213_MIN_YC 0 67 #define T213_MAX_YC 0x07ff 68 69 /* 70 * Per-touchscreen data. 71 */ 72 73 struct touchit213 { 74 struct input_dev *dev; 75 struct serio *serio; 76 int idx; 77 unsigned char csum; 78 unsigned char data[5]; 79 char phys[32]; 80 }; 81 82 static irqreturn_t touchit213_interrupt(struct serio *serio, 83 unsigned char data, unsigned int flags) 84 { 85 struct touchit213 *touchit213 = serio_get_drvdata(serio); 86 struct input_dev *dev = touchit213->dev; 87 88 touchit213->data[touchit213->idx] = data; 89 90 switch (touchit213->idx++) { 91 case 0: 92 if ((touchit213->data[0] & T213_FORMAT_STATUS_MASK) != 93 T213_FORMAT_STATUS_BYTE) { 94 pr_debug("unsynchronized data: 0x%02x\n", data); 95 touchit213->idx = 0; 96 } 97 break; 98 99 case 4: 100 touchit213->idx = 0; 101 input_report_abs(dev, ABS_X, 102 (touchit213->data[1] << 7) | touchit213->data[2]); 103 input_report_abs(dev, ABS_Y, 104 (touchit213->data[3] << 7) | touchit213->data[4]); 105 input_report_key(dev, BTN_TOUCH, 106 touchit213->data[0] & T213_FORMAT_TOUCH_BIT); 107 input_sync(dev); 108 break; 109 } 110 111 return IRQ_HANDLED; 112 } 113 114 /* 115 * touchit213_disconnect() is the opposite of touchit213_connect() 116 */ 117 118 static void touchit213_disconnect(struct serio *serio) 119 { 120 struct touchit213 *touchit213 = serio_get_drvdata(serio); 121 122 input_get_device(touchit213->dev); 123 input_unregister_device(touchit213->dev); 124 serio_close(serio); 125 serio_set_drvdata(serio, NULL); 126 input_put_device(touchit213->dev); 127 kfree(touchit213); 128 } 129 130 /* 131 * touchit213_connect() is the routine that is called when someone adds a 132 * new serio device that supports the Touchright protocol and registers it as 133 * an input device. 134 */ 135 136 static int touchit213_connect(struct serio *serio, struct serio_driver *drv) 137 { 138 struct touchit213 *touchit213; 139 struct input_dev *input_dev; 140 int err; 141 142 touchit213 = kzalloc(sizeof(*touchit213), GFP_KERNEL); 143 input_dev = input_allocate_device(); 144 if (!touchit213 || !input_dev) { 145 err = -ENOMEM; 146 goto fail1; 147 } 148 149 touchit213->serio = serio; 150 touchit213->dev = input_dev; 151 snprintf(touchit213->phys, sizeof(touchit213->phys), 152 "%s/input0", serio->phys); 153 154 input_dev->name = "Sahara Touch-iT213 Serial TouchScreen"; 155 input_dev->phys = touchit213->phys; 156 input_dev->id.bustype = BUS_RS232; 157 input_dev->id.vendor = SERIO_TOUCHIT213; 158 input_dev->id.product = 0; 159 input_dev->id.version = 0x0100; 160 input_dev->dev.parent = &serio->dev; 161 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS); 162 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH); 163 input_set_abs_params(touchit213->dev, ABS_X, 164 T213_MIN_XC, T213_MAX_XC, 0, 0); 165 input_set_abs_params(touchit213->dev, ABS_Y, 166 T213_MIN_YC, T213_MAX_YC, 0, 0); 167 168 serio_set_drvdata(serio, touchit213); 169 170 err = serio_open(serio, drv); 171 if (err) 172 goto fail2; 173 174 err = input_register_device(touchit213->dev); 175 if (err) 176 goto fail3; 177 178 return 0; 179 180 fail3: serio_close(serio); 181 fail2: serio_set_drvdata(serio, NULL); 182 fail1: input_free_device(input_dev); 183 kfree(touchit213); 184 return err; 185 } 186 187 /* 188 * The serio driver structure. 189 */ 190 191 static const struct serio_device_id touchit213_serio_ids[] = { 192 { 193 .type = SERIO_RS232, 194 .proto = SERIO_TOUCHIT213, 195 .id = SERIO_ANY, 196 .extra = SERIO_ANY, 197 }, 198 { 0 } 199 }; 200 201 MODULE_DEVICE_TABLE(serio, touchit213_serio_ids); 202 203 static struct serio_driver touchit213_drv = { 204 .driver = { 205 .name = "touchit213", 206 }, 207 .description = DRIVER_DESC, 208 .id_table = touchit213_serio_ids, 209 .interrupt = touchit213_interrupt, 210 .connect = touchit213_connect, 211 .disconnect = touchit213_disconnect, 212 }; 213 214 module_serio_driver(touchit213_drv); 215