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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * TSC-40 serial touchscreen driver. It should be compatible with
4 * TSC-10 and 25.
5 *
6 * Author: Sebastian Andrzej Siewior <[email protected]>
7 */
8
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/input.h>
13#include <linux/serio.h>
14
15#define PACKET_LENGTH 5
16struct tsc_ser {
17 struct input_dev *dev;
18 struct serio *serio;
19 u32 idx;
20 unsigned char data[PACKET_LENGTH];
21 char phys[32];
22};
23
24static void tsc_process_data(struct tsc_ser *ptsc)
25{
26 struct input_dev *dev = ptsc->dev;
27 u8 *data = ptsc->data;
28 u32 x;
29 u32 y;
30
31 x = ((data[1] & 0x03) << 8) | data[2];
32 y = ((data[3] & 0x03) << 8) | data[4];
33
34 input_report_abs(dev, ABS_X, x);
35 input_report_abs(dev, ABS_Y, y);
36 input_report_key(dev, BTN_TOUCH, 1);
37
38 input_sync(dev);
39}
40
41static irqreturn_t tsc_interrupt(struct serio *serio,
42 unsigned char data, unsigned int flags)
43{
44 struct tsc_ser *ptsc = serio_get_drvdata(serio);
45 struct input_dev *dev = ptsc->dev;
46
47 ptsc->data[ptsc->idx] = data;
48 switch (ptsc->idx++) {
49 case 0:
50 if (unlikely((data & 0x3e) != 0x10)) {
51 dev_dbg(&serio->dev,
52 "unsynchronized packet start (0x%02x)\n", data);
53 ptsc->idx = 0;
54 } else if (!(data & 0x01)) {
55 input_report_key(dev, BTN_TOUCH, 0);
56 input_sync(dev);
57 ptsc->idx = 0;
58 }
59 break;
60
61 case 1:
62 case 3:
63 if (unlikely(data & 0xfc)) {
64 dev_dbg(&serio->dev,
65 "unsynchronized data 0x%02x at offset %d\n",
66 data, ptsc->idx - 1);
67 ptsc->idx = 0;
68 }
69 break;
70
71 case 4:
72 tsc_process_data(ptsc);
73 ptsc->idx = 0;
74 break;
75 }
76
77 return IRQ_HANDLED;
78}
79
80static int tsc_connect(struct serio *serio, struct serio_driver *drv)
81{
82 struct tsc_ser *ptsc;
83 struct input_dev *input_dev;
84 int error;
85
86 ptsc = kzalloc_obj(*ptsc);
87 input_dev = input_allocate_device();
88 if (!ptsc || !input_dev) {
89 error = -ENOMEM;
90 goto fail1;
91 }
92
93 ptsc->serio = serio;
94 ptsc->dev = input_dev;
95 scnprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
96
97 input_dev->name = "TSC-10/25/40 Serial TouchScreen";
98 input_dev->phys = ptsc->phys;
99 input_dev->id.bustype = BUS_RS232;
100 input_dev->id.vendor = SERIO_TSC40;
101 input_dev->id.product = 40;
102 input_dev->id.version = 0x0001;
103 input_dev->dev.parent = &serio->dev;
104
105 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
106 __set_bit(BTN_TOUCH, input_dev->keybit);
107 input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
108 input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
109
110 serio_set_drvdata(serio, ptsc);
111
112 error = serio_open(serio, drv);
113 if (error)
114 goto fail2;
115
116 error = input_register_device(ptsc->dev);
117 if (error)
118 goto fail3;
119
120 return 0;
121
122fail3:
123 serio_close(serio);
124fail2:
125 serio_set_drvdata(serio, NULL);
126fail1:
127 input_free_device(input_dev);
128 kfree(ptsc);
129 return error;
130}
131
132static void tsc_disconnect(struct serio *serio)
133{
134 struct tsc_ser *ptsc = serio_get_drvdata(serio);
135
136 serio_close(serio);
137
138 input_unregister_device(ptsc->dev);
139 kfree(ptsc);
140
141 serio_set_drvdata(serio, NULL);
142}
143
144static const struct serio_device_id tsc_serio_ids[] = {
145 {
146 .type = SERIO_RS232,
147 .proto = SERIO_TSC40,
148 .id = SERIO_ANY,
149 .extra = SERIO_ANY,
150 },
151 { 0 }
152};
153MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
154
155#define DRIVER_DESC "TSC-10/25/40 serial touchscreen driver"
156
157static struct serio_driver tsc_drv = {
158 .driver = {
159 .name = "tsc40",
160 },
161 .description = DRIVER_DESC,
162 .id_table = tsc_serio_ids,
163 .interrupt = tsc_interrupt,
164 .connect = tsc_connect,
165 .disconnect = tsc_disconnect,
166};
167
168module_serio_driver(tsc_drv);
169
170MODULE_AUTHOR("Sebastian Andrzej Siewior <[email protected]>");
171MODULE_DESCRIPTION(DRIVER_DESC);
172MODULE_LICENSE("GPL v2");