1 /*
2 * TSC-40 serial touchscreen driver. It should be compatible with
3 * TSC-10 and 25.
4 *
5 * Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
6 * License: GPLv2 as published by the FSF.
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 #include <linux/init.h>
15
16 #define PACKET_LENGTH 5
17 struct tsc_ser {
18 struct input_dev *dev;
19 struct serio *serio;
20 u32 idx;
21 unsigned char data[PACKET_LENGTH];
22 char phys[32];
23 };
24
tsc_process_data(struct tsc_ser * ptsc)25 static void tsc_process_data(struct tsc_ser *ptsc)
26 {
27 struct input_dev *dev = ptsc->dev;
28 u8 *data = ptsc->data;
29 u32 x;
30 u32 y;
31
32 x = ((data[1] & 0x03) << 8) | data[2];
33 y = ((data[3] & 0x03) << 8) | data[4];
34
35 input_report_abs(dev, ABS_X, x);
36 input_report_abs(dev, ABS_Y, y);
37 input_report_key(dev, BTN_TOUCH, 1);
38
39 input_sync(dev);
40 }
41
tsc_interrupt(struct serio * serio,unsigned char data,unsigned int flags)42 static irqreturn_t tsc_interrupt(struct serio *serio,
43 unsigned char data, unsigned int flags)
44 {
45 struct tsc_ser *ptsc = serio_get_drvdata(serio);
46 struct input_dev *dev = ptsc->dev;
47
48 ptsc->data[ptsc->idx] = data;
49 switch (ptsc->idx++) {
50 case 0:
51 if (unlikely((data & 0x3e) != 0x10)) {
52 dev_dbg(&serio->dev,
53 "unsynchronized packet start (0x%02x)\n", data);
54 ptsc->idx = 0;
55 } else if (!(data & 0x01)) {
56 input_report_key(dev, BTN_TOUCH, 0);
57 input_sync(dev);
58 ptsc->idx = 0;
59 }
60 break;
61
62 case 1:
63 case 3:
64 if (unlikely(data & 0xfc)) {
65 dev_dbg(&serio->dev,
66 "unsynchronized data 0x%02x at offset %d\n",
67 data, ptsc->idx - 1);
68 ptsc->idx = 0;
69 }
70 break;
71
72 case 4:
73 tsc_process_data(ptsc);
74 ptsc->idx = 0;
75 break;
76 }
77
78 return IRQ_HANDLED;
79 }
80
tsc_connect(struct serio * serio,struct serio_driver * drv)81 static int tsc_connect(struct serio *serio, struct serio_driver *drv)
82 {
83 struct tsc_ser *ptsc;
84 struct input_dev *input_dev;
85 int error;
86
87 ptsc = kzalloc(sizeof(struct tsc_ser), GFP_KERNEL);
88 input_dev = input_allocate_device();
89 if (!ptsc || !input_dev) {
90 error = -ENOMEM;
91 goto fail1;
92 }
93
94 ptsc->serio = serio;
95 ptsc->dev = input_dev;
96 snprintf(ptsc->phys, sizeof(ptsc->phys), "%s/input0", serio->phys);
97
98 input_dev->name = "TSC-10/25/40 Serial TouchScreen";
99 input_dev->phys = ptsc->phys;
100 input_dev->id.bustype = BUS_RS232;
101 input_dev->id.vendor = SERIO_TSC40;
102 input_dev->id.product = 40;
103 input_dev->id.version = 0x0001;
104 input_dev->dev.parent = &serio->dev;
105
106 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
107 __set_bit(BTN_TOUCH, input_dev->keybit);
108 input_set_abs_params(ptsc->dev, ABS_X, 0, 0x3ff, 0, 0);
109 input_set_abs_params(ptsc->dev, ABS_Y, 0, 0x3ff, 0, 0);
110 input_set_abs_params(ptsc->dev, ABS_PRESSURE, 0, 0, 0, 0);
111
112 serio_set_drvdata(serio, ptsc);
113
114 error = serio_open(serio, drv);
115 if (error)
116 goto fail2;
117
118 error = input_register_device(ptsc->dev);
119 if (error)
120 goto fail3;
121
122 return 0;
123
124 fail3:
125 serio_close(serio);
126 fail2:
127 serio_set_drvdata(serio, NULL);
128 fail1:
129 input_free_device(input_dev);
130 kfree(ptsc);
131 return error;
132 }
133
tsc_disconnect(struct serio * serio)134 static void tsc_disconnect(struct serio *serio)
135 {
136 struct tsc_ser *ptsc = serio_get_drvdata(serio);
137
138 serio_close(serio);
139
140 input_unregister_device(ptsc->dev);
141 kfree(ptsc);
142
143 serio_set_drvdata(serio, NULL);
144 }
145
146 static struct serio_device_id tsc_serio_ids[] = {
147 {
148 .type = SERIO_RS232,
149 .proto = SERIO_TSC40,
150 .id = SERIO_ANY,
151 .extra = SERIO_ANY,
152 },
153 { 0 }
154 };
155 MODULE_DEVICE_TABLE(serio, tsc_serio_ids);
156
157 #define DRIVER_DESC "TSC-10/25/40 serial touchscreen driver"
158
159 static struct serio_driver tsc_drv = {
160 .driver = {
161 .name = "tsc40",
162 },
163 .description = DRIVER_DESC,
164 .id_table = tsc_serio_ids,
165 .interrupt = tsc_interrupt,
166 .connect = tsc_connect,
167 .disconnect = tsc_disconnect,
168 };
169
tsc_ser_init(void)170 static int __init tsc_ser_init(void)
171 {
172 return serio_register_driver(&tsc_drv);
173 }
174 module_init(tsc_ser_init);
175
tsc_exit(void)176 static void __exit tsc_exit(void)
177 {
178 serio_unregister_driver(&tsc_drv);
179 }
180 module_exit(tsc_exit);
181
182 MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>");
183 MODULE_DESCRIPTION(DRIVER_DESC);
184 MODULE_LICENSE("GPL v2");
185