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 <bigeasy@linutronix.de> |
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 |
16 | struct 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 | |
24 | static 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, value: x); |
35 | input_report_abs(dev, ABS_Y, value: y); |
36 | input_report_key(dev, BTN_TOUCH, value: 1); |
37 | |
38 | input_sync(dev); |
39 | } |
40 | |
41 | static 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, value: 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 | |
80 | static 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(size: sizeof(struct tsc_ser), GFP_KERNEL); |
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 | snprintf(buf: ptsc->phys, size: sizeof(ptsc->phys), fmt: "%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(dev: ptsc->dev, ABS_X, min: 0, max: 0x3ff, fuzz: 0, flat: 0); |
108 | input_set_abs_params(dev: ptsc->dev, ABS_Y, min: 0, max: 0x3ff, fuzz: 0, flat: 0); |
109 | |
110 | serio_set_drvdata(serio, data: 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 | |
122 | fail3: |
123 | serio_close(serio); |
124 | fail2: |
125 | serio_set_drvdata(serio, NULL); |
126 | fail1: |
127 | input_free_device(dev: input_dev); |
128 | kfree(objp: ptsc); |
129 | return error; |
130 | } |
131 | |
132 | static 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(objp: ptsc); |
140 | |
141 | serio_set_drvdata(serio, NULL); |
142 | } |
143 | |
144 | static 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 | }; |
153 | MODULE_DEVICE_TABLE(serio, tsc_serio_ids); |
154 | |
155 | #define DRIVER_DESC "TSC-10/25/40 serial touchscreen driver" |
156 | |
157 | static 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 | |
168 | module_serio_driver(tsc_drv); |
169 | |
170 | MODULE_AUTHOR("Sebastian Andrzej Siewior <bigeasy@linutronix.de>" ); |
171 | MODULE_DESCRIPTION(DRIVER_DESC); |
172 | MODULE_LICENSE("GPL v2" ); |
173 | |