1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * EETI Egalax serial touchscreen driver |
4 | * |
5 | * Copyright (c) 2015 Zoltán Böszörményi <zboszor@pr.hu> |
6 | * |
7 | * based on the |
8 | * |
9 | * Hampshire serial touchscreen driver (Copyright (c) 2010 Adam Bennett) |
10 | */ |
11 | |
12 | |
13 | #include <linux/errno.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> |
16 | #include <linux/slab.h> |
17 | #include <linux/input.h> |
18 | #include <linux/serio.h> |
19 | |
20 | #define DRIVER_DESC "EETI Egalax serial touchscreen driver" |
21 | |
22 | /* |
23 | * Definitions & global arrays. |
24 | */ |
25 | |
26 | #define EGALAX_FORMAT_MAX_LENGTH 6 |
27 | #define EGALAX_FORMAT_START_BIT BIT(7) |
28 | #define EGALAX_FORMAT_PRESSURE_BIT BIT(6) |
29 | #define EGALAX_FORMAT_TOUCH_BIT BIT(0) |
30 | #define EGALAX_FORMAT_RESOLUTION_MASK 0x06 |
31 | |
32 | #define EGALAX_MIN_XC 0 |
33 | #define EGALAX_MAX_XC 0x4000 |
34 | #define EGALAX_MIN_YC 0 |
35 | #define EGALAX_MAX_YC 0x4000 |
36 | |
37 | /* |
38 | * Per-touchscreen data. |
39 | */ |
40 | struct egalax { |
41 | struct input_dev *input; |
42 | struct serio *serio; |
43 | int idx; |
44 | u8 data[EGALAX_FORMAT_MAX_LENGTH]; |
45 | char phys[32]; |
46 | }; |
47 | |
48 | static void egalax_process_data(struct egalax *egalax) |
49 | { |
50 | struct input_dev *dev = egalax->input; |
51 | u8 *data = egalax->data; |
52 | u16 x, y; |
53 | u8 shift; |
54 | u8 mask; |
55 | |
56 | shift = 3 - ((data[0] & EGALAX_FORMAT_RESOLUTION_MASK) >> 1); |
57 | mask = 0xff >> (shift + 1); |
58 | |
59 | x = (((u16)(data[1] & mask) << 7) | (data[2] & 0x7f)) << shift; |
60 | y = (((u16)(data[3] & mask) << 7) | (data[4] & 0x7f)) << shift; |
61 | |
62 | input_report_key(dev, BTN_TOUCH, value: data[0] & EGALAX_FORMAT_TOUCH_BIT); |
63 | input_report_abs(dev, ABS_X, value: x); |
64 | input_report_abs(dev, ABS_Y, value: y); |
65 | input_sync(dev); |
66 | } |
67 | |
68 | static irqreturn_t egalax_interrupt(struct serio *serio, |
69 | unsigned char data, unsigned int flags) |
70 | { |
71 | struct egalax *egalax = serio_get_drvdata(serio); |
72 | int pkt_len; |
73 | |
74 | egalax->data[egalax->idx++] = data; |
75 | |
76 | if (likely(egalax->data[0] & EGALAX_FORMAT_START_BIT)) { |
77 | pkt_len = egalax->data[0] & EGALAX_FORMAT_PRESSURE_BIT ? 6 : 5; |
78 | if (pkt_len == egalax->idx) { |
79 | egalax_process_data(egalax); |
80 | egalax->idx = 0; |
81 | } |
82 | } else { |
83 | dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n" , |
84 | egalax->data[0]); |
85 | egalax->idx = 0; |
86 | } |
87 | |
88 | return IRQ_HANDLED; |
89 | } |
90 | |
91 | /* |
92 | * egalax_connect() is the routine that is called when someone adds a |
93 | * new serio device that supports egalax protocol and registers it as |
94 | * an input device. This is usually accomplished using inputattach. |
95 | */ |
96 | static int egalax_connect(struct serio *serio, struct serio_driver *drv) |
97 | { |
98 | struct egalax *egalax; |
99 | struct input_dev *input_dev; |
100 | int error; |
101 | |
102 | egalax = kzalloc(size: sizeof(struct egalax), GFP_KERNEL); |
103 | input_dev = input_allocate_device(); |
104 | if (!egalax || !input_dev) { |
105 | error = -ENOMEM; |
106 | goto err_free_mem; |
107 | } |
108 | |
109 | egalax->serio = serio; |
110 | egalax->input = input_dev; |
111 | snprintf(buf: egalax->phys, size: sizeof(egalax->phys), |
112 | fmt: "%s/input0" , serio->phys); |
113 | |
114 | input_dev->name = "EETI eGalaxTouch Serial TouchScreen" ; |
115 | input_dev->phys = egalax->phys; |
116 | input_dev->id.bustype = BUS_RS232; |
117 | input_dev->id.vendor = SERIO_EGALAX; |
118 | input_dev->id.product = 0; |
119 | input_dev->id.version = 0x0001; |
120 | input_dev->dev.parent = &serio->dev; |
121 | |
122 | input_set_capability(dev: input_dev, EV_KEY, BTN_TOUCH); |
123 | input_set_abs_params(dev: input_dev, ABS_X, |
124 | EGALAX_MIN_XC, EGALAX_MAX_XC, fuzz: 0, flat: 0); |
125 | input_set_abs_params(dev: input_dev, ABS_Y, |
126 | EGALAX_MIN_YC, EGALAX_MAX_YC, fuzz: 0, flat: 0); |
127 | |
128 | serio_set_drvdata(serio, data: egalax); |
129 | |
130 | error = serio_open(serio, drv); |
131 | if (error) |
132 | goto err_reset_drvdata; |
133 | |
134 | error = input_register_device(input_dev); |
135 | if (error) |
136 | goto err_close_serio; |
137 | |
138 | return 0; |
139 | |
140 | err_close_serio: |
141 | serio_close(serio); |
142 | err_reset_drvdata: |
143 | serio_set_drvdata(serio, NULL); |
144 | err_free_mem: |
145 | input_free_device(dev: input_dev); |
146 | kfree(objp: egalax); |
147 | return error; |
148 | } |
149 | |
150 | static void egalax_disconnect(struct serio *serio) |
151 | { |
152 | struct egalax *egalax = serio_get_drvdata(serio); |
153 | |
154 | serio_close(serio); |
155 | serio_set_drvdata(serio, NULL); |
156 | input_unregister_device(egalax->input); |
157 | kfree(objp: egalax); |
158 | } |
159 | |
160 | /* |
161 | * The serio driver structure. |
162 | */ |
163 | |
164 | static const struct serio_device_id egalax_serio_ids[] = { |
165 | { |
166 | .type = SERIO_RS232, |
167 | .proto = SERIO_EGALAX, |
168 | .id = SERIO_ANY, |
169 | .extra = SERIO_ANY, |
170 | }, |
171 | { 0 } |
172 | }; |
173 | |
174 | MODULE_DEVICE_TABLE(serio, egalax_serio_ids); |
175 | |
176 | static struct serio_driver egalax_drv = { |
177 | .driver = { |
178 | .name = "egalax" , |
179 | }, |
180 | .description = DRIVER_DESC, |
181 | .id_table = egalax_serio_ids, |
182 | .interrupt = egalax_interrupt, |
183 | .connect = egalax_connect, |
184 | .disconnect = egalax_disconnect, |
185 | }; |
186 | module_serio_driver(egalax_drv); |
187 | |
188 | MODULE_AUTHOR("Zoltán Böszörményi <zboszor@pr.hu>" ); |
189 | MODULE_DESCRIPTION(DRIVER_DESC); |
190 | MODULE_LICENSE("GPL v2" ); |
191 | |