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
egalax_process_data(struct egalax * egalax)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, data[0] & EGALAX_FORMAT_TOUCH_BIT);
63 input_report_abs(dev, ABS_X, x);
64 input_report_abs(dev, ABS_Y, y);
65 input_sync(dev);
66 }
67
egalax_interrupt(struct serio * serio,unsigned char data,unsigned int flags)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 */
egalax_connect(struct serio * serio,struct serio_driver * drv)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(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(egalax->phys, sizeof(egalax->phys),
112 "%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(input_dev, EV_KEY, BTN_TOUCH);
123 input_set_abs_params(input_dev, ABS_X,
124 EGALAX_MIN_XC, EGALAX_MAX_XC, 0, 0);
125 input_set_abs_params(input_dev, ABS_Y,
126 EGALAX_MIN_YC, EGALAX_MAX_YC, 0, 0);
127
128 serio_set_drvdata(serio, 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(input_dev);
146 kfree(egalax);
147 return error;
148 }
149
egalax_disconnect(struct serio * serio)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(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