1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Hampshire serial touchscreen driver
4 *
5 * Copyright (c) 2010 Adam Bennett
6 * Based on the dynapro driver (c) Tias Guns
7 */
8
9
10 /*
11 * 2010/04/08 Adam Bennett <abennett72@gmail.com>
12 * Copied dynapro.c and edited for Hampshire 4-byte protocol
13 */
14
15 #include <linux/errno.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/slab.h>
19 #include <linux/input.h>
20 #include <linux/serio.h>
21
22 #define DRIVER_DESC "Hampshire serial touchscreen driver"
23
24 MODULE_AUTHOR("Adam Bennett <abennett72@gmail.com>");
25 MODULE_DESCRIPTION(DRIVER_DESC);
26 MODULE_LICENSE("GPL");
27
28 /*
29 * Definitions & global arrays.
30 */
31
32 #define HAMPSHIRE_FORMAT_TOUCH_BIT 0x40
33 #define HAMPSHIRE_FORMAT_LENGTH 4
34 #define HAMPSHIRE_RESPONSE_BEGIN_BYTE 0x80
35
36 #define HAMPSHIRE_MIN_XC 0
37 #define HAMPSHIRE_MAX_XC 0x1000
38 #define HAMPSHIRE_MIN_YC 0
39 #define HAMPSHIRE_MAX_YC 0x1000
40
41 #define HAMPSHIRE_GET_XC(data) (((data[3] & 0x0c) >> 2) | (data[1] << 2) | ((data[0] & 0x38) << 6))
42 #define HAMPSHIRE_GET_YC(data) ((data[3] & 0x03) | (data[2] << 2) | ((data[0] & 0x07) << 9))
43 #define HAMPSHIRE_GET_TOUCHED(data) (HAMPSHIRE_FORMAT_TOUCH_BIT & data[0])
44
45 /*
46 * Per-touchscreen data.
47 */
48
49 struct hampshire {
50 struct input_dev *dev;
51 struct serio *serio;
52 int idx;
53 unsigned char data[HAMPSHIRE_FORMAT_LENGTH];
54 char phys[32];
55 };
56
hampshire_process_data(struct hampshire * phampshire)57 static void hampshire_process_data(struct hampshire *phampshire)
58 {
59 struct input_dev *dev = phampshire->dev;
60
61 if (HAMPSHIRE_FORMAT_LENGTH == ++phampshire->idx) {
62 input_report_abs(dev, ABS_X, HAMPSHIRE_GET_XC(phampshire->data));
63 input_report_abs(dev, ABS_Y, HAMPSHIRE_GET_YC(phampshire->data));
64 input_report_key(dev, BTN_TOUCH,
65 HAMPSHIRE_GET_TOUCHED(phampshire->data));
66 input_sync(dev);
67
68 phampshire->idx = 0;
69 }
70 }
71
hampshire_interrupt(struct serio * serio,unsigned char data,unsigned int flags)72 static irqreturn_t hampshire_interrupt(struct serio *serio,
73 unsigned char data, unsigned int flags)
74 {
75 struct hampshire *phampshire = serio_get_drvdata(serio);
76
77 phampshire->data[phampshire->idx] = data;
78
79 if (HAMPSHIRE_RESPONSE_BEGIN_BYTE & phampshire->data[0])
80 hampshire_process_data(phampshire);
81 else
82 dev_dbg(&serio->dev, "unknown/unsynchronized data: %x\n",
83 phampshire->data[0]);
84
85 return IRQ_HANDLED;
86 }
87
hampshire_disconnect(struct serio * serio)88 static void hampshire_disconnect(struct serio *serio)
89 {
90 struct hampshire *phampshire = serio_get_drvdata(serio);
91
92 input_get_device(phampshire->dev);
93 input_unregister_device(phampshire->dev);
94 serio_close(serio);
95 serio_set_drvdata(serio, NULL);
96 input_put_device(phampshire->dev);
97 kfree(phampshire);
98 }
99
100 /*
101 * hampshire_connect() is the routine that is called when someone adds a
102 * new serio device that supports hampshire protocol and registers it as
103 * an input device. This is usually accomplished using inputattach.
104 */
105
hampshire_connect(struct serio * serio,struct serio_driver * drv)106 static int hampshire_connect(struct serio *serio, struct serio_driver *drv)
107 {
108 struct hampshire *phampshire;
109 struct input_dev *input_dev;
110 int err;
111
112 phampshire = kzalloc(sizeof(struct hampshire), GFP_KERNEL);
113 input_dev = input_allocate_device();
114 if (!phampshire || !input_dev) {
115 err = -ENOMEM;
116 goto fail1;
117 }
118
119 phampshire->serio = serio;
120 phampshire->dev = input_dev;
121 snprintf(phampshire->phys, sizeof(phampshire->phys),
122 "%s/input0", serio->phys);
123
124 input_dev->name = "Hampshire Serial TouchScreen";
125 input_dev->phys = phampshire->phys;
126 input_dev->id.bustype = BUS_RS232;
127 input_dev->id.vendor = SERIO_HAMPSHIRE;
128 input_dev->id.product = 0;
129 input_dev->id.version = 0x0001;
130 input_dev->dev.parent = &serio->dev;
131 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
132 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
133 input_set_abs_params(phampshire->dev, ABS_X,
134 HAMPSHIRE_MIN_XC, HAMPSHIRE_MAX_XC, 0, 0);
135 input_set_abs_params(phampshire->dev, ABS_Y,
136 HAMPSHIRE_MIN_YC, HAMPSHIRE_MAX_YC, 0, 0);
137
138 serio_set_drvdata(serio, phampshire);
139
140 err = serio_open(serio, drv);
141 if (err)
142 goto fail2;
143
144 err = input_register_device(phampshire->dev);
145 if (err)
146 goto fail3;
147
148 return 0;
149
150 fail3: serio_close(serio);
151 fail2: serio_set_drvdata(serio, NULL);
152 fail1: input_free_device(input_dev);
153 kfree(phampshire);
154 return err;
155 }
156
157 /*
158 * The serio driver structure.
159 */
160
161 static const struct serio_device_id hampshire_serio_ids[] = {
162 {
163 .type = SERIO_RS232,
164 .proto = SERIO_HAMPSHIRE,
165 .id = SERIO_ANY,
166 .extra = SERIO_ANY,
167 },
168 { 0 }
169 };
170
171 MODULE_DEVICE_TABLE(serio, hampshire_serio_ids);
172
173 static struct serio_driver hampshire_drv = {
174 .driver = {
175 .name = "hampshire",
176 },
177 .description = DRIVER_DESC,
178 .id_table = hampshire_serio_ids,
179 .interrupt = hampshire_interrupt,
180 .connect = hampshire_connect,
181 .disconnect = hampshire_disconnect,
182 };
183
184 module_serio_driver(hampshire_drv);
185