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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Fujitsu serial touchscreen driver
4 *
5 * Copyright (c) Dmitry Torokhov <[email protected]>
6 */
7
8
9#include <linux/errno.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/slab.h>
13#include <linux/input.h>
14#include <linux/serio.h>
15
16#define DRIVER_DESC "Fujitsu serial touchscreen driver"
17
18MODULE_AUTHOR("Dmitry Torokhov <[email protected]>");
19MODULE_DESCRIPTION(DRIVER_DESC);
20MODULE_LICENSE("GPL");
21
22#define FUJITSU_LENGTH 5
23
24/*
25 * Per-touchscreen data.
26 */
27struct fujitsu {
28 struct input_dev *dev;
29 struct serio *serio;
30 int idx;
31 unsigned char data[FUJITSU_LENGTH];
32 char phys[32];
33};
34
35/*
36 * Decode serial data (5 bytes per packet)
37 * First byte
38 * 1 C 0 0 R S S S
39 * Where C is 1 while in calibration mode (which we don't use)
40 * R is 1 when no coordinate corection was done.
41 * S are button state
42 */
43static irqreturn_t fujitsu_interrupt(struct serio *serio,
44 unsigned char data, unsigned int flags)
45{
46 struct fujitsu *fujitsu = serio_get_drvdata(serio);
47 struct input_dev *dev = fujitsu->dev;
48
49 if (fujitsu->idx == 0) {
50 /* resync skip until start of frame */
51 if ((data & 0xf0) != 0x80)
52 return IRQ_HANDLED;
53 } else {
54 /* resync skip garbage */
55 if (data & 0x80) {
56 fujitsu->idx = 0;
57 return IRQ_HANDLED;
58 }
59 }
60
61 fujitsu->data[fujitsu->idx++] = data;
62 if (fujitsu->idx == FUJITSU_LENGTH) {
63 input_report_abs(dev, ABS_X,
64 (fujitsu->data[2] << 7) | fujitsu->data[1]);
65 input_report_abs(dev, ABS_Y,
66 (fujitsu->data[4] << 7) | fujitsu->data[3]);
67 input_report_key(dev, BTN_TOUCH,
68 (fujitsu->data[0] & 0x03) != 2);
69 input_sync(dev);
70 fujitsu->idx = 0;
71 }
72
73 return IRQ_HANDLED;
74}
75
76/*
77 * fujitsu_disconnect() is the opposite of fujitsu_connect()
78 */
79static void fujitsu_disconnect(struct serio *serio)
80{
81 struct fujitsu *fujitsu = serio_get_drvdata(serio);
82
83 input_get_device(fujitsu->dev);
84 input_unregister_device(fujitsu->dev);
85 serio_close(serio);
86 serio_set_drvdata(serio, NULL);
87 input_put_device(fujitsu->dev);
88 kfree(fujitsu);
89}
90
91/*
92 * fujitsu_connect() is the routine that is called when someone adds a
93 * new serio device that supports the Fujitsu protocol and registers it
94 * as input device.
95 */
96static int fujitsu_connect(struct serio *serio, struct serio_driver *drv)
97{
98 struct fujitsu *fujitsu;
99 struct input_dev *input_dev;
100 int err;
101
102 fujitsu = kzalloc_obj(*fujitsu);
103 input_dev = input_allocate_device();
104 if (!fujitsu || !input_dev) {
105 err = -ENOMEM;
106 goto fail1;
107 }
108
109 fujitsu->serio = serio;
110 fujitsu->dev = input_dev;
111 scnprintf(fujitsu->phys, sizeof(fujitsu->phys), "%s/input0", serio->phys);
112
113 input_dev->name = "Fujitsu Serial Touchscreen";
114 input_dev->phys = fujitsu->phys;
115 input_dev->id.bustype = BUS_RS232;
116 input_dev->id.vendor = SERIO_FUJITSU;
117 input_dev->id.product = 0;
118 input_dev->id.version = 0x0100;
119 input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
120 input_dev->keybit[BIT_WORD(BTN_TOUCH)] = BIT_MASK(BTN_TOUCH);
121
122 input_set_abs_params(input_dev, ABS_X, 0, 4096, 0, 0);
123 input_set_abs_params(input_dev, ABS_Y, 0, 4096, 0, 0);
124 serio_set_drvdata(serio, fujitsu);
125
126 err = serio_open(serio, drv);
127 if (err)
128 goto fail2;
129
130 err = input_register_device(fujitsu->dev);
131 if (err)
132 goto fail3;
133
134 return 0;
135
136 fail3:
137 serio_close(serio);
138 fail2:
139 serio_set_drvdata(serio, NULL);
140 fail1:
141 input_free_device(input_dev);
142 kfree(fujitsu);
143 return err;
144}
145
146/*
147 * The serio driver structure.
148 */
149static const struct serio_device_id fujitsu_serio_ids[] = {
150 {
151 .type = SERIO_RS232,
152 .proto = SERIO_FUJITSU,
153 .id = SERIO_ANY,
154 .extra = SERIO_ANY,
155 },
156 { 0 }
157};
158
159MODULE_DEVICE_TABLE(serio, fujitsu_serio_ids);
160
161static struct serio_driver fujitsu_drv = {
162 .driver = {
163 .name = "fujitsu_ts",
164 },
165 .description = DRIVER_DESC,
166 .id_table = fujitsu_serio_ids,
167 .interrupt = fujitsu_interrupt,
168 .connect = fujitsu_connect,
169 .disconnect = fujitsu_disconnect,
170};
171
172module_serio_driver(fujitsu_drv);