1// SPDX-License-Identifier: GPL-2.0-only
2
3/*
4 * Driver for input events on QNAP-MCUs
5 *
6 * Copyright (C) 2024 Heiko Stuebner <heiko@sntech.de>
7 */
8
9#include <linux/input.h>
10#include <linux/mfd/qnap-mcu.h>
11#include <linux/module.h>
12#include <linux/platform_device.h>
13#include <linux/slab.h>
14#include <uapi/linux/input-event-codes.h>
15
16/*
17 * The power-key needs to be pressed for a while to create an event,
18 * so there is no use for overly frequent polling.
19 */
20#define POLL_INTERVAL 500
21
22struct qnap_mcu_input_dev {
23 struct input_dev *input;
24 struct qnap_mcu *mcu;
25 struct device *dev;
26
27 struct work_struct beep_work;
28 int beep_type;
29};
30
31static void qnap_mcu_input_poll(struct input_dev *input)
32{
33 struct qnap_mcu_input_dev *idev = input_get_drvdata(dev: input);
34 static const u8 cmd[] = { '@', 'C', 'V' };
35 u8 reply[4];
36 int state, ret;
37
38 /* poll the power button */
39 ret = qnap_mcu_exec(mcu: idev->mcu, cmd_data: cmd, cmd_data_size: sizeof(cmd), reply_data: reply, reply_data_size: sizeof(reply));
40 if (ret)
41 return;
42
43 /* First bytes must mirror the sent command */
44 if (memcmp(p: cmd, q: reply, size: sizeof(cmd))) {
45 dev_err(idev->dev, "malformed data received\n");
46 return;
47 }
48
49 state = reply[3] - 0x30;
50 input_event(dev: input, EV_KEY, KEY_POWER, value: state);
51 input_sync(dev: input);
52}
53
54static void qnap_mcu_input_beeper_work(struct work_struct *work)
55{
56 struct qnap_mcu_input_dev *idev =
57 container_of(work, struct qnap_mcu_input_dev, beep_work);
58 const u8 cmd[] = { '@', 'C', (idev->beep_type == SND_TONE) ? '3' : '2' };
59
60 qnap_mcu_exec_with_ack(mcu: idev->mcu, cmd_data: cmd, cmd_data_size: sizeof(cmd));
61}
62
63static int qnap_mcu_input_event(struct input_dev *input, unsigned int type,
64 unsigned int code, int value)
65{
66 struct qnap_mcu_input_dev *idev = input_get_drvdata(dev: input);
67
68 if (type != EV_SND || (code != SND_BELL && code != SND_TONE))
69 return -EOPNOTSUPP;
70
71 if (value < 0)
72 return -EINVAL;
73
74 /* beep runtime is determined by the MCU */
75 if (value == 0)
76 return 0;
77
78 /* Schedule work to actually turn the beeper on */
79 idev->beep_type = code;
80 schedule_work(work: &idev->beep_work);
81
82 return 0;
83}
84
85static void qnap_mcu_input_close(struct input_dev *input)
86{
87 struct qnap_mcu_input_dev *idev = input_get_drvdata(dev: input);
88
89 cancel_work_sync(work: &idev->beep_work);
90}
91
92static int qnap_mcu_input_probe(struct platform_device *pdev)
93{
94 struct qnap_mcu *mcu = dev_get_drvdata(dev: pdev->dev.parent);
95 struct qnap_mcu_input_dev *idev;
96 struct device *dev = &pdev->dev;
97 struct input_dev *input;
98 int ret;
99
100 idev = devm_kzalloc(dev, size: sizeof(*idev), GFP_KERNEL);
101 if (!idev)
102 return -ENOMEM;
103
104 input = devm_input_allocate_device(dev);
105 if (!input)
106 return -ENOMEM;
107
108 idev->input = input;
109 idev->dev = dev;
110 idev->mcu = mcu;
111
112 input_set_drvdata(dev: input, data: idev);
113
114 input->name = "qnap-mcu";
115 input->phys = "qnap-mcu-input/input0";
116 input->id.bustype = BUS_HOST;
117 input->id.vendor = 0x0001;
118 input->id.product = 0x0001;
119 input->id.version = 0x0100;
120 input->event = qnap_mcu_input_event;
121 input->close = qnap_mcu_input_close;
122
123 input_set_capability(dev: input, EV_KEY, KEY_POWER);
124 input_set_capability(dev: input, EV_SND, SND_BELL);
125 input_set_capability(dev: input, EV_SND, SND_TONE);
126
127 INIT_WORK(&idev->beep_work, qnap_mcu_input_beeper_work);
128
129 ret = input_setup_polling(dev: input, poll_fn: qnap_mcu_input_poll);
130 if (ret)
131 return dev_err_probe(dev, err: ret, fmt: "unable to set up polling\n");
132
133 input_set_poll_interval(dev: input, POLL_INTERVAL);
134
135 ret = input_register_device(input);
136 if (ret)
137 return dev_err_probe(dev, err: ret, fmt: "unable to register input device\n");
138
139 return 0;
140}
141
142static struct platform_driver qnap_mcu_input_driver = {
143 .probe = qnap_mcu_input_probe,
144 .driver = {
145 .name = "qnap-mcu-input",
146 },
147};
148module_platform_driver(qnap_mcu_input_driver);
149
150MODULE_ALIAS("platform:qnap-mcu-input");
151MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
152MODULE_DESCRIPTION("QNAP MCU input driver");
153MODULE_LICENSE("GPL");
154

source code of linux/drivers/input/misc/qnap-mcu-input.c