1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  SGI Volume Button interface driver
4  *
5  *  Copyright (C) 2008  Thomas Bogendoerfer <tsbogend@alpha.franken.de>
6  */
7 #include <linux/input.h>
8 #include <linux/ioport.h>
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/slab.h>
12 
13 #ifdef CONFIG_SGI_IP22
14 #include <asm/sgi/ioc.h>
15 
button_status(void)16 static inline u8 button_status(void)
17 {
18 	u8 status;
19 
20 	status = readb(&sgioc->panel) ^ 0xa0;
21 	return ((status & 0x80) >> 6) | ((status & 0x20) >> 5);
22 }
23 #endif
24 
25 #ifdef CONFIG_SGI_IP32
26 #include <asm/ip32/mace.h>
27 
button_status(void)28 static inline u8 button_status(void)
29 {
30 	u64 status;
31 
32 	status = readq(&mace->perif.audio.control);
33 	writeq(status & ~(3U << 23), &mace->perif.audio.control);
34 
35 	return (status >> 23) & 3;
36 }
37 #endif
38 
39 #define BUTTONS_POLL_INTERVAL	30	/* msec */
40 #define BUTTONS_COUNT_THRESHOLD	3
41 
42 static const unsigned short sgi_map[] = {
43 	KEY_VOLUMEDOWN,
44 	KEY_VOLUMEUP
45 };
46 
47 struct buttons_dev {
48 	unsigned short keymap[ARRAY_SIZE(sgi_map)];
49 	int count[ARRAY_SIZE(sgi_map)];
50 };
51 
handle_buttons(struct input_dev * input)52 static void handle_buttons(struct input_dev *input)
53 {
54 	struct buttons_dev *bdev = input_get_drvdata(input);
55 	u8 status;
56 	int i;
57 
58 	status = button_status();
59 
60 	for (i = 0; i < ARRAY_SIZE(bdev->keymap); i++) {
61 		if (status & (1U << i)) {
62 			if (++bdev->count[i] == BUTTONS_COUNT_THRESHOLD) {
63 				input_event(input, EV_MSC, MSC_SCAN, i);
64 				input_report_key(input, bdev->keymap[i], 1);
65 				input_sync(input);
66 			}
67 		} else {
68 			if (bdev->count[i] >= BUTTONS_COUNT_THRESHOLD) {
69 				input_event(input, EV_MSC, MSC_SCAN, i);
70 				input_report_key(input, bdev->keymap[i], 0);
71 				input_sync(input);
72 			}
73 			bdev->count[i] = 0;
74 		}
75 	}
76 }
77 
sgi_buttons_probe(struct platform_device * pdev)78 static int sgi_buttons_probe(struct platform_device *pdev)
79 {
80 	struct buttons_dev *bdev;
81 	struct input_dev *input;
82 	int error, i;
83 
84 	bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
85 	if (!bdev)
86 		return -ENOMEM;
87 
88 	input = devm_input_allocate_device(&pdev->dev);
89 	if (!input)
90 		return -ENOMEM;
91 
92 	memcpy(bdev->keymap, sgi_map, sizeof(bdev->keymap));
93 
94 	input_set_drvdata(input, bdev);
95 
96 	input->name = "SGI buttons";
97 	input->phys = "sgi/input0";
98 	input->id.bustype = BUS_HOST;
99 
100 	input->keycode = bdev->keymap;
101 	input->keycodemax = ARRAY_SIZE(bdev->keymap);
102 	input->keycodesize = sizeof(unsigned short);
103 
104 	input_set_capability(input, EV_MSC, MSC_SCAN);
105 	__set_bit(EV_KEY, input->evbit);
106 	for (i = 0; i < ARRAY_SIZE(sgi_map); i++)
107 		__set_bit(bdev->keymap[i], input->keybit);
108 	__clear_bit(KEY_RESERVED, input->keybit);
109 
110 	error = input_setup_polling(input, handle_buttons);
111 	if (error)
112 		return error;
113 
114 	input_set_poll_interval(input, BUTTONS_POLL_INTERVAL);
115 
116 	error = input_register_device(input);
117 	if (error)
118 		return error;
119 
120 	return 0;
121 }
122 
123 static struct platform_driver sgi_buttons_driver = {
124 	.probe	= sgi_buttons_probe,
125 	.driver	= {
126 		.name	= "sgibtns",
127 	},
128 };
129 module_platform_driver(sgi_buttons_driver);
130 
131 MODULE_LICENSE("GPL");
132