aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/input/joystick/sensehat-joystick.c
blob: a84df39d3b2fa6e3d88ba9671cfb693ae3b2d85d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Raspberry Pi Sense HAT joystick driver
 * http://raspberrypi.org
 *
 * Copyright (C) 2015 Raspberry Pi
 * Copyright (C) 2021 Charles Mirabile, Mwesigwa Guma, Joel Savitz
 *
 * Original Author: Serge Schneider
 * Revised for upstream Linux by: Charles Mirabile, Mwesigwa Guma, Joel Savitz
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/property.h>

#define JOYSTICK_SMB_REG 0xf2

struct sensehat_joystick {
	struct platform_device *pdev;
	struct input_dev *keys_dev;
	unsigned long prev_states;
	struct regmap *regmap;
};

static const unsigned int keymap[] = {
	BTN_DPAD_DOWN, BTN_DPAD_RIGHT, BTN_DPAD_UP, BTN_SELECT, BTN_DPAD_LEFT,
};

static irqreturn_t sensehat_joystick_report(int irq, void *cookie)
{
	struct sensehat_joystick *sensehat_joystick = cookie;
	unsigned long curr_states, changes;
	unsigned int keys;
	int error;
	int i;

	error = regmap_read(sensehat_joystick->regmap, JOYSTICK_SMB_REG, &keys);
	if (error < 0) {
		dev_err(&sensehat_joystick->pdev->dev,
			"Failed to read joystick state: %d", error);
		return IRQ_NONE;
	}
	curr_states = keys;
	bitmap_xor(&changes, &curr_states, &sensehat_joystick->prev_states,
		   ARRAY_SIZE(keymap));

	for_each_set_bit(i, &changes, ARRAY_SIZE(keymap))
		input_report_key(sensehat_joystick->keys_dev, keymap[i],
				 curr_states & BIT(i));

	input_sync(sensehat_joystick->keys_dev);
	sensehat_joystick->prev_states = keys;
	return IRQ_HANDLED;
}

static int sensehat_joystick_probe(struct platform_device *pdev)
{
	struct sensehat_joystick *sensehat_joystick;
	int error, i, irq;

	sensehat_joystick = devm_kzalloc(&pdev->dev, sizeof(*sensehat_joystick),
					 GFP_KERNEL);
	if (!sensehat_joystick)
		return -ENOMEM;

	sensehat_joystick->pdev = pdev;

	sensehat_joystick->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!sensehat_joystick->regmap) {
		dev_err(&pdev->dev, "unable to get sensehat regmap");
		return -ENODEV;
	}

	sensehat_joystick->keys_dev = devm_input_allocate_device(&pdev->dev);
	if (!sensehat_joystick->keys_dev) {
		dev_err(&pdev->dev, "Could not allocate input device");
		return -ENOMEM;
	}

	sensehat_joystick->keys_dev->name = "Raspberry Pi Sense HAT Joystick";
	sensehat_joystick->keys_dev->phys = "sensehat-joystick/input0";
	sensehat_joystick->keys_dev->id.bustype = BUS_I2C;

	__set_bit(EV_KEY, sensehat_joystick->keys_dev->evbit);
	__set_bit(EV_REP, sensehat_joystick->keys_dev->evbit);
	for (i = 0; i < ARRAY_SIZE(keymap); i++)
		__set_bit(keymap[i], sensehat_joystick->keys_dev->keybit);

	error = input_register_device(sensehat_joystick->keys_dev);
	if (error) {
		dev_err(&pdev->dev, "Could not register input device");
		return error;
	}

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	error = devm_request_threaded_irq(&pdev->dev, irq,
					  NULL, sensehat_joystick_report,
					  IRQF_ONESHOT, "keys",
					  sensehat_joystick);
	if (error) {
		dev_err(&pdev->dev, "IRQ request failed");
		return error;
	}

	return 0;
}

static const struct of_device_id sensehat_joystick_device_id[] = {
	{ .compatible = "raspberrypi,sensehat-joystick" },
	{},
};
MODULE_DEVICE_TABLE(of, sensehat_joystick_device_id);

static struct platform_driver sensehat_joystick_driver = {
	.probe = sensehat_joystick_probe,
	.driver = {
		.name = "sensehat-joystick",
		.of_match_table = sensehat_joystick_device_id,
	},
};

module_platform_driver(sensehat_joystick_driver);

MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
MODULE_AUTHOR("Charles Mirabile <cmirabil@redhat.com>");
MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
MODULE_LICENSE("GPL");