1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Raspberry Pi Sense HAT joystick driver
4 * http://raspberrypi.org
5 *
6 * Copyright (C) 2015 Raspberry Pi
7 * Copyright (C) 2021 Charles Mirabile, Mwesigwa Guma, Joel Savitz
8 *
9 * Original Author: Serge Schneider
10 * Revised for upstream Linux by: Charles Mirabile, Mwesigwa Guma, Joel Savitz
11 */
12
13 #include <linux/module.h>
14 #include <linux/input.h>
15 #include <linux/i2c.h>
16 #include <linux/interrupt.h>
17 #include <linux/platform_device.h>
18 #include <linux/regmap.h>
19 #include <linux/property.h>
20
21 #define JOYSTICK_SMB_REG 0xf2
22
23 struct sensehat_joystick {
24 struct platform_device *pdev;
25 struct input_dev *keys_dev;
26 unsigned long prev_states;
27 struct regmap *regmap;
28 };
29
30 static const unsigned int keymap[] = {
31 BTN_DPAD_DOWN, BTN_DPAD_RIGHT, BTN_DPAD_UP, BTN_SELECT, BTN_DPAD_LEFT,
32 };
33
sensehat_joystick_report(int irq,void * cookie)34 static irqreturn_t sensehat_joystick_report(int irq, void *cookie)
35 {
36 struct sensehat_joystick *sensehat_joystick = cookie;
37 unsigned long curr_states, changes;
38 unsigned int keys;
39 int error;
40 int i;
41
42 error = regmap_read(sensehat_joystick->regmap, JOYSTICK_SMB_REG, &keys);
43 if (error < 0) {
44 dev_err(&sensehat_joystick->pdev->dev,
45 "Failed to read joystick state: %d", error);
46 return IRQ_NONE;
47 }
48 curr_states = keys;
49 bitmap_xor(&changes, &curr_states, &sensehat_joystick->prev_states,
50 ARRAY_SIZE(keymap));
51
52 for_each_set_bit(i, &changes, ARRAY_SIZE(keymap))
53 input_report_key(sensehat_joystick->keys_dev, keymap[i],
54 curr_states & BIT(i));
55
56 input_sync(sensehat_joystick->keys_dev);
57 sensehat_joystick->prev_states = keys;
58 return IRQ_HANDLED;
59 }
60
sensehat_joystick_probe(struct platform_device * pdev)61 static int sensehat_joystick_probe(struct platform_device *pdev)
62 {
63 struct sensehat_joystick *sensehat_joystick;
64 int error, i, irq;
65
66 sensehat_joystick = devm_kzalloc(&pdev->dev, sizeof(*sensehat_joystick),
67 GFP_KERNEL);
68 if (!sensehat_joystick)
69 return -ENOMEM;
70
71 sensehat_joystick->pdev = pdev;
72
73 sensehat_joystick->regmap = dev_get_regmap(pdev->dev.parent, NULL);
74 if (!sensehat_joystick->regmap) {
75 dev_err(&pdev->dev, "unable to get sensehat regmap");
76 return -ENODEV;
77 }
78
79 sensehat_joystick->keys_dev = devm_input_allocate_device(&pdev->dev);
80 if (!sensehat_joystick->keys_dev) {
81 dev_err(&pdev->dev, "Could not allocate input device");
82 return -ENOMEM;
83 }
84
85 sensehat_joystick->keys_dev->name = "Raspberry Pi Sense HAT Joystick";
86 sensehat_joystick->keys_dev->phys = "sensehat-joystick/input0";
87 sensehat_joystick->keys_dev->id.bustype = BUS_I2C;
88
89 __set_bit(EV_KEY, sensehat_joystick->keys_dev->evbit);
90 __set_bit(EV_REP, sensehat_joystick->keys_dev->evbit);
91 for (i = 0; i < ARRAY_SIZE(keymap); i++)
92 __set_bit(keymap[i], sensehat_joystick->keys_dev->keybit);
93
94 error = input_register_device(sensehat_joystick->keys_dev);
95 if (error) {
96 dev_err(&pdev->dev, "Could not register input device");
97 return error;
98 }
99
100 irq = platform_get_irq(pdev, 0);
101 if (irq < 0)
102 return irq;
103
104 error = devm_request_threaded_irq(&pdev->dev, irq,
105 NULL, sensehat_joystick_report,
106 IRQF_ONESHOT, "keys",
107 sensehat_joystick);
108 if (error) {
109 dev_err(&pdev->dev, "IRQ request failed");
110 return error;
111 }
112
113 return 0;
114 }
115
116 static const struct of_device_id sensehat_joystick_device_id[] = {
117 { .compatible = "raspberrypi,sensehat-joystick" },
118 {},
119 };
120 MODULE_DEVICE_TABLE(of, sensehat_joystick_device_id);
121
122 static struct platform_driver sensehat_joystick_driver = {
123 .probe = sensehat_joystick_probe,
124 .driver = {
125 .name = "sensehat-joystick",
126 .of_match_table = sensehat_joystick_device_id,
127 },
128 };
129
130 module_platform_driver(sensehat_joystick_driver);
131
132 MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
133 MODULE_AUTHOR("Charles Mirabile <cmirabil@redhat.com>");
134 MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
135 MODULE_LICENSE("GPL");
136