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
 23struct sensehat_joystick {
 24	struct platform_device *pdev;
 25	struct input_dev *keys_dev;
 26	unsigned long prev_states;
 27	struct regmap *regmap;
 28};
 29
 30static const unsigned int keymap[] = {
 31	BTN_DPAD_DOWN, BTN_DPAD_RIGHT, BTN_DPAD_UP, BTN_SELECT, BTN_DPAD_LEFT,
 32};
 33
 34static 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
 61static 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
116static const struct of_device_id sensehat_joystick_device_id[] = {
117	{ .compatible = "raspberrypi,sensehat-joystick" },
118	{},
119};
120MODULE_DEVICE_TABLE(of, sensehat_joystick_device_id);
121
122static 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
130module_platform_driver(sensehat_joystick_driver);
131
132MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
133MODULE_AUTHOR("Charles Mirabile <cmirabil@redhat.com>");
134MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
135MODULE_LICENSE("GPL");