Quelle  sensehat-joystick.c   Sprache: C

// 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 ");
MODULE_AUTHOR("Serge Schneider ");
MODULE_LICENSE("GPL");