drivers/input/joystick/sensehat-joystick.c

   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
  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
  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                 dev_err(&pdev->dev, "Could not retrieve interrupt request");
 103                 return irq;
 104         }
 105
 106         error = devm_request_threaded_irq(&pdev->dev, irq,
 107                                           NULL, sensehat_joystick_report,
 108                                           IRQF_ONESHOT, "keys",
 109                                           sensehat_joystick);
 110         if (error) {
 111                 dev_err(&pdev->dev, "IRQ request failed");
 112                 return error;
 113         }
 114
 115         return 0;
 116 }
 117
 118 static const struct of_device_id sensehat_joystick_device_id[] = {
 119         { .compatible = "raspberrypi,sensehat-joystick" },
 120         {},
 121 };
 122 MODULE_DEVICE_TABLE(of, sensehat_joystick_device_id);
 123
 124 static struct platform_driver sensehat_joystick_driver = {
 125         .probe = sensehat_joystick_probe,
 126         .driver = {
 127                 .name = "sensehat-joystick",
 128                 .of_match_table = sensehat_joystick_device_id,
 129         },
 130 };
 131
 132 module_platform_driver(sensehat_joystick_driver);
 133
 134 MODULE_DESCRIPTION("Raspberry Pi Sense HAT joystick driver");
 135 MODULE_AUTHOR("Charles Mirabile <cmirabil@redhat.com>");
 136 MODULE_AUTHOR("Serge Schneider <serge@raspberrypi.org>");
 137 MODULE_LICENSE("GPL");