linux/drivers/input/misc/sgi_btns.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  SGI Volume Button interface driver
   4 *
   5 *  Copyright (C) 2008  Thomas Bogendoerfer <tsbogend@alpha.franken.de>
   6 */
   7#include <linux/input.h>
   8#include <linux/ioport.h>
   9#include <linux/module.h>
  10#include <linux/platform_device.h>
  11#include <linux/slab.h>
  12
  13#ifdef CONFIG_SGI_IP22
  14#include <asm/sgi/ioc.h>
  15
  16static inline u8 button_status(void)
  17{
  18        u8 status;
  19
  20        status = readb(&sgioc->panel) ^ 0xa0;
  21        return ((status & 0x80) >> 6) | ((status & 0x20) >> 5);
  22}
  23#endif
  24
  25#ifdef CONFIG_SGI_IP32
  26#include <asm/ip32/mace.h>
  27
  28static inline u8 button_status(void)
  29{
  30        u64 status;
  31
  32        status = readq(&mace->perif.audio.control);
  33        writeq(status & ~(3U << 23), &mace->perif.audio.control);
  34
  35        return (status >> 23) & 3;
  36}
  37#endif
  38
  39#define BUTTONS_POLL_INTERVAL   30      /* msec */
  40#define BUTTONS_COUNT_THRESHOLD 3
  41
  42static const unsigned short sgi_map[] = {
  43        KEY_VOLUMEDOWN,
  44        KEY_VOLUMEUP
  45};
  46
  47struct buttons_dev {
  48        unsigned short keymap[ARRAY_SIZE(sgi_map)];
  49        int count[ARRAY_SIZE(sgi_map)];
  50};
  51
  52static void handle_buttons(struct input_dev *input)
  53{
  54        struct buttons_dev *bdev = input_get_drvdata(input);
  55        u8 status;
  56        int i;
  57
  58        status = button_status();
  59
  60        for (i = 0; i < ARRAY_SIZE(bdev->keymap); i++) {
  61                if (status & (1U << i)) {
  62                        if (++bdev->count[i] == BUTTONS_COUNT_THRESHOLD) {
  63                                input_event(input, EV_MSC, MSC_SCAN, i);
  64                                input_report_key(input, bdev->keymap[i], 1);
  65                                input_sync(input);
  66                        }
  67                } else {
  68                        if (bdev->count[i] >= BUTTONS_COUNT_THRESHOLD) {
  69                                input_event(input, EV_MSC, MSC_SCAN, i);
  70                                input_report_key(input, bdev->keymap[i], 0);
  71                                input_sync(input);
  72                        }
  73                        bdev->count[i] = 0;
  74                }
  75        }
  76}
  77
  78static int sgi_buttons_probe(struct platform_device *pdev)
  79{
  80        struct buttons_dev *bdev;
  81        struct input_dev *input;
  82        int error, i;
  83
  84        bdev = devm_kzalloc(&pdev->dev, sizeof(*bdev), GFP_KERNEL);
  85        if (!bdev)
  86                return -ENOMEM;
  87
  88        input = devm_input_allocate_device(&pdev->dev);
  89        if (!input)
  90                return -ENOMEM;
  91
  92        memcpy(bdev->keymap, sgi_map, sizeof(bdev->keymap));
  93
  94        input_set_drvdata(input, bdev);
  95
  96        input->name = "SGI buttons";
  97        input->phys = "sgi/input0";
  98        input->id.bustype = BUS_HOST;
  99
 100        input->keycode = bdev->keymap;
 101        input->keycodemax = ARRAY_SIZE(bdev->keymap);
 102        input->keycodesize = sizeof(unsigned short);
 103
 104        input_set_capability(input, EV_MSC, MSC_SCAN);
 105        __set_bit(EV_KEY, input->evbit);
 106        for (i = 0; i < ARRAY_SIZE(sgi_map); i++)
 107                __set_bit(bdev->keymap[i], input->keybit);
 108        __clear_bit(KEY_RESERVED, input->keybit);
 109
 110        error = input_setup_polling(input, handle_buttons);
 111        if (error)
 112                return error;
 113
 114        input_set_poll_interval(input, BUTTONS_POLL_INTERVAL);
 115
 116        error = input_register_device(input);
 117        if (error)
 118                return error;
 119
 120        return 0;
 121}
 122
 123static struct platform_driver sgi_buttons_driver = {
 124        .probe  = sgi_buttons_probe,
 125        .driver = {
 126                .name   = "sgibtns",
 127        },
 128};
 129module_platform_driver(sgi_buttons_driver);
 130
 131MODULE_LICENSE("GPL");
 132
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