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-polldev.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        struct input_polled_dev *poll_dev;
  49        unsigned short keymap[ARRAY_SIZE(sgi_map)];
  50        int count[ARRAY_SIZE(sgi_map)];
  51};
  52
  53static void handle_buttons(struct input_polled_dev *dev)
  54{
  55        struct buttons_dev *bdev = dev->private;
  56        struct input_dev *input = dev->input;
  57        u8 status;
  58        int i;
  59
  60        status = button_status();
  61
  62        for (i = 0; i < ARRAY_SIZE(bdev->keymap); i++) {
  63                if (status & (1U << i)) {
  64                        if (++bdev->count[i] == BUTTONS_COUNT_THRESHOLD) {
  65                                input_event(input, EV_MSC, MSC_SCAN, i);
  66                                input_report_key(input, bdev->keymap[i], 1);
  67                                input_sync(input);
  68                        }
  69                } else {
  70                        if (bdev->count[i] >= BUTTONS_COUNT_THRESHOLD) {
  71                                input_event(input, EV_MSC, MSC_SCAN, i);
  72                                input_report_key(input, bdev->keymap[i], 0);
  73                                input_sync(input);
  74                        }
  75                        bdev->count[i] = 0;
  76                }
  77        }
  78}
  79
  80static int sgi_buttons_probe(struct platform_device *pdev)
  81{
  82        struct buttons_dev *bdev;
  83        struct input_polled_dev *poll_dev;
  84        struct input_dev *input;
  85        int error, i;
  86
  87        bdev = kzalloc(sizeof(struct buttons_dev), GFP_KERNEL);
  88        poll_dev = input_allocate_polled_device();
  89        if (!bdev || !poll_dev) {
  90                error = -ENOMEM;
  91                goto err_free_mem;
  92        }
  93
  94        memcpy(bdev->keymap, sgi_map, sizeof(bdev->keymap));
  95
  96        poll_dev->private = bdev;
  97        poll_dev->poll = handle_buttons;
  98        poll_dev->poll_interval = BUTTONS_POLL_INTERVAL;
  99
 100        input = poll_dev->input;
 101        input->name = "SGI buttons";
 102        input->phys = "sgi/input0";
 103        input->id.bustype = BUS_HOST;
 104        input->dev.parent = &pdev->dev;
 105
 106        input->keycode = bdev->keymap;
 107        input->keycodemax = ARRAY_SIZE(bdev->keymap);
 108        input->keycodesize = sizeof(unsigned short);
 109
 110        input_set_capability(input, EV_MSC, MSC_SCAN);
 111        __set_bit(EV_KEY, input->evbit);
 112        for (i = 0; i < ARRAY_SIZE(sgi_map); i++)
 113                __set_bit(bdev->keymap[i], input->keybit);
 114        __clear_bit(KEY_RESERVED, input->keybit);
 115
 116        bdev->poll_dev = poll_dev;
 117        platform_set_drvdata(pdev, bdev);
 118
 119        error = input_register_polled_device(poll_dev);
 120        if (error)
 121                goto err_free_mem;
 122
 123        return 0;
 124
 125 err_free_mem:
 126        input_free_polled_device(poll_dev);
 127        kfree(bdev);
 128        return error;
 129}
 130
 131static int sgi_buttons_remove(struct platform_device *pdev)
 132{
 133        struct buttons_dev *bdev = platform_get_drvdata(pdev);
 134
 135        input_unregister_polled_device(bdev->poll_dev);
 136        input_free_polled_device(bdev->poll_dev);
 137        kfree(bdev);
 138
 139        return 0;
 140}
 141
 142static struct platform_driver sgi_buttons_driver = {
 143        .probe  = sgi_buttons_probe,
 144        .remove = sgi_buttons_remove,
 145        .driver = {
 146                .name   = "sgibtns",
 147        },
 148};
 149module_platform_driver(sgi_buttons_driver);
 150
 151MODULE_LICENSE("GPL");
 152