LXR linux/drivers/input/misc/rb532

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Support for the S1 button on Routerboard 532
   4 *
   5 * Copyright (C) 2009  Phil Sutter <n0-1@freewrt.org>
   6 */
   7
   8#include <linux/input-polldev.h>
   9#include <linux/module.h>
  10#include <linux/platform_device.h>
  11#include <linux/gpio.h>
  12
  13#include <asm/mach-rc32434/gpio.h>
  14#include <asm/mach-rc32434/rb.h>
  15
  16#define DRV_NAME "rb532-button"
  17
  18#define RB532_BTN_RATE 100 /* msec */
  19#define RB532_BTN_KSYM BTN_0
  20
  21/* The S1 button state is provided by GPIO pin 1. But as this
  22 * pin is also used for uart input as alternate function, the
  23 * operational modes must be switched first:
  24 * 1) disable uart using set_latch_u5()
  25 * 2) turn off alternate function implicitly through
  26 *    gpio_direction_input()
  27 * 3) read the GPIO's current value
  28 * 4) undo step 2 by enabling alternate function (in this
  29 *    mode the GPIO direction is fixed, so no change needed)
  30 * 5) turn on uart again
  31 * The GPIO value occurs to be inverted, so pin high means
  32 * button is not pressed.
  33 */
  34static bool rb532_button_pressed(void)
  35{
  36        int val;
  37
  38        set_latch_u5(0, LO_FOFF);
  39        gpio_direction_input(GPIO_BTN_S1);
  40
  41        val = gpio_get_value(GPIO_BTN_S1);
  42
  43        rb532_gpio_set_func(GPIO_BTN_S1);
  44        set_latch_u5(LO_FOFF, 0);
  45
  46        return !val;
  47}
  48
  49static void rb532_button_poll(struct input_polled_dev *poll_dev)
  50{
  51        input_report_key(poll_dev->input, RB532_BTN_KSYM,
  52                         rb532_button_pressed());
  53        input_sync(poll_dev->input);
  54}
  55
  56static int rb532_button_probe(struct platform_device *pdev)
  57{
  58        struct input_polled_dev *poll_dev;
  59        int error;
  60
  61        poll_dev = input_allocate_polled_device();
  62        if (!poll_dev)
  63                return -ENOMEM;
  64
  65        poll_dev->poll = rb532_button_poll;
  66        poll_dev->poll_interval = RB532_BTN_RATE;
  67
  68        poll_dev->input->name = "rb532 button";
  69        poll_dev->input->phys = "rb532/button0";
  70        poll_dev->input->id.bustype = BUS_HOST;
  71        poll_dev->input->dev.parent = &pdev->dev;
  72
  73        dev_set_drvdata(&pdev->dev, poll_dev);
  74
  75        input_set_capability(poll_dev->input, EV_KEY, RB532_BTN_KSYM);
  76
  77        error = input_register_polled_device(poll_dev);
  78        if (error) {
  79                input_free_polled_device(poll_dev);
  80                return error;
  81        }
  82
  83        return 0;
  84}
  85
  86static int rb532_button_remove(struct platform_device *pdev)
  87{
  88        struct input_polled_dev *poll_dev = dev_get_drvdata(&pdev->dev);
  89
  90        input_unregister_polled_device(poll_dev);
  91        input_free_polled_device(poll_dev);
  92
  93        return 0;
  94}
  95
  96static struct platform_driver rb532_button_driver = {
  97        .probe = rb532_button_probe,
  98        .remove = rb532_button_remove,
  99        .driver = {
 100                .name = DRV_NAME,
 101        },
 102};
 103module_platform_driver(rb532_button_driver);
 104
 105MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");
 106MODULE_LICENSE("GPL");
 107MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
 108MODULE_ALIAS("platform:" DRV_NAME);
 109