LXR linux/drivers/input/misc/rb532

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