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