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// SPDX-License-Identifier: GPL-2.0-only
/*
* Support for the S1 button on Routerboard 532
*
* Copyright (C) 2009 Phil Sutter <n0-1@freewrt.org>
*/
#include <linux/input.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <asm/mach-rc32434/gpio.h>
#include <asm/mach-rc32434/rb.h>
#define DRV_NAME "rb532-button"
#define RB532_BTN_RATE 100 /* msec */
#define RB532_BTN_KSYM BTN_0
/* The S1 button state is provided by GPIO pin 1. But as this
* pin is also used for uart input as alternate function, the
* operational modes must be switched first:
* 1) disable uart using set_latch_u5()
* 2) turn off alternate function implicitly through
* gpio_direction_input()
* 3) read the GPIO's current value
* 4) undo step 2 by enabling alternate function (in this
* mode the GPIO direction is fixed, so no change needed)
* 5) turn on uart again
* The GPIO value occurs to be inverted, so pin high means
* button is not pressed.
*/
static bool rb532_button_pressed(void)
{
int val;
set_latch_u5(0, LO_FOFF);
gpio_direction_input(GPIO_BTN_S1);
val = gpio_get_value(GPIO_BTN_S1);
rb532_gpio_set_func(GPIO_BTN_S1);
set_latch_u5(LO_FOFF, 0);
return !val;
}
static void rb532_button_poll(struct input_dev *input)
{
input_report_key(input, RB532_BTN_KSYM, rb532_button_pressed());
input_sync(input);
}
static int rb532_button_probe(struct platform_device *pdev)
{
struct input_dev *input;
int error;
input = devm_input_allocate_device(&pdev->dev);
if (!input)
return -ENOMEM;
input->name = "rb532 button";
input->phys = "rb532/button0";
input->id.bustype = BUS_HOST;
input_set_capability(input, EV_KEY, RB532_BTN_KSYM);
error = input_setup_polling(input, rb532_button_poll);
if (error)
return error;
input_set_poll_interval(input, RB532_BTN_RATE);
error = input_register_device(input);
if (error)
return error;
return 0;
}
static struct platform_driver rb532_button_driver = {
.probe = rb532_button_probe,
.driver = {
.name = DRV_NAME,
},
};
module_platform_driver(rb532_button_driver);
MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
MODULE_ALIAS("platform:" DRV_NAME);
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