// 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/consumer.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 /** * struct rb532_button - RB532 button information * @gpio: GPIO connected to the button */struct rb532_button {	struct gpio_desc	*gpio;}; /* 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(struct rb532_button *button){	int val; 	set_latch_u5(0, LO_FOFF);	gpiod_direction_input(button->gpio); 	val = gpiod_get_value(button->gpio); 	rb532_gpio_set_func(GPIO_BTN_S1);	set_latch_u5(LO_FOFF, 0); 	return val;} static void rb532_button_poll(struct input_dev *input){	struct rb532_button *button = input_get_drvdata(input); 	input_report_key(input, RB532_BTN_KSYM, rb532_button_pressed(button));	input_sync(input);} static int rb532_button_probe(struct platform_device *pdev){	struct rb532_button *button;	struct input_dev *input;	int error; 	button = devm_kzalloc(&pdev->dev, sizeof(*button), GFP_KERNEL);	if (!button)		return -ENOMEM; 	button->gpio = devm_gpiod_get(&pdev->dev, "button", GPIOD_IN);	if (IS_ERR(button->gpio))		return dev_err_probe(&pdev->dev, PTR_ERR(button->gpio),				     "error getting button GPIO\n"); 	input = devm_input_allocate_device(&pdev->dev);	if (!input)		return -ENOMEM;	input_set_drvdata(input, button); 	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; 	platform_set_drvdata(pdev, button); 	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);