cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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rb532_button.c (2265B)

      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.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_dev *input)
     50{
     51	input_report_key(input, RB532_BTN_KSYM, rb532_button_pressed());
     52	input_sync(input);
     53}
     54
     55static int rb532_button_probe(struct platform_device *pdev)
     56{
     57	struct input_dev *input;
     58	int error;
     59
     60	input = devm_input_allocate_device(&pdev->dev);
     61	if (!input)
     62		return -ENOMEM;
     63
     64	input->name = "rb532 button";
     65	input->phys = "rb532/button0";
     66	input->id.bustype = BUS_HOST;
     67
     68	input_set_capability(input, EV_KEY, RB532_BTN_KSYM);
     69
     70	error = input_setup_polling(input, rb532_button_poll);
     71	if (error)
     72		return error;
     73
     74	input_set_poll_interval(input, RB532_BTN_RATE);
     75
     76	error = input_register_device(input);
     77	if (error)
     78		return error;
     79
     80	return 0;
     81}
     82
     83static struct platform_driver rb532_button_driver = {
     84	.probe = rb532_button_probe,
     85	.driver = {
     86		.name = DRV_NAME,
     87	},
     88};
     89module_platform_driver(rb532_button_driver);
     90
     91MODULE_AUTHOR("Phil Sutter <n0-1@freewrt.org>");
     92MODULE_LICENSE("GPL");
     93MODULE_DESCRIPTION("Support for S1 button on Routerboard 532");
     94MODULE_ALIAS("platform:" DRV_NAME);