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