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/*
* uart_sel.c - UART Selection Driver
*
* Copyright (C) 2009 Samsung Electronics
* Kim Kyuwon <q1.kim@samsung.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/uart_select.h>
struct uart_select {
struct uart_select_platform_data *pdata;
struct rw_semaphore rwsem;
};
static int uart_saved_state = UART_SW_PATH_NA;
static ssize_t uart_select_show_state(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct uart_select *uart_sel =
platform_get_drvdata(to_platform_device(dev));
int ret;
int path;
path = uart_sel->pdata->get_uart_switch();
down_read(&uart_sel->rwsem);
uart_saved_state = path;
if (path == UART_SW_PATH_NA)
ret = sprintf(buf, "NA\n");
else if (path == UART_SW_PATH_CP)
ret = sprintf(buf, "CP\n");
else
ret = sprintf(buf, "AP\n");
up_read(&uart_sel->rwsem);
return ret;
}
static ssize_t uart_select_store_state(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct uart_select *uart_sel =
platform_get_drvdata(to_platform_device(dev));
struct uart_select_platform_data *pdata = uart_sel->pdata;
int path;
if (!count)
return -EINVAL;
down_write(&uart_sel->rwsem);
if (!strncmp(buf, "CP", 2))
path = UART_SW_PATH_CP;
else if (!strncmp(buf, "AP", 2))
path = UART_SW_PATH_AP;
else {
up_write(&uart_sel->rwsem);
dev_err(dev, "Invalid cmd !!\n");
return -EINVAL;
}
pdata->set_uart_switch(path);
uart_saved_state = path;
up_write(&uart_sel->rwsem);
return count;
}
static struct device_attribute uart_select_attr = {
.attr = {
.name = "path",
.mode = 0644,
},
.show = uart_select_show_state,
.store = uart_select_store_state,
};
/* Used in uart isr to avoid triggering sysrq when uart is not in AP */
int uart_sel_get_state(void)
{
if (uart_saved_state < 0)
return -EPERM;
else
return uart_saved_state;
}
EXPORT_SYMBOL(uart_sel_get_state);
static int __devinit uart_select_probe(struct platform_device *pdev)
{
struct uart_select *uart_sel;
struct uart_select_platform_data *pdata = pdev->dev.platform_data;
int ret;
uart_sel = kzalloc(sizeof(struct uart_select), GFP_KERNEL);
if (!uart_sel) {
dev_err(&pdev->dev, "failed to allocate driver data\n");
return -ENOMEM;
}
platform_set_drvdata(pdev, uart_sel);
uart_sel->pdata = pdata;
init_rwsem(&uart_sel->rwsem);
uart_saved_state = pdata->get_uart_switch();
ret = device_create_file(&pdev->dev, &uart_select_attr);
if (ret) {
dev_err(&pdev->dev, "failed to crreate device file\n");
return ret;
}
return 0;
}
static int __devexit uart_select_remove(struct platform_device *pdev)
{
device_remove_file(&pdev->dev, &uart_select_attr);
platform_set_drvdata(pdev, NULL);
return 0;
}
static struct platform_driver uart_select_driver = {
.probe = uart_select_probe,
.remove = __devexit_p(uart_select_remove),
.driver = {
.name = "uart-select",
.owner = THIS_MODULE,
},
};
static int __init uart_select_init(void)
{
return platform_driver_register(&uart_select_driver);
}
module_init(uart_select_init);
static void __exit uart_select_exit(void)
{
platform_driver_unregister(&uart_select_driver);
}
module_exit(uart_select_exit);
MODULE_AUTHOR("Kim Kyuwon <q1.kim@samsung.com>");
MODULE_DESCRIPTION("UART Selection Driver");
MODULE_LICENSE("GPL v2");
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