nios2: add gpio support

This patch adds driver for a trivial gpio core, which is described
in http://nioswiki.com/GPIO. It is used for gpio led and nand flash
interface in u-boot.

When CONFIG_SYS_GPIO_BASE is not defined, board may provide
its own driver.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Tested-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
This commit is contained in:
Thomas Chou 2010-04-30 11:34:13 +08:00 committed by Scott McNutt
parent 01f03bda5b
commit cedd341d55

View file

@ -0,0 +1,52 @@
/*
* nios2 gpio driver
*
* This gpio core is described in http://nioswiki.com/GPIO
* bit[0] data
* bit[1] output enable
*
* when CONFIG_SYS_GPIO_BASE is not defined, board may provide
* its own driver.
*
* Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
*
* 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.
*/
#ifndef _ASM_NIOS2_GPIO_H_
#define _ASM_NIOS2_GPIO_H_
#ifdef CONFIG_SYS_GPIO_BASE
#include <asm/io.h>
static inline int gpio_direction_input(unsigned gpio)
{
writel(1, CONFIG_SYS_GPIO_BASE + (gpio << 2));
return 0;
}
static inline int gpio_direction_output(unsigned gpio, int value)
{
writel(value ? 3 : 2, CONFIG_SYS_GPIO_BASE + (gpio << 2));
return 0;
}
static inline int gpio_get_value(unsigned gpio)
{
return readl(CONFIG_SYS_GPIO_BASE + (gpio << 2));
}
static inline void gpio_set_value(unsigned gpio, int value)
{
writel(value ? 3 : 2, CONFIG_SYS_GPIO_BASE + (gpio << 2));
}
#else
extern int gpio_direction_input(unsigned gpio);
extern int gpio_direction_output(unsigned gpio, int value);
extern int gpio_get_value(unsigned gpio);
extern void gpio_set_value(unsigned gpio, int value);
#endif /* CONFIG_SYS_GPIO_BASE */
#endif /* _ASM_NIOS2_GPIO_H_ */