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[ARM] 4602/3: AT91: debugfs interface to view GPIO pin state

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This patch adds a debug interface (if CONFIG_DEBUG_FS is selected) to
display the basic configuration and current state of the GPIO pins on
the Atmel AT91 processors.

Signed-off-by: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Andrew Victor 2007-11-23 16:09:10 +01:00 committed by Russell King
parent 9b73e76f3c
commit b66545e7ae
1 changed files with 62 additions and 0 deletions
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62
arch/arm/mach-at91/gpio.c
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@ -13,6 +13,8 @@
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/debugfs.h>
#include <linux/seq_file.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
@ -414,6 +416,66 @@ static void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
/*--------------------------------------------------------------------------*/
#ifdef CONFIG_DEBUG_FS
static int at91_gpio_show(struct seq_file *s, void *unused)
{
int bank, j;
/* print heading */
seq_printf(s, "Pin\t");
for (bank = 0; bank < gpio_banks; bank++) {
seq_printf(s, "PIO%c\t", 'A' + bank);
};
seq_printf(s, "\n\n");
/* print pin status */
for (j = 0; j < 32; j++) {
seq_printf(s, "%i:\t", j);
for (bank = 0; bank < gpio_banks; bank++) {
unsigned pin = PIN_BASE + (32 * bank) + j;
void __iomem *pio = pin_to_controller(pin);
unsigned mask = pin_to_mask(pin);
if (__raw_readl(pio + PIO_PSR) & mask)
seq_printf(s, "GPIO:%s", __raw_readl(pio + PIO_PDSR) & mask ? "1" : "0");
else
seq_printf(s, "%s", __raw_readl(pio + PIO_ABSR) & mask ? "B" : "A");
seq_printf(s, "\t");
}
seq_printf(s, "\n");
}
return 0;
}
static int at91_gpio_open(struct inode *inode, struct file *file)
{
return single_open(file, at91_gpio_show, NULL);
}
static const struct file_operations at91_gpio_operations = {
.open = at91_gpio_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static int __init at91_gpio_debugfs_init(void)
{
/* /sys/kernel/debug/at91_gpio */
(void) debugfs_create_file("at91_gpio", S_IFREG | S_IRUGO, NULL, NULL, &at91_gpio_operations);
return 0;
}
postcore_initcall(at91_gpio_debugfs_init);
#endif
/*--------------------------------------------------------------------------*/
/*
* Called from the processor-specific init to enable GPIO interrupt support.
*/