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[ARM] 5324/2: ep93xx: support gpio interrupt debounce

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Add debounce support for ep93xx gpio interrupts.

On the EP93xx, GPIO ports A, B, and F can be used to generate
interrupts. For each port, if interrupts are enabled, it is
possible to debouce the input signal. Debouncing is implemented
by passing the input signal through a 2-bit shift register clocked
by a 128Hz clock.

This patch adds a platform specific way to enable the debouce
feature for these input ports.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Hartley Sweeten 2008-10-28 17:55:30 +01:00 committed by Russell King
parent d52a26a956
commit 799a0600ac
2 changed files with 20 additions and 0 deletions
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18
arch/arm/mach-ep93xx/core.c
View File

@ -155,12 +155,14 @@ static unsigned char gpio_int_unmasked[3];
static unsigned char gpio_int_enabled[3];
static unsigned char gpio_int_type1[3];
static unsigned char gpio_int_type2[3];
static unsigned char gpio_int_debouce[3];
/* Port ordering is: A B F */
static const u8 int_type1_register_offset[3] = { 0x90, 0xac, 0x4c };
static const u8 int_type2_register_offset[3] = { 0x94, 0xb0, 0x50 };
static const u8 eoi_register_offset[3] = { 0x98, 0xb4, 0x54 };
static const u8 int_en_register_offset[3] = { 0x9c, 0xb8, 0x58 };
static const u8 int_debounce_register_offset[3] = { 0xa8, 0xc4, 0x64 };
void ep93xx_gpio_update_int_params(unsigned port)
{
@ -183,6 +185,22 @@ void ep93xx_gpio_int_mask(unsigned line)
gpio_int_unmasked[line >> 3] &= ~(1 << (line & 7));
}
void ep93xx_gpio_int_debounce(unsigned int irq, int enable)
{
int line = irq_to_gpio(irq);
int port = line >> 3;
int port_mask = 1 << (line & 7);
if (enable)
gpio_int_debouce[port] |= port_mask;
else
gpio_int_debouce[port] &= ~port_mask;
__raw_writeb(gpio_int_debouce[port],
EP93XX_GPIO_REG(int_debounce_register_offset[port]));
}
EXPORT_SYMBOL(ep93xx_gpio_int_debounce);
/*************************************************************************
* EP93xx IRQ handling
*************************************************************************/

2
arch/arm/mach-ep93xx/include/mach/gpio.h
View File

@ -99,6 +99,8 @@
/* maximum value for irq capable line identifiers */
#define EP93XX_GPIO_LINE_MAX_IRQ EP93XX_GPIO_LINE_F(7)
extern void ep93xx_gpio_int_debounce(unsigned int irq, int enable);
/* new generic GPIO API - see Documentation/gpio.txt */
#include <asm-generic/gpio.h>