linux/arch/xtensa/variants/s6000/gpio.c
Johannes Weiner 1fb137c1e3 xtensa: register gpio chip before use
Platform initialization sets up the LED heartbeat that is controlled
via GPIO.  Requesting the GPIO pins fails, however, as the chip is
only initialized later by a device_initcall().

Fix this up by exporting the initialization function.  Let the
platform set up the chip before it starts using it.

Signed-off-by: Johannes Weiner <jw@emlix.com>
Signed-off-by: Chris Zankel <chris@zankel.net>
2009-05-11 22:00:07 -07:00

71 lines
1.7 KiB
C

/*
* s6000 gpio driver
*
* Copyright (c) 2009 emlix GmbH
* Authors: Oskar Schirmer <os@emlix.com>
* Johannes Weiner <jw@emlix.com>
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/gpio.h>
#include <variant/hardware.h>
#define S6_GPIO_DATA 0x000
#define S6_GPIO_IS 0x404
#define S6_GPIO_IBE 0x408
#define S6_GPIO_IEV 0x40C
#define S6_GPIO_IE 0x410
#define S6_GPIO_RIS 0x414
#define S6_GPIO_MIS 0x418
#define S6_GPIO_IC 0x41C
#define S6_GPIO_AFSEL 0x420
#define S6_GPIO_DIR 0x800
#define S6_GPIO_BANK(nr) ((nr) * 0x1000)
#define S6_GPIO_MASK(nr) (4 << (nr))
#define S6_GPIO_OFFSET(nr) \
(S6_GPIO_BANK((nr) >> 3) + S6_GPIO_MASK((nr) & 7))
static int direction_input(struct gpio_chip *chip, unsigned int off)
{
writeb(0, S6_REG_GPIO + S6_GPIO_DIR + S6_GPIO_OFFSET(off));
return 0;
}
static int get(struct gpio_chip *chip, unsigned int off)
{
return readb(S6_REG_GPIO + S6_GPIO_DATA + S6_GPIO_OFFSET(off));
}
static int direction_output(struct gpio_chip *chip, unsigned int off, int val)
{
unsigned rel = S6_GPIO_OFFSET(off);
writeb(~0, S6_REG_GPIO + S6_GPIO_DIR + rel);
writeb(val ? ~0 : 0, S6_REG_GPIO + S6_GPIO_DATA + rel);
return 0;
}
static void set(struct gpio_chip *chip, unsigned int off, int val)
{
writeb(val ? ~0 : 0, S6_REG_GPIO + S6_GPIO_DATA + S6_GPIO_OFFSET(off));
}
static struct gpio_chip gpiochip = {
.owner = THIS_MODULE,
.direction_input = direction_input,
.get = get,
.direction_output = direction_output,
.set = set,
.base = 0,
.ngpio = 24,
.can_sleep = 0, /* no blocking io needed */
.exported = 0, /* no exporting to userspace */
};
int s6_gpio_init(void)
{
return gpiochip_add(&gpiochip);
}