OpenCloudOS-Kernel/arch/arm/plat-orion/include/plat/gpio.h

39 lines
937 B
C
Raw Normal View History

/*
* arch/arm/plat-orion/include/plat/gpio.h
*
* Marvell Orion SoC GPIO handling.
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#ifndef __PLAT_GPIO_H
#define __PLAT_GPIO_H
/*
* GENERIC_GPIO primitives.
*/
int gpio_request(unsigned pin, const char *label);
void gpio_free(unsigned pin);
int gpio_direction_input(unsigned pin);
int gpio_direction_output(unsigned pin, int value);
int gpio_get_value(unsigned pin);
void gpio_set_value(unsigned pin, int value);
/*
* Orion-specific GPIO API extensions.
*/
void orion_gpio_set_unused(unsigned pin);
void orion_gpio_set_valid(unsigned pin, int valid);
void orion_gpio_set_blink(unsigned pin, int blink);
/*
* GPIO interrupt handling.
*/
[ARM] 5401/1: Orion: fix edge triggered GPIO interrupt support The GPIO interrupts can be configured as either level triggered or edge triggered, with a default of level triggered. When an edge triggered interrupt is requested, the gpio_irq_set_type method is called which currently switches the given IRQ descriptor between two struct irq_chip instances: orion_gpio_irq_level_chip and orion_gpio_irq_edge_chip. This happens via __setup_irq() which also calls irq_chip_set_defaults() to assign default methods to uninitialized ones. The problem is that irq_chip_set_defaults() is called before the irq_chip reference is switched, leaving the new irq_chip (orion_gpio_irq_edge_chip in this case) with uninitialized methods such as chip->startup() causing a kernel oops. Many solutions are possible, such as making irq_chip_set_defaults() global and calling it from gpio_irq_set_type(), or calling __irq_set_trigger() before irq_chip_set_defaults() in __setup_irq(). But those require modifications to the generic IRQ code which might have adverse effect on other architectures, and that would still be a fragile arrangement. Manually copying the missing methods from within gpio_irq_set_type() would be really ugly and it would break again the day new methods with automatic defaults are added. A better solution is to have a single irq_chip instance which can deal with both edge and level triggered interrupts. It is also a good idea to switch the IRQ handler instead, as the edge IRQ handler allows for one edge IRQ event to be queued as the IRQ is actually masked only when that second IRQ is received, at which point the hardware can queue an additional IRQ event, making edge triggered interrupts a bit more reliable. Tested-by: Martin Michlmayr <tbm@cyrius.com> Signed-off-by: Nicolas Pitre <nico@marvell.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-02-18 03:45:50 +08:00
extern struct irq_chip orion_gpio_irq_chip;
void orion_gpio_irq_handler(int irqoff);
#endif