[PATCH 1/3] irq: If an IRQ is a GPIO, request and configure it

Stephen Warren
2011-08-04T23:00:18Z

Many IRQs are associated with GPIO pins. When the pin is used as an IRQ,
it can't be used as anything else; it should be requested. Enhance the
core interrupt code to call gpio_request() and gpio_direction_input() for
any IRQ that is also a GPIO. This prevents duplication of these calls in
each driver that uses an IRQ.

Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
kernel/irq/manage.c | 23 +++++++++++++++++++++--
1 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0a7840a..6e2db72 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -7,6 +7,7 @@
* This file contains driver APIs to the irq subsystem.
*/

+#include <linux/gpio.h>
#include <linux/irq.h>
#include <linux/kthread.h>
#include <linux/module.h>
@@ -875,7 +876,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
struct irqaction *old, **old_ptr;
const char *old_name = NULL;
unsigned long flags, thread_mask = 0;
- int ret, nested, shared = 0;
+ int ret, nested, shared = 0, gpio = -1;
cpumask_var_t mask;

if (!desc)
@@ -978,6 +979,16 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
old = *old_ptr;
} while (old);
shared = 1;
+ } else {
+ gpio = irq_to_gpio(irq);
+ if (gpio_is_valid(gpio)) {
+ ret = gpio_request(gpio, new->name);
+ if (ret < 0)
+ goto out_mask;
+ ret = gpio_direction_input(gpio);
+ if (ret < 0)
+ goto out_mask;
+ }
}

/*
@@ -1083,6 +1094,8 @@ mismatch:
ret = -EBUSY;

out_mask:
+ if (gpio_is_valid(gpio))
+ gpio_free(gpio);
raw_spin_unlock_irqrestore(&desc->lock, flags);
free_cpumask_var(mask);

@@ -1127,6 +1140,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
struct irq_desc *desc = irq_to_desc(irq);
struct irqaction *action, **action_ptr;
unsigned long flags;
+ int gpio;

WARN(in_interrupt(), "Trying to free IRQ %d from IRQ context!\n", irq);

@@ -1165,8 +1179,13 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
#endif

/* If this was the last handler, shut down the IRQ line: */
- if (!desc->action)
+ if (!desc->action) {
irq_shutdown(desc);
+ /* If the IRQ line is a GPIO, it's no longer in use */
+ gpio = irq_to_gpio(irq);
+ if (gpio_is_valid(gpio))
+ gpio_free(gpio);
+ }

#ifdef CONFIG_SMP
/* make sure affinity_hint is cleaned up */
--
1.7.0.4