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    Subject[PATCH 1/3] irq: If an IRQ is a GPIO, request and configure it
    Date
    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@nvidia.com>
    ---
    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


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