root/kernel/irq/devres.c

DEFINITIONS

1. devm_irq_release
2. devm_irq_match
3. devm_request_irq
4. devm_free_irq

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/gfp.h>

/*
 * Device resource management aware IRQ request/free implementation.
 */
struct irq_devres {
        unsigned int irq;
        void *dev_id;
};

static void devm_irq_release(struct device *dev, void *res)
{
        struct irq_devres *this = res;

        free_irq(this->irq, this->dev_id);
}

static int devm_irq_match(struct device *dev, void *res, void *data)
{
        struct irq_devres *this = res, *match = data;

        return this->irq == match->irq && this->dev_id == match->dev_id;
}

/**
 *      devm_request_irq - allocate an interrupt line for a managed device
 *      @dev: device to request interrupt for
 *      @irq: Interrupt line to allocate
 *      @handler: Function to be called when the IRQ occurs
 *      @irqflags: Interrupt type flags
 *      @devname: An ascii name for the claiming device
 *      @dev_id: A cookie passed back to the handler function
 *
 *      Except for the extra @dev argument, this function takes the
 *      same arguments and performs the same function as
 *      request_irq().  IRQs requested with this function will be
 *      automatically freed on driver detach.
 *
 *      If an IRQ allocated with this function needs to be freed
 *      separately, dev_free_irq() must be used.
 */
int devm_request_irq(struct device *dev, unsigned int irq,
                     irq_handler_t handler, unsigned long irqflags,
                     const char *devname, void *dev_id)
{
        struct irq_devres *dr;
        int rc;

        dr = devres_alloc(devm_irq_release, sizeof(struct irq_devres),
                          GFP_KERNEL);
        if (!dr)
                return -ENOMEM;

        rc = request_irq(irq, handler, irqflags, devname, dev_id);
        if (rc) {
                devres_free(dr);
                return rc;
        }

        dr->irq = irq;
        dr->dev_id = dev_id;
        devres_add(dev, dr);

        return 0;
}
EXPORT_SYMBOL(devm_request_irq);

/**
 *      devm_free_irq - free an interrupt
 *      @dev: device to free interrupt for
 *      @irq: Interrupt line to free
 *      @dev_id: Device identity to free
 *
 *      Except for the extra @dev argument, this function takes the
 *      same arguments and performs the same function as free_irq().
 *      This function instead of free_irq() should be used to manually
 *      free IRQs allocated with dev_request_irq().
 */
void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id)
{
        struct irq_devres match_data = { irq, dev_id };

        free_irq(irq, dev_id);
        WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match,
                               &match_data));
}
EXPORT_SYMBOL(devm_free_irq);