devres.c

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#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;
}

int devm_request_threaded_irq(struct device *dev, unsigned int irq,
                  irq_handler_t handler, irq_handler_t thread_fn,
                  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_threaded_irq(irq, handler, thread_fn, 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_threaded_irq);

void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id)
{
    struct irq_devres match_data = { irq, dev_id };

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