linux/kernel/irq/devres.c
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   1#include <linux/module.h>
   2#include <linux/interrupt.h>
   3#include <linux/device.h>
   4#include <linux/gfp.h>
   5
   6/*
   7 * Device resource management aware IRQ request/free implementation.
   8 */
   9struct irq_devres {
  10        unsigned int irq;
  11        void *dev_id;
  12};
  13
  14static void devm_irq_release(struct device *dev, void *res)
  15{
  16        struct irq_devres *this = res;
  17
  18        free_irq(this->irq, this->dev_id);
  19}
  20
  21static int devm_irq_match(struct device *dev, void *res, void *data)
  22{
  23        struct irq_devres *this = res, *match = data;
  24
  25        return this->irq == match->irq && this->dev_id == match->dev_id;
  26}
  27
  28/**
  29 *      devm_request_threaded_irq - allocate an interrupt line for a managed device
  30 *      @dev: device to request interrupt for
  31 *      @irq: Interrupt line to allocate
  32 *      @handler: Function to be called when the IRQ occurs
  33 *      @thread_fn: function to be called in a threaded interrupt context. NULL
  34 *                  for devices which handle everything in @handler
  35 *      @irqflags: Interrupt type flags
  36 *      @devname: An ascii name for the claiming device
  37 *      @dev_id: A cookie passed back to the handler function
  38 *
  39 *      Except for the extra @dev argument, this function takes the
  40 *      same arguments and performs the same function as
  41 *      request_irq().  IRQs requested with this function will be
  42 *      automatically freed on driver detach.
  43 *
  44 *      If an IRQ allocated with this function needs to be freed
  45 *      separately, devm_free_irq() must be used.
  46 */
  47int devm_request_threaded_irq(struct device *dev, unsigned int irq,
  48                              irq_handler_t handler, irq_handler_t thread_fn,
  49                              unsigned long irqflags, const char *devname,
  50                              void *dev_id)
  51{
  52        struct irq_devres *dr;
  53        int rc;
  54
  55        dr = devres_alloc(devm_irq_release, sizeof(struct irq_devres),
  56                          GFP_KERNEL);
  57        if (!dr)
  58                return -ENOMEM;
  59
  60        rc = request_threaded_irq(irq, handler, thread_fn, irqflags, devname,
  61                                  dev_id);
  62        if (rc) {
  63                devres_free(dr);
  64                return rc;
  65        }
  66
  67        dr->irq = irq;
  68        dr->dev_id = dev_id;
  69        devres_add(dev, dr);
  70
  71        return 0;
  72}
  73EXPORT_SYMBOL(devm_request_threaded_irq);
  74
  75/**
  76 *      devm_free_irq - free an interrupt
  77 *      @dev: device to free interrupt for
  78 *      @irq: Interrupt line to free
  79 *      @dev_id: Device identity to free
  80 *
  81 *      Except for the extra @dev argument, this function takes the
  82 *      same arguments and performs the same function as free_irq().
  83 *      This function instead of free_irq() should be used to manually
  84 *      free IRQs allocated with devm_request_irq().
  85 */
  86void devm_free_irq(struct device *dev, unsigned int irq, void *dev_id)
  87{
  88        struct irq_devres match_data = { irq, dev_id };
  89
  90        WARN_ON(devres_destroy(dev, devm_irq_release, devm_irq_match,
  91                               &match_data));
  92        free_irq(irq, dev_id);
  93}
  94EXPORT_SYMBOL(devm_free_irq);
  95
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