kernel/irq/devres.c

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