kernel/irq/devres.c

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