kernel/irq/devres.c

   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  */
   9 struct irq_devres {
  10         unsigned int irq;
  11         void *dev_id;
  12 };
  13
  14 static 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
  21 static 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  */
  47 int 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 }
  73 EXPORT_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  */
  86 void 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 }
  94 EXPORT_SYMBOL(devm_free_irq);