From: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
This function can be used to parse the number of a device's parent PCI
bus from a standard 5-cell PCI resource.
Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
---
drivers/of/of_pci.c | 21 +++++++++++++++++++++
include/linux/of_pci.h | 1 +
2 files changed, 22 insertions(+)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 4dd7b9b..d6e6de5 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -43,6 +43,27 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
EXPORT_SYMBOL_GPL(of_pci_find_child_device);
/**
+ * of_pci_get_bus() - Get bus number for a device node
+ * @np: device node
+ *
+ * Parses a standard 5-cell PCI resource and returns the 8-bit bus number of
+ * the device's parent PCI bus. On error a negative error code is returned.
+ */
+int of_pci_get_bus(struct device_node *np)
+{
+ unsigned int size;
+ const __be32 *reg;
+
+ reg = of_get_property(np, "reg", &size);
+
+ if (!reg || size < 5 * sizeof(__be32))
+ return -EINVAL;
+
+ return (be32_to_cpup(reg) >> 16) & 0xff;
+}
+EXPORT_SYMBOL_GPL(of_pci_get_bus);
+
+/**
* of_pci_get_devfn() - Get device and function numbers for a device node
* @np: device node
*
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 91ec484..9118321 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -10,6 +10,7 @@ int of_irq_map_pci(const struct pci_dev *pdev, struct of_irq *out_irq);
struct device_node;
struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn);
+int of_pci_get_bus(struct device_node *np);
int of_pci_get_devfn(struct device_node *np);
#endif
--
1.7.9.5
--
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