[PATCH v2 1/2] device property: Add device_get_bd_address() and fwnode_get_bd_address()

[Matthias Kaehlcke <mka@xxxxxxxxxxxx>]

Provide an API for Bluetooth drivers to retrieve the Bluetooth Device
address (BD_ADDR) for a device. If the device node has a property
'local-bd-address' the BD address is read from this property.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
---
Changes in v2:
- use bdaddr_t instead of byte pointer + len
- use EXPORT_SYMBOL_GPL for the new functions instead of EXPORT_SYMBOL
- put new functions inside #if IS_ENABLED(CONFIG_BT)
- some new line juggling in property.h
- added 'Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>' tag
---
 drivers/base/property.c  | 46 ++++++++++++++++++++++++++++++++++++++++
 include/linux/property.h |  3 +++
 2 files changed, 49 insertions(+)

diff --git a/drivers/base/property.c b/drivers/base/property.c
index 240ab5230ff6..afe412133188 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -1315,6 +1315,52 @@ void *device_get_mac_address(struct device *dev, char *addr, int alen)
 }
 EXPORT_SYMBOL(device_get_mac_address);
 
+#if IS_ENABLED(CONFIG_BT)
+
+/**
+ * fwnode_get_bd_address - Get the Bluetooth Device Address (BD_ADDR) from the
+ *                         firmware node
+ * @fwnode:	Pointer to the firmware node
+ * @bd_addr:	Pointer to struct to store the BD address in
+ *
+ * Search the firmware node for 'local-bd-address'.
+ *
+ * All-zero BD addresses are rejected, because those could be properties
+ * that exist in the firmware tables, but were not updated by the firmware. For
+ * example, the DTS could define 'local-bd-address', with zero BD addresses.
+ */
+int fwnode_get_bd_address(struct fwnode_handle *fwnode, bdaddr_t *bd_addr)
+{
+	bdaddr_t ba;
+	int ret;
+
+	ret = fwnode_property_read_u8_array(fwnode, "local-bd-address",
+					    (u8 *)&ba, sizeof(bdaddr_t));
+	if (ret < 0)
+		return ret;
+	if (is_zero_ether_addr((u8 *)&ba))
+		return -ENODATA;
+
+	memcpy(bd_addr, &ba, sizeof(bdaddr_t));
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fwnode_get_bd_address);
+
+/**
+ * device_get_bd_address - Get the Bluetooth Device Address (BD_ADDR) for a
+ *                         given device
+ * @dev:	Pointer to the device
+ * @bd_addr:	Pointer to struct to store the BD address in
+ */
+int device_get_bd_address(struct device *dev, bdaddr_t *bd_addr)
+{
+	return fwnode_get_bd_address(dev_fwnode(dev), bd_addr);
+}
+EXPORT_SYMBOL_GPL(device_get_bd_address);
+
+#endif
+
 /**
  * fwnode_irq_get - Get IRQ directly from a fwnode
  * @fwnode:	Pointer to the firmware node
diff --git a/include/linux/property.h b/include/linux/property.h
index ac8a1ebc4c1b..8926cf95d27e 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -15,6 +15,7 @@
 
 #include <linux/fwnode.h>
 #include <linux/types.h>
+#include <net/bluetooth/bluetooth.h>
 
 struct device;
 
@@ -286,10 +287,12 @@ const void *device_get_match_data(struct device *dev);
 int device_get_phy_mode(struct device *dev);
 
 void *device_get_mac_address(struct device *dev, char *addr, int alen);
+int device_get_bd_address(struct device *dev, bdaddr_t *bd_addr);
 
 int fwnode_get_phy_mode(struct fwnode_handle *fwnode);
 void *fwnode_get_mac_address(struct fwnode_handle *fwnode,
 			     char *addr, int alen);
+int fwnode_get_bd_address(struct fwnode_handle *fwnode, bdaddr_t *bd_addr);
 struct fwnode_handle *fwnode_graph_get_next_endpoint(
 	const struct fwnode_handle *fwnode, struct fwnode_handle *prev);
 struct fwnode_handle *
-- 
2.19.0.444.g18242da7ef-goog