[PATCH 1/2] of: Support using 'mask' in making device bus id

[Rob Herring]

Commit 25b892b583cc ("ARM: dts: arm: Update register-bit-led nodes
'reg' and node names") added a 'reg' property to nodes. This change has
the side effect of changing how the kernel generates the device name.
The assumption was a translatable 'reg' address is unique. However, in
the case of the register-bit-led binding (and a few others) that is not
the case. The 'mask' property must also be used in this case to make a
unique device name.

Fixes: 25b892b583cc ("ARM: dts: arm: Update register-bit-led nodes 'reg' and node names")
Reported-by: Guenter Roeck <linux at roeck-us.net>
Cc: stable at vger.kernel.org
Cc: Frank Rowand <frowand.list at gmail.com>
Cc: Linus Walleij <linus.walleij at linaro.org>
Signed-off-by: Rob Herring <robh at kernel.org>
---
This should be applied to stable to minimize DT ABI breakage.
---
 drivers/of/platform.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 07813fb1ef37..b3faf89744aa 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -76,6 +76,7 @@ static void of_device_make_bus_id(struct device *dev)
 	struct device_node *node = dev->of_node;
 	const __be32 *reg;
 	u64 addr;
+	u32 mask;
 
 	/* Construct the name, using parent nodes if necessary to ensure uniqueness */
 	while (node->parent) {
@@ -85,8 +86,13 @@ static void of_device_make_bus_id(struct device *dev)
 		 */
 		reg = of_get_property(node, "reg", NULL);
 		if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
-			dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
-				     addr, node, dev_name(dev));
+			if (!of_property_read_u32(node, "mask", &mask))
+				dev_set_name(dev, dev_name(dev) ? "%llx.%x.%pOFn:%s" : "%llx.%x.%pOFn",
+					     addr, ffs(mask) - 1, node, dev_name(dev));
+
+			else
+				dev_set_name(dev, dev_name(dev) ? "%llx.%pOFn:%s" : "%llx.%pOFn",
+					     addr, node, dev_name(dev));
 			return;
 		}
 
-- 
2.32.0