[PATCH] of/device: Obtain platform dev name and id from bus_id

[Wojciech Baranowski]

When adding new platform device, parse platform_device.dev.bus_id (used as
device name) to get platform_device.name and platform_device.id before
calling device_add. If bus_id cannot be split into name and id, fallback to
the old way.

Currently the name is being set to bus_id and id is being set to -1, even
when bus_id is in the form "some_name.some_number". This might lead to
problems with device-driver matching and index out of bounds error. It is
also not consistent with how the bus_id is generated from name and id.

Signed-off-by: Wojciech Baranowski <baranowski at chromium.org>
---
 drivers/of/device.c |   43 +++++++++++++++++++++++++++++++++++++++----
 1 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 62b4b32..8758c3f 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -47,14 +47,49 @@ void of_dev_put(struct platform_device *dev)
 }
 EXPORT_SYMBOL(of_dev_put);
 
+static int of_dev_parse_devname(struct platform_device *ofdev)
+{
+	const char *name;
+	const char *dot_pos;
+	char *short_name;
+
+	name = dev_name(&ofdev->dev);
+	if (!name)
+		goto std_out;
+
+	dot_pos = strrchr(name, '.');
+	if (!dot_pos)
+		goto std_out;
+
+	short_name = kmalloc(dot_pos - name + 1, GFP_KERNEL);
+	if (!short_name)
+		return -ENOMEM;
+
+	strlcpy(short_name, name, dot_pos - name + 1);
+	ofdev->name = short_name;
+
+	if (kstrtoint(dot_pos + 1, 10, &ofdev->id))
+		goto kfree_out;
+
+	return 0;
+
+kfree_out:
+	kfree(short_name);
+std_out:
+	ofdev->name = name;
+	ofdev->id = -1;
+	return 0;
+}
+
 int of_device_add(struct platform_device *ofdev)
 {
+	int ret;
+
 	BUG_ON(ofdev->dev.of_node == NULL);
 
-	/* name and id have to be set so that the platform bus doesn't get
-	 * confused on matching */
-	ofdev->name = dev_name(&ofdev->dev);
-	ofdev->id = -1;
+	ret = of_dev_parse_devname(ofdev);
+	if (ret)
+		return ret;
 
 	/* device_add will assume that this device is on the same node as
 	 * the parent. If there is no parent defined, set the node
-- 
1.7.3.1