[PATCH v6 03/10] clk: of-provider: look at parent if registered device has no provider info

[Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>]

It seems to be usual for MFD devices that the created 'clock sub-device'
do not have own DT node. The clock provider information is usually in the
main device node which is owned by the MFD device. Change the devm variant
of clk of-provider registration to check the parent device node if given
device has no own node or if the node does not contain the #clock-cells
property. In such case use the parent node if it contains the #clock-cells.

Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>
---
 drivers/clk/clk.c | 27 +++++++++++++++++++++++----
 1 file changed, 23 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 78c90913f987..66dc7c1483d7 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3893,6 +3893,11 @@ static void devm_of_clk_release_provider(struct device *dev, void *res)
 	of_clk_del_provider(*(struct device_node **)res);
 }
 
+static int of_is_clk_provider(struct device_node *np)
+{
+	return !!of_find_property(np, "#clock-cells", NULL);
+}
+
 /**
  * devm_of_clk_add_hw_provider() - Managed clk provider node registration
  * @dev: Device acting as the clock provider. Used for DT node and lifetime.
@@ -3901,8 +3906,11 @@ static void devm_of_clk_release_provider(struct device *dev, void *res)
  *
  * Returns 0 on success or an errno on failure.
  *
- * Registers clock provider for given device's node. Provider is automatically
- * released at device exit.
+ * Registers clock provider for given device's node. If the device has no DT
+ * node or if the device node lacks of clock provider information (#clock-cells)
+ * then the parent device's node is scanned for this information. If parent node
+ * has the #clock-cells then it is used in registration. Provider is
+ * automatically released at device exit.
  */
 int devm_of_clk_add_hw_provider(struct device *dev,
 			struct clk_hw *(*get)(struct of_phandle_args *clkspec,
@@ -3912,12 +3920,17 @@ int devm_of_clk_add_hw_provider(struct device *dev,
 	struct device_node **ptr, *np;
 	int ret;
 
+	np = dev->of_node;
+
+	if (!of_is_clk_provider(dev->of_node))
+		if (of_is_clk_provider(dev->parent->of_node))
+			np = dev->parent->of_node;
+
 	ptr = devres_alloc(devm_of_clk_release_provider, sizeof(*ptr),
 			   GFP_KERNEL);
 	if (!ptr)
 		return -ENOMEM;
 
-	np = dev->of_node;
 	ret = of_clk_add_hw_provider(np, get, data);
 	if (!ret) {
 		*ptr = np;
@@ -3968,9 +3981,15 @@ static int devm_clk_provider_match(struct device *dev, void *res, void *data)
 void devm_of_clk_del_provider(struct device *dev)
 {
 	int ret;
+	struct device_node *np;
+
+	np = dev->of_node;
 
+	if (!of_is_clk_provider(dev->of_node))
+		if (of_is_clk_provider(dev->parent->of_node))
+			np = dev->parent->of_node;
 	ret = devres_release(dev, devm_of_clk_release_provider,
-			     devm_clk_provider_match, dev->of_node);
+			     devm_clk_provider_match, np);
 
 	WARN_ON(ret);
 }
-- 
2.14.3