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clk: of-provider: look at parent if registered device has no provider info

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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@fi.rohmeurope.com>
[sboyd@kernel.org: Add some comment in the code and pull out logic into
a single function to return the provider device_node pointer]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Matti Vaittinen 2018-12-04 13:34:53 +02:00 committed by Stephen Boyd
parent e45838b52c
commit 05502bf9eb
1 changed files with 27 additions and 4 deletions
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31
drivers/clk/clk.c
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@ -3893,14 +3893,36 @@ static void devm_of_clk_release_provider(struct device *dev, void *res)
of_clk_del_provider(*(struct device_node **)res);
}
/*
* We allow a child device to use its parent device as the clock provider node
* for cases like MFD sub-devices where the child device driver wants to use
* devm_*() APIs but not list the device in DT as a sub-node.
*/
static struct device_node *get_clk_provider_node(struct device *dev)
{
struct device_node *np, *parent_np;
np = dev->of_node;
parent_np = dev->parent ? dev->parent->of_node : NULL;
if (!of_find_property(np, "#clock-cells", NULL))
if (of_find_property(parent_np, "#clock-cells", NULL))
np = parent_np;
return np;
}
/**
* devm_of_clk_add_hw_provider() - Managed clk provider node registration
* @dev: Device acting as the clock provider (used for DT node and lifetime)
* @get: callback for decoding clk_hw
* @data: context pointer for @get callback
*
* 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.
*
* Return: 0 on success or an errno on failure.
*/
@ -3917,7 +3939,7 @@ int devm_of_clk_add_hw_provider(struct device *dev,
if (!ptr)
return -ENOMEM;
np = dev->of_node;
np = get_clk_provider_node(dev);
ret = of_clk_add_hw_provider(np, get, data);
if (!ret) {
*ptr = np;
@ -3968,9 +3990,10 @@ 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 = get_clk_provider_node(dev);
ret = devres_release(dev, devm_of_clk_release_provider,
devm_clk_provider_match, dev->of_node);
devm_clk_provider_match, np);
WARN_ON(ret);
}