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SubjectRe: [RESEND PATCH v2 1/2] device property: Add function to search for named child of device
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On 6/9/2016 5:13 PM, Adam Thomson wrote:
> For device nodes in both DT and ACPI, it possible to have named
> child nodes which contain properties (an existing example being
> gpio-leds). This adds a function to find a named child node for
> a device which can be used by drivers for property retrieval.
>
> For ACPI data node name matching, a helper function is also added
> which returns false if CONFIG_ACPI is not set, otherwise it
> performs a string comparison on the data node name. This avoids
> using the acpi_data_node struct for non CONFIG_ACPI builds,
> which would otherwise cause a build failure.
>
> Signed-off-by: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
> Tested-by: Sathyanarayana Nujella <sathyanarayana.nujella@intel.com>

For some reason that didn't make it into the linux-acpi list, or at
least I can't see it there.

> ---
>
> Changes in v2:
> - Rebase to v4.7-rc1
>
> drivers/base/property.c | 28 ++++++++++++++++++++++++++++
> include/acpi/acpi_bus.h | 7 +++++++
> include/linux/acpi.h | 6 ++++++
> include/linux/property.h | 3 +++
> 4 files changed, 44 insertions(+)
>
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index f38c21d..573b361 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -888,6 +888,34 @@ struct fwnode_handle *device_get_next_child_node(struct device *dev,
> EXPORT_SYMBOL_GPL(device_get_next_child_node);
>
> /**
> + * device_get_named_child_node - Return first matching named child node handle
> + * @dev: Device to find the named child node for.
> + * @childname: String to match child node name against.
> + */
> +struct fwnode_handle *device_get_named_child_node(struct device *dev,
> + const char *childname)
> +{
> + struct fwnode_handle *child;
> +
> + /*
> + * Find first matching named child node of this device.
> + * For ACPI this will be a data only sub-node.
> + */
> + device_for_each_child_node(dev, child) {
> + if (is_of_node(child)) {
> + if (!strcasecmp(to_of_node(child)->name, childname))

Why do you use strcasecmp() here?

> + return child;
> + } else if (is_acpi_data_node(child)) {
> + if (acpi_data_node_match(child, childname))
> + return child;
> + }
> + }
> +
> + return NULL;
> +}
> +EXPORT_SYMBOL_GPL(device_get_named_child_node);
> +
> +/**
> * fwnode_handle_put - Drop reference to a device node
> * @fwnode: Pointer to the device node to drop the reference to.
> *
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index 788c6c3..993bdd0 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -420,6 +420,13 @@ static inline struct acpi_data_node *to_acpi_data_node(struct fwnode_handle *fwn
> container_of(fwnode, struct acpi_data_node, fwnode) : NULL;
> }
>
> +static inline bool acpi_data_node_match(struct fwnode_handle *fwnode,
> + const char *name)
> +{
> + return is_acpi_data_node(fwnode) ?
> + (!strcasecmp(to_acpi_data_node(fwnode)->name, name)) : false;
> +}

Is there any particular reason to introduce this function instead of
doing the test in device_get_named_child_node() directly?

> +
> static inline struct fwnode_handle *acpi_fwnode_handle(struct acpi_device *adev)
> {
> return &adev->fwnode;
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 288fac5..03039c4 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -568,6 +568,12 @@ static inline struct acpi_data_node *to_acpi_data_node(struct fwnode_handle *fwn
> return NULL;
> }
>
> +static inline bool acpi_data_node_match(struct fwnode_handle *fwnode,
> + const char *name)
> +{
> + return false;
> +}
> +
> static inline struct fwnode_handle *acpi_fwnode_handle(struct acpi_device *adev)
> {
> return NULL;
> diff --git a/include/linux/property.h b/include/linux/property.h
> index ecab11e..3a2f9ae 100644
> --- a/include/linux/property.h
> +++ b/include/linux/property.h
> @@ -77,6 +77,9 @@ struct fwnode_handle *device_get_next_child_node(struct device *dev,
> for (child = device_get_next_child_node(dev, NULL); child; \
> child = device_get_next_child_node(dev, child))
>
> +struct fwnode_handle *device_get_named_child_node(struct device *dev,
> + const char *childname);
> +
> void fwnode_handle_put(struct fwnode_handle *fwnode);
>
> unsigned int device_get_child_node_count(struct device *dev);
> --

Mika, Heikki, Andy, any feedback on this one?

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