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 --- 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 7f692ac..8b2cb09 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -880,6 +880,34 @@ 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)) + 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 3a93250..6dc3544 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; +} + 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 06ed7e5..c37a385 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -576,6 +576,12 @@ 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 b51fcd3..d2752dc 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); -- 1.9.3