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 DT data node name matching, of_node_cmp() and similar functions are made
available outside of CONFIG_OF block so the new function can reference these
for DT and non-DT builds.
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@xxxxxxxxxxx>
Tested-by: Sathyanarayana Nujella <sathyanarayana.nujella@xxxxxxxxx>
---
Changes in v3:
- Move of_*_cmp() functions in of.h outside of CONFIG_OF block so they are
available for non-DT builds
- In device_get_named_child_node(), use of_node_cmp() helper macro instead of
strcasecmp() (node names not alway case insensitive, depending on platform).
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/of.h | 14 +++++++-------
include/linux/property.h | 3 +++
5 files changed, 51 insertions(+), 7 deletions(-)
diff --git a/drivers/base/property.c b/drivers/base/property.c
index f38c21d..43a36d6 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 (!of_node_cmp(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 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;
+}
+
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/of.h b/include/linux/of.h
index 74eb28c..310e32f 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -238,13 +238,6 @@ static inline unsigned long of_read_ulong(const __be32 *cell, int size)
#define OF_ROOT_NODE_SIZE_CELLS_DEFAULT 1
#endif
-/* Default string compare functions, Allow arch asm/prom.h to override */
-#if !defined(of_compat_cmp)
-#define of_compat_cmp(s1, s2, l) strcasecmp((s1), (s2))
-#define of_prop_cmp(s1, s2) strcmp((s1), (s2))
-#define of_node_cmp(s1, s2) strcasecmp((s1), (s2))
-#endif
-
#define OF_IS_DYNAMIC(x) test_bit(OF_DYNAMIC, &x->_flags)
#define OF_MARK_DYNAMIC(x) set_bit(OF_DYNAMIC, &x->_flags)
@@ -726,6 +719,13 @@ static inline void of_property_clear_flag(struct property *p, unsigned long flag
#define of_match_node(_matches, _node) NULL
#endif /* CONFIG_OF */
+/* Default string compare functions, Allow arch asm/prom.h to override */
+#if !defined(of_compat_cmp)
+#define of_compat_cmp(s1, s2, l) strcasecmp((s1), (s2))
+#define of_prop_cmp(s1, s2) strcmp((s1), (s2))
+#define of_node_cmp(s1, s2) strcasecmp((s1), (s2))
+#endif
+
#if defined(CONFIG_OF) && defined(CONFIG_NUMA)
extern int of_node_to_nid(struct device_node *np);
#else
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);
--
1.9.3
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