Sometimes it is useful to be able to extract an index of certain string
value from an array of strings. A typical use case is to give a name to a
DMA channel, PWM, clock and so on.
Provide an implementation using unified device property accessors that
follows of_property_match_string() but works for all supported fwnodes.
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/base/property.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/property.h | 4 +++
2 files changed, 72 insertions(+)
diff --git a/drivers/base/property.c b/drivers/base/property.c
index 2d75366c61e0..a128db413f01 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c
@@ -287,6 +287,28 @@ int device_property_read_string(struct device *dev, const char *propname,
}
EXPORT_SYMBOL_GPL(device_property_read_string);
+/**
+ * device_property_match_string - find a string in an array and return index
+ * @dev: Device to get the property of
+ * @propname: Name of the property holding the array
+ * @string: String to look for
+ *
+ * Find a given string in a string array and if it is found return the
+ * index back.
+ *
+ * Return: %0 if the property was found (success),
+ * %-EINVAL if given arguments are not valid,
+ * %-ENODATA if the property does not have a value,
+ * %-EPROTO if the property is not an array of strings,
+ * %-ENXIO if no suitable firmware interface is present.
+ */
+int device_property_match_string(struct device *dev, const char *propname,
+ const char *string)
+{
+ return fwnode_property_match_string(dev_fwnode(dev), propname, string);
+}
+EXPORT_SYMBOL_GPL(device_property_match_string);
+
#define OF_DEV_PROP_READ_ARRAY(node, propname, type, val, nval) \
(val) ? of_property_read_##type##_array((node), (propname), (val), (nval)) \
: of_property_count_elems_of_size((node), (propname), sizeof(type))
@@ -479,6 +501,52 @@ int fwnode_property_read_string(struct fwnode_handle *fwnode,
EXPORT_SYMBOL_GPL(fwnode_property_read_string);
/**
+ * fwnode_property_match_string - find a string in an array and return index
+ * @fwnode: Firmware node to get the property of
+ * @propname: Name of the property holding the array
+ * @string: String to look for
+ *
+ * Find a given string in a string array and if it is found return the
+ * index back.
+ *
+ * Return: %0 if the property was found (success),
+ * %-EINVAL if given arguments are not valid,
+ * %-ENODATA if the property does not have a value,
+ * %-EPROTO if the property is not an array of strings,
+ * %-ENXIO if no suitable firmware interface is present.
+ */
+int fwnode_property_match_string(struct fwnode_handle *fwnode,
+ const char *propname, const char *string)
+{
+ const char **values;
+ int nval, ret, i;
+
+ nval = fwnode_property_read_string_array(fwnode, propname, NULL, 0);
+ if (nval < 0)
+ return nval;
+
+ values = kcalloc(nval, sizeof(*values), GFP_KERNEL);
+ if (!values)
+ return -ENOMEM;
+
+ ret = fwnode_property_read_string_array(fwnode, propname, values, nval);
+ if (ret < 0)
+ goto out;
+
+ ret = -ENODATA;
+ for (i = 0; i < nval; i++) {
+ if (!strcmp(values[i], string)) {
+ ret = i;
+ break;
+ }
+ }
+out:
+ kfree(values);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(fwnode_property_match_string);
+
+/**
* device_get_next_child_node - Return the next child node handle for a device
* @dev: Device to find the next child node for.
* @child: Handle to one of the device's child nodes or a null handle.
diff --git a/include/linux/property.h b/include/linux/property.h
index a59c6ee566c2..463de52fe891 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h
@@ -40,6 +40,8 @@ int device_property_read_string_array(struct device *dev, const char *propname,
const char **val, size_t nval);
int device_property_read_string(struct device *dev, const char *propname,
const char **val);
+int device_property_match_string(struct device *dev,
+ const char *propname, const char *string);
bool fwnode_property_present(struct fwnode_handle *fwnode, const char *propname);
int fwnode_property_read_u8_array(struct fwnode_handle *fwnode,
@@ -59,6 +61,8 @@ int fwnode_property_read_string_array(struct fwnode_handle *fwnode,
size_t nval);
int fwnode_property_read_string(struct fwnode_handle *fwnode,
const char *propname, const char **val);
+int fwnode_property_match_string(struct fwnode_handle *fwnode,
+ const char *propname, const char *string);
struct fwnode_handle *device_get_next_child_node(struct device *dev,
struct fwnode_handle *child);
--
2.5.1
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