[PATCH 1/6] property: add fwnode_property_read_string_index()
From: Clément Léger <clement.leger@bootlin.com>
Date: 2022-03-18 16:04:25
Also in:
linux-acpi, linux-i2c, lkml
Subsystem:
driver core, kobjects, debugfs and sysfs, software nodes and device properties, the rest · Maintainers:
Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Linus Torvalds
Add fwnode_property_read_string_index() function which allows to retrieve a string from an array by its index. This function is the equivalent of of_property_read_string_index() but for fwnode support. Signed-off-by: Clément Léger <clement.leger@bootlin.com> --- drivers/base/property.c | 48 ++++++++++++++++++++++++++++++++++++++++ include/linux/property.h | 3 +++ 2 files changed, 51 insertions(+)
diff --git a/drivers/base/property.c b/drivers/base/property.c
index e6497f6877ee..67c33c11f00c 100644
--- a/drivers/base/property.c
+++ b/drivers/base/property.c@@ -451,6 +451,54 @@ int fwnode_property_match_string(const struct fwnode_handle *fwnode, } EXPORT_SYMBOL_GPL(fwnode_property_match_string); +/** + * fwnode_property_read_string_index - read a string in an array using an index + * @fwnode: Firmware node to get the property of + * @propname: Name of the property holding the array + * @index: Index of the string to look for + * @string: Pointer to the string if found + * + * Find a string by a given index in a string array and if it is found return + * the string value in @string. + * + * 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_read_string_index(const struct fwnode_handle *fwnode, + const char *propname, int index, + const char **string) +{ + const char **values; + int nval, ret; + + nval = fwnode_property_read_string_array(fwnode, propname, NULL, 0); + if (nval < 0) + return nval; + + if (index >= nval) + return -EINVAL; + + if (nval == 0) + return -ENODATA; + + 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; + + *string = values[index]; +out: + kfree(values); + return ret; +} +EXPORT_SYMBOL_GPL(fwnode_property_read_string_index); + /** * fwnode_property_get_reference_args() - Find a reference with arguments * @fwnode: Firmware node where to look for the reference
diff --git a/include/linux/property.h b/include/linux/property.h
index 7399a0b45f98..a033920eb10a 100644
--- a/include/linux/property.h
+++ b/include/linux/property.h@@ -70,6 +70,9 @@ int fwnode_property_read_string_array(const struct fwnode_handle *fwnode, size_t nval); int fwnode_property_read_string(const struct fwnode_handle *fwnode, const char *propname, const char **val); +int fwnode_property_read_string_index(const struct fwnode_handle *fwnode, + const char *propname, int index, + const char **string); int fwnode_property_match_string(const struct fwnode_handle *fwnode, const char *propname, const char *string); int fwnode_property_get_reference_args(const struct fwnode_handle *fwnode,
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2.34.1