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authorGrant Likely <grant.likely@secretlab.ca>2013-02-10 22:57:21 +0000
committerGrant Likely <grant.likely@secretlab.ca>2013-02-13 10:09:31 +0000
commitbd69f73f2c81eed9a398708b8c4bb3409ba1b0f9 (patch)
tree0be6f0ee561d13d01b6c44478b693cc60453ff6d /drivers/of/base.c
parent23ce04c0734e33b1042273b0ed11a8e4f7f988ca (diff)
downloadop-kernel-dev-bd69f73f2c81eed9a398708b8c4bb3409ba1b0f9.zip
op-kernel-dev-bd69f73f2c81eed9a398708b8c4bb3409ba1b0f9.tar.gz
of: Create function for counting number of phandles in a property
This patch creates of_count_phandle_with_args(), a new function for counting the number of phandle+argument tuples in a given property. This is better than the existing method of parsing each phandle individually until parsing fails which is a horribly slow way to do the count. Tested on ARM using the selftest code. v3: - Rebased on top of selftest code cleanup patch v2: - fix bug where of_parse_phandle_with_args() could behave like _count_. - made of_gpio_named_count() into a static inline regardless of CONFIG_OF_GPIO Tested-by: Andreas Larsson <andreas@gaisler.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Rob Herring <rob.herring@calxeda.com>
Diffstat (limited to 'drivers/of/base.c')
-rw-r--r--drivers/of/base.c41
1 files changed, 37 insertions, 4 deletions
diff --git a/drivers/of/base.c b/drivers/of/base.c
index c5572cb..321d3ef 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -1091,9 +1091,10 @@ EXPORT_SYMBOL(of_parse_phandle);
* To get a device_node of the `node2' node you may call this:
* of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
*/
-int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
- const char *cells_name, int index,
- struct of_phandle_args *out_args)
+static int __of_parse_phandle_with_args(const struct device_node *np,
+ const char *list_name,
+ const char *cells_name, int index,
+ struct of_phandle_args *out_args)
{
const __be32 *list, *list_end;
int rc = 0, size, cur_index = 0;
@@ -1183,15 +1184,47 @@ int of_parse_phandle_with_args(const struct device_node *np, const char *list_na
* Unlock node before returning result; will be one of:
* -ENOENT : index is for empty phandle
* -EINVAL : parsing error on data
+ * [1..n] : Number of phandle (count mode; when index = -1)
*/
- rc = -ENOENT;
+ rc = index < 0 ? cur_index : -ENOENT;
err:
if (node)
of_node_put(node);
return rc;
}
+
+int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
+ const char *cells_name, int index,
+ struct of_phandle_args *out_args)
+{
+ if (index < 0)
+ return -EINVAL;
+ return __of_parse_phandle_with_args(np, list_name, cells_name, index, out_args);
+}
EXPORT_SYMBOL(of_parse_phandle_with_args);
+/**
+ * of_count_phandle_with_args() - Find the number of phandles references in a property
+ * @np: pointer to a device tree node containing a list
+ * @list_name: property name that contains a list
+ * @cells_name: property name that specifies phandles' arguments count
+ *
+ * Returns the number of phandle + argument tuples within a property. It
+ * is a typical pattern to encode a list of phandle and variable
+ * arguments into a single property. The number of arguments is encoded
+ * by a property in the phandle-target node. For example, a gpios
+ * property would contain a list of GPIO specifies consisting of a
+ * phandle and 1 or more arguments. The number of arguments are
+ * determined by the #gpio-cells property in the node pointed to by the
+ * phandle.
+ */
+int of_count_phandle_with_args(const struct device_node *np, const char *list_name,
+ const char *cells_name)
+{
+ return __of_parse_phandle_with_args(np, list_name, cells_name, -1, NULL);
+}
+EXPORT_SYMBOL(of_count_phandle_with_args);
+
#if defined(CONFIG_OF_DYNAMIC)
static int of_property_notify(int action, struct device_node *np,
struct property *prop)
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