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Commit 64b60e09 authored by Anton Vorontsov's avatar Anton Vorontsov Committed by Benjamin Herrenschmidt
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of: Add new helper of_parse_phandles_with_args() 



The helper is factored out of of_get_gpio(). Will be used by the QE
pin multiplexing functions (they need to parse the gpios = <> too).

Signed-off-by: default avatarAnton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 302905a3

drivers/of/base.c

+109 −0
Original line number Diff line number Diff line
@@ -458,3 +458,112 @@ int of_modalias_node(struct device_node *node, char *modalias, int len) 
}

EXPORT_SYMBOL_GPL(of_modalias_node);



/**

 * of_parse_phandles_with_args - Find a node pointed by phandle in a list

 * @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

 * @index:	index of a phandle to parse out

 * @out_node:	pointer to device_node struct pointer (will be filled)

 * @out_args:	pointer to arguments pointer (will be filled)

 *

 * This function is useful to parse lists of phandles and their arguments.

 * Returns 0 on success and fills out_node and out_args, on error returns

 * appropriate errno value.

 *

 * Example:

 *

 * phandle1: node1 {

 * 	#list-cells = <2>;

 * }

 *

 * phandle2: node2 {

 * 	#list-cells = <1>;

 * }

 *

 * node3 {

 * 	list = <&phandle1 1 2 &phandle2 3>;

 * }

 *

 * To get a device_node of the `node2' node you may call this:

 * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args);

 */

int of_parse_phandles_with_args(struct device_node *np, const char *list_name,

				const char *cells_name, int index,

				struct device_node **out_node,

				const void **out_args)

{

	int ret = -EINVAL;

	const u32 *list;

	const u32 *list_end;

	int size;

	int cur_index = 0;

	struct device_node *node = NULL;

	const void *args;



	list = of_get_property(np, list_name, &size);

	if (!list) {

		ret = -ENOENT;

		goto err0;

	}

	list_end = list + size / sizeof(*list);



	while (list < list_end) {

		const u32 *cells;

		const phandle *phandle;



		phandle = list;

		args = list + 1;



		/* one cell hole in the list = <>; */

		if (!*phandle) {

			list++;

			goto next;

		}



		node = of_find_node_by_phandle(*phandle);

		if (!node) {

			pr_debug("%s: could not find phandle\n",

				 np->full_name);

			goto err0;

		}



		cells = of_get_property(node, cells_name, &size);

		if (!cells || size != sizeof(*cells)) {

			pr_debug("%s: could not get %s for %s\n",

				 np->full_name, cells_name, node->full_name);

			goto err1;

		}



		/* Next phandle is at offset of one phandle cell + #cells */

		list += 1 + *cells;

		if (list > list_end) {

			pr_debug("%s: insufficient arguments length\n",

				 np->full_name);

			goto err1;

		}

next:

		if (cur_index == index)

			break;



		of_node_put(node);

		node = NULL;

		cur_index++;

	}



	if (!node) {

		ret = -ENOENT;

		goto err0;

	}



	*out_node = node;

	*out_args = args;



	return 0;

err1:

	of_node_put(node);

err0:

	pr_debug("%s failed with status %d\n", __func__, ret);

	return ret;

}

EXPORT_SYMBOL(of_parse_phandles_with_args);

drivers/of/gpio.c

+19 −62
Original line number Diff line number Diff line
@@ -28,42 +28,17 @@ 
 */

int of_get_gpio(struct device_node *np, int index)

{

	int ret = -EINVAL;

	int ret;

	struct device_node *gc;

	struct of_gpio_chip *of_gc = NULL;

	int size;

	const u32 *gpios;

	u32 nr_cells;

	int i;

	const void *gpio_spec;

	const u32 *gpio_cells;

	int gpio_index = 0;



	gpios = of_get_property(np, "gpios", &size);

	if (!gpios) {

		ret = -ENOENT;

		goto err0;

	}

	nr_cells = size / sizeof(u32);



	for (i = 0; i < nr_cells; gpio_index++) {

		const phandle *gpio_phandle;



		gpio_phandle = gpios + i;

		gpio_spec = gpio_phandle + 1;



		/* one cell hole in the gpios = <>; */

		if (!*gpio_phandle) {

			if (gpio_index == index)

				return -ENOENT;

			i++;

			continue;

		}



		gc = of_find_node_by_phandle(*gpio_phandle);

		if (!gc) {

			pr_debug("%s: could not find phandle for gpios\n",

				 np->full_name);

	ret = of_parse_phandles_with_args(np, "gpios", "#gpio-cells", index,

					  &gc, &gpio_spec);

	if (ret) {

		pr_debug("%s: can't parse gpios property\n", __func__);

		goto err0;

	}
@@ -71,6 +46,7 @@ int of_get_gpio(struct device_node *np, int index) 
	if (!of_gc) {

		pr_debug("%s: gpio controller %s isn't registered\n",

			 np->full_name, gc->full_name);

		ret = -ENODEV;

		goto err1;

	}
@@ -79,29 +55,10 @@ int of_get_gpio(struct device_node *np, int index) 
			*gpio_cells != of_gc->gpio_cells) {

		pr_debug("%s: wrong #gpio-cells for %s\n",

			 np->full_name, gc->full_name);

		ret = -EINVAL;

		goto err1;

	}



		/* Next phandle is at phandle cells + #gpio-cells */

		i += sizeof(*gpio_phandle) / sizeof(u32) + *gpio_cells;

		if (i >= nr_cells + 1) {

			pr_debug("%s: insufficient gpio-spec length\n",

				 np->full_name);

			goto err1;

		}



		if (gpio_index == index)

			break;



		of_gc = NULL;

		of_node_put(gc);

	}



	if (!of_gc) {

		ret = -ENOENT;

		goto err0;

	}



	ret = of_gc->xlate(of_gc, np, gpio_spec);

	if (ret < 0)

		goto err1;

include/linux/of.h

+3 −0
Original line number Diff line number Diff line
@@ -71,5 +71,8 @@ extern int of_n_size_cells(struct device_node *np); 
extern const struct of_device_id *of_match_node(

	const struct of_device_id *matches, const struct device_node *node);

extern int of_modalias_node(struct device_node *node, char *modalias, int len);

extern int of_parse_phandles_with_args(struct device_node *np,

	const char *list_name, const char *cells_name, int index,

	struct device_node **out_node, const void **out_args);



#endif /* _LINUX_OF_H */