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: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Anton Vorontsov 2008-10-10 04:43:17 +00:00 committed by Benjamin Herrenschmidt
parent 302905a347
commit 64b60e096f
3 changed files with 131 additions and 62 deletions

View file

@ -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);

View file

@ -28,78 +28,35 @@
*/
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;
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;
}
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);
goto err0;
}
of_gc = gc->data;
if (!of_gc) {
pr_debug("%s: gpio controller %s isn't registered\n",
np->full_name, gc->full_name);
goto err1;
}
gpio_cells = of_get_property(gc, "#gpio-cells", &size);
if (!gpio_cells || size != sizeof(*gpio_cells) ||
*gpio_cells != of_gc->gpio_cells) {
pr_debug("%s: wrong #gpio-cells for %s\n",
np->full_name, gc->full_name);
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);
}
of_gc = gc->data;
if (!of_gc) {
ret = -ENOENT;
goto err0;
pr_debug("%s: gpio controller %s isn't registered\n",
np->full_name, gc->full_name);
ret = -ENODEV;
goto err1;
}
gpio_cells = of_get_property(gc, "#gpio-cells", &size);
if (!gpio_cells || size != sizeof(*gpio_cells) ||
*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;
}
ret = of_gc->xlate(of_gc, np, gpio_spec);

View file

@ -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 */