So the GPIO subsystem can be queried about the dependencies of nodes that consume GPIOs, as specified in bindings/gpio/gpio.txt.
Signed-off-by: Tomeu Vizoso <[email protected]> --- drivers/gpio/gpiolib-sysfs.c | 81 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c index b57ed8e..d0a7fb1 100644 --- a/drivers/gpio/gpiolib-sysfs.c +++ b/drivers/gpio/gpiolib-sysfs.c @@ -7,6 +7,7 @@ #include <linux/interrupt.h> #include <linux/kdev_t.h> #include <linux/slab.h> +#include <linux/of.h> #include "gpiolib.h" @@ -515,6 +516,85 @@ done: return status ? : len; } +static bool strends(const char *str, const char *postfix) +{ + if (strlen(str) < strlen(postfix)) + return false; + + return strcmp(str + strlen(str) - strlen(postfix), postfix) == 0; +} + +static void add_dependency(struct fwnode_handle *fwnode, + struct list_head *list) +{ + struct fwnode_dependency *dep; + + dep = kzalloc(sizeof(*dep), GFP_KERNEL); + if (!dep) + return; + + INIT_LIST_HEAD(&dep->dependency); + dep->fwnode = fwnode; + + list_add_tail(&dep->dependency, list); +} + +struct list_head *gpio_get_dependencies(struct fwnode_handle *fwnode) +{ + struct device_node *np = of_node(fwnode); + struct list_head *list = NULL; + struct property *pp; + struct of_phandle_args pspec; + int count, i, ret; + + if (!is_of_node(fwnode)) + return NULL; + + np = of_node(fwnode); + if (!np) + return NULL; + + list = kzalloc(sizeof(*list), GFP_KERNEL); + if (!list) + return NULL; + + INIT_LIST_HEAD(list); + + for_each_property_of_node(np, pp) { + if (strcmp(pp->name, "gpio") && + !strends(pp->name, "-gpios") && + !strends(pp->name, "-gpio")) + continue; + + count = of_count_phandle_with_args(np, pp->name, + "#gpio-cells"); + for (i = 0; i < count; i++) { + ret = of_parse_phandle_with_args(np, pp->name, + "#gpio-cells", i, + &pspec); + if (ret || !pspec.np) + continue; + + add_dependency(&pspec.np->fwnode, list); + + of_node_put(pspec.np); + } + } + + for (i = 0;; i++) { + ret = of_parse_phandle_with_fixed_args(np, "gpio-ranges", 3, + i, &pspec); + if (ret) + break; + + add_dependency(&pspec.np->fwnode, list); + + of_node_put(pspec.np); + } + + return list; +} + static struct class_attribute gpio_class_attrs[] = { __ATTR(export, 0200, NULL, export_store), __ATTR(unexport, 0200, NULL, unexport_store), @@ -526,6 +606,7 @@ static struct class gpio_class = { .owner = THIS_MODULE, .class_attrs = gpio_class_attrs, + .get_dependencies = gpio_get_dependencies, }; -- 2.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
