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 <tomeu.vizoso at collabora.com>
---

Changes in v2: None

 drivers/gpio/gpiolib.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index bf4bd1d..6a3e83f 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2388,4 +2388,58 @@ static int __init gpiolib_debugfs_init(void)
 }
 subsys_initcall(gpiolib_debugfs_init);

+static void gpio_get_dependencies(struct fwnode_handle *fwnode,
+                                 struct list_head *deps)
+{
+       struct device_node *np;
+       struct property *pp;
+       struct of_phandle_args pspec;
+       int count, i, ret;
+
+       np = to_of_node(fwnode);
+       if (!np)
+               return;
+
+       for_each_property_of_node(np, pp) {
+               if (strcmp(pp->name, "gpio") &&
+                   strcmp(pp->name, "gpios") &&
+                   !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;
+
+                       fwnode_add_dependency(&pspec.np->fwnode, deps);
+
+                       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;
+
+               fwnode_add_dependency(&pspec.np->fwnode, deps);
+
+               of_node_put(pspec.np);
+       }
+}
+
+static int __init gpiolib_init(void)
+{
+       fwnode_add_dependency_parser(gpio_get_dependencies);
+
+       return 0;
+}
+device_initcall(gpiolib_init);
+
 #endif /* DEBUG_FS */
-- 
2.4.1

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