gpio: Adjust of_xlate API to support multiple GPIO chips

This patch changes the of_xlate API to make it possible for multiple
gpio_chips to refer to the same device tree node.  This is useful for
banked GPIO controllers that use multiple gpio_chips for a single
device.  With this change the core code will try calling of_xlate on
each gpio_chip that references the device_node and will return the
gpio number for the first one to return 'true'.

Tested-by: Roland Stigge <stigge@antcom.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 38 insertions, 42 deletions

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index bf984b6dc477..d18068a9f3ec 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -15,11 +15,39 @@
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/io.h>
+#include <linux/gpio.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_gpio.h>
 #include <linux/slab.h>
 
+/* Private data structure for of_gpiochip_is_match */
+struct gg_data {
+        enum of_gpio_flags *flags;
+        struct of_phandle_args gpiospec;
+
+        int out_gpio;
+};
+
+/* Private function for resolving node pointer to gpio_chip */
+static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
+{
+        struct gg_data *gg_data = data;
+        int ret;
+
+        if ((gc->of_node != gg_data->gpiospec.np) ||
+            (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
+            (!gc->of_xlate))
+                return false;
+
+        ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
+        if (ret < 0)
+                return false;
+
+        gg_data->out_gpio = ret + gc->base;
+        return true;
+}
+
 /**
  * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  * @np:         device node to get GPIO from
@@ -34,46 +62,25 @@
 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
                            int index, enum of_gpio_flags *flags)
 {
+        struct gg_data gg_data = { .flags = flags, .out_gpio = -ENODEV };
         int ret;
-        struct gpio_chip *gc;
-        struct of_phandle_args gpiospec;
+
+        /* .of_xlate might decide to not fill in the flags, so clear it. */
+        if (flags)
+                *flags = 0;
 
         ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
-                                         &gpiospec);
+                                         &gg_data.gpiospec);
         if (ret) {
                 pr_debug("%s: can't parse gpios property\n", __func__);
-                goto err0;
-        }
-
-        gc = of_node_to_gpiochip(gpiospec.np);
-        if (!gc) {
-                pr_debug("%s: gpio controller %s isn't registered\n",
-                         np->full_name, gpiospec.np->full_name);
-                ret = -ENODEV;
-                goto err1;
-        }
-
-        if (gpiospec.args_count != gc->of_gpio_n_cells) {
-                pr_debug("%s: wrong #gpio-cells for %s\n",
-                         np->full_name, gpiospec.np->full_name);
-                ret = -EINVAL;
-                goto err1;
+                return -EINVAL;
         }
 
-        /* .xlate might decide to not fill in the flags, so clear it. */
-        if (flags)
-                *flags = 0;
-
-        ret = gc->of_xlate(gc, &gpiospec, flags);
-        if (ret < 0)
-                goto err1;
+        gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
 
-        ret += gc->base;
-err1:
-        of_node_put(gpiospec.np);
-err0:
+        of_node_put(gg_data.gpiospec.np);
         pr_debug("%s exited with status %d\n", __func__, ret);
-        return ret;
+        return gg_data.out_gpio;
 }
 EXPORT_SYMBOL(of_get_named_gpio_flags);
 
@@ -227,14 +234,3 @@ void of_gpiochip_remove(struct gpio_chip *chip)
         if (chip->of_node)
                 of_node_put(chip->of_node);
 }
-
-/* Private function for resolving node pointer to gpio_chip */
-static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
-{
-        return chip->of_node == data;
-}
-
-struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
-{
-        return gpiochip_find(np, of_gpiochip_is_match);
-}