gpio: of: remove of_gpiochip_and_xlate() and struct gg_data

The usage of gpiochip_find(&gg_data, of_gpiochip_and_xlate) is odd.

Usually gpiochip_find() is used to find a gpio_chip.  Here, however,
the return value from gpiochip_find() is just discarded.  Instead,
gpiochip_find(&gg_data, of_gpiochip_and_xlate) is called for the
side-effect of the match function.

The match function, of_gpiochip_find_and_xlate(), fills the given
struct gg_data, but a match function should be simply called to
judge the matching.

This commit fixes this distortion and makes the code more readable.
Remove of_gpiochip_find_and_xlate() and struct gg_data.  Instead,
this adds a very simple helper function of_find_gpiochip_by_node().
Now, of_get_named_gpiod_flags() is implemented more straight-forward.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index a68e42d..9f86275 100644 (file)
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -26,38 +26,14 @@
 
 #include "gpiolib.h"
 
-/* Private data structure for of_gpiochip_find_and_xlate */
-struct gg_data {
-       enum of_gpio_flags *flags;
-       struct of_phandle_args gpiospec;
-
-       struct gpio_desc *out_gpio;
-};
-
-/* Private function for resolving node pointer to gpio_chip */
-static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
+static int of_gpiochip_match_node(struct gpio_chip *chip, 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;
+       return chip->gpiodev->dev.of_node == data;
+}
 
-       ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
-       if (ret < 0) {
-               /* We've found a gpio chip, but the translation failed.
-                * Store translation error in out_gpio.
-                * Return false to keep looking, as more than one gpio chip
-                * could be registered per of-node.
-                */
-               gg_data->out_gpio = ERR_PTR(ret);
-               return false;
-        }
-
-       gg_data->out_gpio = gpiochip_get_desc(gc, ret);
-       return true;
+static struct gpio_chip *of_find_gpiochip_by_node(struct device_node *np)
+{
+       return gpiochip_find(np, of_gpiochip_match_node);
 }
 
 /**
@@ -74,34 +50,47 @@ static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
 struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np,
                     const char *propname, int index, enum of_gpio_flags *flags)
 {
-       /* Return -EPROBE_DEFER to support probe() functions to be called
-        * later when the GPIO actually becomes available
-        */
-       struct gg_data gg_data = {
-               .flags = flags,
-               .out_gpio = ERR_PTR(-EPROBE_DEFER)
-       };
+       struct of_phandle_args gpiospec;
+       struct gpio_chip *chip;
+       struct gpio_desc *desc;
        int ret;
 
-       /* .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,
-                                        &gg_data.gpiospec);
+                                        &gpiospec);
        if (ret) {
                pr_debug("%s: can't parse '%s' property of node '%s[%d]'\n",
                        __func__, propname, np->full_name, index);
                return ERR_PTR(ret);
        }
 
-       gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
+       chip = of_find_gpiochip_by_node(gpiospec.np);
+       if (!chip) {
+               desc = ERR_PTR(-EPROBE_DEFER);
+               goto out;
+       }
+       if (chip->of_gpio_n_cells != gpiospec.args_count) {
+               desc = ERR_PTR(-EINVAL);
+               goto out;
+       }
+
+       ret = chip->of_xlate(chip, &gpiospec, flags);
+       if (ret < 0) {
+               desc = ERR_PTR(ret);
+               goto out;
+       }
+
+       desc = gpiochip_get_desc(chip, ret);
+       if (IS_ERR(desc))
+               goto out;
 
-       of_node_put(gg_data.gpiospec.np);
        pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n",
                 __func__, propname, np->full_name, index,
-                PTR_ERR_OR_ZERO(gg_data.out_gpio));
-       return gg_data.out_gpio;
+                PTR_ERR_OR_ZERO(desc));
+
+out:
+       of_node_put(gpiospec.np);
+
+       return desc;
 }
 
 int of_get_named_gpio_flags(struct device_node *np, const char *list_name,