regmap: Split regmap_get_endian() in two functions

Split regmap_get_endian() in two functions, regmap_get_reg_endian() and
regmap_get_val_endian().

This allows to:
  - Get rid of the three switch()es on "type", incl. error handling in
    three "default" cases,
  - Get rid of the regmap_endian_type enum,
  - Get rid of the non-NULL check of "config" (regmap_init() already
    checks for that),
  - Get rid of the "endian" output parameters, and just return the
    regmap_endian enum value, as the functions can no longer fail.

This saves 21 lines of code (despite the still-present
one-comment-per-line over-documentation), and 30 bytes of code on ARM
V7.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 43 insertions, 64 deletions

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index bb4502a48be5..01ae4b829360 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -449,78 +449,64 @@ int regmap_attach_dev(struct device *dev, struct regmap *map,
 }
 EXPORT_SYMBOL_GPL(regmap_attach_dev);
 
-enum regmap_endian_type {
-        REGMAP_ENDIAN_REG,
-        REGMAP_ENDIAN_VAL,
-};
+static enum regmap_endian regmap_get_reg_endian(const struct regmap_bus *bus,
+                                        const struct regmap_config *config)
+{
+        enum regmap_endian endian;
 
-static int regmap_get_endian(struct device *dev,
-                                const struct regmap_bus *bus,
-                                const struct regmap_config *config,
-                                enum regmap_endian_type type,
-                                enum regmap_endian *endian)
+        /* Retrieve the endianness specification from the regmap config */
+        endian = config->reg_format_endian;
+
+        /* If the regmap config specified a non-default value, use that */
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
+
+        /* Retrieve the endianness specification from the bus config */
+        if (bus && bus->reg_format_endian_default)
+                endian = bus->reg_format_endian_default;
+
+        /* If the bus specified a non-default value, use that */
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
+
+        /* Use this if no other value was found */
+        return REGMAP_ENDIAN_BIG;
+}
+
+static enum regmap_endian regmap_get_val_endian(struct device *dev,
+                                        const struct regmap_bus *bus,
+                                        const struct regmap_config *config)
 {
         struct device_node *np = dev->of_node;
-
-        if (!endian || !config)
-                return -EINVAL;
+        enum regmap_endian endian;
 
         /* Retrieve the endianness specification from the regmap config */
-        switch (type) {
-        case REGMAP_ENDIAN_REG:
-                *endian = config->reg_format_endian;
-                break;
-        case REGMAP_ENDIAN_VAL:
-                *endian = config->val_format_endian;
-                break;
-        default:
-                return -EINVAL;
-        }
+        endian = config->val_format_endian;
 
         /* If the regmap config specified a non-default value, use that */
-        if (*endian != REGMAP_ENDIAN_DEFAULT)
-                return 0;
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
         /* Parse the device's DT node for an endianness specification */
-        switch (type) {
-        case REGMAP_ENDIAN_VAL:
-                if (of_property_read_bool(np, "big-endian"))
-                        *endian = REGMAP_ENDIAN_BIG;
-                else if (of_property_read_bool(np, "little-endian"))
-                        *endian = REGMAP_ENDIAN_LITTLE;
-                break;
-        case REGMAP_ENDIAN_REG:
-                break;
-        default:
-                return -EINVAL;
-        }
+        if (of_property_read_bool(np, "big-endian"))
+                endian = REGMAP_ENDIAN_BIG;
+        else if (of_property_read_bool(np, "little-endian"))
+                endian = REGMAP_ENDIAN_LITTLE;
 
         /* If the endianness was specified in DT, use that */
-        if (*endian != REGMAP_ENDIAN_DEFAULT)
-                return 0;
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
         /* Retrieve the endianness specification from the bus config */
-        switch (type) {
-        case REGMAP_ENDIAN_REG:
-                if (bus && bus->reg_format_endian_default)
-                        *endian = bus->reg_format_endian_default;
-                break;
-        case REGMAP_ENDIAN_VAL:
-                if (bus && bus->val_format_endian_default)
-                        *endian = bus->val_format_endian_default;
-                break;
-        default:
-                return -EINVAL;
-        }
+        if (bus && bus->val_format_endian_default)
+                endian = bus->val_format_endian_default;
 
         /* If the bus specified a non-default value, use that */
-        if (*endian != REGMAP_ENDIAN_DEFAULT)
-                return 0;
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
         /* Use this if no other value was found */
-        *endian = REGMAP_ENDIAN_BIG;
-
-        return 0;
+        return REGMAP_ENDIAN_BIG;
 }
 
 /**
@@ -626,15 +612,8 @@ struct regmap *regmap_init(struct device *dev,
                 map->reg_read  = _regmap_bus_read;
         }
 
-        ret = regmap_get_endian(dev, bus, config, REGMAP_ENDIAN_REG,
-                                &reg_endian);
-        if (ret)
-                return ERR_PTR(ret);
-
-        ret = regmap_get_endian(dev, bus, config, REGMAP_ENDIAN_VAL,
-                                &val_endian);
-        if (ret)
-                return ERR_PTR(ret);
+        reg_endian = regmap_get_reg_endian(bus, config);
+        val_endian = regmap_get_val_endian(dev, bus, config);
 
         switch (config->reg_bits + map->reg_shift) {
         case 2: