Merge tag 'dt-endian' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap into spi-fsl-dspi

regmap: Device tree endianness support

This adds generic support for specifying endianess for register map in
the DT.

1 files changed, 50 insertions, 93 deletions

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index e4e567e82b84..01ae4b829360 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -449,100 +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 of_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;
+        enum regmap_endian endian;
 
-        if (!endian || !config)
-                return -EINVAL;
+        /* Retrieve the endianness specification from the regmap config */
+        endian = config->val_format_endian;
 
-        /*
-         * Firstly, try to parse the endianness from driver's config,
-         * this is to be compatible with the none DT or the old drivers.
-         * From the driver's config the endianness value maybe:
-         *   REGMAP_ENDIAN_BIG,
-         *   REGMAP_ENDIAN_LITTLE,
-         *   REGMAP_ENDIAN_NATIVE,
-         *   REGMAP_ENDIAN_DEFAULT.
-         */
-        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;
-        }
+        /* If the regmap config specified a non-default value, use that */
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
-        /*
-         * If the endianness parsed from driver config is
-         * REGMAP_ENDIAN_DEFAULT, that means maybe we are using the DT
-         * node to specify the endianness information.
-         */
-        if (*endian != REGMAP_ENDIAN_DEFAULT)
-                return 0;
+        /* Parse the device's DT node for an endianness specification */
+        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;
 
-        /*
-         * Secondly, try to parse the endianness from DT node if the
-         * driver config does not specify it.
-         * From the DT node the endianness value maybe:
-         *   REGMAP_ENDIAN_BIG,
-         *   REGMAP_ENDIAN_LITTLE,
-         *   REGMAP_ENDIAN_NATIVE,
-         */
-        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;
-                else
-                        *endian = REGMAP_ENDIAN_NATIVE;
-                break;
-        case REGMAP_ENDIAN_REG:
-                break;
-        default:
-                return -EINVAL;
-        }
+        /* If the endianness was specified in DT, use that */
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
-        /*
-         * If the endianness parsed from DT node is REGMAP_ENDIAN_NATIVE, that
-         * maybe means the DT does not care the endianness or it should use
-         * the regmap bus's default endianness, then we should try to check
-         * whether the regmap bus has specified the default endianness.
-         */
-        if (*endian != REGMAP_ENDIAN_NATIVE)
-                return 0;
+        /* Retrieve the endianness specification from the bus config */
+        if (bus && bus->val_format_endian_default)
+                endian = bus->val_format_endian_default;
 
-        /*
-         * Finally, try to parse the endianness from regmap bus config
-         * if in device's DT node the endianness property is absent.
-         */
-        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 the bus specified a non-default value, use that */
+        if (endian != REGMAP_ENDIAN_DEFAULT)
+                return endian;
 
-        return 0;
+        /* Use this if no other value was found */
+        return REGMAP_ENDIAN_BIG;
 }
 
 /**
@@ -648,15 +612,8 @@ struct regmap *regmap_init(struct device *dev,
                 map->reg_read  = _regmap_bus_read;
         }
 
-        ret = of_regmap_get_endian(dev, bus, config, REGMAP_ENDIAN_REG,
-                                   &reg_endian);
-        if (ret)
-                return ERR_PTR(ret);
-
-        ret = of_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: