regmap: Add support for 2/6 register formating

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -76,6 +76,14 @@ static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
 	return true;
 }
 
+static void regmap_format_2_6_write(struct regmap *map,
+				     unsigned int reg, unsigned int val)
+{
+	u8 *out = map->work_buf;
+
+	*out = (reg << 6) | val;
+}
+
 static void regmap_format_4_12_write(struct regmap *map,
 				     unsigned int reg, unsigned int val)
 {
@@ -180,6 +188,16 @@ struct regmap *regmap_init(struct device *dev,
 	}
 
 	switch (config->reg_bits) {
+	case 2:
+		switch (config->val_bits) {
+		case 6:
+			map->format.format_write = regmap_format_2_6_write;
+			break;
+		default:
+			goto err_map;
+		}
+		break;
+
 	case 4:
 		switch (config->val_bits) {
 		case 12: