regmap: Fix regmap_bulk_write for bus writes

The regmap config does not prohibit val_bytes that are not powers of
two. But the current code of regmap_bulk_write for use_single_rw does
limit the possible val_bytes to 1, 2 and 4.

This patch fixes the behaviour to allow bus writes with non-standard
val_bytes sizes.

Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap.c

@@ -1680,9 +1680,15 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 
 	/*
 	 * Some devices don't support bulk write, for
-	 * them we have a series of single write operations.
+	 * them we have a series of single write operations in the first two if
+	 * blocks.
+	 *
+	 * The first if block is used for memory mapped io. It does not allow
+	 * val_bytes of 3 for example.
+	 * The second one is used for busses which do not have this limitation
+	 * and can write arbitrary value lengths.
 	 */
-	if (!map->bus || map->use_single_rw) {
+	if (!map->bus) {
 		map->lock(map->lock_arg);
 		for (i = 0; i < val_count; i++) {
 			unsigned int ival;
@@ -1714,6 +1720,17 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 		}
 out:
 		map->unlock(map->lock_arg);
+	} else if (map->use_single_rw) {
+		map->lock(map->lock_arg);
+		for (i = 0; i < val_count; i++) {
+			ret = _regmap_raw_write(map,
+						reg + (i * map->reg_stride),
+						val + (i * val_bytes),
+						val_bytes);
+			if (ret)
+				break;
+		}
+		map->unlock(map->lock_arg);
 	} else {
 		void *wval;