regmap: add regmap_bulk_write() for register write

The bulk_write() supports the data transfer to multi
register which takes the data into cpu_endianness format
and does formatting of data to device format before
sending to device.
The transfer can be completed in single transfer or multiple
transfer based on data formatting.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap.c

@@ -473,6 +473,56 @@ int regmap_raw_write(struct regmap *map, unsigned int reg,
 }
 EXPORT_SYMBOL_GPL(regmap_raw_write);
 
+/*
+ * regmap_bulk_write(): Write multiple registers to the device
+ *
+ * @map: Register map to write to
+ * @reg: First register to be write from
+ * @val: Block of data to be written, in native register size for device
+ * @val_count: Number of registers to write
+ *
+ * This function is intended to be used for writing a large block of
+ * data to be device either in single transfer or multiple transfer.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
+		     size_t val_count)
+{
+	int ret = 0, i;
+	size_t val_bytes = map->format.val_bytes;
+	void *wval;
+
+	if (!map->format.parse_val)
+		return -EINVAL;
+
+	mutex_lock(&map->lock);
+
+	/* No formatting is require if val_byte is 1 */
+	if (val_bytes == 1) {
+		wval = (void *)val;
+	} else {
+		wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
+		if (!wval) {
+			ret = -ENOMEM;
+			dev_err(map->dev, "Error in memory allocation\n");
+			goto out;
+		}
+		for (i = 0; i < val_count * val_bytes; i += val_bytes)
+			map->format.parse_val(wval + i);
+	}
+	ret = _regmap_raw_write(map, reg, wval, val_bytes * val_count);
+
+	if (val_bytes != 1)
+		kfree(wval);
+
+out:
+	mutex_unlock(&map->lock);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(regmap_bulk_write);
+
 static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
 			    unsigned int val_len)
 {

include/linux/regmap.h

@@ -133,6 +133,8 @@ int regmap_reinit_cache(struct regmap *map,
 int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
 int regmap_raw_write(struct regmap *map, unsigned int reg,
 		     const void *val, size_t val_len);
+int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
+			size_t val_count);
 int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val);
 int regmap_raw_read(struct regmap *map, unsigned int reg,
 		    void *val, size_t val_len);