[PATCH V5 2/2] regmap: add regmap_bulk_write() for register write

[Laxman Dewangan <ldewangan@nvidia.com>]

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>
---
Changes from V1: 
- Change commit message.
- Byte swapping in input data packet.
Changes from V2: 
- Remove formatting if val_byte is 1.
- Allocating proper size of memory for val_byte != 1
Changes from V3:
- Stylish fixes.
Changes from V4:
- Remove support for case when parse_val is not available.

 drivers/base/regmap/regmap.c |   50 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/regmap.h       |    2 +
 2 files changed, 52 insertions(+), 0 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index ba92217..9eb0189 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -482,6 +482,56 @@ 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)
 {
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index a6ed6e6..0925e24 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -135,6 +135,8 @@ 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);
-- 
1.7.1.1