regmap: slimbus: add support to multi read/write

SLIMbus supports upto 16 bytes in value management messages,
so add support to read/writes upto 16 bytes.

This also removes redundant single register reg_read/reg_write.

Also useful for paged register access on SLIMbus interfaced codecs.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/base/regmap/regmap-slimbus.c

@@ -7,33 +7,24 @@
 
 #include "internal.h"
 
-static int regmap_slimbus_byte_reg_read(void *context, unsigned int reg,
-					unsigned int *val)
+static int regmap_slimbus_write(void *context, const void *data, size_t count)
 {
 	struct slim_device *sdev = context;
-	int v;
 
-	v = slim_readb(sdev, reg);
-
-	if (v < 0)
-		return v;
-
-	*val = v;
-
-	return 0;
+	return slim_write(sdev, *(u16 *)data, count - 2, (u8 *)data + 2);
 }
 
-static int regmap_slimbus_byte_reg_write(void *context, unsigned int reg,
-					 unsigned int val)
+static int regmap_slimbus_read(void *context, const void *reg, size_t reg_size,
+			       void *val, size_t val_size)
 {
 	struct slim_device *sdev = context;
 
-	return slim_writeb(sdev, reg, val);
+	return slim_read(sdev, *(u16 *)reg, val_size, val);
 }
 
 static struct regmap_bus regmap_slimbus_bus = {
-	.reg_write = regmap_slimbus_byte_reg_write,
-	.reg_read = regmap_slimbus_byte_reg_read,
+	.write = regmap_slimbus_write,
+	.read = regmap_slimbus_read,
 	.reg_format_endian_default = REGMAP_ENDIAN_LITTLE,
 	.val_format_endian_default = REGMAP_ENDIAN_LITTLE,
 };