nvmem: sc27xx: Convert nvmem offset to block index

The Spreadtrum SC27XX efuse data are organized by blocks and each block
contains 2 bytes data. Moreover the nvmem core always pass the offset
in byte to the controller, so we should change the offset in byte to
the correct block index and block offset to read the data.

Signed-off-by: Freeman Liu <freeman.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/nvmem/sc27xx-efuse.c

@@ -106,10 +106,12 @@ static int sc27xx_efuse_poll_status(struct sc27xx_efuse *efuse, u32 bits)
 static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 {
 	struct sc27xx_efuse *efuse = context;
-	u32 buf;
+	u32 buf, blk_index = offset / SC27XX_EFUSE_BLOCK_WIDTH;
+	u32 blk_offset = (offset % SC27XX_EFUSE_BLOCK_WIDTH) * BITS_PER_BYTE;
 	int ret;
 
-	if (offset > SC27XX_EFUSE_BLOCK_MAX || bytes > SC27XX_EFUSE_BLOCK_WIDTH)
+	if (blk_index > SC27XX_EFUSE_BLOCK_MAX ||
+	    bytes > SC27XX_EFUSE_BLOCK_WIDTH)
 		return -EINVAL;
 
 	ret = sc27xx_efuse_lock(efuse);
@@ -133,7 +135,7 @@ static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 	/* Set the block address to be read. */
 	ret = regmap_write(efuse->regmap,
 			   efuse->base + SC27XX_EFUSE_BLOCK_INDEX,
-			   offset & SC27XX_EFUSE_BLOCK_MASK);
+			   blk_index & SC27XX_EFUSE_BLOCK_MASK);
 	if (ret)
 		goto disable_efuse;
 
@@ -171,8 +173,10 @@ static int sc27xx_efuse_read(void *context, u32 offset, void *val, size_t bytes)
 unlock_efuse:
 	sc27xx_efuse_unlock(efuse);
 
-	if (!ret)
+	if (!ret) {
+		buf >>= blk_offset;
 		memcpy(val, &buf, bytes);
+	}
 
 	return ret;
 }