1 files changed, 11 insertions, 11 deletions

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
index 217510c12af5..92b7bc7f14b9 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
@@ -334,19 +334,21 @@ mcp251xfd_regmap_crc_read(void *context,
 		 * register. It increments once per SYS clock tick,
 		 * which is 20 or 40 MHz.
 		 *
-		 * Observation shows that if the lowest byte (which is
-		 * transferred first on the SPI bus) of that register
-		 * is 0x00 or 0x80 the calculated CRC doesn't always
-		 * match the transferred one.
+		 * Observation on the mcp2518fd shows that if the
+		 * lowest byte (which is transferred first on the SPI
+		 * bus) of that register is 0x00 or 0x80 the
+		 * calculated CRC doesn't always match the transferred
+		 * one. On the mcp2517fd this problem is not limited
+		 * to the first byte being 0x00 or 0x80.
 		 *
 		 * If the highest bit in the lowest byte is flipped
 		 * the transferred CRC matches the calculated one. We
-		 * assume for now the CRC calculation in the chip
-		 * works on wrong data and the transferred data is
-		 * correct.
+		 * assume for now the CRC operates on the correct
+		 * data.
 		 */
 		if (reg == MCP251XFD_REG_TBC &&
-		    (buf_rx->data[0] == 0x0 || buf_rx->data[0] == 0x80)) {
+		    ((buf_rx->data[0] & 0xf8) == 0x0 ||
+		     (buf_rx->data[0] & 0xf8) == 0x80)) {
 			/* Flip highest bit in lowest byte of le32 */
 			buf_rx->data[0] ^= 0x80;
 
@@ -356,10 +358,8 @@ mcp251xfd_regmap_crc_read(void *context,
 								  val_len);
 			if (!err) {
 				/* If CRC is now correct, assume
-				 * transferred data was OK, flip bit
-				 * back to original value.
+				 * flipped data is OK.
 				 */
-				buf_rx->data[0] ^= 0x80;
 				goto out;
 			}
 		}