diff options
Diffstat (limited to 'drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c')
| -rw-r--r-- | drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c | 22 |
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; } } |