[can-next-rfc 03/14] can: mcp251xfd: mcp251xfd_regmap_crc_read(): ignore CRC error only if solely OSC register is read

[Marc Kleine-Budde <mkl@pengutronix.de>]

MCP251XFD_REG_OSC is the first ever reg we read from. The chip may be
in deep sleep and the SPI transfer (i.e. the assertion of the CS) will
wake the chip up. This takes about 3ms. The CRC of this transfer is
wrong, or there isn't a chip at all, in this case the CRC will be
wrong, too. The driver ignores the CRC error and returns the read data
to the caller.

To avoid any confusion, this patch changes the
mcp251xfd_regmap_crc_read() function to only ignore the CRC error if
solely the OSC register is read. So when reading multiple registers at
once the CRC is returned.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
index 297491516a26..e026247812aa 100644
--- a/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
+++ b/drivers/net/can/spi/mcp251xfd/mcp251xfd-regmap.c
@@ -369,7 +369,7 @@ mcp251xfd_regmap_crc_read(void *context,
 		 * to the caller. It will take care of both cases.
 		 *
 		 */
-		if (reg == MCP251XFD_REG_OSC) {
+		if (reg == MCP251XFD_REG_OSC && val_len == sizeof(__le32)) {
 			err = 0;
 			goto out;
 		}
-- 
2.30.2