On Tue, Mar 30, 2021 at 3:02 AM Marc Kleine-Budde [off-list ref] wrote:

Some SPI host controllers do not support full-duplex SPI transfers.

The function mcp251x_spi_trans() does a full duplex transfer. It is
used in several places in the driver, where a TX half duplex transfer
is sufficient.

To fix support for half duplex SPI host controllers, this patch
introduces a new function mcp251x_spi_write() and changes all callers
that do a TX half duplex transfer to use mcp251x_spi_write().

Fixes: e0e25001d088 ("can: mcp251x: add support for half duplex controllers")
Cc: Tim Harvey <tharvey@gateworks.com>
Reported-by: Gerhard Bertelsmann <redacted>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---

Mi Marc and Gerhard,

So was the issue being resolved here that there was another SPI host
controller that wasn't advertising that it was half duplex only or was
something else wrong with e0e25001d088 ("can: mcp251x: add support for
half duplex controllers")?

Best regards,

Tim