On 2/26/20 8:37 AM, Marc Kleine-Budde wrote: >> Your right... there is the mcp251x_hw_rx_frame() call that also uses >> spi_rx_buf after a synchronous transfer (I didn't see any others). >> I'll look at this again. > > Have you hardware to test your changes? I think the SPI framework would > return an -EINVAL in that case....though the return value is sometimes > not checked by the driver :/ See https://elixir.bootlin.com/linux/v5.5.6/source/drivers/spi/spi.c#L3413 If you have really have HW with SPI_CONTROLLER_HALF_DUPLEX (a.k.a SPI_MASTER_HALF_DUPLEX) restrictions, you need to convert _every_ mcp251x_spi_trans() call in the driver, as _always_ both rx_buf _and_ tx_buf are used. Marc -- Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
