[PATCH v4 3/8] spi: stm32: Add 'SPI_SIMPLEX_RX', 'SPI_3WIRE_RX' support for stm32f4

[dillon min]

hi Mark,

Thanks for reviewing.

On Fri, May 22, 2020 at 7:36 PM Mark Brown <broonie at kernel.org> wrote:
>
> On Mon, May 18, 2020 at 07:09:20PM +0800, dillon.minfei at gmail.com wrote:
>
> > 2, use stm32 spi's "In full-duplex (BIDIMODE=0 and RXONLY=0)", as tx_buf is
> > null, we must add dummy data sent out before read data.
> > so, add stm32f4_spi_tx_dummy() to handle this situation.
>
> There are flags SPI_CONTROLLER_MUST_TX and SPI_CONTROLLER_MUST_RX flags
> that the driver can set if it needs to, no need to open code this in the
> driver.

Yes, after check SPI_CONTROLLER_MUST_TX in drivers/spi/spi.c , it's
indeed to meet
this situation,  i will try it and sumbmit a new patch.

thanks.

best regards

Dillon