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SubjectRe: [PATCH] spi: Add SPI_NO_TX/RX support
On Wed, Nov 11, 2020 at 4:45 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Wed, Nov 11, 2020 at 4:13 PM Alexandru Ardelean
> <alexandru.ardelean@analog.com> wrote:
> >
> > From: Dragos Bogdan <dragos.bogdan@analog.com>
> >
> > Transmit/receive only is a valid SPI mode. For example, the MOSI/TX line
> > might be missing from an ADC while for a DAC the MISO/RX line may be
> > optional. This patch adds these two new modes: SPI_NO_TX and
> > SPI_NO_RX. This way, the drivers will be able to identify if any of
> > these two lines is missing and to adjust the transfers accordingly.
>
> Shouldn't this update a binding documentation?

oh,
good catch

>
> ...
>
> > - /* check mode to prevent that DUAL and QUAD set at the same time
> > + /* check mode to prevent that any two of DUAL, QUAD and NO_MOSI/MISO
> > + * are set at the same time
> > */
>
> /*
> * Perhaps switch to proper multi-line comment style
> * at the same time?
> */

¯\_(ツ)_/¯

Not sure what SPI prefers as multi-line comment style,
But ok.

>
> ...
>
> > #define SPI_TX_OCTAL 0x2000 /* transmit with 8 wires */
> > #define SPI_RX_OCTAL 0x4000 /* receive with 8 wires */
> > #define SPI_3WIRE_HIZ 0x8000 /* high impedance turnaround */
> > +#define SPI_NO_TX 0x10000 /* no transmit wire */
> > +#define SPI_NO_RX 0x20000 /* no receive wire */
>
> Perhaps switch to use BIT() instead at some point (as a prerequisite
> patch, for example)

I'll leave this up to the maintainer preference.
Maybe I'll do it as a second patch here, so that I can be dropped.

>
> --
> With Best Regards,
> Andy Shevchenko

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