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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Fri, 27 Nov 2020 16:23:40 +0200
Message-ID: <CAHp75VctXhpyBVB7Zw+SB5LiGcj6r850x+ehL7u2H0R4=y5rVw@mail.gmail.com>
Subject: Re: [PATCH v3 2/3] spi: Add SPI_NO_TX/RX support
To:     Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc:     linux-spi <linux-spi@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Brown <broonie@kernel.org>,
        "Bogdan, Dragos" <dragos.bogdan@analog.com>
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On Fri, Nov 27, 2020 at 4:22 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
> On Fri, Nov 27, 2020 at 3:08 PM Alexandru Ardelean
> <alexandru.ardelean@analog.com> wrote:

...

> > --- a/include/uapi/linux/spi/spi.h
> > +++ b/include/uapi/linux/spi/spi.h
> > @@ -43,5 +43,7 @@
> >  #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 */
>
> Is it really material for uAPI?
> Perhaps we may have something like
> SPI_MODE_USER_MASK in uAPI and
> in internal headers
>
> SPI_MODE_KERNEL_MASK with
> static_assert(_USER_MASK & _KERNEL_MASK); // check conditional
>
> ?

And logically start bits for the kernel from the end (31, 30, ...).

-- 
With Best Regards,
Andy Shevchenko