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From: "Ardelean, Alexandru" <alexandru.Ardelean@analog.com>
To: Andy Shevchenko <andy.shevchenko@gmail.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>
Subject: RE: [PATCH v3 2/3] spi: Add SPI_NO_TX/RX support
Date: Thu, 3 Dec 2020 08:20:57 +0000	[thread overview]
Message-ID: <CY4PR03MB29661063937AD783F6B2A010F9F20@CY4PR03MB2966.namprd03.prod.outlook.com> (raw)
In-Reply-To: <CAHp75VctXhpyBVB7Zw+SB5LiGcj6r850x+ehL7u2H0R4=y5rVw@mail.gmail.com>



> -----Original Message-----
> From: Andy Shevchenko <andy.shevchenko@gmail.com>
> Sent: Friday, November 27, 2020 4:24 PM
> To: Ardelean, Alexandru <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>
> Subject: Re: [PATCH v3 2/3] spi: Add SPI_NO_TX/RX support
> 
> 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

Hmm, in a way this could make sense for some SPIDEVs as well, to set these flags and get an error if they try to TX with the NO_TX flag set.
Not really sure about this.
Initially I mechanically added these here as an inertia to the previous patch which is just unifying the headers.

Any other opinions? Thoughts?
Mark?

> >
> > 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

  reply	other threads:[~2020-12-03  8:21 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-27 13:08 [PATCH v3 1/3] spi: uapi: unify SPI modes into a single spi.h header Alexandru Ardelean
2020-11-27 13:08 ` [PATCH v3 2/3] spi: Add SPI_NO_TX/RX support Alexandru Ardelean
2020-11-27 14:22   ` Andy Shevchenko
2020-11-27 14:23     ` Andy Shevchenko
2020-12-03  8:20       ` Ardelean, Alexandru [this message]
2020-12-03  9:47         ` Mark Brown
2020-11-27 13:08 ` [PATCH v3 3/3] spi: dt-bindings: document zero value for spi-{rx,tx}-bus-width properties Alexandru Ardelean
2020-11-27 14:26   ` Andy Shevchenko
2020-12-03 13:35     ` Ardelean, Alexandru
2020-11-27 14:12 ` [PATCH v3 1/3] spi: uapi: unify SPI modes into a single spi.h header Andy Shevchenko
2020-12-03  8:15   ` Ardelean, Alexandru

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