From: Mark Brown <broonie@kernel.org>
To: Adrian Fiergolski <Adrian.Fiergolski@cern.ch>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>,
linux-spi <linux-spi@vger.kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Subject: Re: [PATCH] spi: Add spi-bits-per-word binding.
Date: Fri, 17 Mar 2017 21:21:43 +0000 [thread overview]
Message-ID: <20170317212143.bogj6efzyvvf24yd@sirena.org.uk> (raw)
In-Reply-To: <5f86da77-c3f9-24e4-6c9a-3e2554bb49d3@cern.ch>
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On Mon, Mar 13, 2017 at 09:26:04PM +0100, Adrian Fiergolski wrote:
> On 13.03.2017 at 20:57, Geert Uytterhoeven wrote:
> > On Mon, Mar 13, 2017 at 7:12 PM, Adrian Fiergolski
d
> >>> I can't see any way in which it follows from the above that it's a good
> >>> idea to try to override bits per word settings in the device tree, that
> >>> just wastes user time and is an abstraction failure. We need better
> >>> handling of defaults done purely in the kernel.
> >> If enforcing by device tree specific for a given device driver SPI_CPHA,
> >> SPIC_CPOL, SPI_CS_HIGH, max_speed_hz, etc. if fine form the abstraction
> >> point of view, why it doesn't apply to bits_per_word ?
> > Because unlike polarity, phase, and speed, bits_per_word is a property
> > of the communication protocol.
> > E.g. you can talk to the same EEPROM using different polarities, phase, or
> > speed, but bits_per_word is fixed.
> In this case, currently, what is the proper way to handle SPI
> controllers (spi-xilinx) without 8-bit transmission support ?
As I said above we should fix the handling of defaults such that it is
possible to instantiate a 16 bit using device on a 16 bit supporting
controller; there should be no need to have anything about device tree
in this.
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prev parent reply other threads:[~2017-03-17 21:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170217101151.hyzmz5a4lgdy7p5m>
2017-02-20 15:35 ` [PATCH] spi: Add spi-bits-per-word binding Adrian Fiergolski
2017-02-21 19:08 ` Mark Brown
2017-03-13 17:25 ` Adrian Fiergolski
2017-03-13 17:55 ` Mark Brown
2017-03-13 18:12 ` Adrian Fiergolski
2017-03-13 19:57 ` Geert Uytterhoeven
2017-03-13 20:26 ` Adrian Fiergolski
2017-03-17 21:21 ` Mark Brown [this message]
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