From: Mark Brown <broonie@kernel.org>
To: Trent Piepho <tpiepho@impinj.com>
Cc: "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>,
"talel@amazon.com" <talel@amazon.com>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"robh+dt@kernel.org" <robh+dt@kernel.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"barakw@amazon.com" <barakw@amazon.com>,
"ronenk@amazon.com" <ronenk@amazon.com>,
"dwmw@amazon.co.uk" <dwmw@amazon.co.uk>
Subject: Re: [PATCH 1/2] dt-bindings: spi: dw: add cs-override property
Date: Thu, 11 Oct 2018 14:46:36 +0100 [thread overview]
Message-ID: <20181011134636.GC25351@sirena.org.uk> (raw)
In-Reply-To: <1539210111.1944.31.camel@impinj.com>
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On Wed, Oct 10, 2018 at 10:21:51PM +0000, Trent Piepho wrote:
> So that's the problem! I, like everyone else I suspect, switched to
> using GPIO chip selects with this driver because of this. I narrowed
That's generally a good idea.
> it down to a CS de-assert when the bus switched from TX to RX, which of
> course makes a SPI register read fail on most devices. The TX FIFO
> would empty at this point, so that would explain it.
> Did the designers of this IP ever read a SPI device datasheet???
> Got to agree with Mark Brown, why would anyone ever want to NOT have it
> work properly? The previous behavior is not "alternate correct", it's
> Broken.
This isn't even that unusual an innovation for hardware to have, for
some reason automatic chip select management is *really* popular and
rarely helpful. It's far from the most entertaining thing I've seen
hardware do.
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prev parent reply other threads:[~2018-10-11 13:46 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-10 7:08 [PATCH 1/2] dt-bindings: spi: dw: add cs-override property Talel Shenhar
2018-10-10 7:08 ` [PATCH 2/2] dw: spi: add 'cs-override' DT property support Talel Shenhar
2018-10-10 10:18 ` [PATCH 1/2] dt-bindings: spi: dw: add cs-override property Mark Brown
2018-10-10 10:34 ` Talel Shenhar
2018-10-10 11:29 ` David Woodhouse
2018-10-10 11:23 ` Talel Shenhar
2018-10-10 11:27 ` Mark Brown
[not found] ` <ba83a08073614d9244c01218da28fe3e23f3bbc2.camel@amazon.co.uk>
2018-10-10 12:27 ` Mark Brown
2018-10-10 22:52 ` Trent Piepho
2018-10-10 15:15 ` [PATCH 1/2] dt-bindings: spi: dw: add compatible for Alpine spi controller Talel Shenhar
2018-10-10 15:15 ` [PATCH 2/2] dw: spi: add support " Talel Shenhar
2018-10-10 22:08 ` Trent Piepho
2018-10-11 11:20 ` [PATCH 1/2] dt-bindings: spi: dw: add compatible for Amazon's " Talel Shenhar
2018-10-11 11:20 ` [PATCH 2/2] dw: spi: add support " Talel Shenhar
2018-10-11 14:58 ` Applied "dw: spi: add support for Amazon's Alpine spi controller" to the spi tree Mark Brown
2018-10-11 13:44 ` [PATCH 1/2] dt-bindings: spi: dw: add compatible for Amazon's Alpine spi controller Mark Brown
2018-10-11 14:58 ` Applied "spi: dw: add compatible for Amazon's Alpine spi controller" to the spi tree Mark Brown
2018-10-11 11:22 ` [PATCH 2/2] dw: spi: add support for Alpine spi controller Talel Shenhar
2018-10-10 22:21 ` [PATCH 1/2] dt-bindings: spi: dw: add cs-override property Trent Piepho
2018-10-11 7:39 ` Talel Shenhar
2018-10-11 13:46 ` Mark Brown [this message]
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