From: broonie@kernel.org (Mark Brown)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] spi: davinci: support adding delay between transmission
Date: Sat, 6 Sep 2014 15:31:14 +0100 [thread overview]
Message-ID: <20140906143113.GI2601@sirena.org.uk> (raw)
In-Reply-To: <5409C704.5070303@ti.com>
On Fri, Sep 05, 2014 at 05:21:56PM +0300, Grygorii Strashko wrote:
> I think we have some misunderstanding here :(
> 1) All new properties a optional and should be specified for SPI Slave devices
> 2) Seems we are talking using different terms:
> - you referring to the term "transfers" - sequence of packets.
> Each packet is one transfer (array of words).
> - while these new properties affect on "transmissions" - sequence of words.
> Each word is one transmission.
That's *very* unusual terminology which doesn't match my expectations at
all. Please describe words as words, that'll be much more obvious.
> Also, below is additional information about properties which
> are used in 5-pin mode (SPI_READY) to improve error detection
> [OMAP-L138/da830 - http://www.ti.com/lit/ug/spruh77a/spruh77a.pdf]:
This is a *whole* other thing, please split these out and work on this
separately. The client device is going to need to be doing the same
thing here so implementing this as a local option in the controller
driver isn't the best way forwards.
> >> SPIFMTn[23].PARPOL - Parity polarity: even or odd. PARPOL can be modified in privilege mode only.
> >> 0 An even parity flag is added at the end of the transmit data stream.
> >> 1 An odd parity flag is added at the end of the transmit data stream.
> > Why would these be specified in DT and not with runtime flags enabled by
> > the device? It looks like they affect the data stream generated by the
> > controller so the client device needs to know about them; I'd expect
> > that it's device driver would be controlling when they are enabled if
> > the controller supports them.
> Could you clarify, pls - Do you mean that struct spi_device.mode and
> common SPI DT bindings should be extended to support this?
Yes, if they aren't something that's purely internal to the device they
need to be generic so that both devices can be configured appropriately.
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next prev parent reply other threads:[~2014-09-06 14:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-21 15:25 [PATCH 0/2] spi: davinci: fixes and updates Grygorii Strashko
2014-08-21 15:25 ` [PATCH 1/2] spi: davinci: fix SPI_NO_CS functionality Grygorii Strashko
2014-08-21 18:10 ` Mark Brown
2014-08-21 15:25 ` [PATCH 2/2] spi: davinci: support adding delay between transmission Grygorii Strashko
2014-08-21 18:20 ` Mark Brown
2014-08-22 13:33 ` Grygorii Strashko
2014-08-22 15:06 ` Mark Brown
2014-09-05 14:21 ` Grygorii Strashko
2014-09-06 14:31 ` Mark Brown [this message]
2014-09-08 13:30 ` Grygorii Strashko
2014-09-08 14:39 ` Mark Brown
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