From: Joel Stanley <joel@jms.id.au>
To: Eddie James <eajames@linux.ibm.com>
Cc: Mark Brown <broonie@kernel.org>,
linux-spi@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
Brad Bishop <bradleyb@fuzziesquirrel.com>,
Rob Herring <robh+dt@kernel.org>, Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH 2/7] spi: fsi: Fix clock running too fast
Date: Tue, 25 Aug 2020 07:10:21 +0000 [thread overview]
Message-ID: <CACPK8XcJnDjt6N9KHNEG7Mhy7=mWX2OYA-Z0tfBbvHdsJC7apA@mail.gmail.com> (raw)
In-Reply-To: <660034d2-c808-3a4b-6ecc-be1769e8a017@linux.ibm.com>
On Thu, 20 Aug 2020 at 21:06, Eddie James <eajames@linux.ibm.com> wrote:
>
>
> On 8/20/20 12:12 PM, Mark Brown wrote:
> > On Thu, Aug 20, 2020 at 12:02:23PM -0500, Eddie James wrote:
> >> From: Brad Bishop <bradleyb@fuzziesquirrel.com>
> >>
> >> Use a clock divider tuned to a 200MHz FSI clock. Use of the previous
> >> divider at 200MHz results in corrupt data from endpoint devices. Ideally
> >> the clock divider would be calculated from the FSI clock, but that
> >> would require some significant work on the FSI driver.
> > Presumably this divider was chosen for FSI clocks that aren't 200MHz -
> > how will those be handled?
>
>
> They aren't handled at the moment, but 200MHz FSI represents the worst
> case, as it's the maximum. Slower FSI clocks will simply result in
> slower SPI clocks.
That would be a good addition to the commit message, as I had the same
question too.
Cheers,
Joel
next prev parent reply other threads:[~2020-08-25 7:10 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 17:02 [PATCH 0/7] spi: Fix FSI-attached controller and AT25 drivers Eddie James
2020-08-20 17:02 ` [PATCH 1/7] spi: fsi: Handle 9 to 15 byte transfers lengths Eddie James
2020-08-20 17:02 ` [PATCH 2/7] spi: fsi: Fix clock running too fast Eddie James
2020-08-20 17:12 ` Mark Brown
2020-08-20 21:06 ` Eddie James
2020-08-25 7:10 ` Joel Stanley [this message]
2020-08-20 17:02 ` [PATCH 3/7] spi: fsi: Fix use of the bneq+ sequencer instruction Eddie James
2020-08-20 17:02 ` [PATCH 4/7] dt-bindings: fsi: fsi2spi: Document new restricted property Eddie James
2020-08-20 17:14 ` Mark Brown
2020-08-20 21:07 ` Eddie James
2020-08-21 12:03 ` Mark Brown
2020-09-08 20:44 ` Rob Herring
2020-08-20 17:02 ` [PATCH 5/7] spi: fsi: Implement restricted size for certain controllers Eddie James
2020-08-20 17:19 ` Mark Brown
2020-08-20 17:02 ` [PATCH 6/7] spi: fsi: Check mux status before transfers Eddie James
2020-08-20 17:02 ` [PATCH 7/7] eeprom: at25: Split reads into chunks and cap write size Eddie James
2020-08-20 17:20 ` Mark Brown
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