From: Eddie James <eajames@linux.ibm.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org,
devicetree@vger.kernel.org, joel@jms.id.au,
bradleyb@fuzziesquirrel.com, robh+dt@kernel.org, arnd@arndb.de
Subject: Re: [PATCH 2/7] spi: fsi: Fix clock running too fast
Date: Thu, 20 Aug 2020 16:06:07 -0500 [thread overview]
Message-ID: <660034d2-c808-3a4b-6ecc-be1769e8a017@linux.ibm.com> (raw)
In-Reply-To: <20200820171257.GG5854@sirena.org.uk>
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.
Thanks,
Eddie
next prev parent reply other threads:[~2020-08-20 21:06 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 [this message]
2020-08-25 7:10 ` Joel Stanley
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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