From: Serge Semin <fancer.lancer@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] spi: Limit the spi device max speed to controller's max speed
Date: Wed, 9 Dec 2020 23:30:42 +0300 [thread overview]
Message-ID: <20201209203042.oqbcijwaxqt5aa7b@mobilestation> (raw)
In-Reply-To: <20201209202552.GE4790@sirena.org.uk>
On Wed, Dec 09, 2020 at 08:25:52PM +0000, Mark Brown wrote:
> On Wed, Dec 09, 2020 at 11:15:35PM +0300, Serge Semin wrote:
> > On Wed, Dec 09, 2020 at 07:54:20PM +0000, Mark Brown wrote:
>
> > > Right, in general we aim to do this sort of fixup on the transfers
> > > and messages rather than the devices, I guess we might be missing
> > > validation in some of the flash acceleration paths or was this an issue
> > > seen through inspection?
>
> > In case of DW SPI driver we just make sure the SPI-client device
> > speed set in the max_speed_hz doesn't exceed the controller SPI-bus
> > clock frequency and clamp it if it does. So the driver is safe in that
> > matter.
>
> Ideally the driver wouldn't have to check though (no harm in doing so of
> course).
If so then we'd need to have a dedicated speed-related field in the
spi_mem_op structure, which would be accordingly initialized by the
SPI-mem core.
-Sergey
next prev parent reply other threads:[~2020-12-09 20:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-09 17:35 [PATCH] spi: Limit the spi device max speed to controller's max speed Tudor Ambarus
2020-12-09 19:46 ` Serge Semin
2020-12-09 19:54 ` Mark Brown
2020-12-09 20:15 ` Serge Semin
2020-12-09 20:25 ` Mark Brown
2020-12-09 20:30 ` Serge Semin [this message]
2020-12-10 8:58 ` Tudor.Ambarus
2020-12-10 15:33 ` Mark Brown
2020-12-10 16:32 ` Tudor.Ambarus
2020-12-10 18:16 ` Mark Brown
2020-12-11 17:51 ` Mark Brown
2020-12-15 14:24 ` Geert Uytterhoeven
2020-12-16 8:25 ` Tudor.Ambarus
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