[PATCH V2] spi: Update speed/mode on change

Tom Rini trini at konsulko.com
Sun Mar 28 23:30:55 CEST 2021


On Fri, Feb 26, 2021 at 03:21:24PM +0100, Marek Vasut wrote:

> The spi_get_bus_and_cs() may be called on the same bus and chipselect
> with different frequency or mode. This is valid usecase, but the code
> fails to notify the controller of such a configuration change. Call
> spi_set_speed_mode() in case bus frequency or bus mode changed to let
> the controller update the configuration.
> 
> The problem can easily be triggered using the sspi command:
> => sspi 0:0 at 1000
> => sspi 0:0 at 2000
> Without this patch, both transfers happen at 1000 Hz. With this patch,
> the later transfer happens correctly at 2000 Hz.
> 
> Signed-off-by: Marek Vasut <marex at denx.de>
> Cc: Jagan Teki <jagan at amarulasolutions.com>
> Cc: Patrick Delaunay <patrick.delaunay at st.com>

So, very reliably I can make:
https://source.denx.de/u-boot/u-boot/-/jobs/245517
happen locally as well building with clang.  It's not obvious to me why
the test now fails however.

-- 
Tom
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