linux-kernel - Re: [PATCH] spi: Fix error code checking in spi_mem_exec

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Date: Wed, 13 Mar 2024 18:33:43 +0100
From: "Michael Walle" <mwalle@...nel.org>
To: "Florian Fainelli" <florian.fainelli@...adcom.com>,
 <linux-spi@...r.kernel.org>
Cc: "Mark Brown" <broonie@...nel.org>, "Miquel Raynal"
 <miquel.raynal@...tlin.com>, "Mika Westerberg"
 <mika.westerberg@...ux.intel.com>, "Chia-Lin Kao (AceLan)"
 <acelan.kao@...onical.com>, "open list" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] spi: Fix error code checking in spi_mem_exec_op()

On Wed Mar 13, 2024 at 6:10 PM CET, Florian Fainelli wrote:
> After commit cff49d58f57e ("spi: Unify error codes by replacing -ENOTSUPP with
> -EOPNOTSUPP"), our SPI NOR flashes would stop probing with the following
> visible in the kernel log:
>
> [    2.196300] brcmstb_qspi f0440920.qspi: using bspi-mspi mode
> [    2.210295] spi-nor: probe of spi1.0 failed with error -95
>
> It turns out that the check in spi_mem_exec_op() was changed to check
> for -ENOTSUPP (old error code) or -EOPNOTSUPP (new error code), but this
> means that for drivers that were converted, the second condition is now
> true, and we stop falling through like we used to. Fix the error to
> check for neither error being neither -ENOTSUPP *nor* -EOPNOTSUPP.
>
> Fixes: cff49d58f57e ("spi: Unify error codes by replacing -ENOTSUPP with -EOPNOTSUPP")
> Signed-off-by: Florian Fainelli <florian.fainelli@...adcom.com>
> Change-Id: I4159811f6c582c4de2143382473d2000b8755872

Ha, thank you!

Reviewed-by: Michael Walle <mwalle@...nel.org>

FWIW in next, there is commit
e63aef9c9121e ("spi: spi-mem: add statistics support to ->exec_op() calls")
that probably will conflict with this one.

Also, - not for this patch - but with that logic, spi_mem_exec_op()
might return EOPNOTSUPP *or* ENOTSUPP, even for drivers which might
still return ENOTSUPP, because there is one condition in
spi_mem_exec_op() which will always return EOPNOTSUPP. That is
somewhat confusing, no?

-michael