linux-kernel - Re: [PATCH 5/7] memory: renesas-rpc-if: Move resource acquisition to .probe()

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Date:   Wed, 29 Jun 2022 20:25:57 +0200
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>
Cc:     Vignesh Raghavendra <vigneshr@...com>,
        Sergey Shtylyov <s.shtylyov@....ru>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Mark Brown <broonie@...nel.org>,
        MTD Maling List <linux-mtd@...ts.infradead.org>,
        Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
        linux-spi <linux-spi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 5/7] memory: renesas-rpc-if: Move resource acquisition to
 .probe()

On 29/06/2022 19:55, Geert Uytterhoeven wrote:
> Hi Krzysztof,
> 
> On Wed, Jun 29, 2022 at 7:44 PM Krzysztof Kozlowski
> <krzysztof.kozlowski@...aro.org> wrote:
>> On 27/06/2022 17:31, Geert Uytterhoeven wrote:
>>> While the acquired resources are tied to the lifetime of the RPC-IF core
>>> device (through the use of managed resource functions), the actual
>>> resource acquisition is triggered from the HyperBus and SPI child
>>> drivers.  Due to this mismatch, unbinding and rebinding the child
>>> drivers manually fails with -EBUSY:
>>>
>>>     # echo rpc-if-hyperflash > /sys/bus/platform/drivers/rpc-if-hyperflash/unbind
>>>     # echo rpc-if-hyperflash > /sys/bus/platform/drivers/rpc-if-hyperflash/bind
>>>     rpc-if ee200000.spi: can't request region for resource [mem 0xee200000-0xee2001ff]
>>>     rpc-if-hyperflash: probe of rpc-if-hyperflash failed with error -16
>>>
>>> Fix this by moving all resource acquisition to the core driver's probe
>>> routine.
>>>
>>> Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be>
>>
>> This looks like a fix, so how about putting it as first in the series,
>> so backporting is easy/automatic?
> 
> Unfortunately that is not as simple as it sounds, as this really
> depends on patch 4.

You sure? Except rebasing I don't see that. rpcif_sw_init() received the
rpcif so it had access to all fields.


> I agree patches 1-3 could be moved later, if you think it is worthwhile.

This would not be enough, it has to be first patch to be backportable.

Best regards,
Krzysztof