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From: Hieu Tran Dang <dangtranhieu2012@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: robh@kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] dt-bindings: spi: fsl-lpspi: Option to allow stalling
Date: Mon, 1 Oct 2018 08:12:42 +0700	[thread overview]
Message-ID: <CAAObPoFfhJZpr_iwcmub2zndTV4GK5byV0DFBybeqA_vB8mbQQ@mail.gmail.com> (raw)
In-Reply-To: <20180927224723.GF20825@sirena.org.uk>

Agree. I will create new patch which will just allow stalling by default.

Vào Th 6, 28 thg 9, 2018 vào lúc 05:47 Mark Brown <broonie@kernel.org> đã viết:
>
> On Wed, Sep 26, 2018 at 09:37:39PM +0700, Đặng Trần Hiếu wrote:
>
> > Default value of the register is to allow stalling (NOSTALL bit not
> > set) but the spi-fsl-lpspi driver defaults to setting the NOSTALL bit
> > in CFGR1. To me, it's more logical to leave the NOSTALL bit off with
> > fsl,nostall binding to set the bit but as I am not sure if there are
> > other drivers depending on the NOSTALL bit being set and not wanting
> > to break other drivers hence introduction of this binding to keep the
> > current default behavior.
>
> I can't see a situation where you'd actively want to report an error
> rather than stall, stalling allows us to handle things gracefully by
> restarting things.  Even if it's a timeout situation it sounds like we
> can unblock by reading/writing the stalled FIFO, and normally you'd be
> resetting the entire IP anyway.  I'd imagine the driver is this way
> either through an oversight or because there's some bug on some silicon
> which means that stalling breaks.
>
> Probably best to just always enable stalling unless I'm misreading
> things, if it is silicon bugs on some versions then either a whitelist
> or blacklist of SoCs to enable on (depending on how common the bug is)
> would be the way forwards - that way SoCs where it works get the benefit.

  reply	other threads:[~2018-10-01  1:12 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-25 20:36 [PATCH 0/2] spi: fsl-lpspi: Option to prevent FIFO under/overrun Hieu Tran Dang
2018-09-25 20:37 ` [PATCH 1/2] dt-bindings: spi: fsl-lpspi: Option to allow stalling Hieu Tran Dang
2018-09-26 14:26   ` Rob Herring
2018-09-26 14:37     ` Đặng Trần Hiếu
2018-09-27 22:47       ` Mark Brown
2018-10-01  1:12         ` Hieu Tran Dang [this message]
2018-09-25 20:37 ` [PATCH 2/2] spi: fsl-lpspi: Option to prevent FIFO under/overrun Hieu Tran Dang

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