Received-SPF: pass (google.com: domain of linux-crypto-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Thu, 30 Jun 2022 16:51:47 +0200
From:   LABBE Corentin <clabbe@baylibre.com>
To:     John Keeping <john@metanate.com>
Cc:     heiko@sntech.de, ardb@kernel.org, herbert@gondor.apana.org.au,
        krzysztof.kozlowski+dt@linaro.org, robh+dt@kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v7 14/33] crypto: rockchip: handle reset also in PM
Message-ID: <Yr24g3LoO5uFuCux@Red>
References: <20220508185957.3629088-1-clabbe@baylibre.com>
 <20220508185957.3629088-15-clabbe@baylibre.com>
 <YrBUODGF51oUsF1f@donbot>
 <YrF74tmA9qc+I3JF@Red>
 <YrHJn6Pl5B/1pj9L@donbot>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <YrHJn6Pl5B/1pj9L@donbot>
Precedence: bulk

Le Tue, Jun 21, 2022 at 02:37:35PM +0100, John Keeping a ?crit :
> On Tue, Jun 21, 2022 at 10:05:54AM +0200, LABBE Corentin wrote:
> > Le Mon, Jun 20, 2022 at 12:04:24PM +0100, John Keeping a ?crit :
> > > On Sun, May 08, 2022 at 06:59:38PM +0000, Corentin Labbe wrote:
> > > > reset could be handled by PM functions.
> > > 
> > > Is there any further rationale for this?
> > > 
> > > After this change there is no longer a guaranteed reset pulse on probe
> > > since the reset control may already be de-asserted.  This is normally
> > > the most important case for a reset as it's the only time when the state
> > > of the hardware is unknown.
> > > 
> > > The original use of devm_add_action_or_reset() seems a bit weird already
> > > since there doesn't seem to be any need to assert reset when the driver
> > > is unloaded.
> > > 
> > 
> > I am not an hw engineer, so my knowledge on reset is low.
> > So why not having a reset pulse on probe is a problem ?
> 
> The point of the reset is to bring the hardware back to a known state.
> Since we don't know what state the hardware will be in following the
> bootloader or previous OS, I think the reset in probe is the only place
> that it is important.
> 
> If this patch isn't fixing anything, I suggest just dropping it.

Thanks for the explanation, I will re-add the reset at probe.