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Date: Mon, 26 Feb 2024 11:13:36 +0100
Message-Id: <CZEXIZWQO1XB.1YY4P72A2K1HJ@bootlin.com>
From: =?utf-8?q?Th=C3=A9o_Lebrun?= <theo.lebrun@bootlin.com>
Subject: Re: [PATCH v3 4/8] usb: cdns3-ti: support reset-on-resume behavior
Cc: "Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
 =?utf-8?q?Gr=C3=A9gory_Clement?= <gregory.clement@bootlin.com>, "Kevin
 Hilman" <khilman@kernel.org>, "Alan Stern" <stern@rowland.harvard.edu>,
 <linux-usb@vger.kernel.org>, <devicetree@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, <linux-arm-kernel@lists.infradead.org>
To: "Sergei Shtylyov" <sergei.shtylyov@gmail.com>, "Greg Kroah-Hartman"
 <gregkh@linuxfoundation.org>, "Rob Herring" <robh+dt@kernel.org>,
 "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>, "Conor Dooley"
 <conor+dt@kernel.org>, "Roger Quadros" <rogerq@kernel.org>, "Peter Chen"
 <peter.chen@kernel.org>, "Pawel Laszczak" <pawell@cadence.com>, "Nishanth
 Menon" <nm@ti.com>, "Vignesh Raghavendra" <vigneshr@ti.com>, "Tero Kristo"
 <kristo@kernel.org>
References: <20240223-j7200-usb-suspend-v3-0-b41c9893a130@bootlin.com>
 <20240223-j7200-usb-suspend-v3-4-b41c9893a130@bootlin.com>
 <b778d2e8-3fcf-afe4-2e48-0348be19a085@gmail.com>
In-Reply-To: <b778d2e8-3fcf-afe4-2e48-0348be19a085@gmail.com>

Hello Sergey,

On Sat Feb 24, 2024 at 10:08 AM CET, Sergei Shtylyov wrote:
> On 2/23/24 7:05 PM, Th=C3=A9o Lebrun wrote:
> > Add match data support, with one boolean to indicate whether the
> > hardware resets after a system-wide suspend. If hardware resets, we
> > force execute ->runtime_resume() at system-wide resume to run the
> > hardware init sequence.
> >=20
> > No compatible exploits this functionality, just yet.
> >=20
> > Signed-off-by: Th=C3=A9o Lebrun <theo.lebrun@bootlin.com>
> > ---
> >  drivers/usb/cdns3/cdns3-ti.c | 27 +++++++++++++++++++++++++++
> >  1 file changed, 27 insertions(+)
> >=20
> > diff --git a/drivers/usb/cdns3/cdns3-ti.c b/drivers/usb/cdns3/cdns3-ti.=
c
> > index 4c8a557e6a6f..f76327566798 100644
> > --- a/drivers/usb/cdns3/cdns3-ti.c
> > +++ b/drivers/usb/cdns3/cdns3-ti.c
> [...]
> > @@ -220,8 +226,29 @@ static int cdns_ti_runtime_resume(struct device *d=
ev)
> >  	return 0;
> >  }
> > =20
> > +static int cdns_ti_suspend(struct device *dev)
> > +{
> > +	struct cdns_ti *data =3D dev_get_drvdata(dev);
> > +
> > +	if (data->match_data && data->match_data->reset_on_resume)
> > +		return pm_runtime_force_suspend(dev);
> > +	else
>
>    Pointless *else* after *return*...

Indeed! I used this form explicitely as it reads nicely: "if reset on
reset, force suspend, else do nothing". It also prevents the error of
adding behavior below the if-statement without seeing that it won't
apply to both cases.

If you do believe it would make the code better I'll happily change it
for the next revision, I do not mind.

Thanks for the review Sergey!

--
Th=C3=A9o Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com