linux-kernel - Re: [PATCH v2] pwm-backlight: fix the panel power sequence

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1446538299.2449.8.camel@mtksdaap41>
Date:	Tue, 3 Nov 2015 16:11:39 +0800
From:	YH Huang <yh.huang@...iatek.com>
To:	Philipp Zabel <p.zabel@...gutronix.de>
CC:	<linux-pwm@...r.kernel.org>, <linux-fbdev@...r.kernel.org>,
	Jingoo Han <jingoohan1@...il.com>,
	Tomi Valkeinen <tomi.valkeinen@...com>,
	Jean-Christophe Plagniol-Villard <plagnioj@...osoft.com>,
	<linux-kernel@...r.kernel.org>,
	Thierry Reding <thierry.reding@...il.com>,
	<linux-mediatek@...ts.infradead.org>,
	Sascha Hauer <kernel@...gutronix.de>,
	Matthias Brugger <matthias.bgg@...il.com>,
	<yingjoe.chen@...iatek.com>, "Lee Jones" <lee.jones@...aro.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v2] pwm-backlight: fix the panel power sequence

On Fri, 2015-10-30 at 11:34 +0100, Philipp Zabel wrote:
> Am Freitag, den 30.10.2015, 15:41 +0800 schrieb YH Huang:
> > > That won't work if the gpio is still configured as input. How about I
> > > add the GPIOD_ASIS change to my patch you remove that and the above from
> > > yours?
> > 
> > I revise these two lines 
> > if (pb->enable_gpio)
> > 	gpiod_direction_output(pb->enable_gpio, 0);
> > into
> > if (pb->enable_gpio) {
> > 	if(gpiod_get_value(pb->enable_gpio) == 0)
> > 		gpiod_direction_output(pb->enable_gpio, 0);
> > 	else
> > 		gpiod_direction_output(pb->enable_gpio, 1);
> > }
> 
> If the GPIO is still configured as an input, the return value of
> gpiod_get_value could be random.
> 
> > I am not sure what "phandle" is working for.
> 
> The reasoning is that devices where there is no phandle link pointing to
> the backlight (for example from a simple-panel node), we should keep the
> current default behaviour (enable during probe).

I have a little problem for the current default behaviour.
Should we enable during probe?

Before this patch ( http://patchwork.ozlabs.org/patch/324690/ ),
we disable "enable-gpio" in the probe function.

Do you have any idea of this?

Regards,
YH Huang


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/