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From: YH Huang <yh.huang@mediatek.com>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2] pwm-backlight: fix the panel power sequence
Date: Tue, 03 Nov 2015 08:11:39 +0000	[thread overview]
Message-ID: <1446538299.2449.8.camel@mtksdaap41> (raw)
In-Reply-To: <1446201271.3334.22.camel@pengutronix.de>

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



  reply	other threads:[~2015-11-03  8:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-16  9:17 [PATCH v2] pwm-backlight: fix the panel power sequence YH Huang
2015-10-16  9:36 ` Philipp Zabel
2015-10-22 15:12   ` YH Huang
2015-10-29 15:40     ` Philipp Zabel
2015-10-30  7:41       ` YH Huang
2015-10-30 10:34         ` Philipp Zabel
2015-11-03  8:11           ` YH Huang [this message]
2015-11-03 11:08             ` Philipp Zabel
2015-11-04  1:47               ` YH Huang
2015-11-05  9:40                 ` Philipp Zabel
2015-11-06  8:31                   ` YH Huang

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