Message-ID: <1446798690.6203.3.camel@mtksdaap41>
Subject: Re: [PATCH v2] pwm-backlight: fix the panel power sequence
From: YH Huang <yh.huang@mediatek.com>
To: Philipp Zabel <p.zabel@pengutronix.de>
CC: <linux-pwm@vger.kernel.org>, <linux-fbdev@vger.kernel.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Tomi Valkeinen <tomi.valkeinen@ti.com>,
        Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
        <linux-kernel@vger.kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        <linux-mediatek@lists.infradead.org>,
        Sascha Hauer <kernel@pengutronix.de>,
        Matthias Brugger <matthias.bgg@gmail.com>, <yingjoe.chen@mediatek.com>,
        "Lee Jones" <lee.jones@linaro.org>,
        <linux-arm-kernel@lists.infradead.org>
Date: Fri, 6 Nov 2015 16:31:30 +0800
In-Reply-To: <1446716430.3894.12.camel@pengutronix.de>
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On Thu, 2015-11-05 at 10:40 +0100, Philipp Zabel wrote:
> > 
> > Based on this, could we disable it initially and update in the
> > backlight_update_status function?
> > 
> > Like this,
> > 
> > if (pb->enable_gpio) {
> > 	if (phandle &&
> > 	    gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT &&
> > 	    gpiod_get_value(pb->enable_gpio) == 1)
> > 		gpiod_direction_output(pb->enable_gpio, 1);
> 
> The gpiod_direction_output call is a no-op, since the direction is
> already output and the value is already 1.
> Also, I propose to set initial blanking to FB_BLANK_POWERDOWN in this
> case, and wait for the panel driver to enable the backlight at the
> appropriate time.

Thanks your kindly reply.
Your patch looks good to me.

Regards,
YH Huang

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