netdev - Re: [PATCH 2/2 v3] net: smsc911x: request and deassert optional RESET GPIO

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Message-Id: <20160907.210617.685340162025675932.davem@davemloft.net>
Date:   Wed, 07 Sep 2016 21:06:17 -0700 (PDT)
From:   David Miller <davem@...emloft.net>
To:     linus.walleij@...aro.org
Cc:     netdev@...r.kernel.org, steve.glendinning@...well.net,
        linux@...ck-us.net, jeremy.linton@....com,
        kamlakant.patel@...adcom.com, p.fedin@...sung.com
Subject: Re: [PATCH 2/2 v3] net: smsc911x: request and deassert optional
 RESET GPIO

From: Linus Walleij <linus.walleij@...aro.org>
Date: Wed,  7 Sep 2016 15:53:42 +0200

> On some systems (such as the Qualcomm APQ8060 Dragonboard) the
> RESET signal of the SMSC911x is not pulled up by a resistor (or
> the internal pull-up that will pull it up if the pin is not
> even connected) but instead connected to a GPIO line, so that
> the operating system must explicitly deassert RESET before use.
> 
> Support this in the SMSC911x driver so this ethernet connector
> can be used on such targets.
> 
> Notice that we request the line to go logical low (deassert)
> whilst the line on the actual component is active low. This
> is managed in the respective hardware description when
> specifying the GPIO line with e.g. device tree or ACPI. With
> device tree it looks like this in one case:
> 
>   reset-gpios = <&tlmm 30 GPIO_ACTIVE_LOW>;
> 
> Which means that logically requesting the RESET line to be
> deasserted will result in the line being driven high, taking
> the device out of reset.
> 
> Cc: Jeremy Linton <jeremy.linton@....com>
> Signed-off-by: Linus Walleij <linus.walleij@...aro.org>

Applied.