From: Stephen Warren <swarren@wwwdotorg.org>
To: Tomasz Maciej Nowak <tmn505@gmail.com>
Cc: thierry.reding@gmail.com, jonathanh@nvidia.com,
linux-tegra@vger.kernel.org, robh+dt@kernel.org,
mark.rutland@arm.com, linux@armlinux.org.uk,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ARM: dtc: tegra: enable front panel leds in TrimSlice
Date: Wed, 21 Feb 2018 09:46:28 -0700 [thread overview]
Message-ID: <f291dd94-107f-cf03-a8e8-bc0806421c2d@wwwdotorg.org> (raw)
In-Reply-To: <873b01dc-3ca5-3151-2654-a8272cb9dd88@gmail.com>
On 02/21/2018 09:20 AM, Tomasz Maciej Nowak wrote:
> W dniu 20.02.2018 o 20:55, Stephen Warren pisze:
>> On 02/19/2018 01:16 PM, Tomasz Maciej Nowak wrote:
>>> Adds device nodes for two front panel LEDs.
>>
>> Why do you need to change the pinmux settings? Configuring a pin as a
>> GPIO should override any pinmux special function selection and hence
>> make it irrelevant, so I don't think you should need to change the
>> pinmux.
>
> At first I did exactly that without changing the pinmux, but the LEDs
> didn't light up. After that I compared with CompuLab source tree [1].
> The pinmux was specified as in my patch. With this change the LEDs are
> fully functional.
>
> 1.
> https://gitorious.org/trimslice-kernel/trimslice-kernel?p=trimslice-kernel:trimslice-kernel.git;a=blob;f=arch/arm/mach-tegra/board-trimslice-pinmux.c;h=cc6d5225d97eb9327c820bf1d5b2bc16ab8c6dda;hb=d25bf45d6314089489b30d218ed8a0d6d94417f9#l45
Oh I see. Your patch isn't changing the pinmux function selection but
the other configuration bits, which are relevant even when the pin is in
GPIO mode. In particular, it clears the tristate bit for the dte
pingroup. That makes perfect sense.
prev parent reply other threads:[~2018-02-21 16:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-19 20:16 [PATCH] ARM: dtc: tegra: enable front panel leds in TrimSlice Tomasz Maciej Nowak
2018-02-20 19:55 ` Stephen Warren
2018-02-21 16:20 ` Tomasz Maciej Nowak
2018-02-21 16:46 ` Stephen Warren [this message]
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