linux-kernel - Re: [RESEND PATCH] arm64: dts: tegra: Fix boolean properties with values

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Date:   Mon, 25 Apr 2022 12:20:04 +0100
From:   Jon Hunter <jonathanh@...dia.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Rob Herring <robh@...nel.org>, Arnd Bergmann <arnd@...db.de>
Cc:     Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Avi Fishman <avifishman70@...il.com>,
        Tomer Maimon <tmaimon77@...il.com>,
        Tali Perry <tali.perry1@...il.com>,
        Patrick Venture <venture@...gle.com>,
        Nancy Yuen <yuenn@...gle.com>,
        Benjamin Fair <benjaminfair@...gle.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-stm32@...md-mailman.stormreply.com, soc@...nel.org,
        devicetree@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RESEND PATCH] arm64: dts: tegra: Fix boolean properties with
 values


On 12/04/2022 10:05, Thierry Reding wrote:
> On Wed, Apr 06, 2022 at 02:17:30PM -0500, Rob Herring wrote:
>> Boolean properties in DT are present or not present and don't take a value.
>> A property such as 'foo = <0>;' evaluated to true. IOW, the value doesn't
>> matter.
>>
>> It may have been intended that 0 values are false, but there is no change
>> in behavior with this patch.
>>
>> Signed-off-by: Rob Herring <robh@...nel.org>
>> ---
>> Can someone apply this for 5.18.
>>
>>   arch/arm64/boot/dts/nvidia/tegra186-p3310.dtsi            | 8 ++++----
>>   .../boot/dts/nvidia/tegra186-p3509-0000+p3636-0001.dts    | 8 ++++----
>>   arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi            | 6 +++---
>>   arch/arm64/boot/dts/nvidia/tegra194-p3668.dtsi            | 6 +++---
>>   arch/arm64/boot/dts/nvidia/tegra210-p2180.dtsi            | 6 +++---
>>   arch/arm64/boot/dts/nvidia/tegra210-p2894.dtsi            | 8 ++++----
>>   arch/arm64/boot/dts/nvidia/tegra210-p3450-0000.dts        | 8 ++++----
>>   arch/arm64/boot/dts/nvidia/tegra210-smaug.dts             | 4 ++--
>>   8 files changed, 27 insertions(+), 27 deletions(-)
> 
> This causes multiple regressions on Tegra boards. The reason for this is
> that these properties are not in fact boolean, despite what the DT
> bindings say. If you look at the code that handles these, you'll notice
> that they are single-cell properties, typically with <0> and <1> values.
> What may have led to the conclusion that these are boolean is that there
> is also a special case where these can be left out, but the meaning of
> that is not the "false" (<0>) value. Instead, leaving these out means
> that the values should be left at whatever is currently in the register.
> 
> See pinconf_generic_parse_dt_config() and parse_dt_cfg() specifically in
> drivers/pinctrl/pinconf-generic.c.
> 
> Arnd, can you please revert this so that these boards can be unbroken?


Arnd, any feedback on this? A lot of Tegra boards are still not booting 
with v5.18-rc4.

Jon

-- 
nvpublic