linux-kernel - Re: [alsa-devel] [PATCH 2/9] ASoC: tlv320aic3x: Fix typo in DT binding documentation

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Message-ID: <CA+sos78vOjcY=9B3-pFthe9UUBqiEUps967UDEY=o=fUu230=Q@mail.gmail.com>
Date:   Thu, 9 Nov 2017 21:26:00 +0100
From:   Benoît Thébaudeau 
        <benoit.thebaudeau.dev@...il.com>
To:     "Andrew F. Davis" <afd@...com>
Cc:     Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Benoît Cousson <bcousson@...libre.com>,
        Tony Lindgren <tony@...mide.com>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <kernel@...gutronix.de>,
        devicetree@...r.kernel.org,
        Alsa-devel <alsa-devel@...a-project.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [alsa-devel] [PATCH 2/9] ASoC: tlv320aic3x: Fix typo in DT
 binding documentation

Dear Andrew F. Davis,

On Wed, Nov 8, 2017 at 10:24 PM, Andrew F. Davis <afd@...com> wrote:
> The property used to specify a GPIO intended for reset is "reset-gpio",
> this binding uses "gpio-reset", as almost all other bindings use the
> former name this use of the latter is certainly not intended and
> was a typo. It is not compatible with newer methods used to fetch
> GPIO pins and to prevent the spread of this error to other bindings
> lets fix this here.
>
> We also standardize the pin as active-low, different device trees have
> marked the GPIO different ways, luckily the driver currently uses the
> low-level GPIO set function which does not respect the active-low flag,
> but future changes may change this. This is an active-low reset, mark
> it as such.
>
> Lastly, add an example of use for this property.
>
> Fixes: c24fdc886fde ("ASoC: tlv320aic3x: Add device tree bindings")
>
> Signed-off-by: Andrew F. Davis <afd@...com>
> ---
>  Documentation/devicetree/bindings/sound/tlv320aic3x.txt | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/sound/tlv320aic3x.txt b/Documentation/devicetree/bindings/sound/tlv320aic3x.txt
> index ba5b45c483f5..9e8eaa08ce90 100644
> --- a/Documentation/devicetree/bindings/sound/tlv320aic3x.txt
> +++ b/Documentation/devicetree/bindings/sound/tlv320aic3x.txt
> @@ -17,7 +17,7 @@ Required properties:
>
>  Optional properties:
>
> -- gpio-reset - gpio pin number used for codec reset
> +- reset-gpio - GPIO specification for the active low RESET input.
>  - ai3x-gpio-func - <array of 2 int> - AIC3X_GPIO1 & AIC3X_GPIO2 Functionality
>                                     - Not supported on tlv320aic3104
>  - ai3x-micbias-vg - MicBias Voltage required.
> @@ -61,10 +61,14 @@ The pins can be used in referring sound node's audio-routing property.
>
>  Example:
>
> +#include <dt-bindings/gpio/gpio.h>
> +
>  tlv320aic3x: tlv320aic3x@1b {
>         compatible = "ti,tlv320aic3x";
>         reg = <0x1b>;
>
> +       reset-gpio = <&gpio1 17 GPIO_ACTIVE_LOW>;
> +
>         AVDD-supply = <&regulator>;
>         IOVDD-supply = <&regulator>;
>         DRVDD-supply = <&regulator>;

According to Documentation/devicetree/bindings/gpio/gpio.txt:
"GPIO properties should be named "[<name>-]gpios", with <name> being the purpose
of this GPIO for the device. While a non-existent <name> is considered valid
for compatibility reasons (resolving to the "gpios" property), it is not allowed
for new bindings. Also, GPIO properties named "[<name>-]gpio" are valid and old
bindings use it, but are only supported for compatibility reasons and should not
be used for newer bindings since it has been deprecated."

So it should be "reset-gpios" for new bindings.

Also, sound/soc/codecs/tlv320aic3x.c still uses "gpio-reset", and I do
not see any patch in your series changing this:
ret = of_get_named_gpio(np, "gpio-reset", 0);

Same remarks for your "[PATCH 6/9] ARM: dts: imx: Fix the audio
CODEC's reset pin". I don't know if there are other DTS files using
this, but they should all be updated accordingly. This would anyway
break all of the out-of-tree DTS files using this, which I think is
not allowed, so the driver should be changed in a way still allowing
the legacy naming besides the new one.

Best regards,
Benoît