linux-kernel - Re: [PATCH 2/3] Input: gpio-keys - allow setting wakeup interrupt trigger type in DT

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Message-ID: <20180209234246.GA252335@ban.mtv.corp.google.com>
Date:   Fri, 9 Feb 2018 15:42:47 -0800
From:   Brian Norris <briannorris@...omium.org>
To:     Jeffy Chen <jeffy.chen@...k-chips.com>
Cc:     linux-kernel@...r.kernel.org, briannorris@...gle.com,
        dtor@...gle.com, dianders@...gle.com, devicetree@...r.kernel.org,
        Rob Herring <robh+dt@...nel.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-input@...r.kernel.org, Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH 2/3] Input: gpio-keys - allow setting wakeup interrupt
 trigger type in DT

Hi Jeffy,

On Fri, Feb 09, 2018 at 07:55:09PM +0800, Jeffy Chen wrote:
> Allow specifying a different interrupt trigger type for wakeup when
> using the gpio-keys input device as a wakeup source.
> 
> Signed-off-by: Jeffy Chen <jeffy.chen@...k-chips.com>
> ---
> 
>  Documentation/devicetree/bindings/input/gpio-keys.txt | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/input/gpio-keys.txt b/Documentation/devicetree/bindings/input/gpio-keys.txt
> index a94940481e55..61926cef708f 100644
> --- a/Documentation/devicetree/bindings/input/gpio-keys.txt
> +++ b/Documentation/devicetree/bindings/input/gpio-keys.txt
> @@ -26,6 +26,15 @@ Optional subnode-properties:
>  	  If not specified defaults to 5.
>  	- wakeup-source: Boolean, button can wake-up the system.
>  			 (Legacy property supported: "gpio-key,wakeup")
> +	- wakeup-trigger-type: Specifies the interrupt trigger type for wakeup.
> +		 The value is defined in <dt-bindings/interrupt-controller/irq.h>

Do you really want to codify interrupt triggers here? It seems like most
of the information about edge vs. level is already codified elsewhere,
so this becomes a little redundant. And in fact, some bindings may be
specifying a "gpio", not technically an interrupt (at least not
directly), so it feels weird to apply IRQ_* flags to them right here.
Anyway, I think he only piece you really want to describe here is, do we
wake on "event asserted", "event deasserted", or both. (The "none" case
would just mean you shouldn't have the "wakeup-source" property.)

So maybe:

	wakeup-trigger-type: Specifies whether the key should wake the
	system when asserted, when deasserted, or both. This property is
	only valid for keys that wake up the system (e.g., when the
	"wakeup-source" property is also provided). Supported values
	are:
	  1: asserted
	  2: deasserted
	  3: both asserted and deasserted

? We could still make macros out of those, if we want
(input/linux-event-codes.h?). And then leave it up to the driver to
determine how to translate that into the appropriate edge or level
triggers.

Brian

> +		 Only the following flags are supported:
> +			IRQ_TYPE_NONE
> +			IRQ_TYPE_EDGE_RISING
> +			IRQ_TYPE_EDGE_FALLING
> +			IRQ_TYPE_EDGE_BOTH
> +			IRQ_TYPE_LEVEL_HIGH
> +			IRQ_TYPE_LEVEL_LOW
>  	- linux,can-disable: Boolean, indicates that button is connected
>  	  to dedicated (not shared) interrupt which can be disabled to
>  	  suppress events from the button.
> -- 
> 2.11.0
> 
>