linux-kernel - Re: [PATCH v7 7/7] doc: bindings: act8945a-charger: Update properties

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Message-ID: <20160823030329.zy6kgncj2ov5ypnj@earth>
Date:   Tue, 23 Aug 2016 05:03:29 +0200
From:   Sebastian Reichel <sre@...nel.org>
To:     Wenyou Yang <wenyou.yang@...el.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     Pawel Moll <pawel.moll@....com>, Mark Brown <broonie@...nel.org>,
        Ian Campbell <ijc+devicetree@...lion.org.uk>,
        Kumar Gala <galak@...eaurora.org>,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        Nicolas Ferre <nicolas.ferre@...el.com>,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v7 7/7] doc: bindings: act8945a-charger: Update properties

Hi,

On Mon, Aug 22, 2016 at 02:49:17PM +0800, Wenyou Yang wrote:
> Due the driver improvements, update the properties,
>  - Remove "active-semi,check-battery-temperature" property.
>  - Add the properties, "active-semi,irq_gpio"
>    and "active-semi,lbo-gpios".
> 
> Signed-off-by: Wenyou Yang <wenyou.yang@...el.com>
> Acked-by: Rob Herring <robh@...nel.org>

I wonder if it's too late to slightly break the DT API by
introducing a proper sub-device for the charger and having all those
charger specific details described there. Not being able to use the
devm_ functions because all properties are assigned to the parent
device is not very nice.

We could easily support reading timeouts and threshold information
from the both (parent and sub-device) and just mark the parent
binding deprecated. The only real API break would be
"active-semi,chglev-gpios", which is currently broken anyways in the
driver as far as I can see (I should have reviewed this more
carefully previously).

In other words I suggest the following:

pmic@5b {
    compatible = "active-semi,act8945a";
    reg = <0x5b>;
    status = "okay";

    /* the following 3 are deprecated, but still supported */
    //active-semi,input-voltage-threshold-microvolt = <6600>;
    //active-semi,precondition-timeout = <40>;
    //active-semi,total-timeout = <3>;

    /* no longer supported, never worked properly */
    //active-semi,chglev-gpios = <&pioA 12 GPIO_ACTIVE_HIGH>;

    /* this is new, mfd should register charger sub-dev independently
     * of the subnode for backwards compatibility. Then optional
     * gpios/irqs are not available. But those either never worked
     * or did not exist before this update. */
    charger {
        active-semi,chglev-gpios = <&pioA 12 GPIO_ACTIVE_HIGH>;
        active-semi,lbo-gpios = <&pioA 72 GPIO_ACTIVE_LOW>;
		interrupt-parent = <&pioA>;
        interrupts = <45 GPIO_ACTIVE_LOW>

        active-semi,input-voltage-threshold-microvolt = <6600>;
        active-semi,precondition-timeout = <40>;
        active-semi,total-timeout = <3>;
    };
};

-- Sebastian

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