linux-kernel - Re: [PATCH v2 1/2] dt-bindings: power: supply: Document max17040 extensions

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Date:   Fri, 19 Jun 2020 17:59:38 +0200
From:   Sebastian Reichel <sre@...nel.org>
To:     Iskren Chernev <iskren.chernev@...il.com>
Cc:     Rob Herring <robh+dt@...nel.org>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        ~postmarketos/upstreaming@...ts.sr.ht,
        Jonathan Bakker <xc-racer2@...e.ca>,
        Vladimir Barinov <vladimir.barinov@...entembedded.com>
Subject: Re: [PATCH v2 1/2] dt-bindings: power: supply: Document max17040
 extensions

Hi,

On Thu, Jun 18, 2020 at 01:13:39PM +0300, Iskren Chernev wrote:
> Maxim max17040 is a fuel gauge from a larger family utilising the Model
> Gauge technology. Document all different compatible strings that the
> max17040 driver recognizes.
> 
> Some devices in the wild report double the capacity. The
> maxim,double-soc (from State-Of-Charge) property fixes that.
> 
> Complete device reset might lead to very inaccurate readings. Specify
> maxim,skip-reset to avoid that.
> 
> To compensate for the battery chemistry and operating conditions the
> chips support a compensation value. Specify one or two byte compensation
> via the maxim,rcomp byte array.
> 
> Signed-off-by: Iskren Chernev <iskren.chernev@...il.com>
> ---
> v1: https://lkml.org/lkml/2020/6/8/682
> 
> Changes in v2:
> - add maxim,skip-reset
> - remove 2 byte rcomp from example, the specified compat string supports 1 byte
>   rcomp
> 
>  .../power/supply/max17040_battery.txt         | 24 ++++++++++++++++++-
>  1 file changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/power/supply/max17040_battery.txt b/Documentation/devicetree/bindings/power/supply/max17040_battery.txt
> index 4e0186b8380fa..3ee91c295027f 100644
> --- a/Documentation/devicetree/bindings/power/supply/max17040_battery.txt
> +++ b/Documentation/devicetree/bindings/power/supply/max17040_battery.txt
> @@ -2,7 +2,9 @@ max17040_battery
>  ~~~~~~~~~~~~~~~~
>  
>  Required properties :
> - - compatible : "maxim,max17040" or "maxim,max77836-battery"
> + - compatible : "maxim,max17040", "maxim,max17041", "maxim,max17043",
> + 		"maxim,max17044", "maxim,max17048", "maxim,max17049",
> +		"maxim,max17058", "maxim,max17059" or "maxim,max77836-battery"
>   - reg: i2c slave address
>  
>  Optional properties :
> @@ -11,6 +13,18 @@ Optional properties :
>  				generated. Can be configured from 1 up to 32
>  				(%). If skipped the power up default value of
>  				4 (%) will be used.
> +- maxim,double-soc : 		Certain devices return double the capacity.
> +				Specify this boolean property to divide the
> +				reported value in 2 and thus normalize it.
> +				SOC == State of Charge == Capacity.

Can this be derived from the compatible?

> +- maxim,skip-reset :		Do not reset device on driver initialization.
> +				Some devices report extremely inaccurately after
> +				a hard reset.

Same question.

-- Sebastian

> +- maxim,rcomp :			A value to compensate readings for various
> +				battery chemistries and operating temperatures.
> +				max17040,41 have 2 byte rcomp, default to
> +				0x97 0x00. All other devices have one byte
> +				rcomp, default to 0x97.
>  - interrupts : 			Interrupt line see Documentation/devicetree/
>  				bindings/interrupt-controller/interrupts.txt
>  - wakeup-source :		This device has wakeup capabilities. Use this
> @@ -31,3 +45,11 @@ Example:
>  		interrupts = <2 IRQ_TYPE_EDGE_FALLING>;
>  		wakeup-source;
>  	};
> +
> +	battery-fuel-gauge@36 {
> +		compatible = "maxim,max17048";
> +		reg = <0x36>;
> +		maxim,rcomp = /bits/ 8 <0x97>;
> +		maxim,alert-low-soc-level = <10>;
> +		maxim,double-soc;
> +	};
> 
> base-commit: 1713116fa907cc7290020f0d8632ec646d2936f8
> -- 
> 2.27.0
> 

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