linux-kernel - Re: [PATCH] power: supply: ltc2941-battery-gauge: Add LTC2944 support

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Date:   Tue, 11 Jul 2017 16:23:09 +0200
From:   Ladislav Michl <ladis@...ux-mips.org>
To:     Dragos Bogdan <dragos.bogdan@...log.com>
Cc:     Sebastian Reichel <sre@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] power: supply: ltc2941-battery-gauge: Add LTC2944 support

On Tue, Jul 11, 2017 at 05:05:09PM +0300, Dragos Bogdan wrote:
> The only difference between the already supported LTC2943 and LTC2944 is the
> operating range (3.6V - 20V compared to 3.6V - 60V).

So it is using different voltage and current conversion, but patch does not
handle it at all resulting into incorrect values being reported.

> Signed-off-by: Dragos Bogdan <dragos.bogdan@...log.com>
> ---
>  Documentation/devicetree/bindings/power/supply/ltc2941.txt | 10 +++++-----
>  drivers/power/supply/ltc2941-battery-gauge.c               | 11 ++++++++---
>  2 files changed, 13 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/power/supply/ltc2941.txt b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> index a9d7aa60558b..ed0f02846d10 100644
> --- a/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> +++ b/Documentation/devicetree/bindings/power/supply/ltc2941.txt
> @@ -1,9 +1,9 @@
> -binding for LTC2941 and LTC2943 battery gauges
> +binding for LTC2941, LTC2943 and LTC2944 battery gauges
>  
> -Both the LTC2941 and LTC2943 measure battery capacity.
> -The LTC2943 is compatible with the LTC2941, it adds voltage and
> -temperature monitoring, and uses a slightly different conversion
> -formula for the charge counter.
> +All the LTC2941, LTC2943 and LTC2944 measure battery capacity.
> +The LTC2943 and LTC2944 are compatible with the LTC2941, they add voltage and
> +temperature monitoring, and use a slightly different conversion formula for the
> +charge counter.
>  
>  Required properties:
>  - compatible: Should contain "lltc,ltc2941" or "lltc,ltc2943" which also
> diff --git a/drivers/power/supply/ltc2941-battery-gauge.c b/drivers/power/supply/ltc2941-battery-gauge.c
> index 7efb908f4451..48af7b6fb704 100644
> --- a/drivers/power/supply/ltc2941-battery-gauge.c
> +++ b/drivers/power/supply/ltc2941-battery-gauge.c
> @@ -1,5 +1,5 @@
>  /*
> - * I2C client/driver for the Linear Technology LTC2941 and LTC2943
> + * I2C client/driver for the Linear Technology LTC2941, LTC2943 and LTC2944
>   * Battery Gas Gauge IC
>   *
>   * Copyright (C) 2014 Topic Embedded Systems
> @@ -145,7 +145,7 @@ static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
>  
>  	control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
>  				LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
> -	/* Put the 2943 into "monitor" mode, so it measures every 10 sec */
> +	/* Put the 2943/4 into "monitor" mode, so it measures every 10 sec */
>  	if (info->num_regs == LTC2943_NUM_REGS)
>  		control |= LTC2943_REG_CONTROL_MODE_SCAN;
>  
> @@ -494,6 +494,7 @@ static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
>  static const struct i2c_device_id ltc294x_i2c_id[] = {
>  	{"ltc2941", LTC2941_NUM_REGS},
>  	{"ltc2943", LTC2943_NUM_REGS},
> +	{"ltc2944", LTC2943_NUM_REGS},
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
> @@ -507,6 +508,10 @@ static const struct of_device_id ltc294x_i2c_of_match[] = {
>  		.compatible = "lltc,ltc2943",
>  		.data = (void *)LTC2943_NUM_REGS
>  	},
> +	{
> +		.compatible = "lltc,ltc2944",
> +		.data = (void *)LTC2943_NUM_REGS
> +	},
>  	{ },
>  };
>  MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
> @@ -525,5 +530,5 @@ module_i2c_driver(ltc294x_driver);
>  
>  MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
>  MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
> -MODULE_DESCRIPTION("LTC2941/LTC2943 Battery Gas Gauge IC driver");
> +MODULE_DESCRIPTION("LTC2941/LTC2943/LTC2944 Battery Gas Gauge IC driver");
>  MODULE_LICENSE("GPL");
> -- 
> 2.11.0