linux-kernel - Re: [PATCH 1/2] power: supply: bq27xxx_battery: Notify about all battery changes

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Date:   Tue, 26 May 2020 21:24:39 -0400
From:   "Andrew F. Davis" <afd@...com>
To:     Krzysztof Kozlowski <krzk@...nel.org>,
        Pali Rohár <pali@...nel.org>,
        Sebastian Reichel <sre@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...ceq.com>,
        <linux-kernel@...r.kernel.org>, <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 1/2] power: supply: bq27xxx_battery: Notify about all
 battery changes

On 5/25/20 10:11 AM, Krzysztof Kozlowski wrote:
> All battery related data could be important for user-space.  For example
> time-to-full could be shown to user on the screen or health could be
> monitored for any issues.  Instead of comparing few selected old/new
> values, just check if anything changed in the cache.
> 


At least some value will change every time we poll the battery, are we
okay with having power_supply_changed() called every time?

Andrew


> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> ---
>  drivers/power/supply/bq27xxx_battery.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
> index 942c92127b6d..33c26d42cd02 100644
> --- a/drivers/power/supply/bq27xxx_battery.c
> +++ b/drivers/power/supply/bq27xxx_battery.c
> @@ -1612,12 +1612,10 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di)
>  			di->charge_design_full = bq27xxx_battery_read_dcap(di);
>  	}
>  
> -	if ((di->cache.capacity != cache.capacity) ||
> -	    (di->cache.flags != cache.flags))
> +	if (memcmp(&di->cache, &cache, sizeof(cache)) != 0) {
>  		power_supply_changed(di->bat);
> -
> -	if (memcmp(&di->cache, &cache, sizeof(cache)) != 0)
>  		di->cache = cache;
> +	}
>  
>  	di->last_update = jiffies;
>  }
>