Re: [REPOST Patch v1 2/3] power: power_supply: Add core support for supplied_from

[Stephen Warren <swarren@wwwdotorg.org>]

On 03/25/2013 08:24 PM, Rhyland Klein wrote:
> This patch adds support for supplies to register a list of char *'s
> which represent the list of supplies which supply them. This is the
> opposite as the supplied_to list.
> 
> This change maintains support for supplied_to until all drivers which
> make use of it already are converted.

> diff --git a/drivers/power/power_supply_core.c b/drivers/power/power_supply_core.c

> +static int __power_supply_is_supplied_by(struct power_supply *supplier,
> +					 struct power_supply *supply)

Shouldn't this function return a Boolean since it's "is" something? At
least, 1 for yes 0 for no would be more comprehensible than 0 for yes
and error for no?

> +{
> +	int i;
> +
> +	if (!supply->supplied_from && !supplier->supplied_to)
> +		return -EINVAL;
> +
> +	/* Support both supplied_to and supplied_from modes */
> +	if (supply->supplied_from) {
> +		for (i = 0; i < supply->num_supplies; i++) {
> +			if (!supplier->name)
> +				continue;

That test is loop invariant. Why put it inside the loop?

Why wouldn't a supply have a name? The loop in
__power_supply_changed_work() that this function replaces doesn't test
for NULL names.

> +			if (!strcmp(supplier->name, supply->supplied_from[i]))
> +				return 0;

Don't you want to return something true here, so that the if block
inside __power_supply_changed_work() is executed in this case?

Similar comment for the else block.

>  static int __power_supply_changed_work(struct device *dev, void *data)

> -	for (i = 0; i < psy->num_supplicants; i++)
> -		if (!strcmp(psy->supplied_to[i], pst->name)) {
> -			if (pst->external_power_changed)
> -				pst->external_power_changed(pst);
> -		}
> +	if (__power_supply_is_supplied_by(psy, pst)) {
> +		if (pst->external_power_changed)
> +			pst->external_power_changed(pst);
> +	}
> +
>  	return 0;
>  }