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Message-ID: <53082075-852f-4698-b354-ed30e7fd2683@redhat.com>
Date: Mon, 5 Feb 2024 10:52:17 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Thomas Weißschuh <linux@...ssschuh.net>,
Sebastian Reichel <sre@...nel.org>, Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: Re: [PATCH 1/4] power: supply: core: fix charge_behaviour formatting
Hi Thomas,
Thank you for your patches for this.
On 2/4/24 18:26, Thomas Weißschuh wrote:
> This property is documented to have a special format which exposes all
> available behaviours and the currently active one at the same time.
> For this special format some helpers are provided.
>
> However the default property logic in power_supply_sysfs.c is not using
> the helper and the default logic only prints the currently active
> behaviour.
>
> Adjust power_supply_sysfs.c to follow the documented format.
>
> There are currently two in-tree drivers exposing charge behaviours:
> thinkpad_acpi and mm8013.
> thinkpad_acpi is not affected by the change, as it directly uses the
> helpers and does not use the power_supply_sysfs.c logic.
>
> As mm8013 does not implement POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR_AVAILABLE
> the new logic will preserve the simple output format in this case.
>
> Fixes: 1b0b6cc8030d ("power: supply: add charge_behaviour attributes")
> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> ---
> drivers/power/supply/power_supply_sysfs.c | 32 +++++++++++++++++++++++++++++++
> include/linux/power_supply.h | 1 +
> 2 files changed, 33 insertions(+)
>
> diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c
> index 977611e16373..3680cfc2e908 100644
> --- a/drivers/power/supply/power_supply_sysfs.c
> +++ b/drivers/power/supply/power_supply_sysfs.c
> @@ -271,6 +271,32 @@ static ssize_t power_supply_show_usb_type(struct device *dev,
> return count;
> }
>
> +static ssize_t power_supply_show_charge_behaviour(struct device *dev,
> + struct power_supply *psy,
> + struct power_supply_attr *ps_attr,
> + union power_supply_propval *value,
> + char *buf)
> +{
> + union power_supply_propval available;
> + int ret;
> +
> + ret = power_supply_get_property(psy,
> + POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
> + value);
> + if (ret < 0)
> + return ret;
> +
> + ret = power_supply_get_property(psy,
> + POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR_AVAILABLE,
> + &available);
> + if (ret == -EINVAL)
> + return sysfs_emit(buf, "%s\n", ps_attr->text_values[value->intval]);
> + else if (ret < 0)
No need for "else if" here since the if above does a return. So you can just do:
if (ret < 0)
return ret;
> + return ret;
> +
> + return power_supply_charge_behaviour_show(dev, available.intval, value->intval, buf);
> +}
> +
> static ssize_t power_supply_show_property(struct device *dev,
> struct device_attribute *attr,
> char *buf) {
> @@ -282,6 +308,8 @@ static ssize_t power_supply_show_property(struct device *dev,
>
> if (psp == POWER_SUPPLY_PROP_TYPE) {
> value.intval = psy->desc->type;
> + } else if (psp == POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR) {
> + value.intval = -1;
> } else {
> ret = power_supply_get_property(psy, psp, &value);
>
I'm not a fan of this, I guess that you are doing this because you do not
want to enter this if:
if (ps_attr->text_values_len > 0 &&
value.intval < ps_attr->text_values_len && value.intval >= 0) {
return sysfs_emit(buf, "%s\n", ps_attr->text_values[value.intval]);
}
But by doing this you add both the special case of setting value.intval = -1
here and you now need to do the power_supply_get_property() which is in the else
manually in power_supply_show_charge_behaviour() and the error handling / logging
of power_supply_get_property() in power_supply_show_charge_behaviour() is different.
What I think you can (and should) do here instead is move:
if (ps_attr->text_values_len > 0 &&
value.intval < ps_attr->text_values_len && value.intval >= 0) {
return sysfs_emit(buf, "%s\n", ps_attr->text_values[value.intval]);
}
into the default case of the switch (psp) {} below it in a preparation patch.
This if is never entered for the 2 non default cases in that switch, so it
is safe to move it into the default case, e.g. something like this:
default:
if (ps_attr->text_values_len > 0 &&
value.intval < ps_attr->text_values_len && value.intval >= 0)
ret = sysfs_emit(buf, "%s\n", ps_attr->text_values[value.intval]);
else
ret = sysfs_emit(buf, "%d\n", value.intval);
I think that also actually makes things a bit cleaner then the current
early-exit for printing enum values.
And then in the next patch you can just add:
case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
ret = power_supply_show_charge_behaviour(dev, psy, ps_attr,
&value, buf);
break;
Without needing to set intval = -1 and without needing to get the value
inside power_supply_show_charge_behaviour() since that will already
be done for you then.
Regards,
Hans
> @@ -308,6 +336,10 @@ static ssize_t power_supply_show_property(struct device *dev,
> ret = power_supply_show_usb_type(dev, psy->desc,
> &value, buf);
> break;
> + case POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR:
> + ret = power_supply_show_charge_behaviour(dev, psy, ps_attr,
> + &value, buf);
> + break;
> case POWER_SUPPLY_PROP_MODEL_NAME ... POWER_SUPPLY_PROP_SERIAL_NUMBER:
> ret = sysfs_emit(buf, "%s\n", value.strval);
> break;
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index c0992a77feea..9a6e6b488164 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -135,6 +135,7 @@ enum power_supply_property {
> POWER_SUPPLY_PROP_CHARGE_CONTROL_START_THRESHOLD, /* in percents! */
> POWER_SUPPLY_PROP_CHARGE_CONTROL_END_THRESHOLD, /* in percents! */
> POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR,
> + POWER_SUPPLY_PROP_CHARGE_BEHAVIOUR_AVAILABLE,
> POWER_SUPPLY_PROP_INPUT_CURRENT_LIMIT,
> POWER_SUPPLY_PROP_INPUT_VOLTAGE_LIMIT,
> POWER_SUPPLY_PROP_INPUT_POWER_LIMIT,
>
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