Hi,
On Tue, Oct 10, 2023 at 01:19:36PM +0100, Mark Brown wrote:
> On Tue, Oct 10, 2023 at 10:59:06AM +0200, Oleksij Rempel wrote:
> > Add handler to forward under-voltage events.
> > On systems for more or less complicated regulator chains we need to
> > forward under-voltage events to actual driver which need to react on
> > them.
>
> It isn't clear to me why this would be implemented in one specific
> driver, nor why this would be done unconditionally. Could you provide
> some information on the problem you're trying to solve here?
The hardware I am working with has an under-voltage sensor on the 24V
supply regulator and some backup capacitors to run SoC for 100ms. I want
to forward under-voltage events across a chain of different regulators
to a designated consumer. For instance, to the mmc driver, enabling it
to initiate shutdown before power loss occurs. Additionally, a bit can
be set in the volatile memory of a scratch pad in an RTC clock to record
sudden power loss, which can be checked on the next system start.
> This feels like something that should be a core feature.
Agreed. I am relatively new to the regulator framework and am uncertain
about the optimal location for registering the event forwarding. Could
you advise on this?
> > +static int reg_fixed_regulator_notifier(struct notifier_block *nb,
> > + unsigned long event, void *data)
> > +{
> > + struct fixed_voltage_data *priv =
> > + container_of(nb, struct fixed_voltage_data, nb);
> > + struct regulator_dev *rdev = priv->dev;
> > +
> > + if (event != REGULATOR_EVENT_UNDER_VOLTAGE_WARN &&
> > + event != REGULATOR_EVENT_UNDER_VOLTAGE)
> > + return NOTIFY_OK;
> > +
> > + regulator_notifier_call_chain(rdev, event, NULL);
>
> This would be better written as a switch statement for extensibility,
ack.
> and it's not clear why the filtering?
I started with a conservative approach because I'm not sure about the
possible effects of forwarding all events. If forwarding all events is a
good idea, I can do it.
Regards,
Oleksij
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