Re: [PATCH v6 2/2] hwmon: ibmpowernv: Add attributes to enable/disable sensor groups

[Guenter Roeck]

On 07/18/2018 11:59 PM, Stewart Smith wrote:
> Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx> writes:
> > On-Chip-Controller(OCC) is an embedded micro-processor in POWER9 chip
> > which measures various system and chip level sensors. These sensors
> > comprises of environmental sensors (like power, temperature, current
> > and voltage) and performance sensors (like utilization, frequency).
> > All these sensors are copied to main memory at a regular interval of
> > 100ms. OCC provides a way to select a group of sensors that is copied
> > to the main memory to increase the update frequency of selected sensor
> > groups. When a sensor-group is disabled, OCC will not copy it to main
> > memory and those sensors read 0 values.
>
> OCC is an implementation detail rather than a core part of this firmware
> API.
>
> Why not something like this:
>
> OPAL firmware provides the facility for some groups of sensors to be
> enabled/disabled at runtime to give the user the option of using the
> system resources for collecting these sensors or not.
>
> For example, on POWER9 systems, the On Chip Controller (OCC) gathers
> various system and chip level sensors and maintains their values in main
> memory.
>
>
> > +static int init_sensor_group_data(struct platform_device *pdev,
> > +				  struct platform_data *pdata)
> > +{
> > +	struct sensor_group_data *sgrp_data;
> > +	struct device_node *groups, *sgrp;
> > +	enum sensors type;
> > +	int count = 0, ret = 0;
> > +
> > +	groups = of_find_node_by_path("/ibm,opal/sensor-groups");
> > +	if (!groups)
> > +		return ret;
>
> Why not look for the compatible property?

For both, I don't really care either way. Can you folks get to an agreement
and let me know after you decided ?

Thanks,
Guenter