[PATCH linux 2/6] hwmon: occ: Add sysfs interface

[Eddie James]

Will do Andrew.

Just had some discussion with Brad and Patrick. I think we can use the
"bind/unbind" sysfs api to cause the occ i2c device to probe when we
want it to. Will investigate that today.

Thanks,
Eddie

On Tue, Jan 3, 2017 at 7:53 PM, Andrew Jeffery <andrew at aj.id.au> wrote:
> On Wed, 2017-01-04 at 10:55 +1030, Andrew Jeffery wrote:
>> On Tue, 2017-01-03 at 19:13 -0500, Brad Bishop wrote:
>> > > > > On Jan 3, 2017, at 7:06 PM, Joel Stanley <joel at jms.id.au>
>> > > > > wrote:
>> > >
>> > > On Wed, Jan 4, 2017 at 10:49 AM, Brad Bishop
>> > > > > <bradleyb at fuzziesquirrel.com> wrote:
>> > > >
>> > > > What if the driver is built into the kernel?  Is there such a
>> > > > thing as module only drivers?
>> > >
>> > > Our kernel is build with module loading disabled at present.
>> > >
>> > > modprobing the driver when userspace is ready is a neat hack that
>> > > we
>> > > could use for now. However, the driver will need a mechanism that
>> >
>> > Do you happen to know if ‘a mechanism’ is something that needs to
>> > be invented or
>> > if Linux already has something?
>>
>> I spoke with Rusty about this and by his response there's no existing
>> "event-bus" mechanism. His suggestions for the problem were:
>>
>> 1. As userspace is coordinating the host power-on, do the modprobe in
>> userspace
>
> After some discussion between Jeremy, Joel, Alistair and myself it was
> decided that managing the problem from userspace was the way to go.
>
> The rough approach is to describe the devices in the devicetree, but
> mark them as 'status = "disabled";' so they are not bound to drivers on
> boot. It is then userspace's job to trigger the binding as necessary,
> but exactly how it should be done is unknown.
>
> Eddie: Can you investigate what we might need to do to make this work?
>
> Andrew
>
>>
>> 2. Push the power-on logic into the kernel so it can trigger hotplug
>> events to probe the drivers, and expose a power-{on,off}/{soft,hard}-
>> reboot interface to userspace.
>>
>> Andrew