| Message ID | 20180607181214.30338-11-mka@chromium.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Thu, Jun 07, 2018 at 11:12:13AM -0700, Matthias Kaehlcke wrote: > The cros_ec_throttler monitors events from the Chrome OS Embedded > Controller to throttle the system if needed, using the mechanisms > provided by the throttler core. > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > --- > Changes in v2: > - patch added to series > > Documentation/devicetree/bindings/misc/cros_ec_throttler.txt | 4 ++++ > 1 file changed, 4 insertions(+) > create mode 100644 Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > diff --git a/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > new file mode 100644 > index 000000000000..7316dcc0ef75 > --- /dev/null > +++ b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > @@ -0,0 +1,4 @@ > +* cros_ec_throttler driver Bindings are for h/w, not drivers. I continue to fail to see why this needs to be in DT. There are other ways to instantiate drivers. > + > +Required properties: > +- compatible: "google,cros-ec-throttler" > -- > 2.18.0.rc1.242.g61856ae69a-goog >
Hi Rob, On Tue, Jun 12, 2018 at 01:10:11PM -0600, Rob Herring wrote: > On Thu, Jun 07, 2018 at 11:12:13AM -0700, Matthias Kaehlcke wrote: > > The cros_ec_throttler monitors events from the Chrome OS Embedded > > Controller to throttle the system if needed, using the mechanisms > > provided by the throttler core. > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > --- > > Changes in v2: > > - patch added to series > > > > Documentation/devicetree/bindings/misc/cros_ec_throttler.txt | 4 ++++ > > 1 file changed, 4 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > > > diff --git a/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > new file mode 100644 > > index 000000000000..7316dcc0ef75 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > @@ -0,0 +1,4 @@ > > +* cros_ec_throttler driver > > Bindings are for h/w, not drivers. (OK, sure, don't call this "driver". And maybe this could use some more description about what kind of events are emitted by this sort of device.) > I continue to fail to see why this needs to be in DT. There are other > ways to instantiate drivers. This is mostly relevant to: [PATCH v2 08/11] dt-bindings: PM / OPP: add opp-throttlers property so it's probably good to take a look at that one too. The primary purpose is to have a target to point at when determining who is the source of throttling. This is similar to other CrOS EC subdevices (e.g., PWM) where we technically don't require a subnode (the EC firmware can its own PWM hardware without DT), but it is important that, e.g., a backlight device has something to point at when it's using a PWM attached to the EC. So we have a PWM subnode. In this case, we're a little vague about what exactly the hardware is here, but there *is* hardware that's emitting "throttle" events (hint: here, it's related to sensing too high of system current). This is all abstracted by firmware, which simply tells us we need to scale back our power usage. So, what do you think of patch 8? Should OPPs have phandles to such a throttler? If so, should the phandle just point at the main EC device (see mfd/cros-ec.txt), or is it reasonable to have a subnode to represent something more specific? Or maybe this is entirely on the wrong track. But this is the resulting proposal after your comments on v1, so it's probably best we have a clearer overall review of what makes sense here, so we don't just go in cycles on new proposals that get rejected. Brian > > + > > +Required properties: > > +- compatible: "google,cros-ec-throttler" > > -- > > 2.18.0.rc1.242.g61856ae69a-goog > >
On Tue, Jun 12, 2018 at 01:40:22PM -0700, Brian Norris wrote: > Hi Rob, > > On Tue, Jun 12, 2018 at 01:10:11PM -0600, Rob Herring wrote: > > On Thu, Jun 07, 2018 at 11:12:13AM -0700, Matthias Kaehlcke wrote: > > > The cros_ec_throttler monitors events from the Chrome OS Embedded > > > Controller to throttle the system if needed, using the mechanisms > > > provided by the throttler core. > > > > > > Signed-off-by: Matthias Kaehlcke <mka@chromium.org> > > > --- > > > Changes in v2: > > > - patch added to series > > > > > > Documentation/devicetree/bindings/misc/cros_ec_throttler.txt | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > create mode 100644 Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > > > > > diff --git a/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > > new file mode 100644 > > > index 000000000000..7316dcc0ef75 > > > --- /dev/null > > > +++ b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt > > > @@ -0,0 +1,4 @@ > > > +* cros_ec_throttler driver > > > > Bindings are for h/w, not drivers. > > (OK, sure, don't call this "driver". And maybe this could use some more > description about what kind of events are emitted by this sort of > device.) > > > I continue to fail to see why this needs to be in DT. There are other > > ways to instantiate drivers. > > This is mostly relevant to: > [PATCH v2 08/11] dt-bindings: PM / OPP: add opp-throttlers property > > so it's probably good to take a look at that one too. > > The primary purpose is to have a target to point at when determining who > is the source of throttling. This is similar to other CrOS EC subdevices > (e.g., PWM) where we technically don't require a subnode (the EC > firmware can its own PWM hardware without DT), but it is important that, > e.g., a backlight device has something to point at when it's using a PWM > attached to the EC. So we have a PWM subnode. > > In this case, we're a little vague about what exactly the hardware is > here, but there *is* hardware that's emitting "throttle" events (hint: > here, it's related to sensing too high of system current). This is all > abstracted by firmware, which simply tells us we need to scale back our > power usage. > > So, what do you think of patch 8? Should OPPs have phandles to such a > throttler? If so, should the phandle just point at the main EC device > (see mfd/cros-ec.txt), or is it reasonable to have a subnode to > represent something more specific? > > Or maybe this is entirely on the wrong track. But this is the resulting > proposal after your comments on v1, so it's probably best we have a > clearer overall review of what makes sense here, so we don't just go in > cycles on new proposals that get rejected. I also think we need to clarify if this is the right direction. Since Rob proposed the OPP hints and didn't object when I replied with the opp-throttlers example I assumed he was ok with it.
diff --git a/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt new file mode 100644 index 000000000000..7316dcc0ef75 --- /dev/null +++ b/Documentation/devicetree/bindings/misc/cros_ec_throttler.txt @@ -0,0 +1,4 @@ +* cros_ec_throttler driver + +Required properties: +- compatible: "google,cros-ec-throttler"
The cros_ec_throttler monitors events from the Chrome OS Embedded Controller to throttle the system if needed, using the mechanisms provided by the throttler core. Signed-off-by: Matthias Kaehlcke <mka@chromium.org> --- Changes in v2: - patch added to series Documentation/devicetree/bindings/misc/cros_ec_throttler.txt | 4 ++++ 1 file changed, 4 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/cros_ec_throttler.txt