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[1/3] Documentation: dtb: xgene: Add hwmon dts binding documentation

Message ID 1463415447-29903-2-git-send-email-hotran@apm.com (mailing list archive)
State Changes Requested
Headers show

Commit Message

hotran May 16, 2016, 4:17 p.m. UTC 
This patch adds the APM X-Gene hwmon device tree node documentation.

Signed-off-by: Hoan Tran <hotran@apm.com>
---
 .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt

Comments

Rob Herring May 23, 2016, 8:30 p.m. UTC | #1 
On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
> This patch adds the APM X-Gene hwmon device tree node documentation.
> 
> Signed-off-by: Hoan Tran <hotran@apm.com>
> ---
>  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
>  1 file changed, 14 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> 
> diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> new file mode 100644
> index 0000000..49a482e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> @@ -0,0 +1,14 @@
> +APM X-Gene hwmon driver
> +
> +Hwmon driver accesses sensors over the "SLIMpro" mailbox.

DT bindings describe h/w, not driver data. I'm not sure this belongs in 
DT and perhaps the devices for the mailbox should be created by the 
mailbox driver.

> +
> +Required properties :
> + - compatible : should be "apm,xgene-slimpro-hwmon"
> + - mboxes : use the label reference for the mailbox as the first parameter.
> +	    The second parameter is the channel number.

When do you expect this to be different mailbox numbers? 

> +
> +Example :
> +	hwmonslimpro {
> +		compatible = "apm,xgene-slimpro-hwmon";
> +		mboxes = <&mailbox 7>;
> +	};
> -- 
> 1.9.1
> 
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hotran May 24, 2016, 1:01 a.m. UTC | #2 
Hi Rob,

Thanks for your review !

On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
>
> On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
> > This patch adds the APM X-Gene hwmon device tree node documentation.
> >
> > Signed-off-by: Hoan Tran <hotran@apm.com>
> > ---
> >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> >
> > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > new file mode 100644
> > index 0000000..49a482e
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > @@ -0,0 +1,14 @@
> > +APM X-Gene hwmon driver
> > +
> > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
>
> DT bindings describe h/w, not driver data.
How about this description: "APM X-Gene SOC sensors are accessed over
the "SLIMpro" mailbox" ?
> I'm not sure this belongs in
> DT and perhaps the devices for the mailbox should be created by the
> mailbox driver.
I don't think the current mailbox supports it.
>
> > +
> > +Required properties :
> > + - compatible : should be "apm,xgene-slimpro-hwmon"
> > + - mboxes : use the label reference for the mailbox as the first parameter.
> > +         The second parameter is the channel number.
>
> When do you expect this to be different mailbox numbers?
No, this number is not changed. This "mboxes" property is used and
required by mailbox.c when hwmon driver requests a mailbox channel

Thanks and Regards
Hoan
>
>
> > +
> > +Example :
> > +     hwmonslimpro {
> > +             compatible = "apm,xgene-slimpro-hwmon";
> > +             mboxes = <&mailbox 7>;
> > +     };
> > --
> > 1.9.1
> >
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Rob Herring May 25, 2016, 5:09 p.m. UTC | #3 
On Mon, May 23, 2016 at 06:01:14PM -0700, Hoan Tran wrote:
> Hi Rob,
> 
> Thanks for your review !
> 
> On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
> >
> > On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
> > > This patch adds the APM X-Gene hwmon device tree node documentation.
> > >
> > > Signed-off-by: Hoan Tran <hotran@apm.com>
> > > ---
> > >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
> > >  1 file changed, 14 insertions(+)
> > >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > >
> > > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > > new file mode 100644
> > > index 0000000..49a482e
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > > @@ -0,0 +1,14 @@
> > > +APM X-Gene hwmon driver
> > > +
> > > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
> >
> > DT bindings describe h/w, not driver data.
> How about this description: "APM X-Gene SOC sensors are accessed over
> the "SLIMpro" mailbox" ?
> > I'm not sure this belongs in
> > DT and perhaps the devices for the mailbox should be created by the
> > mailbox driver.
> I don't think the current mailbox supports it.

Then add it. The mailbox binding is really only needed when other h/w 
blocks use a mailbox. As this is purely a firmware interface then the 
mailbox driver can create any devices it needs. The devices don't have 
to be in DT to be created.

Rob
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hotran June 7, 2016, 4:31 p.m. UTC | #4 
Hi Rob,

On Wed, May 25, 2016 at 10:09 AM, Rob Herring <robh@kernel.org> wrote:
>
> On Mon, May 23, 2016 at 06:01:14PM -0700, Hoan Tran wrote:
> > Hi Rob,
> >
> > Thanks for your review !
> >
> > On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
> > >
> > > On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
> > > > This patch adds the APM X-Gene hwmon device tree node documentation.
> > > >
> > > > Signed-off-by: Hoan Tran <hotran@apm.com>
> > > > ---
> > > >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
> > > >  1 file changed, 14 insertions(+)
> > > >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > > > new file mode 100644
> > > > index 0000000..49a482e
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
> > > > @@ -0,0 +1,14 @@
> > > > +APM X-Gene hwmon driver
> > > > +
> > > > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
> > >
> > > DT bindings describe h/w, not driver data.
> > How about this description: "APM X-Gene SOC sensors are accessed over
> > the "SLIMpro" mailbox" ?
> > > I'm not sure this belongs in
> > > DT and perhaps the devices for the mailbox should be created by the
> > > mailbox driver.
> > I don't think the current mailbox supports it.
>
> Then add it. The mailbox binding is really only needed when other h/w
> blocks use a mailbox. As this is purely a firmware interface then the
> mailbox driver can create any devices it needs. The devices don't have
> to be in DT to be created.

Yes, I'll create a function inside mailbox. It allows client request a
channel by mailbox name and index without DT node.

Thanks
Hoan


>
>
> Rob
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Jassi Brar June 7, 2016, 5:20 p.m. UTC | #5 
On Tue, May 24, 2016 at 6:31 AM, Hoan Tran <hotran@apm.com> wrote:
> Hi Rob,
>
> Thanks for your review !
>
> On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
>>
>> On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
>> > This patch adds the APM X-Gene hwmon device tree node documentation.
>> >
>> > Signed-off-by: Hoan Tran <hotran@apm.com>
>> > ---
>> >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
>> >  1 file changed, 14 insertions(+)
>> >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>> >
>> > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>> > new file mode 100644
>> > index 0000000..49a482e
>> > --- /dev/null
>> > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>> > @@ -0,0 +1,14 @@
>> > +APM X-Gene hwmon driver
>> > +
>> > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
>>
>> DT bindings describe h/w, not driver data.
> How about this description: "APM X-Gene SOC sensors are accessed over
> the "SLIMpro" mailbox" ?
>> I'm not sure this belongs in
>> DT and perhaps the devices for the mailbox should be created by the
>> mailbox driver.
> I don't think the current mailbox supports it.
>>
>> > +
>> > +Required properties :
>> > + - compatible : should be "apm,xgene-slimpro-hwmon"
>> > + - mboxes : use the label reference for the mailbox as the first parameter.
>> > +         The second parameter is the channel number.
>>
>> When do you expect this to be different mailbox numbers?
> No, this number is not changed. This "mboxes" property is used and
> required by mailbox.c when hwmon driver requests a mailbox channel
>
I think that's inaccurate.

The h/w and the firmware combined is the "platform" from Linux POV.
Channels are physical resources provided by a mailbox controller.
Currently the firmware listens on Channel-7 but some future revision
might switch to, say, Channel-9.  Or say the same firmware on next
revision of h/w may have to switch to Channel-3 because it has only 4
channels. So I see the mailbox channel number as a hardware property
just like an IRQ (which very often change with SoC iterations).

Cheers.
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hotran June 7, 2016, 6:05 p.m. UTC | #6 
Hi Jassi,

Thanks for your reply !

On Tue, Jun 7, 2016 at 10:20 AM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
> On Tue, May 24, 2016 at 6:31 AM, Hoan Tran <hotran@apm.com> wrote:
>> Hi Rob,
>>
>> Thanks for your review !
>>
>> On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
>>>
>>> On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
>>> > This patch adds the APM X-Gene hwmon device tree node documentation.
>>> >
>>> > Signed-off-by: Hoan Tran <hotran@apm.com>
>>> > ---
>>> >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
>>> >  1 file changed, 14 insertions(+)
>>> >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>> >
>>> > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>> > new file mode 100644
>>> > index 0000000..49a482e
>>> > --- /dev/null
>>> > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>> > @@ -0,0 +1,14 @@
>>> > +APM X-Gene hwmon driver
>>> > +
>>> > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
>>>
>>> DT bindings describe h/w, not driver data.
>> How about this description: "APM X-Gene SOC sensors are accessed over
>> the "SLIMpro" mailbox" ?
>>> I'm not sure this belongs in
>>> DT and perhaps the devices for the mailbox should be created by the
>>> mailbox driver.
>> I don't think the current mailbox supports it.
>>>
>>> > +
>>> > +Required properties :
>>> > + - compatible : should be "apm,xgene-slimpro-hwmon"
>>> > + - mboxes : use the label reference for the mailbox as the first parameter.
>>> > +         The second parameter is the channel number.
>>>
>>> When do you expect this to be different mailbox numbers?
>> No, this number is not changed. This "mboxes" property is used and
>> required by mailbox.c when hwmon driver requests a mailbox channel
>>
> I think that's inaccurate.
>
> The h/w and the firmware combined is the "platform" from Linux POV.
> Channels are physical resources provided by a mailbox controller.
> Currently the firmware listens on Channel-7 but some future revision
> might switch to, say, Channel-9.  Or say the same firmware on next
> revision of h/w may have to switch to Channel-3 because it has only 4
> channels. So I see the mailbox channel number as a hardware property
> just like an IRQ (which very often change with SoC iterations).

Agree about that. I suppose this number is not changed. But as you
said, the mailbox channel number can be changed based on SoC or
Firmware. It would be better if this channel number is specified
inside a DT node.

Hi Rob, do you have any comments ?

Thanks
Hoan

>
> Cheers.
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hotran June 23, 2016, 4:42 p.m. UTC | #7 
On Tue, Jun 7, 2016 at 11:05 AM, Hoan Tran <hotran@apm.com> wrote:
> Hi Jassi,
>
> Thanks for your reply !
>
> On Tue, Jun 7, 2016 at 10:20 AM, Jassi Brar <jassisinghbrar@gmail.com> wrote:
>> On Tue, May 24, 2016 at 6:31 AM, Hoan Tran <hotran@apm.com> wrote:
>>> Hi Rob,
>>>
>>> Thanks for your review !
>>>
>>> On Mon, May 23, 2016 at 1:30 PM, Rob Herring <robh@kernel.org> wrote:
>>>>
>>>> On Mon, May 16, 2016 at 09:17:25AM -0700, Hoan Tran wrote:
>>>> > This patch adds the APM X-Gene hwmon device tree node documentation.
>>>> >
>>>> > Signed-off-by: Hoan Tran <hotran@apm.com>
>>>> > ---
>>>> >  .../devicetree/bindings/hwmon/apm-xgene-hwmon.txt          | 14 ++++++++++++++
>>>> >  1 file changed, 14 insertions(+)
>>>> >  create mode 100644 Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>>> >
>>>> > diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>>> > new file mode 100644
>>>> > index 0000000..49a482e
>>>> > --- /dev/null
>>>> > +++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
>>>> > @@ -0,0 +1,14 @@
>>>> > +APM X-Gene hwmon driver
>>>> > +
>>>> > +Hwmon driver accesses sensors over the "SLIMpro" mailbox.
>>>>
>>>> DT bindings describe h/w, not driver data.
>>> How about this description: "APM X-Gene SOC sensors are accessed over
>>> the "SLIMpro" mailbox" ?
>>>> I'm not sure this belongs in
>>>> DT and perhaps the devices for the mailbox should be created by the
>>>> mailbox driver.
>>> I don't think the current mailbox supports it.
>>>>
>>>> > +
>>>> > +Required properties :
>>>> > + - compatible : should be "apm,xgene-slimpro-hwmon"
>>>> > + - mboxes : use the label reference for the mailbox as the first parameter.
>>>> > +         The second parameter is the channel number.
>>>>
>>>> When do you expect this to be different mailbox numbers?
>>> No, this number is not changed. This "mboxes" property is used and
>>> required by mailbox.c when hwmon driver requests a mailbox channel
>>>
>> I think that's inaccurate.
>>
>> The h/w and the firmware combined is the "platform" from Linux POV.
>> Channels are physical resources provided by a mailbox controller.
>> Currently the firmware listens on Channel-7 but some future revision
>> might switch to, say, Channel-9.  Or say the same firmware on next
>> revision of h/w may have to switch to Channel-3 because it has only 4
>> channels. So I see the mailbox channel number as a hardware property
>> just like an IRQ (which very often change with SoC iterations).
>
> Agree about that. I suppose this number is not changed. But as you
> said, the mailbox channel number can be changed based on SoC or
> Firmware. It would be better if this channel number is specified
> inside a DT node.
>
> Hi Rob, do you have any comments ?
>
> Thanks
> Hoan
>
>>
>> Cheers.

Hi Rob,

Do you have any comments on Jassi's reply ?
If not, I'll send another version which included the binding document
and DT node.

Thanks
Hoan
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diff mbox

Patch

diff --git a/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
new file mode 100644
index 0000000..49a482e
--- /dev/null
+++ b/Documentation/devicetree/bindings/hwmon/apm-xgene-hwmon.txt
@@ -0,0 +1,14 @@ 
+APM X-Gene hwmon driver
+
+Hwmon driver accesses sensors over the "SLIMpro" mailbox.
+
+Required properties :
+ - compatible : should be "apm,xgene-slimpro-hwmon"
+ - mboxes : use the label reference for the mailbox as the first parameter.
+	    The second parameter is the channel number.
+
+Example :
+	hwmonslimpro {
+		compatible = "apm,xgene-slimpro-hwmon";
+		mboxes = <&mailbox 7>;
+	};