RE: [PATCH V10 1/4] dt-bindings: fsl: scu: add thermal binding

[Anson Huang <anson.huang@nxp.com>]

Ping...

Hi, Eduardo
	Looks like we are going around in circle, can we make decision of which direction to go?

Best Regards!
Anson Huang

> -----Original Message-----
> From: Anson Huang
> Sent: 2019年3月1日 9:41
> To: 'Rob Herring' <robh@kernel.org>; edubezval@gmail.com
> Cc: mark.rutland@arm.com; shawnguo@kernel.org;
> s.hauer@pengutronix.de; kernel@pengutronix.de; festevam@gmail.com;
> catalin.marinas@arm.com; will.deacon@arm.com; rui.zhang@intel.com;
> edubezval@gmail.com; daniel.lezcano@linaro.org; Aisheng Dong
> <aisheng.dong@nxp.com>; ulf.hansson@linaro.org; sboyd@kernel.org;
> Daniel Baluta <daniel.baluta@nxp.com>; Andy Gross
> <andy.gross@linaro.org>; horms+renesas@verge.net.au; heiko@sntech.de;
> arnd@arndb.de; maxime.ripard@bootlin.com; bjorn.andersson@linaro.org;
> jagan@amarulasolutions.com; enric.balletbo@collabora.com;
> marc.w.gonzalez@free.fr; olof@lixom.net; devicetree@vger.kernel.org;
> linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> pm@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
> Subject: RE: [PATCH V10 1/4] dt-bindings: fsl: scu: add thermal binding
> 
> Hi, Rob/Eduardo
> 
> Best Regards!
> Anson Huang
> 
> > -----Original Message-----
> > From: Rob Herring [mailto:robh@kernel.org]
> > Sent: 2019年2月28日 22:49
> > To: Anson Huang <anson.huang@nxp.com>
> > Cc: mark.rutland@arm.com; shawnguo@kernel.org;
> s.hauer@pengutronix.de;
> > kernel@pengutronix.de; festevam@gmail.com; catalin.marinas@arm.com;
> > will.deacon@arm.com; rui.zhang@intel.com; edubezval@gmail.com;
> > daniel.lezcano@linaro.org; Aisheng Dong <aisheng.dong@nxp.com>;
> > ulf.hansson@linaro.org; sboyd@kernel.org; Daniel Baluta
> > <daniel.baluta@nxp.com>; Andy Gross <andy.gross@linaro.org>;
> > horms+renesas@verge.net.au; heiko@sntech.de; arnd@arndb.de;
> > maxime.ripard@bootlin.com; bjorn.andersson@linaro.org;
> > jagan@amarulasolutions.com; enric.balletbo@collabora.com;
> > marc.w.gonzalez@free.fr; olof@lixom.net; devicetree@vger.kernel.org;
> > linux-kernel@vger.kernel.org; linux-arm-kernel@lists.infradead.org;
> > linux- pm@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
> > Subject: Re: [PATCH V10 1/4] dt-bindings: fsl: scu: add thermal
> > binding
> >
> > On Wed, Feb 27, 2019 at 6:48 PM Anson Huang <anson.huang@nxp.com>
> > wrote:
> > >
> > > Hi, Rob
> > >
> > > Best Regards!
> > > Anson Huang
> > >
> > > > -----Original Message-----
> > > > From: Rob Herring [mailto:robh@kernel.org]
> > > > Sent: 2019年2月28日 7:55
> > > > To: Anson Huang <anson.huang@nxp.com>
> > > > Cc: mark.rutland@arm.com; shawnguo@kernel.org;
> > > > s.hauer@pengutronix.de; kernel@pengutronix.de;
> festevam@gmail.com;
> > > > catalin.marinas@arm.com; will.deacon@arm.com;
> rui.zhang@intel.com;
> > > > edubezval@gmail.com; daniel.lezcano@linaro.org; Aisheng Dong
> > > > <aisheng.dong@nxp.com>; ulf.hansson@linaro.org; sboyd@kernel.org;
> > > > Daniel Baluta <daniel.baluta@nxp.com>; Andy Gross
> > > > <andy.gross@linaro.org>; horms+renesas@verge.net.au;
> > > > heiko@sntech.de; arnd@arndb.de; maxime.ripard@bootlin.com;
> > > > bjorn.andersson@linaro.org; jagan@amarulasolutions.com;
> > > > enric.balletbo@collabora.com; marc.w.gonzalez@free.fr;
> > > > olof@lixom.net; devicetree@vger.kernel.org;
> > > > linux-kernel@vger.kernel.org;
> > > > linux-arm-kernel@lists.infradead.org;
> > > > linux- pm@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>
> > > > Subject: Re: [PATCH V10 1/4] dt-bindings: fsl: scu: add thermal
> > > > binding
> > > >
> > > > On Wed, Feb 27, 2019 at 08:46:21AM +0000, Anson Huang wrote:
> > > > > NXP i.MX8QXP is an ARMv8 SoC with a Cortex-M4 core inside as
> > > > > system controller, the system controller is in charge of system
> > > > > power, clock and thermal sensors etc. management, Linux kernel
> > > > > has to communicate with system controller via MU (message unit)
> > > > > IPC to get temperature from thermal sensors, this patch adds
> > > > > binding doc for i.MX system controller thermal driver.
> > > > >
> > > > > Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
> > > > > ---
> > > > > Changes since V9:
> > > > >     - change #thermal-sensor-cells value in example to 1, since
> > > > > there are
> > > > other
> > > > >       thermal sensors inside system controller, it is just
> > > > > because there are
> > > > still
> > > > >       some issue, so system controller does NOT expose them for
> > > > > now,
> > > > they could
> > > > >       be exposed later, so it should be 1 from HW perspective.
> > > > > ---
> > > > >  .../devicetree/bindings/arm/freescale/fsl,scu.txt   | 21
> > > > +++++++++++++++++++++
> > > > >  1 file changed, 21 insertions(+)
> > > > >
> > > > > diff --git
> > > > > a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> > > > > b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> > > > > index 72d481c..855270b 100644
> > > > > ---
> > > > > a/Documentation/devicetree/bindings/arm/freescale/fsl,scu.txt
> > > > > +++ b/Documentation/devicetree/bindings/arm/freescale/fsl,scu.tx
> > > > > +++ t
> > > > > @@ -122,6 +122,21 @@ RTC bindings based on SCU Message
> Protocol
> > > > > Required properties:
> > > > >  - compatible: should be "fsl,imx8qxp-sc-rtc";
> > > > >
> > > > > +Thermal bindings based on SCU Message Protocol
> > > > > +------------------------------------------------------------
> > > > > +
> > > > > +Required properties:
> > > > > +- compatible:                      Should be :
> > > > > +                             "fsl,imx8qxp-sc-thermal"
> > > > > +                           followed by "fsl,imx-sc-thermal";
> > > > > +
> > > > > +- #thermal-sensor-cells:   See
> > > > Documentation/devicetree/bindings/thermal/thermal.txt
> > > > > +                           for a description.
> > > > > +
> > > > > +- imx,sensor-resource-id:  A single integer for single thermal
> > > > > +zone's
> > > > resource ID or
> > > > > +                           an array of integers to specify each
> > > > > + thermal
> > > > zone's sensor
> > > > > +                           resource ID.
> > > >
> > > > Can't you put the resource ids in the thermal-sensor cells? Why do
> > > > you need to list them here?
> > >
> > > For the thermal-sensor cells, if you meant the argument of tsens
> > > phandle, then the reason is that argument is for sensor index
> > > starting from 0, previous I use it for our resource ID, but it looks
> > > confused, since user will think there are many sensors there per
> Eduardo's comment.
> > >
> > > +                       thermal-sensors = <&tsens 0>;
> > >
> > > If you meant putting it in each thermal sensor node instead of "tsens"
> > > node, then in previous patch series, I put this "
> > > imx,sensor-resource-id " property in each thermal sensor node, but
> > > the thermal sensor nodes are parsed by common thermal framework,
> > > thermal driver will need to find the thermal zone node and go
> > > through every child node to get the resource id again, so Eduardo
> > > suggested to put it in
> > our platform tsens node, that makes our thermal driver code much more
> > simple.
> >
> > The phandle args are meant to be an id typically. There's absolutely
> > no requirement they are 0-N based. They often are because things like
> > interrupts are 0-N or clocks have no h/w id. If you already have an id, use it.
> > Don't invent your own.
> 
> At the beginning, I put the HW resource ID in the "tsens" phandle argument
> of "thermal-sensors" node, see  below patch I sent before, the benefit is I do
> NOT need to add new property for passing HW resource ID to driver, the
> disadvantage is, I have to parse the thermal_zones' each child node and get
> the HW resource ID from phandle argument(searing thermal_zones node
> and go through all its child node, and get the phandle argument), they are by
> default ONLY parsed by thermal core driver. When we register thermal zone,
> we have to pass the HW resource ID when calling
> devm_thermal_zone_of_sensor_register(), if we add our own property to
> pass the HW resource ID, then no need to do so, we just pass the index 0-N
> for each thermal sensors in devicetree which also with phandle argument 0-
> N. So using our own property makes the driver much more simple.
> 
> So, @Eduardo, which direction I should go? Looks like Rob suggests just put
> the HW resource ID in the phandle argument like what I did at the beginning,
> can you advise?
> 
> Thanks,
> Anson.
> 
> https://patchwork.kernel.org/patch/10703849/
> > +	thermal_zones: thermal-zones {
> > +		cpu-thermal0 {
> > +			polling-delay-passive = <250>;
> > +			polling-delay = <2000>;
> > +			thermal-sensors = <&tsens 355>;
> > +			trips {
> > +				cpu_alert0: trip0 {
> > +					temperature = <107000>;
> > +					hysteresis = <2000>;
> > +					type = "passive";
> > +				};
> 
> >
> > Rob
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