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

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

Ping...
Hi, Eduardo
	Can you take a look at this thread? Thanks.


Best Regards!
Anson Huang

> -----Original Message-----
> From: Anson Huang
> Sent: 2019年3月6日 13:27
> To: 'Rob Herring' <robh@kernel.org>; 'edubezval@gmail.com'
> <edubezval@gmail.com>
> Cc: 'mark.rutland@arm.com' <mark.rutland@arm.com>;
> 'shawnguo@kernel.org' <shawnguo@kernel.org>; 's.hauer@pengutronix.de'
> <s.hauer@pengutronix.de>; 'kernel@pengutronix.de'
> <kernel@pengutronix.de>; 'festevam@gmail.com' <festevam@gmail.com>;
> 'catalin.marinas@arm.com' <catalin.marinas@arm.com>;
> 'will.deacon@arm.com' <will.deacon@arm.com>; 'rui.zhang@intel.com'
> <rui.zhang@intel.com>; 'edubezval@gmail.com' <edubezval@gmail.com>;
> 'daniel.lezcano@linaro.org' <daniel.lezcano@linaro.org>; Aisheng Dong
> <aisheng.dong@nxp.com>; 'ulf.hansson@linaro.org'
> <ulf.hansson@linaro.org>; 'sboyd@kernel.org' <sboyd@kernel.org>; Daniel
> Baluta <daniel.baluta@nxp.com>; Andy Gross <andy.gross@linaro.org>;
> 'horms+renesas@verge.net.au' <horms+renesas@verge.net.au>;
> 'heiko@sntech.de' <heiko@sntech.de>; 'arnd@arndb.de' <arnd@arndb.de>;
> 'maxime.ripard@bootlin.com' <maxime.ripard@bootlin.com>;
> 'bjorn.andersson@linaro.org' <bjorn.andersson@linaro.org>;
> 'jagan@amarulasolutions.com' <jagan@amarulasolutions.com>;
> 'enric.balletbo@collabora.com' <enric.balletbo@collabora.com>;
> 'marc.w.gonzalez@free.fr' <marc.w.gonzalez@free.fr>; 'olof@lixom.net'
> <olof@lixom.net>; 'devicetree@vger.kernel.org'
> <devicetree@vger.kernel.org>; 'linux-kernel@vger.kernel.org' <linux-
> kernel@vger.kernel.org>; 'linux-arm-kernel@lists.infradead.org' <linux-arm-
> kernel@lists.infradead.org>; 'linux-pm@vger.kernel.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
> 
> 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