Re: [PATCH v4 01/10] dt-bindings: firmware: qcom: tmd: add TMD device type constants

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On Mon, Jul 06, 2026 at 07:03:18PM +0200, Daniel Lezcano wrote:
> On 7/3/26 17:42, Dmitry Baryshkov wrote:
> > On Fri, Jul 03, 2026 at 07:43:39PM +0530, Gaurav Kohli wrote:
> > > 
> > > 
> > > On 7/3/2026 1:23 PM, Konrad Dybcio wrote:
> > > > On 7/3/26 7:03 AM, Gaurav Kohli wrote:
> > > > > Add Device Tree binding constants for Qualcomm Thermal Mitigation
> > > > > Device (TMD) types used by remoteproc-backed thermal cooling devices.
> > > > > 
> > > > > Qualcomm remote processors expose thermal mitigation endpoints
> > > > > through QMI. These endpoints can be registered with the thermal
> > > > > framework via the `#cooling-cells` property on the remoteproc node.
> > > > > 
> > > > > The QMI TMD protocol identifies devices using string names (for example,
> > > > > "pa", "modem", and "cdsp_sw"), while the DT cooling-device binding with
> > > > > `#cooling-cells = <3>` requires numeric device id in the form:
> > > > > 
> > > > >     <&phandle device_id min_state max_state>
> > > > > 
> > > > > Define common TMD device index constants shared across currently
> > > > > supported platforms. If a future target requires a different mapping,
> > > > > additional target-specific constants can be introduced while preserving
> > > > > existing DT ABI.
> > > > > 
> > > > > Signed-off-by: Gaurav Kohli <gaurav.kohli@oss.qualcomm.com>
> > > > > ---
> > > > >    MAINTAINERS                                 |  1 +
> > > > >    include/dt-bindings/firmware/qcom,qmi-tmd.h | 20 ++++++++++++++++++++
> > > > >    2 files changed, 21 insertions(+)
> > > > > 
> > > > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > > > index 57656ec0e9d5..ffd85fd1dd80 100644
> > > > > --- a/MAINTAINERS
> > > > > +++ b/MAINTAINERS
> > > > > @@ -3410,6 +3410,7 @@ F:	drivers/firmware/qcom/
> > > > >    F:	drivers/soc/qcom/
> > > > >    F:	drivers/watchdog/gunyah_wdt.c
> > > > >    F:	include/dt-bindings/arm/qcom,ids.h
> > > > > +F:	include/dt-bindings/firmware/qcom,qmi-tmd.h
> > > > >    F:	include/dt-bindings/firmware/qcom,scm.h
> > > > >    F:	include/dt-bindings/soc/qcom*
> > > > >    F:	include/linux/firmware/qcom
> > > > > diff --git a/include/dt-bindings/firmware/qcom,qmi-tmd.h b/include/dt-bindings/firmware/qcom,qmi-tmd.h
> > > > > new file mode 100644
> > > > > index 000000000000..73efecef0f3c
> > > > > --- /dev/null
> > > > > +++ b/include/dt-bindings/firmware/qcom,qmi-tmd.h
> > > > > @@ -0,0 +1,20 @@
> > > > > +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> > > > > +/*
> > > > > + * Qualcomm QMI TMD (Thermal Mitigation Device) cooling device indices
> > > > > + *
> > > > > + * These indices are used in device tree cooling-maps to reference
> > > > > + * specific TMD devices provided by remote processors via QMI.
> > > > > + *
> > > > > + * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
> > > > > + */
> > > > > +#ifndef _DT_BINDINGS_FIRMWARE_QCOM_QMI_TMD_H
> > > > > +#define _DT_BINDINGS_FIRMWARE_QCOM_QMI_TMD_H
> > > > > +
> > > > > +/* CDSP thermal mitigation device id */
> > > > > +#define QCOM_CDSP_TMD_CDSP_SW	0
> > > > > +
> > > > > +/* Modem thermal mitigation device id */
> > > > > +#define QCOM_MODEM_TMD_PA	0
> > > > > +#define QCOM_MODEM_TMD_MODEM	1
> > > > 
> > > > What about the dozens other ones that Dmitry's laptop reports?Ri
> > > > 
> > > 
> > > Thanks for the review, Konrad.
> > > 
> > > We are only defining constants for the TMD devices that are actually used
> > > for thermal mitigation on the platforms supported by this series.
> > 
> > Why are you using only those TMD devices?
> > 
> > > More constants can be added as needed.
> > 
> > Kodiak is one of the supported platforms.
> 
> What would be the benefit of having more than thirteen cooling devices
> declared in the thermal framework and having only a couple of them mapped in
> a thermal zone ?
> 
> I agree there are more TMDs but if they are unused for the moment, why do we
> need to add them ? Can we do that incrementally ?

That's what I am trying to understand: why the implementation uses only
the selected two devices, if the modem on Kodiak supports others. How
can we find out, which TMDs to use on other devices.

-- 
With best wishes
Dmitry