[v4,3/6] dt-bindings: power: tegra: Add binding for core power domain

All NVIDIA Tegra SoCs have a core power domain where majority of hardware
blocks reside. Add binding for the core power domain.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 .../power/nvidia,tegra20-core-domain.yaml     | 51 +++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

On Sun, Mar 14, 2021 at 07:48:07PM +0300, Dmitry Osipenko wrote:
> All NVIDIA Tegra SoCs have a core power domain where majority of hardware

> blocks reside. Add binding for the core power domain.

> 

> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

> ---

>  .../power/nvidia,tegra20-core-domain.yaml     | 51 +++++++++++++++++++

>  1 file changed, 51 insertions(+)

>  create mode 100644 Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> 

> diff --git a/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> new file mode 100644

> index 000000000000..4692489d780a

> --- /dev/null

> +++ b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> @@ -0,0 +1,51 @@

> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause

> +%YAML 1.2

> +---

> +$id: http://devicetree.org/schemas/power/nvidia,tegra20-core-domain.yaml#

> +$schema: http://devicetree.org/meta-schemas/core.yaml#

> +

> +title: NVIDIA Tegra Core Power Domain

> +

> +maintainers:

> +  - Dmitry Osipenko <digetx@gmail.com>

> +  - Jon Hunter <jonathanh@nvidia.com>

> +  - Thierry Reding <thierry.reding@gmail.com>

> +

> +allOf:

> +  - $ref: power-domain.yaml#

> +

> +properties:

> +  compatible:

> +    enum:

> +      - nvidia,tegra20-core-domain

> +      - nvidia,tegra30-core-domain

> +

> +  operating-points-v2:

> +    description:

> +      Should contain level, voltages and opp-supported-hw property.

> +      The supported-hw is a bitfield indicating SoC speedo or process

> +      ID mask.

> +

> +  "#power-domain-cells":

> +    const: 0

> +

> +  power-supply:

> +    description:

> +      Phandle to voltage regulator connected to the SoC Core power rail.

> +

> +required:

> +  - compatible

> +  - operating-points-v2

> +  - "#power-domain-cells"

> +  - power-supply

> +

> +additionalProperties: false

> +

> +examples:

> +  - |

> +    power-domain {

> +        compatible = "nvidia,tegra20-core-domain";

> +        operating-points-v2 = <&opp_table>;

> +        power-supply = <&regulator>;

> +        #power-domain-cells = <0>;


AFAICT, there's no way to access this 'hardware'?

> +    };

> -- 

> 2.30.2

>

24.03.2021 01:48, Rob Herring пишет:
> On Sun, Mar 14, 2021 at 07:48:07PM +0300, Dmitry Osipenko wrote:
>> All NVIDIA Tegra SoCs have a core power domain where majority of hardware
>> blocks reside. Add binding for the core power domain.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
>> ---
>>  .../power/nvidia,tegra20-core-domain.yaml     | 51 +++++++++++++++++++
>>  1 file changed, 51 insertions(+)
>>  create mode 100644 Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml
>> new file mode 100644
>> index 000000000000..4692489d780a
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml
>> @@ -0,0 +1,51 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/power/nvidia,tegra20-core-domain.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: NVIDIA Tegra Core Power Domain
>> +
>> +maintainers:
>> +  - Dmitry Osipenko <digetx@gmail.com>
>> +  - Jon Hunter <jonathanh@nvidia.com>
>> +  - Thierry Reding <thierry.reding@gmail.com>
>> +
>> +allOf:
>> +  - $ref: power-domain.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - nvidia,tegra20-core-domain
>> +      - nvidia,tegra30-core-domain
>> +
>> +  operating-points-v2:
>> +    description:
>> +      Should contain level, voltages and opp-supported-hw property.
>> +      The supported-hw is a bitfield indicating SoC speedo or process
>> +      ID mask.
>> +
>> +  "#power-domain-cells":
>> +    const: 0
>> +
>> +  power-supply:
>> +    description:
>> +      Phandle to voltage regulator connected to the SoC Core power rail.
>> +
>> +required:
>> +  - compatible
>> +  - operating-points-v2
>> +  - "#power-domain-cells"
>> +  - power-supply
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    power-domain {
>> +        compatible = "nvidia,tegra20-core-domain";
>> +        operating-points-v2 = <&opp_table>;
>> +        power-supply = <&regulator>;
>> +        #power-domain-cells = <0>;
> 
> AFAICT, there's no way to access this 'hardware'?
correct

On Wed, Mar 24, 2021 at 02:01:29AM +0300, Dmitry Osipenko wrote:
> 24.03.2021 01:48, Rob Herring пишет:

> > On Sun, Mar 14, 2021 at 07:48:07PM +0300, Dmitry Osipenko wrote:

> >> All NVIDIA Tegra SoCs have a core power domain where majority of hardware

> >> blocks reside. Add binding for the core power domain.

> >>

> >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

> >> ---

> >>  .../power/nvidia,tegra20-core-domain.yaml     | 51 +++++++++++++++++++

> >>  1 file changed, 51 insertions(+)

> >>  create mode 100644 Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> >>

> >> diff --git a/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> >> new file mode 100644

> >> index 000000000000..4692489d780a

> >> --- /dev/null

> >> +++ b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

> >> @@ -0,0 +1,51 @@

> >> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause

> >> +%YAML 1.2

> >> +---

> >> +$id: http://devicetree.org/schemas/power/nvidia,tegra20-core-domain.yaml#

> >> +$schema: http://devicetree.org/meta-schemas/core.yaml#

> >> +

> >> +title: NVIDIA Tegra Core Power Domain

> >> +

> >> +maintainers:

> >> +  - Dmitry Osipenko <digetx@gmail.com>

> >> +  - Jon Hunter <jonathanh@nvidia.com>

> >> +  - Thierry Reding <thierry.reding@gmail.com>

> >> +

> >> +allOf:

> >> +  - $ref: power-domain.yaml#

> >> +

> >> +properties:

> >> +  compatible:

> >> +    enum:

> >> +      - nvidia,tegra20-core-domain

> >> +      - nvidia,tegra30-core-domain

> >> +

> >> +  operating-points-v2:

> >> +    description:

> >> +      Should contain level, voltages and opp-supported-hw property.

> >> +      The supported-hw is a bitfield indicating SoC speedo or process

> >> +      ID mask.

> >> +

> >> +  "#power-domain-cells":

> >> +    const: 0

> >> +

> >> +  power-supply:

> >> +    description:

> >> +      Phandle to voltage regulator connected to the SoC Core power rail.

> >> +

> >> +required:

> >> +  - compatible

> >> +  - operating-points-v2

> >> +  - "#power-domain-cells"

> >> +  - power-supply

> >> +

> >> +additionalProperties: false

> >> +

> >> +examples:

> >> +  - |

> >> +    power-domain {

> >> +        compatible = "nvidia,tegra20-core-domain";

> >> +        operating-points-v2 = <&opp_table>;

> >> +        power-supply = <&regulator>;

> >> +        #power-domain-cells = <0>;

> > 

> > AFAICT, there's no way to access this 'hardware'?

> correct


To avoid exposing this "virtual" device in device tree, could this
instead be modelled as a child node of the PMC node? We already expose a
couple of generic power domains that way on Tegra210 and later, so
perhaps some of that infrastructure can be reused? I suppose given that
this is different from the standard powergate domains that we expose so
far, this may need a different implementation, but from a device tree
bindings point of view it could fit in with that.

Thierry

25.03.2021 17:49, Thierry Reding пишет:
> On Wed, Mar 24, 2021 at 02:01:29AM +0300, Dmitry Osipenko wrote:

>> 24.03.2021 01:48, Rob Herring пишет:

>>> On Sun, Mar 14, 2021 at 07:48:07PM +0300, Dmitry Osipenko wrote:

>>>> All NVIDIA Tegra SoCs have a core power domain where majority of hardware

>>>> blocks reside. Add binding for the core power domain.

>>>>

>>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

>>>> ---

>>>>  .../power/nvidia,tegra20-core-domain.yaml     | 51 +++++++++++++++++++

>>>>  1 file changed, 51 insertions(+)

>>>>  create mode 100644 Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

>>>>

>>>> diff --git a/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

>>>> new file mode 100644

>>>> index 000000000000..4692489d780a

>>>> --- /dev/null

>>>> +++ b/Documentation/devicetree/bindings/power/nvidia,tegra20-core-domain.yaml

>>>> @@ -0,0 +1,51 @@

>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause

>>>> +%YAML 1.2

>>>> +---

>>>> +$id: http://devicetree.org/schemas/power/nvidia,tegra20-core-domain.yaml#

>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#

>>>> +

>>>> +title: NVIDIA Tegra Core Power Domain

>>>> +

>>>> +maintainers:

>>>> +  - Dmitry Osipenko <digetx@gmail.com>

>>>> +  - Jon Hunter <jonathanh@nvidia.com>

>>>> +  - Thierry Reding <thierry.reding@gmail.com>

>>>> +

>>>> +allOf:

>>>> +  - $ref: power-domain.yaml#

>>>> +

>>>> +properties:

>>>> +  compatible:

>>>> +    enum:

>>>> +      - nvidia,tegra20-core-domain

>>>> +      - nvidia,tegra30-core-domain

>>>> +

>>>> +  operating-points-v2:

>>>> +    description:

>>>> +      Should contain level, voltages and opp-supported-hw property.

>>>> +      The supported-hw is a bitfield indicating SoC speedo or process

>>>> +      ID mask.

>>>> +

>>>> +  "#power-domain-cells":

>>>> +    const: 0

>>>> +

>>>> +  power-supply:

>>>> +    description:

>>>> +      Phandle to voltage regulator connected to the SoC Core power rail.

>>>> +

>>>> +required:

>>>> +  - compatible

>>>> +  - operating-points-v2

>>>> +  - "#power-domain-cells"

>>>> +  - power-supply

>>>> +

>>>> +additionalProperties: false

>>>> +

>>>> +examples:

>>>> +  - |

>>>> +    power-domain {

>>>> +        compatible = "nvidia,tegra20-core-domain";

>>>> +        operating-points-v2 = <&opp_table>;

>>>> +        power-supply = <&regulator>;

>>>> +        #power-domain-cells = <0>;

>>>

>>> AFAICT, there's no way to access this 'hardware'?

>> correct

> 

> To avoid exposing this "virtual" device in device tree, could this

> instead be modelled as a child node of the PMC node? We already expose a

> couple of generic power domains that way on Tegra210 and later, so

> perhaps some of that infrastructure can be reused? I suppose given that

> this is different from the standard powergate domains that we expose so

> far, this may need a different implementation, but from a device tree

> bindings point of view it could fit in with that.


At a quick glance this should be too troublesome because OPP and regulator frameworks require a proper/real backing device.

Perhaps we could either turn the whole PMC into a core-domain or add a virtual device as a child of PMC, like this:

diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
index 79364cdafeab..717273048caf 100644
--- a/arch/arm/boot/dts/tegra20.dtsi
+++ b/arch/arm/boot/dts/tegra20.dtsi
@@ -850,6 +850,12 @@ pd_mpe: mpe {
 				#power-domain-cells = <0>;
 			};
 		};
+
+		pd_core: core-domain {
+			compatible = "nvidia,tegra20-core-domain";
+			operating-points-v2 = <&core_opp_table>;
+			#power-domain-cells = <0>;
+		};
 	};
 
 	mc: memory-controller@7000f000 {

but then this is still a virtual device, although in a bit nicer way.

It feels like yours suggestion might result in a hardware description that is closer to reality since PMC controls fan out of all power rails within SoC.