Re: [PATCH v2 4/7] dt-bindings: soc: mediatek: apusys: Add new document for APU power domain

Flora Fu
2021-04-16T03:54:12Z

On Thu, 2021-04-15 at 10:25 -0500, Rob Herring wrote:
> On Thu, Apr 15, 2021 at 01:52:37PM +0800, Flora Fu wrote:
> > Document the bindings for APU power domain on MediaTek SoC.
> >
> > Signed-off-by: Flora Fu <flora.fu@mediatek.com>
> > ---
> > Note:
> > This patch depends on MT8192 clock[1] patches which haven't yet been accepted.
> > [1] https://urldefense.com/v3/__https://patchwork.kernel.org/project/linux-mediatek/patch/20210324104110.13383-7-chun-jie.chen@mediatek.com/__;!!CTRNKA9wMg0ARbw!zINTC3jweo4_C2yxqf9kHaxAXhO-k-I_JplIY4OQ390IeSfk5QCR4ojmFz2gPbBV$
> > ---
> > .../soc/mediatek/mediatek,apu-pm.yaml | 145 ++++++++++++++++++
> > 1 file changed, 145 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/soc/mediatek/mediatek,apu-pm.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/soc/mediatek/mediatek,apu-pm.yaml b/Documentation/devicetree/bindings/soc/mediatek/mediatek,apu-pm.yaml
> > new file mode 100644
> > index 000000000000..6ff966920917
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/soc/mediatek/mediatek,apu-pm.yaml
> > @@ -0,0 +1,145 @@
> > +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: https://urldefense.com/v3/__http://devicetree.org/schemas/soc/mediatek/mediatek,apu-pm.yaml*__;Iw!!CTRNKA9wMg0ARbw!zINTC3jweo4_C2yxqf9kHaxAXhO-k-I_JplIY4OQ390IeSfk5QCR4ojmF_yHpQUx$
> > +$schema: https://urldefense.com/v3/__http://devicetree.org/meta-schemas/core.yaml*__;Iw!!CTRNKA9wMg0ARbw!zINTC3jweo4_C2yxqf9kHaxAXhO-k-I_JplIY4OQ390IeSfk5QCR4ojmFy1L2FzU$
> > +
> > +title: Mediatek APU Power Domains
> > +
> > +maintainers:
> > + - Flora Fu <flora.fu@mediatek.com>
> > +
> > +description: |
> > + Mediatek AI Process Unit (APU) include support for power domains which can be
> > + powered up/down by software.
> > + APU subsys belonging to a power domain should contain a 'power-domains'
> > + property that is a phandle for apuspm node representing the domain.
> > +
> > +properties:
> > + compatible:
> > + items:
> > + - enum:
> > + - mediatek,mt8192-apu-pm
> > + - const: syscon
> > +
> > + reg:
> > + description: Address range of the APU power domain controller.
> > + maxItems: 1
> > +
> > + '#address-cells':
> > + const: 1
> > +
> > + '#size-cells':
> > + const: 0
> > +
> > + '#power-domain-cells':
> > + const: 1
> > +
> > + vsram-supply:
> > + description: apu sram regulator supply.
> > +
> > + mediatek,scpsys:
> > + $ref: /schemas/types.yaml#/definitions/phandle
> > + description: |
> > + phandle to the device containing the scpsys register range.
> > +
> > + mediatek,apu-conn:
> > + $ref: /schemas/types.yaml#/definitions/phandle
> > + description: |
> > + phandle to the device containing the scpsys apu conn register range.
> > +
> > + mediatek,apu-conn1:
> > + $ref: /schemas/types.yaml#/definitions/phandle
> > + description: |
> > + phandle to the device containing the scpsys apu conn1 register range.
> > +
> > + mediatek,apu-vcore:
> > + $ref: /schemas/types.yaml#/definitions/phandle
> > + description: |
> > + phandle to the device containing the scpsys apu vcore register range.
> > +
> > +patternProperties:
> > + "^power-domain@[0-9a-f]+$":
> > + type: object
> > + description: |
> > + Represents the power domains within the power controller node as
> > + documented in Documentation/devicetree/bindings/power/power-domain.yaml.
> > +
> > + properties:
> > + reg:
> > + description: |
> > + Power domain index. Valid values are defined in:
> > + "include/dt-bindings/power/mt8182-apu-power.h"
> > + maxItems: 1
> > +
> > + '#power-domain-cells':
> > + description: |
> > + Must be 0 for nodes representing a single PM domain and 1 for nodes
> > + providing multiple PM.
> > +
> > + clocks:
> > + description: |
> > + List of phandles of clocks list. Specify by order according to
> > + power-up sequence.
> > +
> > + clock-names:
> > + description: |
> > + List of names of clocks. Specify by order according to power-up
> > + sequence.
> > +
> > + assigned-clocks:
> > + maxItems: 2
> > +
> > + assigned-clock-parents:
> > + maxItems: 2
> > +
> > + domain-supply:
> > + description: domain regulator supply.
> > +
> > + required:
> > + - reg
> > + - '#power-domain-cells'
> > +
> > + additionalProperties: false
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - '#power-domain-cells'
> > + - vsram-supply
> > + - mediatek,scpsys
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/clock/mt8192-clk.h>
> > + apuspm: power-domain@190f0000 {
> > + compatible = "mediatek,mt8192-apu-pm", "syscon";
> > + reg = <0x190f0000 0x1000>;
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > + #power-domain-cells = <1>;
>
> So you have domains provided by this node and then...
>
> > + vsram-supply = <&mt6359_vsram_md_ldo_reg>;
> > + mediatek,scpsys = <&scpsys>;
> > + mediatek,apu-conn = <&apu_conn>;
> > + mediatek,apu-vcore = <&apu_vcore>;
> > +
> > + apu_top: power-domain@0 {
> > + reg = <0>;
> > + #power-domain-cells = <0>;
>
> ...each child node provides a domain. What's the difference?

The hardware @190f0000 have controller for several child power domains
in apu subsys and now only one domain (apu_top) is exposed to mt8192
kernel. For the software extension purpose, the driver parses child
nodes even if it has only one child. In previous v1 patch, I add a
domain id index in a header file but it seems not necessary to create a
standalone file for the case. So I just set the index in the device tree
but keep dts structure to present hardware design.

>
> > + clocks = <&topckgen CLK_TOP_DSP_SEL>,
> > + <&topckgen CLK_TOP_IPU_IF_SEL>,
> > + <&clk26m>,
> > + <&topckgen CLK_TOP_UNIVPLL_D6_D2>;
> > + clock-names = "clk_top_conn",
> > + "clk_top_ipu_if",
> > + "clk_off",
> > + "clk_on_default";
> > + assigned-clocks = <&topckgen CLK_TOP_DSP_SEL>,
> > + <&topckgen CLK_TOP_IPU_IF_SEL>;
> > + assigned-clock-parents = <&topckgen CLK_TOP_UNIVPLL_D6_D2>,
> > + <&topckgen CLK_TOP_UNIVPLL_D6_D2>;
> > + domain-supply = <&mt6359_vproc1_buck_reg>;
> > + };
> > + };
> > --
> > 2.18.0
> >