Re: [PATCH v4 1/2] dt-bindings: usb: qcom,dwc3: Convert USB DWC3 bindings

From: Sandeep Maheswaram (Temp)
Date: Fri Mar 13 2020 - 08:12:02 EST

Hi Stephen,

On 2/11/2020 3:01 AM, Stephen Boyd wrote:
Quoting Sandeep Maheswaram (2020-02-09 22:36:44)
diff --git a/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml b/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml
new file mode 100644
index 0000000..0353401
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/qcom,dwc3.yaml
@@ -0,0 +1,155 @@
+# SPDX-License-Identifier: GPL-2.0-only
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/qcom,dwc3.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm SuperSpeed DWC3 USB SoC controller
+
+maintainers:
+ - Manu Gautam <mgautam@xxxxxxxxxxxxxx>
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - qcom,msm8996-dwc3
+ - qcom,msm8998-dwc3
+ - qcom,sdm845-dwc3
+ - const: qcom,dwc3
+
+ reg:
+ description: Offset and length of register set for QSCRATCH wrapper
+ maxItems: 1
+
+ "#address-cells":
+ enum: [ 1, 2 ]
+
+ "#size-cells":
+ enum: [ 1, 2 ]
+
+ power-domains:
+ description: specifies a phandle to PM domain provider node
+ maxItems: 1
+
+ clocks:
+ description:
+ A list of phandle and clock-specifier pairs for the clocks
+ listed in clock-names.
+ items:
+ - description: System Config NOC clock.
+ - description: Master/Core clock, has to be >= 125 MHz
+ for SS operation and >= 60MHz for HS operation.
+ - description: System bus AXI clock.
+ - description: Mock utmi clock needed for ITP/SOF generation
+ in host mode.Its frequency should be 19.2MHz.
Please add a space between the end of sentence and next one.
will do in next version

+ - description: Sleep clock, used for wakeup when
+ USB3 core goes into low power mode (U3).
+
+ clock-names:
+ items:
+ - const: cfg_noc
+ - const: core
+ - const: iface
+ - const: mock_utmi
+ - const: sleep
+
+ assigned-clocks:
+ items:
+ - description: Phandle to MOCK_UTMI_CLK.
+ - description: Phandle to MASTER_CLK.
It's a phandle and clock specifier pair, not always just a phandle.
Maybe the base schema can enforce that somehow, but the description
isn't accurate.
will do in next version

+
+ assigned-clock-rates:
+ items:
+ - description: Must be 19.2MHz (19200000).
+ - description: Must be >= 60 MHz in HS mode, >= 125 MHz in SS mode.
Can this be more strict? I see in [1] that it was suggested to update
the schema checker. Did you try that?

Tried that but need to add maximum value also and even after that getting some errors as below.

/Documentation/devicetree/bindings/usb/qcom,dwc3.example.dt.yaml: usb@a6f8800: assigned-clock-rates: Additional items are not allowed ([150000000] was unexpected)

/local/mnt/workspace/sandeep/bu_build/src/third_party/kernel/linux-next/Documentation/devicetree/bindings/usb/qcom,dwc3.example.dt.yaml: usb@a6f8800: assigned-clock-rates:0: [19200000] is too short

+
+ resets:
+ maxItems: 1
+
+ interrupts:
+ items:
+ - description: The interrupt that is asserted
+ when a wakeup event is received on USB2 bus.
+ - description: The interrupt that is asserted
+ when a wakeup event is received on USB3 bus.
+ - description: Wakeup event on DM line.
+ - description: Wakeup event on DP line.
+
+ interrupt-names:
+ items:
+ - const: hs_phy_irq
+ - const: ss_phy_irq
+ - const: dm_hs_phy_irq
+ - const: dp_hs_phy_irq
+
+ qcom,select-utmi-as-pipe-clk:
+ description:
+ If present, disable USB3 pipe_clk requirement.
+ Used when dwc3 operates without SSPHY and only
+ HS/FS/LS modes are supported.
+ type: boolean
+
+# Required child node:
+
+patternProperties:
+ "^dwc3@[0-9a-f]+$":
+ type: object
+ description:
+ A child node must exist to represent the core DWC3 IP block
+ The content of the node is defined in dwc3.txt.
+
+required:
+ - compatible
+ - reg
+ - "#address-cells"
+ - "#size-cells"
+ - power-domains
+ - clocks
+ - clock-names
Why aren't interrupts required? They're always present, aren't they?
In qcom,dwc3.txt file interrupts are mentioned in Optional properties and I also didnt find any interrupts in 8996.dtsi

+
+examples:
+ - |
+ #include <dt-bindings/clock/qcom,gcc-sdm845.h>
+ #include <dt-bindings/interrupt-controller/arm-gic.h>
It would be good to include <dt-bindings/interrupt-controller/irq.h>
here too, just in case someone wants to move that include out of
arm-gic.h, which is possible.

+ usb_1: usb@a6f8800 {
Can we drop the phandle? It's not used.
will do in next version

+ compatible = "qcom,sdm845-dwc3", "qcom,dwc3";
+ reg = <0 0x0a6f8800 0 0x400>;
+
+ #address-cells = <2>;
+ #size-cells = <2>;
+
+ clocks = <&gcc GCC_CFG_NOC_USB3_PRIM_AXI_CLK>,
+ <&gcc GCC_USB30_PRIM_MASTER_CLK>,
+ <&gcc GCC_AGGRE_USB3_PRIM_AXI_CLK>,
+ <&gcc GCC_USB30_PRIM_MOCK_UTMI_CLK>,
+ <&gcc GCC_USB30_PRIM_SLEEP_CLK>;
+ clock-names = "cfg_noc", "core", "iface", "mock_utmi",
+ "sleep";
Spacing looks off. Are there tabs?
will correct in next version

+
+ assigned-clocks = <&gcc GCC_USB30_PRIM_MOCK_UTMI_CLK>,
+ <&gcc GCC_USB30_PRIM_MASTER_CLK>;
+ assigned-clock-rates = <19200000>, <150000000>;
+
+ interrupts = <GIC_SPI 131 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 486 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 488 IRQ_TYPE_LEVEL_HIGH>,
+ <GIC_SPI 489 IRQ_TYPE_LEVEL_HIGH>;
+ interrupt-names = "hs_phy_irq", "ss_phy_irq",
+ "dm_hs_phy_irq", "dp_hs_phy_irq";
Same spacing nit
will correct in next version

+
+ power-domains = <&gcc USB30_PRIM_GDSC>;
+
+ resets = <&gcc GCC_USB30_PRIM_BCR>;
+
+ usb_1_dwc3: dwc3@a600000 {
Drop this phandle too? It isn't used.
will correct in next version

+ compatible = "snps,dwc3";
+ reg = <0 0x0a600000 0 0xcd00>;
+ interrupts = <GIC_SPI 133 IRQ_TYPE_LEVEL_HIGH>;
+ iommus = <&apps_smmu 0x740 0>;
+ snps,dis_u2_susphy_quirk;
+ snps,dis_enblslpm_quirk;
+ phys = <&usb_1_hsphy>, <&usb_1_ssphy>;
+ phy-names = "usb2-phy", "usb3-phy";
+ };
[1] https://lkml.kernel.org/r/20191218221310.GA4624@bogus

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