[EXT] Re: [PATCH v2 1/3] dt-bindings: usb: cdns-imx8qm: add imx8qm cdns3 glue bindings
Frank Li
frank.li at nxp.com
Fri Mar 17 07:55:06 PDT 2023
> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski at linaro.org>
> Sent: Friday, March 17, 2023 4:09 AM
> To: Frank Li <frank.li at nxp.com>; shawnguo at kernel.org
> Cc: devicetree at vger.kernel.org; festevam at gmail.com; imx at lists.linux.dev;
> kernel at pengutronix.de; krzysztof.kozlowski+dt at linaro.org; linux-arm-
> kernel at lists.infradead.org; dl-linux-imx <linux-imx at nxp.com>; linux-
> kernel at vger.kernel.org; robh+dt at kernel.org; s.hauer at pengutronix.de
> Subject: [EXT] Re: [PATCH v2 1/3] dt-bindings: usb: cdns-imx8qm: add
> imx8qm cdns3 glue bindings
>
> Caution: EXT Email
>
> On 16/03/2023 22:27, Frank Li wrote:
> > NXP imx8qm integrates 1 cdns3 IP. This is glue layer device bindings.
> >
>
> Subject: drop second/last, redundant "bindings". The "dt-bindings"
> prefix is already stating that these are bindings.
>
> > Signed-off-by: Frank Li <Frank.Li at nxp.com>
> > ---
> > .../bindings/usb/fsl,imx8qm-cdns3.yaml | 122 ++++++++++++++++++
> > 1 file changed, 122 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/usb/fsl,imx8qm-
> cdns3.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/usb/fsl,imx8qm-
> cdns3.yaml b/Documentation/devicetree/bindings/usb/fsl,imx8qm-
> cdns3.yaml
> > new file mode 100644
> > index 000000000000..fc24df1e4483
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/usb/fsl,imx8qm-cdns3.yaml
> > @@ -0,0 +1,122 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +# Copyright (c) 2020 NXP
> > +%YAML 1.2
> > +---
> > +$id:
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevice
> tree.org%2Fschemas%2Fusb%2Ffsl%2Cimx8qm-
> cdns3.yaml%23&data=05%7C01%7CFrank.Li%40nxp.com%7Cac9af3d617dc4cf
> 14baf08db26c74b07%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7C0%7C6
> 38146409617970248%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMD
> AiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C
> &sdata=EczZhjyMUGnnp7ZGfSvTj4lmOUuGlOtWYIsxxXIlNXw%3D&reserved
> =0
> > +$schema:
> https://eur01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevice
> tree.org%2Fmeta-
> schemas%2Fcore.yaml%23&data=05%7C01%7CFrank.Li%40nxp.com%7Cac9a
> f3d617dc4cf14baf08db26c74b07%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C
> 0%7C0%7C638146409617970248%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiM
> C4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000
> %7C%7C%7C&sdata=uTNYuDm%2ByhZ56oQET2pX8sHpEqVvsUYtmOBCPXEK
> v40%3D&reserved=0
> > +
> > +title: NXP iMX8QM Soc USB Controller
> > +
> > +maintainers:
> > + - Frank Li <Frank.Li at nxp.com>
> > +
> > +properties:
> > + compatible:
> > + const: fsl,imx8qm-usb3
> > +
> > + reg:
> > + items:
> > + - description: Address and length of the register set for iMX USB3
> Platform Control
>
> Drop "Address and length of the"... or actually just maxItems: 1,
> because the description is a bit obvious.
>
> > +
> > + "#address-cells":
> > + enum: [ 1, 2 ]
> > +
> > + "#size-cells":
> > + enum: [ 1, 2 ]
> > +
> > + ranges: true
> > +
> > + clocks:
> > + description:
> > + A list of phandle and clock-specifier pairs for the clocks
> > + listed in clock-names.
>
> Drop description.
>
> > + items:
> > + - description: Standby clock. Used during ultra low power states.
> > + - description: USB bus clock for usb3 controller.
> > + - description: AXI clock for AXI interface.
> > + - description: ipg clock for register access.
> > + - description: Core clock for usb3 controller.
> > +
> > + clock-names:
> > + items:
> > + - const: usb3_lpm_clk
> > + - const: usb3_bus_clk
> > + - const: usb3_aclk
> > + - const: usb3_ipg_clk
> > + - const: usb3_core_pclk
> > +
> > + assigned-clocks:
> > + items:
> > + - description: Phandle and clock specifier of IMX_SC_PM_CLK_PER.
> > + - description: Phandle and clock specifoer of IMX_SC_PM_CLK_MISC.
> > + - description: Phandle and clock specifoer of
> IMX_SC_PM_CLK_MST_BUS.
> > +
> > + assigned-clock-rates:
> > + items:
> > + - description: Must be 125 Mhz.
> > + - description: Must be 12 Mhz.
> > + - description: Must be 250 Mhz.
>
> I would argue that both properties above are not needed. If your
> hardware requires fixed frequencies, clock provider can fix them, can't it?
Clock provider don't know fixed value and turn on only used by client.
>
> > +
> > + power-domains:
> > + maxItems: 1
> > +
> > +# Required child node:
> > +
> > +patternProperties:
> > + "^usb@[0-9a-f]+$":
> > + $ref: cdns,usb3.yaml#
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - "#address-cells"
> > + - "#size-cells"
> > + - ranges
> > + - clocks
> > + - clock-names
> > + - power-domains
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/clock/imx8-lpcg.h>
> > + #include <dt-bindings/firmware/imx/rsrc.h>
> > + #include <dt-bindings/interrupt-controller/arm-gic.h>
> > +
> > + usbotg3: usb at 5b110000 {
>
> Drop label, unused
>
> > + compatible = "fsl,imx8qm-usb3";
> > + ranges;
> > + reg = <0x5b110000 0x10000>;
>
> reg is second property
>
> > + clocks = <&usb3_lpcg IMX_LPCG_CLK_1>,
> > + <&usb3_lpcg IMX_LPCG_CLK_0>,
> > + <&usb3_lpcg IMX_LPCG_CLK_7>,
> > + <&usb3_lpcg IMX_LPCG_CLK_4>,
> > + <&usb3_lpcg IMX_LPCG_CLK_5>;
> > + clock-names = "usb3_lpm_clk", "usb3_bus_clk", "usb3_aclk",
> > + "usb3_ipg_clk", "usb3_core_pclk";
> > + assigned-clocks = <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_PER>,
> > + <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_MISC>,
> > + <&clk IMX_SC_R_USB_2 IMX_SC_PM_CLK_MST_BUS>;
> > + assigned-clock-rates = <125000000>, <12000000>, <250000000>;
> > + power-domains = <&pd IMX_SC_R_USB_2>;
> > + #address-cells = <1>;
> > + #size-cells = <1>;
> > + status = "disabled";
>
> Drop status
>
> > +
> > + usbotg3_cdns3: usb at 5b120000 {
>
> Drop label
>
> > + compatible = "cdns,usb3";
> > + interrupt-parent = <&gic>;
> > + interrupts = <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> > + <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> > + <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>,
> > + <GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH>;
> > + interrupt-names = "host", "peripheral", "otg", "wakeup";
> > + reg = <0x5b120000 0x10000>, /* memory area for OTG/DRD
> registers */
> > + <0x5b130000 0x10000>, /* memory area for HOST registers */
> > + <0x5b140000 0x10000>; /* memory area for DEVICE registers */
> > + reg-names = "otg", "xhci", "dev";
>
> reg is second property, reg-names third.
>
> > + phys = <&usb3_phy>;
> > + phy-names = "cdns3,usb3-phy";
> > + };
> > + };
>
> Best regards,
> Krzysztof
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