On 1/23/23 06:01, Kunihiko Hayashi wrote:
Hi Marek,
Hello Hayashi-san,
[...]
On the other hand, the PXS2 controller for example is not a bus:
arch/arm/dts/uniphier-pxs2.dtsi: 596 _usb0: usb@65a00000 { 597 compatible = "socionext,uniphier-dwc3", "snps,dwc3"; 598 status = "disabled"; 599 reg = <0x65a00000 0xcd00>; ... 610 };
I understand. However, this node isn't used in u-boot. (see below for details)
Is this needed for socionext dwc3 variant to handle the simple-mfd in e.g. arch/arm/dts/uniphier-pxs3.dtsi :
614 usb-glue@65b00000 { 615 compatible = "socionext,uniphier-pxs3-dwc3-glue", 616 "simple-mfd";
?
In case of U-Boot, the glue driver is probed by:
/* FIXME: U-Boot own node */ usb@65b00000 { compatible = "socionext,uniphier-pxs3-dwc3";
And dwc3-uniphier is also declared as UCLASS_SIMPLE_BUS. Even if using "simple-mfd", this is included in drivers/core/simple-bus.c which is declared as UCLASS_SIMPLE_BUS.
If I understand this correctly, node compatible with "socionext,uniphier-pxs3-dwc3-glue" is not used at all , right ?
Yes. Original uniphier devicetree has the following usb nodes.
usb@65a00000 { compatible = "snps,dwc3"; }; usb-glue@65b00000 { compatible = "socionext,uniphier-pxs3-dwc3-glue", "simple-mfd"; };
However, U-Boot dwc3-generic needs to put dwc3 node under the glue node.
Have a look at arch/arm/dts/imx8mq.dtsi which does not use any glue node, the snps,dwc3 compatible node is directly placed on the soc@0 bus:
1417 1418 usb_dwc3_0: usb@38100000 { 1419 compatible = "fsl,imx8mq-dwc3", "snps,dwc3"; 1420 reg = <0x38100000 0x10000>; 1421 clocks = <&clk IMX8MQ_CLK_USB1_CTRL_ROOT>,
Due to this restriction, there is another usb node dedicated to u-boot.
/* FIXME: U-Boot own node */ usb@65b00000 { /* glue */ compatible = "socionext,uniphier-pxs3-dwc3";
dwc3@65a00000 { compatible = "snps,dwc3"; }; };
So instead of "socionext,uniphier-pxs3-dwc3-glue", the glue driver uses "socionext,uniphier-pxs3-dwc3" in U-Boot.
Can we use the same method as imx8mq.dtsi uses, to avoid this special node workaround ?
The generic driver binds to node compatible with "socionext,uniphier-dwc3" , right ?
No, the generic driver binds "socionext,uniphier-pxs3-dwc3".
That means, there is nothing which would be a bus, and so the dwc3-uniphier.c can be switched from UCLASS_SIMPLE_BUS to UCLASS_NOP , is that correct ?
There is still the issue of different usb node between Original and u-boot, however, the glue driver can be switched to UCLASS_NOP.
Understood, thank you for the clarification.