[PATCH v7 1/2] phy: rockchip-inno-usb2: Add usb2phy clock provider of 480MHz clock

[Jagan Teki]

On Mon, Jun 5, 2023 at 8:35 PM Xavier Drudis Ferran <xdrudis at tinet.cat> wrote:
>
> arch/arm/dts/rk3399.dtsi has a node
>
>   usb_host0_ehci: usb at fe380000 {
>        compatible = "generic-ehci";
>
> with clocks:
>
>        clocks = <&cru HCLK_HOST0>, <&cru HCLK_HOST0_ARB>,
>                 <&u2phy0>;
>
> The first 2 refer to nodes with class UCLASS_CLK, but &u2phy0
> has class UCLASS_PHY.
>
>   u2phy0: usb2phy at e450 {
>        compatible = "rockchip,rk3399-usb2phy";
>
> Since clk_get_bulk() only looks for devices with UCLASS_CLK,
> it fails with -ENODEV and then ehci_usb_probe() aborts.
>
> The consequence is peripherals connected to a USB 2 port (e.g. in a
> Rock Pi 4 the white port, nearer the edge) not being detected.
> They're detected if CONFIG_USB_OHCI_GENERIC is selected in Kconfig,
> because ohci_usb_probe() does not abort when one clk_get_by_index()
> fails, but then they work in USB 1 mode.
>
> rk3399.dtsi comes from linux and the  u2phy0 was added[1] to the clock
> list in:
>
>     commit b5d1c57299734f5b54035ef2e61706b83041f20c
>     Author: William wu <wulf at rock-chips.com>
>     Date:   Wed Dec 21 18:41:05 2016 +0800
>
>     arm64: dts: rockchip: add u2phy clock for ehci and ohci of rk3399
>
>     We found that the suspend process was blocked when it run into
>     ehci/ohci module due to clk-480m of usb2-phy was disabled.
>     [...]
>
> Suspend concerns don't apply to U-Boot, and the problem with U-Boot
> failing to probe EHCI doesn't apply to linux, because in linux
> rockchip_usb2phy_clk480m_register makes u2phy0 a proper clock provider
> when called by rockchip_usb2phy_probe().
>
> So I can think of a few alternative solutions:
>
> 1- Change ehci_usb_probe() to make it more similar to
>    ohci_usb_probe(), and survive failure to get one clock. Looks a
>    little harder, and I don't know whether it could break something if
>    it ignored a clock that was important for something else than
>    suspend.
>
> 2- Change rk3399.dtsi effectively reverting the linux commit
>    b5d1c57299734f5b54035ef2e61706b83041f20c. This dealigns the .dtsi
>    from linux and seems fragile at the next synchronisation.
>
> 3- Change the clock list in rk3399-u-boot.dtsi or somewhere else.
>    This survives .dts* sync but may survive "too much" and miss some
>    change from linux that we might want.
>
> 4- Enable CONFIG_USB_OHCI_GENERIC and use the ports in USB 1 mode.
>    This would need to be made for all boards using rk3399.  In a
>    simple test reading one file from USB storage it gave 769.5 KiB/s
>    instead of 20.5 MiB/s with solution 2.
>
> 5- Trying to replicate linux and have usb2phy somehow provide a clk,
>    or have a separate clock device for usb2phy in addition to the phy
>    device.
>
> This patch tries to implement option 5 as Marek Vasut requested in
> December 5th.  Options 1 and 3 didn't get through [2][3].
>
> It just registers usb2phy as a clock driver (device_bind_driver()
> didn't work but device_bind_driver_to_node() did), without any
> specific operations, so that ehci-generic.c finds it and is happy. It
> worked in my tests on a Rock Pi 4 B+ (rk3399).
>
> Link: [1] https://lkml.kernel.org/lkml/1731551.Q6cHK6n5ZM@phil/T/
>       [2] https://patchwork.ozlabs.org/project/uboot/patch/20220701185959.GC1700@begut/
>       [3] https://patchwork.ozlabs.org/project/uboot/patch/Y44+ayJfUlI08ptM@localhost/
>
> Cc: Simon Glass <sjg at chromium.org>
> Cc: Philipp Tomsich <philipp.tomsich at vrull.eu>
> Cc: Kever Yang <kever.yang at rock-chips.com>
> Cc: Lukasz Majewski <lukma at denx.de>
> Cc: Sean Anderson <seanga2 at gmail.com>
> Cc: Marek Vasut <marex at denx.de>
> Cc: Christoph Fritz <chf.fritz at googlemail.com>
> Cc: Jagan Teki <jagan at amarulasolutions.com>
>
> Signed-off-by: Xavier Drudis Ferran <xdrudis at tinet.cat>
> ---

Thanks for fixing USB from the last couple of releases.

Reviewed-by: Jagan Teki <jagan at amarulasolutions.com>
Tested-by: Jagan Teki <jagan at amarulasolutions.com> # rk3399, rk3328, rv1126