Hi Marcel,
Am Montag, 19. Februar 2018, 16:12:52 CEST schrieb Marcel Ziswiler:
> From: Marcel Ziswiler <marcel.ziswiler@xxxxxxxxxxx>
>
> Since commit f8f8f1d04494 ("clk: Don't touch hardware when reparenting
> during registration") ULPI has been broken on Tegra20 leading to the
> following error message during boot:
>
> [ 1.974698] ulpi_phy_power_on: ulpi write failed
> [ 1.979384] tegra-ehci c5004000.usb: Failed to power on the phy
> [ 1.985434] tegra-ehci: probe of c5004000.usb failed with error -110
>
> Debugging through the changes and finally also consulting the TRM
> revealed that rather than the CDEV2 clock off OSC requiring such pin
> muxing actually the PLL_P_OUT4 clock is in use. It looks like so far it
> just worked by chance of that one having been enabled which Stephen's
> commit now changed when reparenting sclk away from pll_p_out4 leaving
> that one disabled. Fix this by properly assigning the PLL_P_OUT4 clock
> as the ULPI PHY clock.
I booted 4.17-rc1 (which includes this fix) on an AC100 (T20 paz00 board) and
the error above is still there. Surprisingly the error vanishes when I revert
your patch. So this patch actually *causes* the problem above on my board.
Could it be, that we need all four clocks? Dimitry mentioned on IRC that it
could also be a problem in the clock init table. I don't have the technical
background myself to fix it, but I still wonder what could be so different
between TrimSlice and AC100.
Marc
> Signed-off-by: Marcel Ziswiler <marcel.ziswiler@xxxxxxxxxxx>
>
> ---
>
> arch/arm/boot/dts/tegra20.dtsi | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
> index 864a95872b8d..e05b6bb2599f 100644
> --- a/arch/arm/boot/dts/tegra20.dtsi
> +++ b/arch/arm/boot/dts/tegra20.dtsi
> @@ -741,7 +741,7 @@
> phy_type = "ulpi";
> clocks = <&tegra_car TEGRA20_CLK_USB2>,
> <&tegra_car TEGRA20_CLK_PLL_U>,
> - <&tegra_car TEGRA20_CLK_CDEV2>;
> + <&tegra_car TEGRA20_CLK_PLL_P_OUT4>;
> clock-names = "reg", "pll_u", "ulpi-link";
> resets = <&tegra_car 58>, <&tegra_car 22>;
> reset-names = "usb", "utmi-pads";
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