Re: [PATCH v1 0/4] Restore ULPI USB on Tegra20

[Thierry Reding <thierry.reding@gmail.com>]

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On Fri, Apr 27, 2018 at 02:58:14AM +0300, Dmitry Osipenko wrote:
> Hello,
> 
> This series of patches fixes ULPI USB on Tegra20. The original problem
> was reported by Marcel Ziswiler, he found that "ulpi-link" clock was
> incorrectly set to CDEV2 instead of PLL_P_OUT4. Marcel made a patch
> that changed the "ulpi-link" clock to PLL_P_OUT4 and that fixed issue
> with the USB for the devices that have CDEV2 being enabled by bootloader.
> The patch got into the kernel and later Marc Dietrich found that USB
> stopped working on the "paz00" Tegra20 board. After a bit of discussion
> was revealed that PLL_P_OUT4 is the parent clock of the CDEV2 and clock
> driver was setting CDEV2's parent incorrectly. The parent clock is actually
> determined by the pinmuxing config of CDEV2 pingroup. This patchset fixes
> the parent of CDEV2 clock by making Tegra's pinctrl driver a clock provider,
> providing CDEV1/2 clock muxes (thanks to Peter De Schrijver for the
> suggestion), and then setting these clock muxes as parents for the CDEV1/2
> clocks. In the end Marcel's CDEV2->PLL_P_OUT4 change is reverted since CDEV2
> (aka MCLK2) is the actual clock source for "ulpi-link".
> 
> Dmitry Osipenko (4):
>   clk: tegra20: Add DEV1/DEV2 OSC dividers
>   pinctrl: tegra20: Provide CDEV1/2 clock muxes
>   clk: tegra20: Set correct parents for CDEV1/2 clocks
>   ARM: dts: tegra20: Revert "Fix ULPI regression on Tegra20"
> 
>  arch/arm/boot/dts/tegra20.dtsi          |  2 +-
>  drivers/clk/tegra/clk-tegra20.c         | 18 +++++++++++----
>  drivers/pinctrl/tegra/pinctrl-tegra.c   | 11 ---------
>  drivers/pinctrl/tegra/pinctrl-tegra.h   | 11 +++++++++
>  drivers/pinctrl/tegra/pinctrl-tegra20.c | 30 ++++++++++++++++++++++++-
>  5 files changed, 55 insertions(+), 17 deletions(-)

Stephen, Michael, Linus,

as far as I can tell there aren't any build dependencies between the
above, so technically these could all be merged through the individual
trees. There's a runtime dependency from patch 2 on patch 1 and from
patch 3 on patch 2, though I don't think they will cause any actual
failures at runtime.

But I can also pick this up into the Tegra tree and send out pull
requests to you for v4.18 (at around v4.17-rc6), if that's what you
prefer.

Thierry

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