linux-kernel - Re: [PATCH v2 0/4] Restore ULPI USB on Tegra20

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Date:   Fri, 04 May 2018 15:33:49 +0200
From:   Marcel Ziswiler <marcel@...wiler.com>
To:     Dmitry Osipenko <digetx@...il.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Prashant Gaikwad <pgaikwad@...dia.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Marc Dietrich <marvin24@....de>
Cc:     linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 0/4] Restore ULPI USB on Tegra20

Hi Dmitry

On Fri, 2018-05-04 at 01:55 +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".
> 
> Changelog:
> 
> v2:
> 	- Added new patch "Add quirk for getting CDEV1/2 clocks",
> assuring
> 	  that clk user won't get CDEV1/2 clocks until parent clk muxes
> 	  are available, i.e. resolves potential issue with CDEV-user
> driver
> 	  vs pinctrl driver probe order.
> 
> 	- Factored out "pinctrl" patch from the patchset as was
> requested by
> 	  Linus Walleij.
> 
> 	- Addressed v1 review comments: fixed swapped DEV1/2 clk div
> bits,
> 	  made DEV1/2 divs read-only, etc minor changes.
> 
> Dmitry Osipenko (4):
>   clk: tegra20: Add DEV1/DEV2 OSC dividers
>   clk: tegra20: Correct parents of CDEV1/2 clocks
>   clk: tegra: Add quirk for getting 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 | 20 +++++++++++++++----
>  drivers/clk/tegra/clk.c         | 34
> ++++++++++++++++++++++++++++++++-
>  3 files changed, 50 insertions(+), 6 deletions(-)

Beautiful (;-p).

root@...ibri-t20:~# cat /sys/kernel/debug/clk/clk_summary | grep -E
'pll_p_out4|cdev2'
          pll_p_out4_div              1        1        0    24000000  
        0 0  
             pll_p_out4               2        2        0    24000000  
        0 0  
                cdev2_mux             1        1        0    24000000  
        0 0  
                   cdev2              1        1        0    24000000  
        0 0  

You may add my reviewed and tested bys to the remaining patches as
well.

Thanks!

Cheers

Marcel