Re: [PATCH v6 00/41] ARM: davinci: convert to common clock framework​

[David Lechner]

On 01/23/2018 08:54 AM, Bartosz Golaszewski wrote:
> 2018-01-22 18:30 GMT+01:00 David Lechner <david at lechnology.com>:
>> On 01/22/2018 05:14 AM, Bartosz Golaszewski wrote:
>>>
>>> 2018-01-20 18:13 GMT+01:00 David Lechner <david at lechnology.com>:
>>>>
>>>> This series converts mach-davinci to use the common clock framework.
>>>>
>>>> The series works like this, the first 19 patches create new clock drivers
>>>> using the common clock framework. There are basically 3 groups of clocks
>>>> -
>>>> PLL, PSC and CFGCHIP (syscon). There are six different SoCs that each
>>>> have
>>>> unique init data, which is the reason for so many patches.
>>>>
>>>> Then, starting with "ARM: da830: add new clock init using common clock",
>>>> we get the mach code ready for the switch by adding the code needed for
>>>> the new clock drivers and adding #ifndef CONFIG_COMMON_CLK around the
>>>> legacy clocks so that we can switch easily between the old and the new.
>>>>
>>>> "ARM: davinci: switch to common clock framework" actually flips the
>>>> switch
>>>> to start using the new clock drivers. Then the next 8 patches remove all
>>>> of the old clock code.
>>>>
>>>> The final three patches add device tree clock support to the one SoC that
>>>> supports it.
>>>>
>>>> v6 changes (also see individual patches for details):
>>>> - All of the device tree bindings are changed
>>>> - All of the clock drivers are changed significantly
>>>> - Fixed issues brought up during review of v5
>>>> - "ARM: davinci: move davinci_clk_init() to init_time" is removed from
>>>> this
>>>>     series and submitted separately
>>>>
>>>> v5 changes:
>>>> - Basically, this is an entirely new series
>>>> - Patches are broken up into bite-sized pieces
>>>> - Converted PSC clock driver to use regmap
>>>> - Restored "force" flag for certain DA850 clocks
>>>> - Added device tree bindings
>>>> - Moved more of the clock init to drivers/clk
>>>> - Fixed frequency scaling (maybe*)
>>>>
>>>> * I have frequency scaling using cpufreq-dt, so I know the clocks are
>>>> doing
>>>>     what they need to do to make this work, but I haven't figured out how
>>>> to
>>>>     test davinci-cpufreq driver yet. (Patches to make cpufreq-dt work will
>>>> be
>>>>     sent separately after this series has landed.)
>>>>
>>>> Dependencies:
>>>>
>>>> This series applies on top of linux-davinci/master plus the following
>>>> patches:
>>>> - [1] "clk: fix reentrancy of clk_enable() on UP systems" (in clk-next)
>>>> - [2] "clk: add helper functions for managing clk_onecell_data"
>>>> - [3] "clk: divider: read-only divider can propagate rate change"
>>>> - [4],[5],[6],[7],[8],[9] series "ARM: davinci: common clock prep work"
>>>>
>>>
>>> Hi David,
>>>
>>> I'm getting a splat[1] when trying to mount the rootfs over nfs on a
>>> da850-lcdk.
>>>
>>> I'll try to figure out what's happening.
>>>
>>> Best regards,
>>> Bartosz Golaszewski
>>>
>>> [1] https://pastebin.com/D94z8SAe
>>>
>>
>> Could it have something to do with the "rmii" clock? I don't think I added
>> that
>> in the device tree.
>>
> 
> I'm looking at it now. There are problems with emac & mdio both in
> legacy and in DT mode.

Adam, is networking working for you on the DA850 EVM?

> 
> The davinci_mdio driver seems to not get an actual functional clock
> (phy is reported as down). I'm seeing that in old legacy code,
> mdio_clk has emac_clk as parent, while after your changes they share
> pll0_sysclk4 as parent, although I'm not sure if that has anything to
> do with it.

The two clocks prior to these changes was a hack to work around a
limitation of the old lock code (because of the way it used a linked list
each clock could only be used once) so, yes, that should not have anything
to do with it.

I see that there is no clk_prepare_enable() in the mdio driver or the emac
driver. I suppose it expects pm_runtime to take care of this maybe?

You can see if the clock is enabled by running:

     cat /sys/kernel/debug/clk/clk_summary

> 
> I'll see about the rmii clock too.
FWIW, the rmii clock is in the clock init for non-DT da850.