[PATCHv4 00/15] clk: ti: add support for hwmod clocks

[Tero Kristo]

On 28/10/16 03:53, Stephen Boyd wrote:
> On 10/18, Tero Kristo wrote:
>> Hi,
>>
>> As a recap, this series is part of the ongoing work to get rid of the
>> hwmod database under mach-omap2 folder. This series converts the
>> existing clock related functionality to a new clock type, which will
>> allow removing all the .clkctrl related items from hwmod database.
>> This series adds sample solution for OMAP4 only, rest of the SoCs can
>> be converted automatically once the approach is acceptable.
>>
>> v4 has the following high level changes compared to v3:
>> - Clock data is now statically built-in to the driver
>> - Adds clockdomain provider support, which can be used to fetch
>>   clocks based on clockdomain relation. Only clockdomains need to be
>>   registered within DT.
>> - Added some automatic clock alias generation support to the TI clock
>>   drivers, if this is not acceptable, I can change this to add all the
>>   aliases under the individual drivers/clk/ti/clk-xyz.c files
>
> Is there a plan to get rid of the aliases entirely? Or we can't
> do that because DT is not fully supported on these platforms? I'm
> mostly wondering how long that sort of code is going to stick
> around and if it's better to fully compartmentalize it to the
> SoCs that are affected or if it should be a core feature of TI
> driver.

Eventually that should happen. However, we have plenty of legacy code 
still in place which depend on clk_get functionality within kernel. The 
major contributing factor is the hwmod codebase, for which we have plans to:

- get this clock driver merged
- implement a new interconnect driver for OMAP family SoCs
- interconnect driver will use DT handles for fetching clocks, rather 
than clock aliases
- reset handling will be implemented as part of the interconnect driver 
somehow (no prototype / clear plans for that as of yet)
- all the hwmod stuff can be dropped

The clock alias handling is still needed as a transition phase until all 
the above is done, then we can start dropping them. Basically anything 
that is using omap_hwmod depends on the clock aliases right now.

>
>> - As a sample, only omap4 clock data is available with this set
>>
>> After this series, the clock data can be dropped from the hwmod database
>> for OMAP4, I have working patches for this for anybody interested. Also,
>> the DT files require some modifications to add proper support for
>> clockdomain providers, and drop some unnecessary clock nodes.
>
> Can this be shared as a git tree on the web? Hopefully I can see
> the resulting DTS and understand what's going on better.

Sure, here is a test branch I've been using, it has some extra hacks on 
top for debugging purposes, but the DTS changes are visible also.

https://github.com/t-kristo/linux-pm/tree/4.9-rc1-hwmod-clks-w-data


>
>>
>> Boot + simple PM test seems to be working on OMAP4 with this set, and
>> boot test with other boards I have access to don't seem to cause any
>> issues. Applies on top of 4.9-rc1.
>>
>
> Awesome!
>