Re: [RESEND PATCH 0/8] clk: core: support clocks which requires parents on

[Dong Aisheng]

On Thu, Jun 2, 2016 at 11:20 PM, Dong Aisheng <dongas86@xxxxxxxxx> wrote:
> On Wed, Apr 20, 2016 at 05:34:32PM +0800, Dong Aisheng wrote:
>> This is a RESEND patch series.
>> The original one can be found at here:
>> http://www.spinics.net/lists/arm-kernel/msg435136.html
>> It has no functional changes but improve the commit message and
>> comments a bit.
>>
>> This patch series adds support in clock framework for clocks which all the
>> operations like gate/ungate, set_rate, set_parent must require its parent
>> clock on.
>>
>> This special HW requirement can be found on Freescale i.MX7D platform.
>> Besides i.MX7D, it seems lpc18xx clock has a similar requirement.
>> (see: http://www.spinics.net/lists/arm-kernel/msg439307.html)
>> And there may be other SoCs in the same situation.
>>
>> Current clock core can not support such type of clock well.
>>
>> This patch introduce a new flag CLK_SET_PARENT_ON to handle this special
>> case in clock core that enable its parent clock firstly for each operation
>> and disable it later after operation complete.
>>
>> There're two special cases for handling this issue:
>>
>> One is fixing the possible disabling clocks while its parent is already off
>> during kernel booting phase in clk_disable_unused_subtree()
>> Since this state misalign only happens during booting time,
>> so we simply enable the parent clocks before disable it if flag is set.
>> For normal clk_disable after kernel booting, there's no such issue
>> since the clock tree is already created which makes sure no such issue exist.
>>
>> Another special case is for set_parent() operation.
>> It requires both parent, old one and new one, to be enabled at the same
>> time during the operation.
>>
>> Patch 1~4 does this work.
>>
>> After clk core supports mx7d type clocks, we don't have to enable all clock
>> by default anymore, then we remove the enable of all clocks code and instead
>> only enable set of minimum required clocks.
>>
>> Patch 5~8 does this work.
>>
>> The whole patch series is based on for-next branch of clock tree:
>> git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git
>>
>
> Hi Stephen,
>
> Could you give some comments about this patch series?
>

Ping...

> Regards
> Dong Aisheng
>
>> Dong Aisheng (8):
>>   clk: introduce clk_core_enable_lock and clk_core_disable_lock
>>     functions
>>   clk: move clk_disable_unused after clk_core_disable_unprepare function
>>   clk: core: support clocks which requires parents on (part 1)
>>   clk: core: support clocks which requires parents on (part 2)
>>   clk: imx: re-order and concentrate the same type of clk api
>>   clk: imx: add clk api for supporting clk_OPS_PARENT_ON clocks
>>   clk: imx7d: using api with flag CLK_OPS_PARENT_ON
>>   clk: imx7d: only enable minimum required clocks
>>
>>  drivers/clk/clk.c            | 329 +++++++++++--------
>>  drivers/clk/imx/clk-imx7d.c  | 732 ++++++++++++++++++++++---------------------
>>  drivers/clk/imx/clk.h        |  90 ++++--
>>  include/linux/clk-provider.h |   2 +
>>  4 files changed, 623 insertions(+), 530 deletions(-)
>>
>> --
>> 1.9.1
>>
>>
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