Re: [PATCH v5 1/6] clk: hisilicon: add CRG driver for hi3519 soc

From: Tomeu Vizoso
Date: Wed Jan 20 2016 - 01:38:47 EST

On 19 January 2016 at 19:20, Rob Herring <robh+dt@xxxxxxxxxx> wrote:
> On Fri, Jan 15, 2016 at 1:57 AM, xuejiancheng <xuejiancheng@xxxxxxxxxx> wrote:
>> On 2016/1/14 21:16, xuejiancheng wrote:
>>> Hi Mike,
>>> On 2016/1/14 2:57, Michael Turquette wrote:
>>>> Quoting xuejiancheng (2016-01-12 19:03:01)
>>>>> Hi Stephen,
>>>>> Thank you very much for your reply.
>>>>> On 2016/1/13 6:12, Stephen Boyd wrote:
>>>>>> On 01/08, Jiancheng Xue wrote:
>>>>>>> diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig
>>>>>>> index e434854..b6baebf 100644
>>>>>>> --- a/drivers/clk/hisilicon/Kconfig
>>>>>>> +++ b/drivers/clk/hisilicon/Kconfig
>>>>>>> @@ -1,3 +1,10 @@
>>>>>>> +config COMMON_CLK_HI3519
>>>>>>> + tristate "Clock Driver for Hi3519"
>>>>>> It looks like this has to be bool. Otherwise it needs to be a
>>>>>> platform driver and the hisilicon APIs need to be exported and
>>>>>> lose their __init markings.
>>>>> Yes,it's a problem. I will fix it in next version. Thank you.
>>>> The best solution would be to make this clock driver a real platform
>>>> driver.
>>> Now the work clock of the clocksource timer-sp804 is provided by this driver. So
>>> it need to be registered early by CLK_OF_DECLARE. If the timer clock is treated
>>> as a fixed-clock provider, this driver can be implemented as a platform driver.
>>> Then the crg device must be registered before other clock consumer devices.Accordingly
>>> the crg device node must be written above all other clock consumer devices node in dts files.
>>> I think it is also a dependence.
>>> Can you help me understand why it is better to make this driver a platform driver?
>>> Thank you very much!
>> arch_initcall(customize_machine)
>> -->of_platform_populate
>> -->of_platform_bus_create
>> -->of_amba_device_create
>> -->amba_device_add
>> -->amba_get_enable_pclk
>> The call sequence above shows that the clock of the amba device must be registered before
>> amba_device_add. The clock of "arm,pl011" uart is registered in the probe function of the
>> platform driver "hi3519-crg". So the platform device "hi3519-crg" must be created before
>> the amba device "arm,pl011" uart.
> It is a problem, but Tomeu had a fix to support deferred probes here.
> That was part of the on-demand probing series, but maybe it needs to
> be applied separately if we are moving clock drivers to platform
> drivers.


Marek Szyprowski has kindly taken those two patches as part of a series of him:

I think it would be great if you could test them and report.