Subject: Re: [PATCH v10 2/4] clk: clk-loongson2: add clock controller driver
 support
From:   zhuyinbo <zhuyinbo@loongson.cn>
To:     Stephen Boyd <sboyd@kernel.org>,
        Huacai Chen <chenhuacai@kernel.org>,
        Jianmin Lv <lvjianmin@loongson.cn>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Michael Turquette <mturquette@baylibre.com>,
        Rob Herring <robh+dt@kernel.org>,
        WANG Xuerui <kernel@xen0n.name>,
        Yang Li <yang.lee@linux.alibaba.com>,
        devicetree@vger.kernel.org, linux-clk@vger.kernel.org,
        linux-kernel@vger.kernel.org, liupeibao@loongson.cn,
        loongarch@lists.linux.dev, wanghongliang@loongson.cn
References: <20221129034157.15036-1-zhuyinbo@loongson.cn>
 <20221129034157.15036-2-zhuyinbo@loongson.cn>
 <31c690a347f858a477bbba9c838984ed.sboyd@kernel.org>
 <4b5fd886-57ce-01ef-8224-432898b7fb1c@loongson.cn>
 <8332a1cf44b01f06bdd5db9dc5d7f387.sboyd@kernel.org>
 <01ee3dc6-a868-fd2b-93aa-11e6bdfcc9df@loongson.cn>
 <9e8952c9415973dc7276185e3cdf5ae7.sboyd@kernel.org>
 <d92223a0-6d4c-33ea-1473-3d40bdd0ad9e@loongson.cn>
Message-ID: <834da7dc-bb5d-3427-43e5-938e40a2d180@loongson.cn>
Date:   Wed, 22 Feb 2023 13:10:14 +0800
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在 2023/2/22 上午10:02, zhuyinbo 写道:
>
> 在 2023/2/22 上午7:07, Stephen Boyd 写道:
>> Quoting zhuyinbo (2023-02-19 21:44:51)
>>> 在 2023/2/18 上午6:15, Stephen Boyd 写道:
>>>> Quoting zhuyinbo (2023-02-14 23:35:22)
>>>>> 在 2023/2/11 上午7:42, Stephen Boyd 写道:
>>>>>>> +
>>>>>>> +err:
>>>>>>> +       iounmap(loongson2_pll_base);
>>>>>>> +}
>>>>>>> +
>>>>>>> +CLK_OF_DECLARE(loongson2_clk, "loongson,ls2k-clk", 
>>>>>>> loongson2_clocks_init);
>>>>>> Any reason this can't be a platform driver?
>>> Your question is that  why I don't use the platform_driver_register to
>>> register  clk and use CLK_OF_DECLARE ?
>> Yes.
>>
>>> I was  consider other clock controllers of Loongson-2 series may be
>>> different with 2k1000 and I can add a line
>>>
>>> CLK_OF_DECLARE() for compatible other platform in the future. eg.
>>>
>>> CLK_OF_DECLARE(loongson2_clk, "loongson,ls2k-clk", 
>>> loongson2_clocks_init);
>>>
>>> +  CLK_OF_DECLARE(xxx1, xxx2,  xxx3);  // for other clock 
>>> controllers of
>>> Loongson-2 series
>>>
>>>>> For the compatible consideration of other clock controllers of
>>>>> Loongson-2 series in the future, the way of using dts can be
>>>>>
>>>>> better compatible.
>>>>>
>>>> Sorry that sentence doesn't make sense to me. The use of dts doesn't
>>>> require the use of CLK_OF_DECLARE.
>>> yes, the use of dts doesn't require the use of CLK_OF_DECLARE and can
>>> use platform_driver_register
>>>
>>> but my drvier not use platform_driver_register to register clk and use
>>> CLK_OF_DECLARE to match of_clk_init.
>> of_clk_init() is there to register clks that are needed for early init,
>> i.e. the clockevent/clocksource or the root interrupt controller
>> (irqchip). Otherwise, it isn't necessary to register clks via
>> of_clk_init().
> okay, I got it.

and,  the time driver  get clock by CCF that ask loongson2 clock driver 
use CLK_OF_DECLARE

to match of_clk_init.   because  the timer_probe  is very early and the 
timer driver was use TIMER_OF_DECLARE

to match time_probe.