Re: [PATCH v13 2/2] clk: clk-loongson2: add clock controller driver support

[zhuyinbo <zhuyinbo@loongson.cn>]

在 2023/3/14 上午2:20, Stephen Boyd 写道:
> Quoting Krzysztof Kozlowski (2023-03-10 00:42:47)
>> On 10/03/2023 00:47, Stephen Boyd wrote:
>>> Quoting zhuyinbo (2023-03-08 18:58:02)
>>>> 在 2023/3/8 下午8:16, kernel test robot 写道:
>>>>> Hi Yinbo,
>>>>>
>>> [...]
>>>>>      drivers/clk/clk-loongson2.c: In function 'loongson2_calc_pll_rate':
>>>>>>> drivers/clk/clk-loongson2.c:79:15: error: implicit declaration of function 'readq'; did you mean 'readl'? [-Werror=implicit-function-declaration]
>>>>>         79 |         val = readq(loongson2_pll_base + offset);
>>>>>            |               ^~~~~
>>>>>            |               readl
>>>>>      cc1: some warnings being treated as errors
>>>> The CONFIG_64BIT not enabled in your config file, I will add a depend on
>>>> "CONFIG_64BIT" in my clock driver to fix this compile error.
>>> Do you need to use readq() here? Can you read two 32-bit registers with
>>> readl() and put them together for a 64-bit number?
>> If the platform supports 64-bit reads and these are actually one
>> register, then readq makes sense - code is more readable, smaller, more
>> efficient.
>>
> Please read the section in Documentation/driver-api/device-io.rst about
> hi_lo_readq() and <linux/io-64-nonatomic-lo-hi.h>. We shouldn't need to
> restrict the driver to CONFIG_64BIT. Instead, include one of these
> header files to get the IO access primitives.

okay, I got it.

Thanks your advice!