Re: [PATCH v3 08/10] clk: sunxi-ng: support R40 SoC

[Chen-Yu Tsai <wens@csie.org>]

On Sat, Aug 12, 2017 at 12:51 PM,  <icenowy@aosc.io> wrote:
> 在 2017-08-12 12:04，Chen-Yu Tsai 写道：
>>
>> On Sat, Jul 22, 2017 at 11:00 AM,  <icenowy@aosc.io> wrote:
>>>
>>> 在 2017-05-29 15:34，Chen-Yu Tsai 写道：
>>>>
>>>>
>>>> Hi,
>>>>
>>>> On Sat, May 27, 2017 at 06:23:06PM +0800, Icenowy Zheng wrote:
>>
>>
>> [...]
>>
>>>>> +
>>>>> +/*
>>>>> + * For the special bit in gate part, please see the BSP source code at
>>>>> + *
>>>>>
>>>>> https://github.com/BPI-SINOVOIP/BPI-M2U-bsp/blob/master/linux-sunxi/drivers/clk/sunxi/clk-sun8iw11.c#L665
>>>>> + */
>>>>> +static SUNXI_CCU_NKM_WITH_GATE_LOCK(pll_sata_clk, "pll-sata",
>>>>> +                                   "osc24M", 0x034,
>>>>> +                                   8, 5,       /* N */
>>>>> +                                   4, 2,       /* K */
>>>>> +                                   0, 2,       /* M */
>>>>> +                                   BIT(31) | BIT(14),  /* gate */
>>>>> +                                   BIT(28),    /* lock */
>>>>> +                                   0);
>>>>
>>>>
>>>>
>>>> I think this is a somewhat simplified approach. From what I understand
>>>> of the user manual, the SATA clock path look like:
>>>>
>>>>
>>>> [ PLL-PERIPH0-SATA ] -\
>>>>                       mux @ 0x34 bit 30 --- gate @ 0x34 bit 14 --- ...
>>>> [ PLL-SATA ] ---------/
>>>>
>>>> ... from above ... ------\
>>>>                          mux @ 0xc8 bit 24 --- gate @ 0xc8 bit 31
>>>> [ external oscillator ] -/
>>>>
>>>> If you choose to simplify the implementation, please include a detailed
>>>> note as to why you chose to do so, and the validity of the
>>>> simplification.
>>>
>>>
>>>
>>> I think it can be fully implemented...
>>>
>>> But how should I call the internal clock controlled by the mux @ 0x34 bit
>>> 30?
>>
>>
>> sata-pll-mux?
>
>
> I choose to call it pll-sata-out, as the mux @ 0x34 bit 30 is called
> "PLL_OUTPUT_SEL".

Cool. Note that the clock names don't really matter for end users.
The only place this is visible is debugfs, or if some driver prints
it out for debug messages. So the only real requirement is that the
name makes some sense to any developers using it, in a way that they
can spot if they are using it wrong, like accidentally using a clock
for another module, and being able to roughly match it up to the
datasheet.

ChenYu