[PATCH v3 05/11] clk: k210: Move the clint clock to under aclk

[Damien Le Moal]

On 2021/04/09 11:58, Sean Anderson wrote:
> 
> On 4/8/21 10:54 PM, Damien Le Moal wrote:
>> On 2021/04/09 11:13, Sean Anderson wrote:
>>> No other (real) clocks have the cpu clock as their parent; instead they are
>>> children of aclk. Move the clint clock under aclk to match them.
>>>
>>> Signed-off-by: Sean Anderson <seanga2 at gmail.com>
>>> ---
>>>
>>> (no changes since v2)
>>>
>>> Changes in v2:
>>> - New
>>>
>>>   drivers/clk/kendryte/clk.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/clk/kendryte/clk.c b/drivers/clk/kendryte/clk.c
>>> index ab86533bb4..5091f07eb0 100644
>>> --- a/drivers/clk/kendryte/clk.c
>>> +++ b/drivers/clk/kendryte/clk.c
>>> @@ -643,7 +643,7 @@ static int k210_clk_probe(struct udevice *dev)
>>>   
>>>   	/* The MTIME register in CLINT runs at one 50th the CPU clock speed */
>>>   	clk_dm(K210_CLK_CLINT,
>>> -	       clk_register_fixed_factor(NULL, "clint", "cpu", 0, 1, 50));
>>> +	       clk_register_fixed_factor(NULL, "clint", "aclk", 0, 1, 50));
>>>   
>>>   	return 0;
>>>   }
>>>
>>
>> Looks good, but representing this clock is in fact useless, at least in Linux,
>> since the clint driver does not use it directly and derives its rate from
>> riscv_timebase which is set from the timebase-frequency DT property.
>>
>> Not sure how u-boot handles that though. Since your code allows changing the
>> PLLs frequency, the timebase-frequency property may end up being buggy if it is
>> not changed too.
>>
> 
> U-Boot uses the clocks property since 47d7e3b5eb ("riscv: Move timer
> portions of SiFive CLINT to drivers/timer") :)

I remember that adding the clock property to Linux DT gave warning with make
dtb_check. Hence I removed it. driver/clocksoure/timer-riscv.c also make the
timebase-frequency DT property mandatory. Time for some more patching on Linux
side I guess :)


> 
> --Sean
> 


-- 
Damien Le Moal
Western Digital Research