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

[Damien Le Moal]

On 2021/04/09 11:54, 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.

Actually, thinking about this some more, the clint DT node should have an
optional clock entry and use that clock rate to set riscv_timebase if the clock
entry is present. riscv_timebase can be set using timebase-frequency DT property
if the clock is not set.

> 


-- 
Damien Le Moal
Western Digital Research