Re: [PATCH v2 6/7] clk: samsung: s3c2410: fix PLL rates

[Chanwoo Choi <cw00.choi@samsung.com>]

On 2018년 02월 16일 23:57, Andrzej Hajda wrote:
> Rates declared in PLL rate tables should match exactly rates calculated
> from PLL coefficients. If that is not the case, rate of parent might be being
> set not as expected. For instance, if in the PLL rates table we have
> a 393216000 Hz entry and the real value as returned by the PLL's recalc_rate
> callback is 393216003, after setting PLL's clk rate to 393216000 clk_get_rate
> will return 393216003. If we now attempt to set rate of a PLL's child divider
> clock to 393216000/2 its rate will be 131072001, rather than 196608000.
> That is the divider will be set to 3 instead of 2, because 393216003/2 is
> greater than 196608000.
> 
> To fix this issue declared rates are changed to exactly match rates generated
> by a PLL, as calculated from the P, M, S, K coefficients.
> 
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
> ---
>  drivers/clk/samsung/clk-s3c2410.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/clk/samsung/clk-s3c2410.c b/drivers/clk/samsung/clk-s3c2410.c
> index e0650c33863b..d8e58a659467 100644
> --- a/drivers/clk/samsung/clk-s3c2410.c
> +++ b/drivers/clk/samsung/clk-s3c2410.c
> @@ -168,7 +168,7 @@ static struct samsung_pll_rate_table pll_s3c2410_12mhz_tbl[] __initdata = {
>  	PLL_35XX_RATE(226000000, 105, 1, 1),
>  	PLL_35XX_RATE(210000000, 132, 2, 1),
>  	/* 2410 common */
> -	PLL_35XX_RATE(203000000, 161, 3, 1),
> +	PLL_35XX_RATE(202800000, 161, 3, 1),
>  	PLL_35XX_RATE(192000000, 88, 1, 1),
>  	PLL_35XX_RATE(186000000, 85, 1, 1),
>  	PLL_35XX_RATE(180000000, 82, 1, 1),
> @@ -178,18 +178,18 @@ static struct samsung_pll_rate_table pll_s3c2410_12mhz_tbl[] __initdata = {
>  	PLL_35XX_RATE(147000000, 90, 2, 1),
>  	PLL_35XX_RATE(135000000, 82, 2, 1),
>  	PLL_35XX_RATE(124000000, 116, 1, 2),
> -	PLL_35XX_RATE(118000000, 150, 2, 2),
> +	PLL_35XX_RATE(118500000, 150, 2, 2),
>  	PLL_35XX_RATE(113000000, 105, 1, 2),
> -	PLL_35XX_RATE(101000000, 127, 2, 2),
> +	PLL_35XX_RATE(101250000, 127, 2, 2),
>  	PLL_35XX_RATE(90000000, 112, 2, 2),
> -	PLL_35XX_RATE(85000000, 105, 2, 2),
> +	PLL_35XX_RATE(84750000, 105, 2, 2),
>  	PLL_35XX_RATE(79000000, 71, 1, 2),
> -	PLL_35XX_RATE(68000000, 82, 2, 2),
> -	PLL_35XX_RATE(56000000, 142, 2, 3),
> +	PLL_35XX_RATE(67500000, 82, 2, 2),
> +	PLL_35XX_RATE(56250000, 142, 2, 3),
>  	PLL_35XX_RATE(48000000, 120, 2, 3),
> -	PLL_35XX_RATE(51000000, 161, 3, 3),
> +	PLL_35XX_RATE(50700000, 161, 3, 3),
>  	PLL_35XX_RATE(45000000, 82, 1, 3),
> -	PLL_35XX_RATE(34000000, 82, 2, 3),
> +	PLL_35XX_RATE(33750000, 82, 2, 3),
>  	{ /* sentinel */ },
>  };
>  
> 

Looks good to me.
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics