Re: [PATCH v2 5/7] clk: samsung: exynos7: 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-exynos7.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/clk/samsung/clk-exynos7.c b/drivers/clk/samsung/clk-exynos7.c
> index 5931a4140c3d..bbfa57b4e017 100644
> --- a/drivers/clk/samsung/clk-exynos7.c
> +++ b/drivers/clk/samsung/clk-exynos7.c
> @@ -140,7 +140,7 @@ static const struct samsung_div_clock topc_div_clks[] __initconst = {
>  };
>  
>  static const struct samsung_pll_rate_table pll1460x_24mhz_tbl[] __initconst = {
> -	PLL_36XX_RATE(491520000, 20, 1, 0, 31457),
> +	PLL_36XX_RATE(491519897, 20, 1, 0, 31457),
>  	{},
>  };
>  
> 

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


-- 
Best Regards,
Chanwoo Choi
Samsung Electronics