From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: MIME-version: 1.0 Content-type: text/plain; charset="UTF-8" Message-id: <5A8BC9ED.7010303@samsung.com> Date: Tue, 20 Feb 2018 16:10:37 +0900 From: Chanwoo Choi To: Andrzej Hajda , Sylwester Nawrocki Cc: Bartlomiej Zolnierkiewicz , Marek Szyprowski , Tomasz Figa , Michael Turquette , Stephen Boyd , Kukjin Kim , Krzysztof Kozlowski , "moderated list:SAMSUNG SOC CLOCK DRIVERS" , "open list:COMMON CLK FRAMEWORK" Subject: Re: [PATCH v2 6/7] clk: samsung: s3c2410: fix PLL rates In-reply-to: <20180216145754.14428-7-a.hajda@samsung.com> References: <20180216145754.14428-1-a.hajda@samsung.com> <20180216145754.14428-7-a.hajda@samsung.com> List-ID: 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 > Acked-by: Tomasz Figa > --- > 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 -- Best Regards, Chanwoo Choi Samsung Electronics