[U-Boot] [PATCH] Exynos5: clock: Update the equation to calculate PLL output frequency

Akshay Saraswat akshay.s at samsung.com
Wed Mar 27 09:58:49 CET 2013


>On Fri, Mar 22, 2013 at 5:26 AM, Akshay Saraswat <akshay.s at samsung.com> wrote:
>> According to the latest exynos5 user manual, the equation for
>> calculating PLL output was changed to
>> FOUT= MDIV x FIN/(PDIV x 2^SDIV)
>> earlier it was
>> FOUT= MDIV x FIN/(PDIV x 2^(SDIV -1))
>> So updating the clock code accordingly.
>>
>> Signed-off-by: Hatim Ali <hatim.rv at samsung.com>
>> Signed-off-by: Akshay Saraswat <akshay.s at samsung.com>
>
>Acked-by: Simon Glass <sjg at chromium.org>
>
>I think this is EVT1 silicon, right?
>

Yes, this is for evt1 silicon.

>> ---
>>  arch/arm/cpu/armv7/exynos/clock.c | 6 ++----
>>  1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/cpu/armv7/exynos/clock.c b/arch/arm/cpu/armv7/exynos/clock.c
>> index 956427c..5299bc7 100644
>> --- a/arch/arm/cpu/armv7/exynos/clock.c
>> +++ b/arch/arm/cpu/armv7/exynos/clock.c
>> @@ -73,10 +73,8 @@ static int exynos_get_pll_clk(int pllreg, unsigned int r, unsigned int k)
>>                 /* FOUT = (MDIV + K / 1024) * FIN / (PDIV * 2^SDIV) */
>>                 fout = (m + k / 1024) * (freq / (p * (1 << s)));
>>         } else {
>> -               if (s < 1)
>> -                       s = 1;
>> -               /* FOUT = MDIV * FIN / (PDIV * 2^(SDIV - 1)) */
>> -               fout = m * (freq / (p * (1 << (s - 1))));
>> +               /* FOUT = MDIV * FIN / (PDIV * 2^SDIV) */
>> +               fout = m * (freq / (p * (1 << s)));
>>         }
>>
>>         return fout;
>> --
>> 1.8.0
>>
>

Regards,
Akshay Saraswat


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