[PATCH v4 2/2] clk: bcm2835: Minimise clock jitter for PCM clock

Stephen Boyd sboyd at codeaurora.org
Fri Jun 2 15:45:26 PDT 2017


On 06/01, Phil Elwell wrote:
> Fractional clock dividers generate accurate average frequencies but
> with jitter, particularly when the integer divisor is small.
> 
> Introduce a new metric of clock accuracy to penalise clocks with a good
> average but worse jitter compared to clocks with an average which is no
> better but with lower jitter. The metric is the ideal rate minus the
> worse deviation from that ideal using the nearest integer divisors.
> 
> Use this metric for parent selection for clocks requiring low jitter
> (currently just PCM).
> 
> Signed-off-by: Phil Elwell <phil at raspberrypi.org>
> Reviewed-by: Eric Anholt <eric at anholt.net>
> Acked-by: Stefan Wahren <stefan.wahren at i2se.com>
> ---

Applied to clk-next

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