Messages in this thread | | | Subject | Re: [PATCH v2 0/2] clk: bcm2835: PCM clock improvements | From | Stefan Wahren <> | Date | Wed, 31 May 2017 16:58:01 +0200 |
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Am 31.05.2017 um 11:18 schrieb Phil Elwell: > The switch to using the upstream bcm2835_cprman clock driver caused a > few problems for users of PCM (I2S) peripherals. Audio applications > require accurate, stable clocks, and the cprman driver wasn't > conservative enough in its choice of clock sources. > > These patches restrict the clock sources for the PCM peripheral in two > ways: the first causes all possible sources except OSC and PLLD_PER > to be ignored, while the second allows clocks to be specified as > "low_jitter", causing the effects of fractional divisors to be taken > into account when comparing potential clocks for accuracy. In practice, > the combined effect of the two patches is to choose OSC as a source if > an integer divisor can be used, otherwise PLLD_PER is chosen. > > Changes in v2: > * Extended bcm2835_pcm_per_parents to cover the pllh_aux slot, and gave > it a comment in patch 1. > * Added a REGISTER_PCM_CLK analagous to REGISTER_PER_CLK in patch 1. > * Renamed temporary variable idiv to int_div in patch 2. > > Phil Elwell (2): > clk: bcm2835: Limit PCM clock to OSC and PLLD_PER > clk: bcm2835: Minimise clock jitter for PCM clock > > drivers/clk/bcm/clk-bcm2835.c | 50 ++++++++++++++++++++++++++++++++++++++----- > 1 file changed, 45 insertions(+), 5 deletions(-) > For the whole series:
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
I hope Eric as the author of the driver has a chance to look over the patches.
Stefan
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