On Wed, Dec 05, 2018 at 06:11:49PM +0800, Chen-Yu Tsai wrote: > Hi everyone, > > This series improves audio support on the A33. Like other Allwinner > SoCs, the A33 requires the use of a sigma-delta modulation fractional-N > PLL to generate the correct clock used for audio playback. Otherwise the > pitch would be slightly off. > > Patch 1 enables sigma-delta modulation for the audio PLL on the A33. > > Patch 2 is only slightly related. It sets the CLK_SET_RATE_PARENT flag > for all audio-related module clocks > > Patch 3 lowers the audio codec's oversampling rate, so that it can > play back audio sampled at beyond 48 KHz. > > This is the same as what has recently been done for the A64, which > shares the same audio codec hardware design. > > However, on the A33 it seems the PLL doesn't always immediately lock on > to the new clock frequency when there is a rate change. Also since the > codec is only put in standby instead of turned off, runtime PM never > kicks in, and the audio related clocks never get turned off. I'm still > looking into this. > > On an unrelated note, if you get pops when playing back audio on sunxi, > it might be related to cpufreq. Try setting the governor to performance > and see if that removes the pops. Applied all 3 patches, thanks! Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
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