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SubjectRe: [PATCH v4 0/9] add support for Sama5d2 audio PLLs and enable ClassD
On 25/07/2017 at 17:44:19 +0200, Nicolas Ferre wrote:
> On 25/07/2017 at 09:37, Quentin Schulz wrote:
> > This patch series adds support for the audio PLLs and enables ClassD that
> > can be found in ATMEL Sama5d2 SoC.
> >
> > There are two audio PLLs (PMC and PAD) that shares the same parent (FRAC).
> > FRAC can output between 620 and 700MHz and only multiply the rate of its
> > parent. The two audio PLLs then divide the FRAC rate to best match the
> > asked rate.
> >
> > I basically took an old patch series posted by Nicolas on December, 6th
> > 2016[1][2][3] and the comments Boris did on the first version[4] Nicolas
> > sent on July, 15th 2015.
> >
> > I also fixed the function used to compute the divisors, removed useless
> > spinlocks and added a range to the audio frac PLL to stay within vendor's
> > supported range. Clocks that are children of gclk (generated-clk) are now
> > able to propagate rate to the audio PLL clocks when needed.
> >
> > However, there are multiple children clocks that could technically
> > change the rate of audio_pll (via gck). With the rate locking introduced
> > in Jerome Brunet's patch series[5], the first consumer to enable the clock
> > will be the one definitely setting the rate of the clock. Without the rate
> > locking, the last consumer to set the rate will be able to mess with the
> > rate.
> > Since audio IPs are most likely to request the same rate, we enforce
> > that the only clks able to modify gck rate are those of audio IPs.
> >
> > To remain consistent, we deny other clocks to be children of audio_pll.
> Quentin,
> Thanks for having revived this series. Everything's okay on my side for
> this v4. I think that my tag isn't missing from any patch of this
> series. Now we surely need to define which path it must take...

I'll take the two dts patches now as the bindings have been acked.
Everything else should probably go through the clk tree.

Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering

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