This patch series adds support for the audio PLL and enables ClassD that can be found in ATMEL Sama5d2 SoCs.
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, since there is no rate locking, we enforce that classd_gclk be the only child of audio_pll_pmc so we avoid multiple children modifiying parent's rate, and classd driver modifying parent's rate which would impact the rate of each of parent's children.
Thanks, Quentin
[1] https://patchwork.kernel.org/patch/9462351/ [2] https://patchwork.kernel.org/patch/9462347/ [3] https://patchwork.kernel.org/patch/9462349/ [4] https://www.spinics.net/lists/arm-kernel/msg436120.html
Cyrille Pitchen (2): ARM: dts: at91: sama5d2: add classd nodes ARM: dts: at91: sama5d2_xplained: add pin muxing and enable classd
Nicolas Ferre (1): clk: at91: add audio pll clock driver
Quentin Schulz (3): clk: at91: clk-generated: remove useless divisor loop clk: at91: clk-generated: create function to find best_diff clk: at91: clk-generated: make gclk determine audio_pll rate
.../devicetree/bindings/clock/at91-clock.txt | 10 + arch/arm/boot/dts/at91-sama5d2_xplained.dts | 16 ++ arch/arm/boot/dts/sama5d2.dtsi | 39 +++- arch/arm/mach-at91/Kconfig | 4 + drivers/clk/at91/Makefile | 2 + drivers/clk/at91/clk-audio-pll-pad.c | 204 ++++++++++++++++++ drivers/clk/at91/clk-audio-pll-pmc.c | 175 +++++++++++++++ drivers/clk/at91/clk-audio-pll.c | 237 +++++++++++++++++++++ drivers/clk/at91/clk-generated.c | 79 +++++-- include/linux/clk/at91_pmc.h | 25 +++ sound/soc/atmel/atmel-classd.c | 20 +- 11 files changed, 772 insertions(+), 39 deletions(-) create mode 100644 drivers/clk/at91/clk-audio-pll-pad.c create mode 100644 drivers/clk/at91/clk-audio-pll-pmc.c create mode 100644 drivers/clk/at91/clk-audio-pll.c