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    SubjectRe: [PATCH 01/25] ASoC: sun8i-codec: Set up clock tree at probe time
    On Wed, Sep 30, 2020 at 09:11:24PM -0500, Samuel Holland wrote:
    > The sun8i codec is effectively an on-die variant of the X-Powers AC100
    > codec. The AC100 can derive its clocks from either of two I2S master
    > clocks or an internal PLL. For the on-die variant, Allwinner replaced
    > the codec's own PLL with a connection to SoC's existing PLL_AUDIO, and
    > they connected both I2S MCLK inputs to the same source -- which happens
    > to be an integer divider from the same PLL_AUDIO.
    >
    > So there's actually no clocking flexibility. To run SYSCLK at the
    > required rate, it must be run straight from the PLL. The only choice is
    > whether it goes through AIF1CLK or AIF2CLK. Since both run at the same
    > rate, the only effect of that choice is which field in SYS_SR_CTRL
    > (AIF1_FS or AIF2_FS) controls the system sample rate.
    >
    > Since AIFnCLK is required to bring up the corresponding DAI, and AIF1
    > (connected to the CPU) is used most often, let's use AIF1CLK as the
    > SYSCLK parent. That means we no longer need to set AIF2_FS.
    >
    > Since this clock tree never changes, we can program it from the
    > component probe function, instead of using DAPM widgets. The DAPM
    > widgets unnecessarily change clock parents when the codec goes in/out
    > of idle and the supply widgets are powered up/down.
    >
    > Signed-off-by: Samuel Holland <samuel@sholland.org>

    Acked-by: Maxime Ripard <mripard@kernel.org>

    Maxime
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