clk: imx: pll14xx: Support dynamic rates

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The pll1443x PLL so far only supports rates from a rate table passed
during initialization. Calculating PLL settings dynamically helps audio
applications to get their desired rates, so support for this is added
in this patch.

The strategy to get to the PLL setting for a rate is:

- First try to only adjust kdiv which specifies the fractional part of the PLL.
  This setting can be changed without glitches on the output and is therefore
  preferred
- When that isn't possible then the rate table is searched for suitable rates,
  so for standard rates the same settings are used as without this patch
- As a last resort the best settings are calculated dynamically

The code in this patch is based on patches from Adrian Alonso <adrian.alonso@nxp.com>
and Mads Bligaard Nielsen <bli@bang-olufsen.dk>

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Reviewed-by: Abel Vesa <abel.vesa@nxp.com>
Link: https://lore.kernel.org/r/20220304125256.2125023-9-s.hauer@pengutronix.de
Signed-off-by: Abel Vesa <abel.vesa@nxp.com>

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This commit is contained in:

Sascha Hauer 2022-03-04 13:52:56 +01:00 • committed by Abel Vesa

parent 80cbc80612

commit b09c68dc57

1 changed files with 126 additions and 17 deletions

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drivers/clk/imx/clk-pll14xx.c

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