On 08.10.2021 17:43, Sam Protsenko wrote:
pll0831x PLL is used in Exynos850 SoC for top-level fractional PLLs. The
code was derived from very similar pll36xx type, with next differences:
1. Lock time for pll0831x is 500*P_DIV, when for pll36xx it's 3000*P_DIV
2. It's not suggested in Exynos850 TRM that S_DIV change doesn't require
performing PLL lock procedure (which is done in pll36xx
implementation)
3. The offset from PMS-values register to K-value register is 0x8 for
pll0831x, when for pll36xx it's 0x4
When defining pll0831x type, CON3 register offset should be provided as
a "con" parameter of PLL() macro, like this:
PLL(pll_0831x, 0, "fout_mmc_pll", "oscclk",
PLL_LOCKTIME_PLL_MMC, PLL_CON3_PLL_MMC, pll0831x_26mhz_tbl),
To define PLL rates table, one can use PLL_36XX_RATE() macro, e.g.:
PLL_36XX_RATE(26 * MHZ, 799999877, 31, 1, 0, -15124)
as it's completely appropriate for pl0831x type and there is no sense in
duplicating that.
If bit #1 (MANUAL_PLL_CTRL) is not set in CON1 register, it won't be
possible to set new rate, with next error showing in kernel log:
Could not lock PLL fout_mmc_pll
That can happen for example if bootloader clears that bit beforehand.
PLL driver doesn't account for that, so if MANUAL_PLL_CTRL bit was
cleared, it's assumed it was done for a reason and it shouldn't be
possible to change that PLL's rate at all.
Signed-off-by: Sam Protsenko<semen.protsenko@xxxxxxxxxx>
Reviewed-by: Krzysztof Kozlowski<krzysztof.kozlowski@xxxxxxxxxxxxx>
Acked-by: Chanwoo Choi<cw00.choi@xxxxxxxxxxx>
Applied, thanks.
