On Fri, Oct 25, 2024 at 10:06:55PM +0200, Gabor Juhos wrote:
> 2024. 10. 25. 8:18 keltezéssel, Dmitry Baryshkov írta:
> > On Mon, Oct 21, 2024 at 10:21:59PM +0200, Gabor Juhos wrote:
> >> Since both the 'alpha' and 'alpha_hi' members of the configuration is
> >> initialized with zero values, the output rate of the PLL will be the
> >> same whether alpha mode is enabled or not.
> >>
> >> Remove the initialization of the alpha* members to make it clear that
> >> alpha mode is not required to get the desired output rate.
> >>
> >> While at it, also add a comment to indicate the frequency the PLL runs
> >> at with the current configuration.
> >>
> >> No functional changes, the PLL runs at 1.2 GHz both before and after
> >> the change.
> >>
> >> Tested on Xiaomi Mi Router AX1800 (IPQ6018, out-of-tree board).
> >>
> >> Signed-off-by: Gabor Juhos <j4g8y7@xxxxxxxxx>
> >> ---
> >> drivers/clk/qcom/gcc-ipq6018.c | 4 +---
> >> 1 file changed, 1 insertion(+), 3 deletions(-)
> >>
> >> diff --git a/drivers/clk/qcom/gcc-ipq6018.c b/drivers/clk/qcom/gcc-ipq6018.c
> >> index ab0f7fc665a9790dd8edba0cf4b86c5c672a337d..d861191b0c85ccc105ac0e62d7a68210c621fc13 100644
> >> --- a/drivers/clk/qcom/gcc-ipq6018.c
> >> +++ b/drivers/clk/qcom/gcc-ipq6018.c
> >> @@ -4194,10 +4194,9 @@ static const struct alpha_pll_config ubi32_pll_config = {
> >> .test_ctl_hi_val = 0x4000,
> >> };
> >>
> >> +/* 1200 MHz configuration */
> >> static const struct alpha_pll_config nss_crypto_pll_config = {
> >> .l = 0x32,
> >> - .alpha = 0x0,
> >> - .alpha_hi = 0x0,
> >
> > I'd say this serves documentation purposes: zero alpha value
>
> For me, setting 'alpha_en_mask' means that the alpha values will be used. If it
> is not set, then it means that the alpha values are getting ignored. If those
> will be ignored eventually, specifying even zero alpha values explicitly is
> pointless in my opinion.
Ack, it matches the behaviour by several other CLK drivers.
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>
> If we really need that for documentation purposes, the comment before the
> configuration can be changed to indicate that alpha values are not needed.
>
> >
> >> .config_ctl_val = 0x4001055b,
> >> .main_output_mask = BIT(0),
> >> .pre_div_val = 0x0,
> >> @@ -4206,7 +4205,6 @@ static const struct alpha_pll_config nss_crypto_pll_config = {
> >> .post_div_mask = GENMASK(11, 8),
> >> .vco_mask = GENMASK(21, 20),
> >> .vco_val = 0x0,
> >> - .alpha_en_mask = BIT(24),
> >
> > This is okay
>
> Regards,
> Gabor
--
With best wishes
Dmitry
