Re: [PATCH V9 3/4] clk: meson: S4: add support for Amlogic S4 SoC PLL clock driver

[Dmitry Rokosov <ddrokosov@sberdevices.ru>]

Hello Jerome,

On Thu, Jun 08, 2023 at 10:53:31AM +0200, Jerome Brunet wrote:
> 
> >>> +
> >>> +static struct clk_regmap s4_fclk_div4 = {
> >>> +     .data = &(struct clk_regmap_gate_data){
> >>> +             .offset = ANACTRL_FIXPLL_CTRL1,
> >>> +             .bit_idx = 21,
> >>> +     },
> >>> +     .hw.init = &(struct clk_init_data){
> >>> +             .name = "fclk_div4",
> >>> +             /*
> >>> +              * For more information, please refer to s4_fixed_pll_dco.
> >>> +              */
> >> While div2 and div3 got an explanation from previous SoCs, they others -
> >> like div4/div7/etc ... - have been able to cope with rw ops so far.
> >> Why is the S4 different for all these clocks ?
> >
> > The chip was changed fixed pll for security reasons.
> >
> > Fixed PLL registers are not writable in the kernel phase. Write of fixed
> > PLL-related register will cause the system to crash.
> >
> 
> That is definitely worth mentionning
> 
> >> Requiring RO ops (or fishy clock flags) is usually a sign that a clock
> >> is used without an appropriate driver.
> >>
> 
> Neil is currently dealing with the dt-bindings, please
> * Adjust your patchset accordingly
> * Wait for his v2 to land, you'll need it.
> 

I saw Neil patch series with merging 'private' and 'public' clock
bindings parts. Should I send the same patchset for a1 clocks after v6.5
landed?

> >>> +             .ops = &clk_regmap_gate_ro_ops,
> >>> +             .parent_hws = (const struct clk_hw *[]) {
> >>> +                     &s4_fclk_div4_div.hw
> >>> +             },
> >>> +             .num_parents = 1,
> >>> +     },
> >>> +};
> >>> +
> 
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-- 
Thank you,
Dmitry

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