[PATCH V9 3/4] clk: meson: S4: add support for Amlogic S4 SoC PLL clock driver
Jerome Brunet
jbrunet at baylibre.com
Thu Jun 8 01:53:31 PDT 2023
>>> +
>>> +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.
>>> + .ops = &clk_regmap_gate_ro_ops,
>>> + .parent_hws = (const struct clk_hw *[]) {
>>> + &s4_fclk_div4_div.hw
>>> + },
>>> + .num_parents = 1,
>>> + },
>>> +};
>>> +
More information about the linux-amlogic
mailing list