On 3/15/24 13:22, Jerome Brunet wrote:
>
> On Fri 15 Mar 2024 at 11:00, Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxx> wrote:
>
>> On 15/03/2024 00:21, Jan Dakinevich wrote:
>>> This option allow to redefine the rate of DSP system clock.
>>
>> And why is it suitable for bindings? Describe the hardware, not what you
>> want to do in the driver.
>>
>>>
>>> Signed-off-by: Jan Dakinevich <jan.dakinevich@xxxxxxxxxxxxxxxxx>
>>> ---
>>> Documentation/devicetree/bindings/sound/amlogic,axg-pdm.yaml | 4 ++++
>>> 1 file changed, 4 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/sound/amlogic,axg-pdm.yaml b/Documentation/devicetree/bindings/sound/amlogic,axg-pdm.yaml
>>> index df21dd72fc65..d2f23a59a6b6 100644
>>> --- a/Documentation/devicetree/bindings/sound/amlogic,axg-pdm.yaml
>>> +++ b/Documentation/devicetree/bindings/sound/amlogic,axg-pdm.yaml
>>> @@ -40,6 +40,10 @@ properties:
>>> resets:
>>> maxItems: 1
>>>
>>> + sysrate:
>>> + $ref: /schemas/types.yaml#/definitions/uint32
>>> + description: redefine rate of DSP system clock
>>
>> No vendor prefix, so is it a generic property? Also, missing unit
>> suffix, but more importantly I don't understand why this is a property
>> of hardware.
>
> +1.
>
> The appropriate way to set rate of the clock before the driver take over
> is 'assigned-rate', if you need to customize this for different
> platform.
>
It would be great, but it doesn't work. Below, is what I want to see:
assigned-clocks =
<&clkc_audio AUD2_CLKID_PDM_SYSCLK_SEL>,
<&clkc_audio AUD2_CLKID_PDM_SYSCLK_DIV>;
assigned-clock-parents =
<&clkc_pll CLKID_FCLK_DIV3>,
<0>;
assigned-clock-rates =
<0>,
<256000000>;
But regardles of this declaration, PDM's driver unconditionally sets
sysclk'rate to 250MHz and throws away everything that was configured
before, reparents audio2_pdm_sysclk_mux to hifi_pll and changes
hifi_pll's rate.
This value 250MHz is declared here:
static const struct axg_pdm_cfg axg_pdm_config = {
.filters = &axg_default_filters,
.sys_rate = 250000000,
};
The property 'sysrate' is intended to redefine hardcoded 'sys_rate'
value in 'axg_pdm_config'.
> Then you don't have to deal with it in the device driver.
>
>>
>> Best regards,
>> Krzysztof
>
>
--
Best regards
Jan Dakinevich
