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Message-ID: <6feba9ff-8bbf-4494-93f0-732679bc4032@salutedevices.com>
Date: Sun, 17 Mar 2024 18:52:15 +0300
From: Jan Dakinevich <jan.dakinevich@...utedevices.com>
To: Jerome Brunet <jbrunet@...libre.com>, Krzysztof Kozlowski
<krzysztof.kozlowski@...aro.org>
CC: Neil Armstrong <neil.armstrong@...aro.org>, Michael Turquette
<mturquette@...libre.com>, Stephen Boyd <sboyd@...nel.org>, Rob Herring
<robh@...nel.org>, Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley <conor+dt@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>,
Kevin Hilman <khilman@...libre.com>, Martin Blumenstingl
<martin.blumenstingl@...glemail.com>, Liam Girdwood <lgirdwood@...il.com>,
Mark Brown <broonie@...nel.org>, Linus Walleij <linus.walleij@...aro.org>,
Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
<linux-amlogic@...ts.infradead.org>, <linux-clk@...r.kernel.org>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>, <alsa-devel@...a-project.org>,
<linux-sound@...r.kernel.org>, <linux-gpio@...r.kernel.org>,
<kernel@...utedevices.com>
Subject: Re: [PATCH 13/25] ASoC: dt-bindings: meson: axg-pdm: document
'sysrate' property
On 3/15/24 13:22, Jerome Brunet wrote:
>
> On Fri 15 Mar 2024 at 11:00, Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> 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@...utedevices.com>
>>> ---
>>> 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
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