Query on sysclk source

Query on sysclk source

[Sameer Pujar]

Hi All,

I do have a query for snd_soc_dai_set_sysclk(). It takes 'clk_id' as 
argument which is used for sysclk source purpose in some drivers and in 
some it seems to be used for clock ID specifically. Please see below 
references.
   - 
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/tree/sound/soc/atmel/sam9g20_wm8731.c#n105(clk_id 
as sysclk source)
   - 
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/tree/sound/soc/atmel/sam9x5_wm8731.c#n50(clk_id 
as sysclk source)
   - 
https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git/tree/sound/soc/intel/boards/bytcr_wm5102.c#n78(clk_id 
actually seems refer to specific clock id)

To add snd_soc_component_sysclk() takes both 'clk_id' and 'source' 
arguments.

Currently snd_soc_dai_set_sysclk() has following implementation.
------------------------------------------------------------------
/    int snd_soc_dai_set_sysclk(struct snd_soc_dai *dai, int clk_id,//
//                   unsigned int freq, int dir)//
//    {//
//        int ret;//
//
//        if (dai->driver->ops &&//
//dai->driver->ops->set_sysclk)//
//            ret = dai->driver->ops->set_sysclk(dai, clk_id, freq, dir);//
//        else//
//            ret = snd_soc_component_set_sysclk(dai->component, clk_id, 
0,//
//                               freq, dir);//
//
//        return soc_dai_ret(dai, ret);//
//    }/
-------------------------------------------------------------------

The 'source' for snd_soc_component_set_sysclk() is hardcoded to 0 
always, which may not be the case always. Please see below.
   - 
https://elixir.bootlin.com/linux/v5.11/source/sound/soc/samsung/bells.c#L161

Hence I am wondering if 'clk_id' argument is being used inconsistently 
for snd_soc_dai_set_sysclk() and should we rather have a separate 
'source' argument for this as well?


Thanks,
Sameer.

Re: Query on sysclk source

[Mark Brown]

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On Mon, Feb 22, 2021 at 09:32:53PM +0530, Sameer Pujar wrote:

> Hence I am wondering if 'clk_id' argument is being used inconsistently for
> snd_soc_dai_set_sysclk() and should we rather have a separate 'source'
> argument for this as well?

Yeah, we should in case someone wants to use it with one of the few
devices with selectable sources implemented.

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