[PATCH 1/2] ASoC: rt5682: Add CCF usage for providing I2S clks

Derek [方德義] derek.fang at realtek.com
Tue Feb 18 07:33:19 CET 2020


> Subject: Re: [PATCH 1/2] ASoC: rt5682: Add CCF usage for providing I2S clks
> 
> On Mon, Feb 17, 2020 at 10:59:55AM +0000, Derek [方德義] wrote:
> > > Subject: Re: [PATCH 1/2] ASoC: rt5682: Add CCF usage for providing I2S clks
> 
> > > > +	if (parent_rate != CLK_PLL2_FIN)
> > > > +		dev_warn(component->dev, "clk %s only support %d Hz
> input\n",
> > > > +			clk_name, CLK_PLL2_FIN);
> 
> > > > +	if (rate != CLK_48) {
> > > > +		dev_warn(component->dev, "clk %s only support %d Hz
> output\n",
> > > > +			clk_name, CLK_48);
> > > > +		rate = CLK_48;
> > > > +	}
> 
> > > Are these genuine restrictions of the hardware or is this just being
> > > hard coded in the driver?
> 
> > It's hard coded for an application case.
> > Generate a 48kHz clk with a parent 48 MHz clk.
> 
> I see...  obviously this is really not good quality of implementation
> although it doesn't actually break any external interfaces so I guess we
> could take it.  I would at least want to see some clear comments in both
> the code and the changelog explaining that this limitation is just a
> temporary hack until a better implementation is done though.

Ok. Thanks for the advice.
I will add more comments both in the source and commit to clearly describe
the driver support and limitation, and then send the PATCH v2.

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