Re: [PATCH v6 5/6] ASoC: codecs: wcd938x: add mux control support for hp audio mux

[Dmitry Baryshkov]

On 03/04/2025 15:19, Srinivas Kandagatla wrote:
> On 02/04/2025 10:12, Johan Hovold wrote:
> > On Thu, Mar 27, 2025 at 10:06:32AM +0000, Srinivas Kandagatla wrote:
> > > From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > >
> > > On some platforms to minimise pop and click during switching between
> > > CTIA and OMTP headset an additional HiFi mux is used. Most common
> > > case is that this switch is switched on by default, but on some
> > > platforms this needs a regulator enable.
> > >
> > > move to using mux control to enable both regulator and handle gpios,
> > > deprecate the usage of gpio.
> > >
> > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > > Tested-by: Christopher Obbard <christopher.obbard@xxxxxxxxxx>
> >
> > > @@ -3261,11 +3276,26 @@ static int wcd938x_populate_dt_data(struct 
> > > wcd938x_priv *wcd938x, struct device
> > >           return dev_err_probe(dev, wcd938x->reset_gpio,
> > >                        "Failed to get reset gpio\n");
> > > -    wcd938x->us_euro_gpio = devm_gpiod_get_optional(dev, "us-euro",
> > > -                        GPIOD_OUT_LOW);
> > > -    if (IS_ERR(wcd938x->us_euro_gpio))
> > > -        return dev_err_probe(dev, PTR_ERR(wcd938x->us_euro_gpio),
> > > -                     "us-euro swap Control GPIO not found\n");
> > > +    wcd938x->us_euro_mux = devm_mux_control_get(dev, NULL);
> Thanks Johan,
> > Running with this patch on the CRD I noticed that this now prints an
> > error as there is no optional mux (or gpio) defined:
> >
> >     wcd938x_codec audio-codec: /audio-codec: failed to get mux-control 
> > (0)
>
> This is not from codec driver, mux control is throwing up this.
>
> > You need to suppress that error in mux_get() to allow for optional muxes
> > to be looked up like this.
> I have a plan for this,
>
> I proposed some changes to mux api for exclusive apis at https:// 
> lkml.org/lkml/2025/3/26/955
>
> This should also allow us to easily add an optional api, which I plan to 
> do once i get some feedback on this patch.

I'd rather suggest an API to switch the state without deselecting the 
the mux.

> --srini
>
> >

--
With best wishes
Dmitry