Re: [PATCH v2 4/5] ASoC: codecs: wcd938x: add mux control support for hp audio mux

[Christopher Obbard <christopher.obbard@linaro.org>]

Hi Srini,

On Thu, 20 Mar 2025 at 12:03, <srinivas.kandagatla@linaro.org> wrote:
>
> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>
> 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@linaro.org>

Tested-by: Christopher Obbard <christopher.obbard@linaro.org>

> ---
>  sound/soc/codecs/Kconfig   |  2 ++
>  sound/soc/codecs/wcd938x.c | 38 ++++++++++++++++++++++++++++++--------
>  2 files changed, 32 insertions(+), 8 deletions(-)
>
> diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
> index ee35f3aa5521..b04076282c8b 100644
> --- a/sound/soc/codecs/Kconfig
> +++ b/sound/soc/codecs/Kconfig
> @@ -2226,6 +2226,8 @@ config SND_SOC_WCD938X
>         tristate
>         depends on SOUNDWIRE || !SOUNDWIRE
>         select SND_SOC_WCD_CLASSH
> +       select MULTIPLEXER
> +       imply MUX_GPIO
>
>  config SND_SOC_WCD938X_SDW
>         tristate "WCD9380/WCD9385 Codec - SDW"
> diff --git a/sound/soc/codecs/wcd938x.c b/sound/soc/codecs/wcd938x.c
> index f2a4f3262bdb..b7a235eef6ba 100644
> --- a/sound/soc/codecs/wcd938x.c
> +++ b/sound/soc/codecs/wcd938x.c
> @@ -19,6 +19,7 @@
>  #include <linux/regmap.h>
>  #include <sound/soc.h>
>  #include <sound/soc-dapm.h>
> +#include <linux/mux/consumer.h>
>  #include <linux/regulator/consumer.h>
>
>  #include "wcd-clsh-v2.h"
> @@ -178,6 +179,8 @@ struct wcd938x_priv {
>         int variant;
>         int reset_gpio;
>         struct gpio_desc *us_euro_gpio;
> +       struct mux_control *us_euro_mux;
> +       u32 mux_state;
>         u32 micb1_mv;
>         u32 micb2_mv;
>         u32 micb3_mv;
> @@ -3243,9 +3246,16 @@ static bool wcd938x_swap_gnd_mic(struct snd_soc_component *component, bool activ
>
>         wcd938x = snd_soc_component_get_drvdata(component);
>
> -       value = gpiod_get_value(wcd938x->us_euro_gpio);
> +       if (!wcd938x->us_euro_mux) {
> +               value = gpiod_get_value(wcd938x->us_euro_gpio);
>
> -       gpiod_set_value(wcd938x->us_euro_gpio, !value);
> +               gpiod_set_value(wcd938x->us_euro_gpio, !value);
> +       } else {
> +               mux_control_deselect(wcd938x->us_euro_mux);
> +               wcd938x->mux_state = !wcd938x->mux_state;
> +               if (mux_control_select(wcd938x->us_euro_mux, wcd938x->mux_state))
> +                       dev_err(component->dev, "Unable to select us/euro mux state\n");
> +       }
>
>         return true;
>  }
> @@ -3261,14 +3271,23 @@ 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);
> +       if (IS_ERR(wcd938x->us_euro_mux)) {
> +               if (PTR_ERR(wcd938x->us_euro_mux) == -EPROBE_DEFER)
> +                       return -EPROBE_DEFER;
> +
> +               /* mux is optional and now fallback to using gpio */
> +               wcd938x->us_euro_mux = NULL;
> +               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");
> +       } else {
> +               if (mux_control_select(wcd938x->us_euro_mux, wcd938x->mux_state))
> +                       dev_err(dev, "Unable to select us/euro mux state\n");
> +       }
>
>         cfg->swap_gnd_mic = wcd938x_swap_gnd_mic;
> -
>         wcd938x->supplies[0].supply = "vdd-rxtx";
>         wcd938x->supplies[1].supply = "vdd-io";
>         wcd938x->supplies[2].supply = "vdd-buck";
> @@ -3581,6 +3600,9 @@ static void wcd938x_remove(struct platform_device *pdev)
>         pm_runtime_set_suspended(dev);
>         pm_runtime_dont_use_autosuspend(dev);
>
> +       if (wcd938x->us_euro_mux)
> +               mux_control_deselect(wcd938x->us_euro_mux);
> +
>         regulator_bulk_disable(WCD938X_MAX_SUPPLY, wcd938x->supplies);
>         regulator_bulk_free(WCD938X_MAX_SUPPLY, wcd938x->supplies);
>  }
> --
> 2.39.5
>
>