Re: [PATCH v3 5/6] ASoC: codecs: wcd938x: add mux control support for hp audio mux

[Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>]

On 24/03/2025 14:04, Srinivas Kandagatla wrote:
> 
> 
> On 24/03/2025 11:20, Dmitry Baryshkov wrote:
>> On 24/03/2025 13:06, 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   |  1 +
>>>   sound/soc/codecs/wcd938x.c | 38 ++++++++++++++++++++++++++++++--------
>>>   2 files changed, 31 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
>>> index ee35f3aa5521..a2829d76e108 100644
>>> --- a/sound/soc/codecs/Kconfig
>>> +++ b/sound/soc/codecs/Kconfig
>>> @@ -2226,6 +2226,7 @@ config SND_SOC_WCD938X
>>>       tristate
>>>       depends on SOUNDWIRE || !SOUNDWIRE
>>>       select SND_SOC_WCD_CLASSH
>>> +    select MULTIPLEXER
>>>   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 dfaa3de31164..948b5f6cc45a 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)
>>>       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);
>>
>> Is it possible to use mux_state for both GPIO and MUX paths?
> 
> Ideally I would like to do that the way that gpio is done, which is 
> clear reflection of hw state, however mux f/w is lacking such api.

Anyway, both paths should use the same flow.

> 
> 
>>
>>> +    } 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");
>>
>> This can lead to mux being deselected next time even if the 
>> mux_control_select returned an error. I think mux_control API needs a 
>> way to toggle the state without deselecting it first. Anyway, an error 
>> from mux_control_select() must prevent you from calling 
>> mux_control_deselect() next time.
> 
> We can rearrange deselect to be done only on successful select, that 
> should cleanup some of this.

Yes, please.

> 
> --srini
>>
>>> +    }
>>>       return true;
>>>   }
>>
>>


-- 
With best wishes
Dmitry