[1/2] ASoC: codec: wcd938x: Add switch control for selecting CTIA/OMTP Headset

Add switch control for selecting CTIA or OMTP Headset by swapping
gnd and mic with the help of GPIO.

Signed-off-by: Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
Co-developed-by: Venkata Prasad Potturu <quic_potturu@quicinc.com>
Signed-off-by: Venkata Prasad Potturu <quic_potturu@quicinc.com>
---
 sound/soc/codecs/wcd938x.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

Quoting Srinivasa Rao Mandadapu (2022-02-12 04:24:31)
> diff --git a/sound/soc/codecs/wcd938x.c b/sound/soc/codecs/wcd938x.c
> index eff200a..08d16a9 100644
> --- a/sound/soc/codecs/wcd938x.c
> +++ b/sound/soc/codecs/wcd938x.c
> @@ -194,6 +194,7 @@ struct wcd938x_priv {
>         int ear_rx_path;
>         int variant;
>         int reset_gpio;
> +       int us_euro_gpio;
>         u32 micb1_mv;
>         u32 micb2_mv;
>         u32 micb3_mv;
> @@ -4196,6 +4197,33 @@ static void wcd938x_dt_parse_micbias_info(struct device *dev, struct wcd938x_pri
>                 dev_info(dev, "%s: Micbias4 DT property not found\n", __func__);
>  }
>
> +static bool wcd938x_swap_gnd_mic(struct snd_soc_component *component, bool active)
> +{
> +       int value;
> +
> +       struct wcd938x_priv *wcd938x;
> +
> +       if (!component) {

So component is NULL

> +               dev_err(component->dev, "%s component is NULL\n", __func__);

And now we deref component. Great NULL pointer exception Batman! Please
test your code and remove useless checks. It makes the code harder to
read and slows things down.

> +               return false;
> +       }
> +
> +       wcd938x = snd_soc_component_get_drvdata(component);
> +       if (!wcd938x) {
> +               dev_err(component->dev, "%s private data is NULL\n", __func__);

Is this possible? I doubt it so can we just remove it?

> +               return false;
> +       }
> +
> +       value = gpio_get_value(wcd938x->us_euro_gpio);
> +
> +       gpio_set_value(wcd938x->us_euro_gpio, !value);
> +       /* 20us sleep required after changing the gpio state*/

Add a space before ending comment with */

> +       usleep_range(20, 30);
> +
> +       return true;
> +}
> +
> +
>  static int wcd938x_populate_dt_data(struct wcd938x_priv *wcd938x, struct device *dev)
>  {
>         struct wcd_mbhc_config *cfg = &wcd938x->mbhc_cfg;
> @@ -4208,6 +4236,16 @@ static int wcd938x_populate_dt_data(struct wcd938x_priv *wcd938x, struct device
>                 return wcd938x->reset_gpio;
>         }
>
> +       wcd938x->us_euro_gpio = of_get_named_gpio(dev->of_node, "us-euro-gpios", 0);

Why do we need to use of GPIO APIs here? Can this driver be converted to
use GPIO descriptors via the gpiod APIs?

> +       if (wcd938x->us_euro_gpio < 0) {
> +               dev_err(dev, "Failed to get us-euro-gpios gpio: err = %d\n", wcd938x->us_euro_gpio);
> +       } else {
> +               cfg->swap_gnd_mic = wcd938x_swap_gnd_mic;
> +               gpio_direction_output(wcd938x->us_euro_gpio, 0);
> +               /* 20us sleep required after pulling the reset gpio to LOW */
> +               usleep_range(20, 30);
> +       }
> +

On 2/15/2022 3:17 AM, Stephen Boyd wrote:
Thanks for your time Stephen!!!
> Quoting Srinivasa Rao Mandadapu (2022-02-12 04:24:31)
>> diff --git a/sound/soc/codecs/wcd938x.c b/sound/soc/codecs/wcd938x.c
>> index eff200a..08d16a9 100644
>> --- a/sound/soc/codecs/wcd938x.c
>> +++ b/sound/soc/codecs/wcd938x.c
>> @@ -194,6 +194,7 @@ struct wcd938x_priv {
>>          int ear_rx_path;
>>          int variant;
>>          int reset_gpio;
>> +       int us_euro_gpio;
>>          u32 micb1_mv;
>>          u32 micb2_mv;
>>          u32 micb3_mv;
>> @@ -4196,6 +4197,33 @@ static void wcd938x_dt_parse_micbias_info(struct device *dev, struct wcd938x_pri
>>                  dev_info(dev, "%s: Micbias4 DT property not found\n", __func__);
>>   }
>>
>> +static bool wcd938x_swap_gnd_mic(struct snd_soc_component *component, bool active)
>> +{
>> +       int value;
>> +
>> +       struct wcd938x_priv *wcd938x;
>> +
>> +       if (!component) {
> So component is NULL
>
>> +               dev_err(component->dev, "%s component is NULL\n", __func__);
> And now we deref component. Great NULL pointer exception Batman! Please
> test your code and remove useless checks. It makes the code harder to
> read and slows things down.
Okay. In last minute, changed from pr_err to dev_err and overlooked this 
mistake. Will remove it.
>
>> +               return false;
>> +       }
>> +
>> +       wcd938x = snd_soc_component_get_drvdata(component);
>> +       if (!wcd938x) {
>> +               dev_err(component->dev, "%s private data is NULL\n", __func__);
> Is this possible? I doubt it so can we just remove it?
Okay. Will remove it.
>
>> +               return false;
>> +       }
>> +
>> +       value = gpio_get_value(wcd938x->us_euro_gpio);
>> +
>> +       gpio_set_value(wcd938x->us_euro_gpio, !value);
>> +       /* 20us sleep required after changing the gpio state*/
> Add a space before ending comment with */
Okay.
>
>> +       usleep_range(20, 30);
>> +
>> +       return true;
>> +}
>> +
>> +
>>   static int wcd938x_populate_dt_data(struct wcd938x_priv *wcd938x, struct device *dev)
>>   {
>>          struct wcd_mbhc_config *cfg = &wcd938x->mbhc_cfg;
>> @@ -4208,6 +4236,16 @@ static int wcd938x_populate_dt_data(struct wcd938x_priv *wcd938x, struct device
>>                  return wcd938x->reset_gpio;
>>          }
>>
>> +       wcd938x->us_euro_gpio = of_get_named_gpio(dev->of_node, "us-euro-gpios", 0);
> Why do we need to use of GPIO APIs here? Can this driver be converted to
> use GPIO descriptors via the gpiod APIs?
Okay.  will look into it and proceed accordingly!!!
>
>> +       if (wcd938x->us_euro_gpio < 0) {
>> +               dev_err(dev, "Failed to get us-euro-gpios gpio: err = %d\n", wcd938x->us_euro_gpio);
>> +       } else {
>> +               cfg->swap_gnd_mic = wcd938x_swap_gnd_mic;
>> +               gpio_direction_output(wcd938x->us_euro_gpio, 0);
>> +               /* 20us sleep required after pulling the reset gpio to LOW */
>> +               usleep_range(20, 30);
>> +       }
>> +