Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Subject: Re: [PATCH 1/2] ASoC: codec: wcd938x: Add switch control for
 selecting CTIA/OMTP Headset
To:     Stephen Boyd <swboyd@chromium.org>, <agross@kernel.org>,
        <alsa-devel@alsa-project.org>, <bgoswami@codeaurora.org>,
        <bjorn.andersson@linaro.org>, <broonie@kernel.org>,
        <devicetree@vger.kernel.org>, <judyhsiao@chromium.org>,
        <lgirdwood@gmail.com>, <linux-arm-msm@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <perex@perex.cz>,
        <quic_plai@quicinc.com>, <robh+dt@kernel.org>,
        <rohitkr@codeaurora.org>, <srinivas.kandagatla@linaro.org>,
        <tiwai@suse.com>
CC:     Venkata Prasad Potturu <quic_potturu@quicinc.com>
References: <1644668672-29790-1-git-send-email-quic_srivasam@quicinc.com>
 <1644668672-29790-2-git-send-email-quic_srivasam@quicinc.com>
 <CAE-0n52uBY7GzjtFwV67y5mfqZRoK9ooW-kT3=4sH=8NtVK7FQ@mail.gmail.com>
From:   Srinivasa Rao Mandadapu <quic_srivasam@quicinc.com>
Organization: Qualcomm
Message-ID: <cc99e97d-5256-b121-2785-1290505bc994@quicinc.com>
Date:   Tue, 15 Feb 2022 10:13:39 +0530
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <CAE-0n52uBY7GzjtFwV67y5mfqZRoK9ooW-kT3=4sH=8NtVK7FQ@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Transfer-Encoding: 8bit
Content-Language: en-US
Precedence: bulk


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);
>> +       }
>> +