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Subject: Re: [PATCH v2 8/8] ASoC: qcom: apq8096: add kcontrols to set PCM rate
To:     Adam Serbinski <adam@serbinski.com>,
        Mark Brown <broonie@kernel.org>,
        Srini Kandagatla <srinivas.kandagatla@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Bjorn Andersson <bjorn.andersson@linaro.org>
Cc:     Andy Gross <agross@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Patrick Lai <plai@codeaurora.org>,
        Banajit Goswami <bgoswami@codeaurora.org>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
References: <20200207205013.12274-1-adam@serbinski.com>
 <20200209154748.3015-1-adam@serbinski.com>
 <20200209154748.3015-9-adam@serbinski.com>
From:   Jaroslav Kysela <perex@perex.cz>
Message-ID: <317edce5-a982-549b-84c2-84cdc1d92c9a@perex.cz>
Date:   Mon, 10 Feb 2020 17:18:38 +0100
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Dne 09. 02. 20 v 16:47 Adam Serbinski napsal(a):
> This makes it possible for the backend sample rate to be
> set to 8000 or 16000 Hz, depending on the needs of the HFP
> call being set up.

Two points:

Why enum? It adds just more code than the integer value handlers.

Also, this belongs to the PCM interface, so it should be handled with 
SNDRV_CTL_ELEM_IFACE_PCM not mixer.

The name should be probably "Rate" and assigned to the corresponding PCM device.

Add this to Documentation/sound/designs/control-names.rst .

					Jaroslav

> 
> Signed-off-by: Adam Serbinski <adam@serbinski.com>
> CC: Andy Gross <agross@kernel.org>
> CC: Mark Rutland <mark.rutland@arm.com>
> CC: Liam Girdwood <lgirdwood@gmail.com>
> CC: Patrick Lai <plai@codeaurora.org>
> CC: Banajit Goswami <bgoswami@codeaurora.org>
> CC: Jaroslav Kysela <perex@perex.cz>
> CC: Takashi Iwai <tiwai@suse.com>
> CC: alsa-devel@alsa-project.org
> CC: linux-arm-msm@vger.kernel.org
> CC: devicetree@vger.kernel.org
> CC: linux-kernel@vger.kernel.org
> ---
>   sound/soc/qcom/apq8096.c | 92 +++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 90 insertions(+), 2 deletions(-)
> 
> diff --git a/sound/soc/qcom/apq8096.c b/sound/soc/qcom/apq8096.c
> index 1edcaa15234f..882f2c456321 100644
> --- a/sound/soc/qcom/apq8096.c
> +++ b/sound/soc/qcom/apq8096.c
> @@ -16,6 +16,9 @@
>   #define MI2S_BCLK_RATE			1536000
>   #define PCM_BCLK_RATE			1024000
>   
> +static int pri_pcm_sample_rate = 16000;
> +static int quat_pcm_sample_rate = 16000;
> +
>   static int msm_snd_hw_params(struct snd_pcm_substream *substream,
>   			     struct snd_pcm_hw_params *params)
>   {
> @@ -33,10 +36,15 @@ static int msm_snd_hw_params(struct snd_pcm_substream *substream,
>   	switch (cpu_dai->id) {
>   	case PRIMARY_PCM_RX:
>   	case PRIMARY_PCM_TX:
> +		rate->min = pri_pcm_sample_rate;
> +		rate->max = pri_pcm_sample_rate;
> +		channels->min = 1;
> +		channels->max = 1;
> +		break;
>   	case QUATERNARY_PCM_RX:
>   	case QUATERNARY_PCM_TX:
> -		rate->min = 16000;
> -		rate->max = 16000;
> +		rate->min = quat_pcm_sample_rate;
> +		rate->max = quat_pcm_sample_rate;
>   		channels->min = 1;
>   		channels->max = 1;
>   		break;
> @@ -121,6 +129,83 @@ static struct snd_soc_ops apq8096_ops = {
>   	.startup = msm_snd_startup,
>   };
>   
> +static char const *pcm_sample_rate_text[] = {"8 kHz", "16 kHz"};
> +static const struct soc_enum pcm_snd_enum =
> +		SOC_ENUM_SINGLE_EXT(2, pcm_sample_rate_text);
> +
> +static int get_sample_rate_idx(int sample_rate)
> +{
> +	int sample_rate_idx = 0;
> +
> +	switch (sample_rate) {
> +	case 8000:
> +		sample_rate_idx = 0;
> +		break;
> +	case 16000:
> +	default:
> +		sample_rate_idx = 1;
> +		break;
> +	}
> +
> +	return sample_rate_idx;
> +}
> +
> +static int pri_pcm_sample_rate_get(struct snd_kcontrol *kcontrol,
> +				   struct snd_ctl_elem_value *ucontrol)
> +{
> +	ucontrol->value.integer.value[0] =
> +		get_sample_rate_idx(pri_pcm_sample_rate);
> +	return 0;
> +}
> +
> +static int quat_pcm_sample_rate_get(struct snd_kcontrol *kcontrol,
> +				    struct snd_ctl_elem_value *ucontrol)
> +{
> +	ucontrol->value.integer.value[0] =
> +		get_sample_rate_idx(quat_pcm_sample_rate);
> +	return 0;
> +}
> +
> +static int get_sample_rate(int idx)
> +{
> +	int sample_rate_val = 0;
> +
> +	switch (idx) {
> +	case 0:
> +		sample_rate_val = 8000;
> +		break;
> +	case 1:
> +	default:
> +		sample_rate_val = 16000;
> +		break;
> +	}
> +
> +	return sample_rate_val;
> +}
> +
> +static int pri_pcm_sample_rate_put(struct snd_kcontrol *kcontrol,
> +				   struct snd_ctl_elem_value *ucontrol)
> +{
> +	pri_pcm_sample_rate =
> +		get_sample_rate(ucontrol->value.integer.value[0]);
> +	return 0;
> +}
> +
> +static int quat_pcm_sample_rate_put(struct snd_kcontrol *kcontrol,
> +				    struct snd_ctl_elem_value *ucontrol)
> +{
> +	quat_pcm_sample_rate =
> +		get_sample_rate(ucontrol->value.integer.value[0]);
> +	return 0;
> +}
> +
> +static const struct snd_kcontrol_new card_controls[] = {
> +	SOC_ENUM_EXT("PRI_PCM SampleRate", pcm_snd_enum,
> +		     pri_pcm_sample_rate_get, pri_pcm_sample_rate_put),
> +	SOC_ENUM_EXT("QUAT_PCM SampleRate", pcm_snd_enum,
> +		     quat_pcm_sample_rate_get, quat_pcm_sample_rate_put),
> +};
> +
>   static int apq8096_init(struct snd_soc_pcm_runtime *rtd)
>   {
>   	struct snd_soc_dai *codec_dai = rtd->codec_dai;
> @@ -182,6 +267,9 @@ static int apq8096_platform_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto err_card_register;
>   
> +	snd_soc_add_card_controls(card, card_controls,
> +				  ARRAY_SIZE(card_controls));
> +
>   	return 0;
>   
>   err_card_register:
> 


-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.