Message-ID: <CACqcpZCSMwj2WOhX0ddD43VKCgOcNyrkkZrR0sWEsHE+H27TVg@mail.gmail.com>
Date:	Tue, 24 Nov 2015 09:21:55 +0100
From:	Raphaël Poggi <poggi.raph@...il.com>
To:	Michael Trimarchi <michael@...rulasolutions.com>
Cc:	perex@...ex.cz, tiwai@...e.com,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [alsa-devel] [PATCH 4/4] sound: codecs: pcm1792a: introduce
 channel side

Hi,

2015-11-21 10:37 GMT+01:00 Michael Trimarchi <michael@...rulasolutions.com>:
> Hi
>
> On Fri, Nov 20, 2015 at 11:09 AM, Raphael Poggi <poggi.raph@...il.com> wrote:
>> From: Raphael Poggi <poggi.raph@...il.com>
>>
>> Add possibility to choose the channel side using the device tree,
>> and also modify it using alsa ctrl.
>>
>> Signed-off-by: Raphael Poggi <poggi.raph@...il.com>
>> ---
>>  sound/soc/codecs/pcm1792a.c | 46 +++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 46 insertions(+)
>>
>> diff --git a/sound/soc/codecs/pcm1792a.c b/sound/soc/codecs/pcm1792a.c
>> index febaa48..005b679 100644
>> --- a/sound/soc/codecs/pcm1792a.c
>> +++ b/sound/soc/codecs/pcm1792a.c
>> @@ -65,6 +65,12 @@ static const struct reg_default pcm1792a_reg_defaults[] = {
>>         { PCM1792A_DEVICE_ID, 0x00 },
>>  };
>>
>> +enum __pcm1792_side {
>> +       STEREO,
>> +       MONORAL_LEFT,
>> +       MONORAL_RIGHT
>> +};
>> +
>>  static bool pcm1792a_accessible_reg(struct device *dev, unsigned int reg)
>>  {
>>         return reg >= 0x10 && reg <= 0x17;
>> @@ -83,6 +89,7 @@ struct pcm1792a_private {
>>         struct regmap *regmap;
>>         unsigned int format;
>>         unsigned int rate;
>> +       unsigned int side;
>>  };
>>
>>  static int pcm1792a_set_dai_fmt(struct snd_soc_dai *codec_dai,
>> @@ -153,6 +160,13 @@ static int pcm1792a_hw_params(struct snd_pcm_substream *substream,
>>         ret = regmap_update_bits(priv->regmap, PCM1792A_FMT_CONTROL,
>>                                  PCM1792A_FMT_MASK | PCM1792A_ATLD_ENABLE, val);
>>
>> +       if (priv->side == MONORAL_LEFT)
>> +               val = PCM1792A_CHANNEL_MONO_LEFT;
>> +       else if (priv->side == MONORAL_RIGHT)
>> +               val = PCM1792A_CHANNEL_MONO_RIGHT;
>> +
>> +       regmap_update_bits(priv->regmap, PCM1792A_CHANNEL, PCM1792A_CHANNEL_MONO_MASK, val);
>> +
>>         return ret;
>>  }
>>
>> @@ -222,10 +236,31 @@ static struct snd_soc_codec_driver soc_codec_dev_pcm1792a = {
>>         .num_dapm_routes        = ARRAY_SIZE(pcm1792a_dapm_routes),
>>  };
>>
>> +static int pcm1792a_of_init(struct spi_device *spi)
>> +{
>> +       int ret = 0;
>> +       struct pcm1792a_private *pcm1792a = dev_get_drvdata(&spi->dev);
>> +       const char *name;
>> +       struct device_node *np = spi->dev.of_node;
>> +
>> +       name = of_get_property(np, "ti,side", NULL);
>> +       if (name) {
>> +               if (!strcmp(name, "left"))
>> +                       pcm1792a->side = MONORAL_LEFT;
>> +               else
>> +                       pcm1792a->side = MONORAL_RIGHT;
>> +       }
>> +       else
>> +               pcm1792a->side = STEREO;
>> +
>> +       return ret;
>> +}
>> +
>>  static int pcm1792a_spi_probe(struct spi_device *spi)
>>  {
>>         struct pcm1792a_private *pcm1792a;
>>         int ret;
>> +       struct device_node *np = spi->dev.of_node;
>>
>>         pcm1792a = devm_kzalloc(&spi->dev, sizeof(struct pcm1792a_private),
>>                                 GFP_KERNEL);
>> @@ -241,6 +276,17 @@ static int pcm1792a_spi_probe(struct spi_device *spi)
>>                 return ret;
>>         }
>>
>> +       if (np) {
>> +               ret = pcm1792a_of_init(spi);
>> +               if (ret)
>> +                       return ret;
>> +       }
>> +
>> +       if (pcm1792a->side == MONORAL_LEFT)
>> +               regmap_update_bits(pcm1792a->regmap, PCM1792A_CHANNEL, PCM1792A_CHANNEL_MONO_MASK, PCM1792A_CHANNEL_MONO_LEFT);
>> +       else if (pcm1792a->side == MONORAL_RIGHT)
>> +               regmap_update_bits(pcm1792a->regmap, PCM1792A_CHANNEL, PCM1792A_CHANNEL_MONO_MASK, PCM1792A_CHANNEL_MONO_RIGHT);
>> +
>
> Why this is a part of dts and not a part of mixer control?
>
> Michael
>

The "channel side" bindings should be used when the pcm7192a is used
in monaural mode (which requires two DACs, both DACs operate in a
balanced mode for one channel of audio input data).
This is a hardware level design, it will never change at runtime.
I feel that a device tree binding is more appropriate than a control.

>>         return snd_soc_register_codec(&spi->dev,
>>                         &soc_codec_dev_pcm1792a, &pcm1792a_dai, 1);
>>  }
>> --
>> 2.1.0
>>
>> _______________________________________________
>> Alsa-devel mailing list
>> Alsa-devel@...a-project.org
>> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
>
>
>
> --
> | Michael Nazzareno Trimarchi                     Amarula Solutions BV |
> | COO  -  Founder                                      Cruquiuskade 47 |
> | +31(0)851119172                                 Amsterdam 1018 AM NL |
> |                  [`as] http://www.amarulasolutions.com               |
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