[PATCH v2] ASoC: simple-card: add support for aux devices

[Nikita Yushchenko]

This patch makes it possible to use simple-card in setups where separate
amplifier chip is connected to codec's output.

Changes from v1:
- moved example usage from commit message to Documentation/, as
  suggested by Kuninori Morimoto,
- fixed typo in example usage.

Signed-off-by: Nikita Yushchenko <nikita.yo...@cogentembedded.com>
---
 .../devicetree/bindings/sound/simple-card.txt      | 37 ++++++++++++++++++++++
 sound/soc/generic/simple-card.c                    | 34 ++++++++++++++++++++
 2 files changed, 71 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/simple-card.txt 
b/Documentation/devicetree/bindings/sound/simple-card.txt
index 59d8628..c7a9393 100644
--- a/Documentation/devicetree/bindings/sound/simple-card.txt
+++ b/Documentation/devicetree/bindings/sound/simple-card.txt
@@ -22,6 +22,8 @@ Optional properties:
                                          headphones are attached.
 - simple-audio-card,mic-det-gpio       : Reference to GPIO that signals when
                                          a microphone is attached.
+- simple-audio-card,aux-devs           : List of phandles pointing to 
auxiliary devices, such
+                                         as amplifiers, to be added to the 
sound card.
 
 Optional subnodes:
 
@@ -162,3 +164,38 @@ sound {
                };
        };
 };
+
+Example 3 - route audio from IMX6 SSI2 through TLV320DAC3100 codec
+through TPA6130A2 amplifier to headphones:
+
+&i2c0 {
+       codec: tlv320dac3100@18 {
+               compatible = "ti,tlv320dac3100";
+               ...
+       }
+
+       amp: tpa6130a2@60 {
+               compatible = "ti,tpa6130a2";
+               ...
+       }
+}
+
+sound {
+       compatible = "simple-audio-card";
+       ...
+       simple-audio-card,widgets =
+               "Headphone", "Headphone Jack";
+       simple-audio-card,routing =
+               "Headphone Jack", "HPLEFT",
+               "Headphone Jack", "HPRIGHT",
+               "LEFTIN", "HPL",
+               "RIGHTIN", "HPR";
+       simple-audio-card,aux-devs = <&amp>;
+       simple-audio-card,cpu {
+               sound-dai = <&ssi2>;
+       };
+       simple-audio-card,codec {
+               sound-dai = <&codec>;
+               clocks = ...
+       };
+};
diff --git a/sound/soc/generic/simple-card.c b/sound/soc/generic/simple-card.c
index 43295f0..f989f34 100644
--- a/sound/soc/generic/simple-card.c
+++ b/sound/soc/generic/simple-card.c
@@ -417,6 +417,36 @@ dai_link_of_err:
        return ret;
 }
 
+static int asoc_simple_card_parse_aux_devs(struct device_node *node,
+                                          struct simple_card_data *priv)
+{
+       struct device *dev = simple_priv_to_dev(priv);
+       struct device_node *aux_node;
+       int i, n, len;
+
+       if (!of_find_property(node, PREFIX "aux-devs", &len))
+               return 0;               /* Ok to have no aux-devs */
+
+       n = len / sizeof(__be32);
+       if (n <= 0)
+               return -EINVAL;
+
+       priv->snd_card.aux_dev = devm_kzalloc(dev,
+                       n * sizeof(*priv->snd_card.aux_dev), GFP_KERNEL);
+       if (!priv->snd_card.aux_dev)
+               return -ENOMEM;
+
+       for (i = 0; i < n; i++) {
+               aux_node = of_parse_phandle(node, PREFIX "aux-devs", i);
+               if (!aux_node)
+                       return -EINVAL;
+               priv->snd_card.aux_dev[i].codec_of_node = aux_node;
+       }
+
+       priv->snd_card.num_aux_devs = n;
+       return 0;
+}
+
 static int asoc_simple_card_parse_of(struct device_node *node,
                                     struct simple_card_data *priv)
 {
@@ -474,6 +504,10 @@ static int asoc_simple_card_parse_of(struct device_node 
*node,
        if (ret)
                return ret;
 
+       ret = asoc_simple_card_parse_aux_devs(node, priv);
+       if (ret)
+               return ret;
+
        return 0;
 }
 
-- 
2.1.4