ASoC: audio-graph-card: add widgets and routing for external amplifier support

It's very common that audio card has a machine level amplifier which is
controlled by GPIO.  The patch adds DAPM widgets and routing support
into audio-graph-card driver, and creates an output driver widget with
event to control the amplifier via GPIO.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index ee752f6..105ec3a 100644 (file)
--- a/sound/soc/generic/audio-graph-card.c
+++ b/sound/soc/generic/audio-graph-card.c
@@ -13,6 +13,7 @@
 #include <linux/clk.h>
 #include <linux/device.h>
 #include <linux/gpio.h>
+#include <linux/gpio/consumer.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
@@ -30,6 +31,34 @@ struct graph_card_data {
                struct asoc_simple_dai codec_dai;
        } *dai_props;
        struct snd_soc_dai_link *dai_link;
+       struct gpio_desc *pa_gpio;
+};
+
+static int asoc_graph_card_outdrv_event(struct snd_soc_dapm_widget *w,
+                                       struct snd_kcontrol *kcontrol,
+                                       int event)
+{
+       struct snd_soc_dapm_context *dapm = w->dapm;
+       struct graph_card_data *priv = snd_soc_card_get_drvdata(dapm->card);
+
+       switch (event) {
+       case SND_SOC_DAPM_POST_PMU:
+               gpiod_set_value_cansleep(priv->pa_gpio, 1);
+               break;
+       case SND_SOC_DAPM_PRE_PMD:
+               gpiod_set_value_cansleep(priv->pa_gpio, 0);
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static const struct snd_soc_dapm_widget asoc_graph_card_dapm_widgets[] = {
+       SND_SOC_DAPM_OUT_DRV_E("Amplifier", SND_SOC_NOPM,
+                              0, 0, NULL, 0, asoc_graph_card_outdrv_event,
+                              SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
 };
 
 #define graph_priv_to_card(priv) (&(priv)->snd_card)
@@ -180,8 +209,16 @@ static int asoc_graph_card_parse_of(struct graph_card_data *priv)
        int rc, idx = 0;
        int ret;
 
+       ret = asoc_simple_card_of_parse_widgets(card, NULL);
+       if (ret < 0)
+               return ret;
+
+       ret = asoc_simple_card_of_parse_routing(card, NULL, 1);
+       if (ret < 0)
+               return ret;
+
        /*
-        * we need to consider "widgets", "routing", "mclk-fs" around here
+        * we need to consider "mclk-fs" around here
         * see simple-card
         */
 
@@ -233,6 +270,13 @@ static int asoc_graph_card_probe(struct platform_device *pdev)
        if (!dai_props || !dai_link)
                return -ENOMEM;
 
+       priv->pa_gpio = devm_gpiod_get_optional(dev, "pa", GPIOD_OUT_LOW);
+       if (IS_ERR(priv->pa_gpio)) {
+               ret = PTR_ERR(priv->pa_gpio);
+               dev_err(dev, "failed to get amplifier gpio: %d\n", ret);
+               return ret;
+       }
+
        priv->dai_props                 = dai_props;
        priv->dai_link                  = dai_link;
 
@@ -242,6 +286,8 @@ static int asoc_graph_card_probe(struct platform_device *pdev)
        card->dev       = dev;
        card->dai_link  = dai_link;
        card->num_links = num;
+       card->dapm_widgets = asoc_graph_card_dapm_widgets;
+       card->num_dapm_widgets = ARRAY_SIZE(asoc_graph_card_dapm_widgets);
 
        ret = asoc_graph_card_parse_of(priv);
        if (ret < 0) {