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>

1 files changed, 47 insertions, 1 deletions

diff --git a/sound/soc/generic/audio-graph-card.c b/sound/soc/generic/audio-graph-card.c
index ee752f62d89d..105ec3a6e30d 100644
--- 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) {