[alsa-devel] [PATCH v2 1/3] ALSA SoC: Add OpenFirmware helper for matching bus and codec drivers

[Grant Likely]

From: Grant Likely <grant.likely at secretlab.ca>

Simple utility layer for creating ASoC machine instances based on data
in the OpenFirmware device tree.  OF aware platform drivers and codec
drivers register themselves with this framework and the framework
automatically instantiates a machine driver.

This is most likely temporary glue code to work around limitations in
the ASoC v1 framework.  I expect ASoC v2 won't need this.
---

 include/sound/soc-of.h |   21 ++++++
 sound/soc/Kconfig      |    3 +
 sound/soc/Makefile     |    1 
 sound/soc/soc-of.c     |  171 ++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 196 insertions(+), 0 deletions(-)

diff --git a/include/sound/soc-of.h b/include/sound/soc-of.h
new file mode 100644
index 0000000..a963032
--- /dev/null
+++ b/include/sound/soc-of.h
@@ -0,0 +1,21 @@
+/*
+ * OF helpers for ALSA SoC
+ *
+ * Copyright (C) 2008, Secret Lab Technologies Ltd.
+ */
+
+#ifndef _INCLUDE_SOC_OF_H_
+#define _INCLUDE_SOC_OF_H_
+
+#include <linux/of.h>
+#include <sound/soc.h>
+
+int of_snd_soc_register_codec(struct snd_soc_codec_device *codec_dev,
+			      void *codec_data, struct snd_soc_codec_dai *dai,
+			      struct device_node *node);
+
+int of_snd_soc_register_platform(struct snd_soc_platform *platform,
+				 struct device_node *node,
+				 struct snd_soc_cpu_dai *cpu_dai);
+
+#endif /* _INCLUDE_SOC_OF_H_ */
diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
index 18f28ac..99118ed 100644
--- a/sound/soc/Kconfig
+++ b/sound/soc/Kconfig
@@ -23,6 +23,9 @@ config SND_SOC
 	  This ASoC audio support can also be built as a module.  If so, the module
 	  will be called snd-soc-core.
 
+config SND_SOC_OF
+	tristate
+
 # All the supported Soc's
 source "sound/soc/at91/Kconfig"
 source "sound/soc/pxa/Kconfig"
diff --git a/sound/soc/Makefile b/sound/soc/Makefile
index 782db21..191c2e5 100644
--- a/sound/soc/Makefile
+++ b/sound/soc/Makefile
@@ -2,3 +2,4 @@ snd-soc-core-objs := soc-core.o soc-dapm.o
 
 obj-$(CONFIG_SND_SOC)	+= snd-soc-core.o
 obj-$(CONFIG_SND_SOC)	+= codecs/ at91/ pxa/ s3c24xx/ sh/ fsl/ davinci/ omap/
+obj-$(CONFIG_SND_SOC_OF)	+= soc-of.o
diff --git a/sound/soc/soc-of.c b/sound/soc/soc-of.c
new file mode 100644
index 0000000..0c855df
--- /dev/null
+++ b/sound/soc/soc-of.c
@@ -0,0 +1,171 @@
+/*
+ * OF helpers for ALSA SoC Layer
+ *
+ * Copyright (C) 2008, Secret Lab Technologies Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/pm.h>
+#include <linux/bitops.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/soc-of.h>
+#include <sound/initval.h>
+
+MODULE_AUTHOR("Grant Likely <grant.likely at secretlab.ca>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("ALSA SoC OpenFirmware bindings");
+
+static DEFINE_MUTEX(of_snd_soc_mutex);
+static LIST_HEAD(of_snd_soc_device_list);
+static int of_snd_soc_next_index;
+
+struct of_snd_soc_device {
+	int id;
+	struct list_head list;
+	struct snd_soc_device device;
+	struct snd_soc_machine machine;
+	struct snd_soc_dai_link dai_link;
+	struct platform_device *pdev;
+	struct device_node *platform_node;
+	struct device_node *codec_node;
+};
+
+static struct snd_soc_ops of_snd_soc_ops = {
+};
+
+static struct of_snd_soc_device *
+of_snd_soc_get_device(struct device_node *codec_node)
+{
+	struct of_snd_soc_device *of_soc;
+
+	list_for_each_entry(of_soc, &of_snd_soc_device_list, list) {
+		if (of_soc->codec_node == codec_node)
+			return of_soc;
+	}
+
+	of_soc = kzalloc(sizeof(struct of_snd_soc_device), GFP_KERNEL);
+	if (!of_soc)
+		return NULL;
+
+	/* Initialize the structure and add it to the global list */
+	of_soc->codec_node = codec_node;
+	of_soc->id = of_snd_soc_next_index++;
+	of_soc->machine.dai_link = &of_soc->dai_link;
+	of_soc->machine.num_links = 1;
+	of_soc->device.machine = &of_soc->machine;
+	of_soc->dai_link.ops = &of_snd_soc_ops;
+	list_add(&of_soc->list, &of_snd_soc_device_list);
+
+	return of_soc;
+}
+
+static void of_snd_soc_register_device(struct of_snd_soc_device *of_soc)
+{
+	struct platform_device *pdev;
+	int rc;
+
+	/* Only register the device if both the codec and platform have
+	 * been registered */
+	if ((!of_soc->device.codec_data) || (!of_soc->platform_node))
+		return;
+
+	pr_info("platform<-->codec match achieved; registering machine\n");
+
+	pdev = platform_device_alloc("soc-audio", of_soc->id);
+	if (!pdev) {
+		pr_err("of_soc: platform_device_alloc() failed\n");
+		return;
+	}
+
+	pdev->dev.platform_data = of_soc;
+	platform_set_drvdata(pdev, &of_soc->device);
+	of_soc->device.dev = &pdev->dev;
+
+	/* The ASoC device is complete; register it */
+	rc = platform_device_add(pdev);
+	if (rc) {
+		pr_err("of_soc: platform_device_add() failed\n");
+		return;
+	}
+
+}
+
+int of_snd_soc_register_codec(struct snd_soc_codec_device *codec_dev,
+			      void *codec_data, struct snd_soc_codec_dai *dai,
+			      struct device_node *node)
+{
+	struct of_snd_soc_device *of_soc;
+	int rc = 0;
+
+	pr_info("registering ASoC codec driver: %s\n", node->full_name);
+
+	mutex_lock(&of_snd_soc_mutex);
+	of_soc = of_snd_soc_get_device(node);
+	if (!of_soc) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	/* Store the codec data */
+	of_soc->device.codec_data = codec_data;
+	of_soc->device.codec_dev = codec_dev;
+	of_soc->dai_link.name = node->name;
+	of_soc->dai_link.stream_name = node->name;
+	of_soc->dai_link.codec_dai = dai;
+
+	/* Now try to register the SoC device */
+	of_snd_soc_register_device(of_soc);
+
+ out:
+	mutex_unlock(&of_snd_soc_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(of_snd_soc_register_codec);
+
+int of_snd_soc_register_platform(struct snd_soc_platform *platform,
+				 struct device_node *node,
+				 struct snd_soc_cpu_dai *cpu_dai)
+{
+	struct of_snd_soc_device *of_soc;
+	struct device_node *codec_node;
+	const phandle *handle;
+	int len, rc = 0;
+
+	pr_info("registering ASoC platform driver: %s\n", node->full_name);
+
+	handle = of_get_property(node, "codec-handle", &len);
+	if (!handle || len < sizeof(handle))
+		return -ENODEV;
+	codec_node = of_find_node_by_phandle(*handle);
+	if (!codec_node)
+		return -ENODEV;
+	pr_info("looking for codec: %s\n", codec_node->full_name);
+
+	mutex_lock(&of_snd_soc_mutex);
+	of_soc = of_snd_soc_get_device(codec_node);
+	if (!of_soc) {
+		rc = -ENOMEM;
+		goto out;
+	}
+
+	of_soc->platform_node = node;
+	of_soc->dai_link.cpu_dai = cpu_dai;
+	of_soc->device.platform = platform;
+	of_soc->machine.name = of_soc->dai_link.cpu_dai->name;
+
+	/* Now try to register the SoC device */
+	of_snd_soc_register_device(of_soc);
+
+ out:
+	mutex_unlock(&of_snd_soc_mutex);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(of_snd_soc_register_platform);