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

On 7/1/08, Grant Likely [off-list ref] wrote:

From: Grant Likely <redacted>

 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.
 ---

  sound/soc/Kconfig  |    6 ++
  sound/soc/Makefile |    1
  sound/soc/soc-of.c |  171 ++++++++++++++++++++++++++++++++++++++++++++++++++++
  3 files changed, 178 insertions(+), 0 deletions(-)

 diff --git a/sound/soc/Kconfig b/sound/soc/Kconfig
 index 18f28ac..c5736e5 100644
 --- a/sound/soc/Kconfig
 +++ b/sound/soc/Kconfig
 @@ -23,6 +23,12 @@ 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 "OF helpers for SoC audio support"
 +       depends on SND_SOC
 +       ---help---
 +         Add support for OpenFirmware device tree descriptions of sound device
 +
  # 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..9694979
 --- /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 [off-list ref]");
 +MODULE_LICENSE("GPL");
 +MODULE_DESCRIPTION("ALSA SoC OpenFirmware bindings");
 +
 +DEFINE_MUTEX(of_snd_soc_mutex);
 +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;
 +       }

Is there a driver for this device?  Is another file missing?
sof_of.h is missing too.

 +
 +}
 +
 +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);

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-- 
Jon Smirl
jonsmirl@gmail.com