Subject: Re: [PATCH v2 1/3] ALSA SoC: Add OpenFirmware helper for matching bus and codec drivers

From: Anton Vorontsov <[email-masked]>
Date: Mon, 14 Jul 2008 18:16:06 +0400

On Sat, Jul 12, 2008 at 02:39:29AM -0600, Grant Likely wrote:
> From: Grant Likely <[email-masked]>
> 
> 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.
> ---
[...]
> --- /dev/null
> +++ b/sound/soc/soc-of.c

It's quite inconvenient to spread the firmware-specific bits over the
whole kernel source tree. So, can we place this in driver/of/, just as
we did for i2c, spi and gpio?

> @@ -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 <[email-masked]>");
> +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);

Thanks,

-- 
Anton Vorontsov
email: [email-masked]
irc://irc.freenode.net/bd2