ASoC: Add more natural support for no-DMA DAIs

Since we can now support multiple platforms allow machines to not specify
a platform in a DAI link. Since the rest of the code requires that we have
a struct device for all objects we do this by substituting in a dummy
device that we register automatically.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Jassi Brar <jassisinghbrar@gmail.com>
Acked-by: Liam Girdwood <lrg@ti.com>

2 files changed, 66 insertions, 5 deletions

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index 9dc13113fa26..16be3e5cf9e7 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1299,6 +1299,7 @@ static int soc_bind_dai_link(struct snd_soc_card *card, int num)
         struct snd_soc_codec *codec;
         struct snd_soc_platform *platform;
         struct snd_soc_dai *codec_dai, *cpu_dai;
+        const char *platform_name;
 
         if (rtd->complete)
                 return 1;
@@ -1351,13 +1352,18 @@ find_codec:
                         dai_link->codec_name);
 
 find_platform:
-        /* do we already have the CODEC DAI for this link ? */
-        if (rtd->platform) {
+        /* do we need a platform? */
+        if (rtd->platform)
                 goto out;
-        }
-        /* no, then find CPU DAI from registered DAIs*/
+
+        /* if there's no platform we match on the empty platform */
+        platform_name = dai_link->platform_name;
+        if (!platform_name)
+                platform_name = "snd-soc-dummy";
+
+        /* no, then find one from the set of registered platforms */
         list_for_each_entry(platform, &platform_list, list) {
-                if (!strcmp(platform->name, dai_link->platform_name)) {
+                if (!strcmp(platform->name, platform_name)) {
                         rtd->platform = platform;
                         goto out;
                 }
diff --git a/sound/soc/soc-utils.c b/sound/soc/soc-utils.c
index 3f45e6a439bf..286579140882 100644
--- a/sound/soc/soc-utils.c
+++ b/sound/soc/soc-utils.c
@@ -13,6 +13,7 @@
  *  option) any later version.
  */
 
+#include <linux/platform_device.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -55,3 +56,57 @@ int snd_soc_params_to_bclk(struct snd_pcm_hw_params *params)
                 return ret;
 }
 EXPORT_SYMBOL_GPL(snd_soc_params_to_bclk);
+
+static struct snd_soc_platform_driver dummy_platform;
+
+static __devinit int snd_soc_dummy_probe(struct platform_device *pdev)
+{
+        return snd_soc_register_platform(&pdev->dev, &dummy_platform);
+}
+
+static __devexit int snd_soc_dummy_remove(struct platform_device *pdev)
+{
+        snd_soc_unregister_platform(&pdev->dev);
+
+        return 0;
+}
+
+static struct platform_driver soc_dummy_driver = {
+        .driver = {
+                .name = "snd-soc-dummy",
+                .owner = THIS_MODULE,
+        },
+        .probe = snd_soc_dummy_probe,
+        .remove = __devexit_p(snd_soc_dummy_remove),
+};
+
+static struct platform_device *soc_dummy_dev;
+
+static int __init snd_soc_util_init(void)
+{
+        int ret;
+
+        soc_dummy_dev = platform_device_alloc("snd-soc-dummy", -1);
+        if (!soc_dummy_dev)
+                return -ENOMEM;
+
+        ret = platform_device_add(soc_dummy_dev);
+        if (ret != 0) {
+                platform_device_put(soc_dummy_dev);
+                return ret;
+        }
+
+        ret = platform_driver_register(&soc_dummy_driver);
+        if (ret != 0)
+                platform_device_unregister(soc_dummy_dev);
+
+        return ret;
+}
+module_init(snd_soc_util_init);
+
+static void __exit snd_soc_util_exit(void)
+{
+        platform_device_unregister(soc_dummy_dev);
+        platform_driver_unregister(&soc_dummy_driver);
+}
+module_exit(snd_soc_util_exit);