[alsa-devel] [PATCH 2/7] ASoC: ac97: Add support for resetting device before registration

[Lars-Peter Clausen]

AC97 devices need to be initially reset before they can be used. Currently
each driver does this on its own.

Add support for resetting the device to core in snd_soc_new_ac97_codec().
If the caller supplies a device ID and device ID mask the function will
reset the device and verify that it has the correct ID, if it does not a
error is returned.

This will allow to remove custom code with similar functionality from
individual drivers.

Signed-off-by: Lars-Peter Clausen <lars at metafoo.de>
---
 include/sound/soc.h         |  3 ++-
 sound/soc/codecs/ad1980.c   |  2 +-
 sound/soc/codecs/stac9766.c |  2 +-
 sound/soc/soc-ac97.c        | 30 +++++++++++++++++++++++++-----
 4 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/include/sound/soc.h b/include/sound/soc.h
index add5097..4cef20e 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -526,7 +526,8 @@ int snd_soc_test_bits(struct snd_soc_codec *codec, unsigned int reg,
 
 #ifdef CONFIG_SND_SOC_AC97_BUS
 struct snd_ac97 *snd_soc_alloc_ac97_codec(struct snd_soc_codec *codec);
-struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec);
+struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec,
+	unsigned int id, unsigned int id_mask);
 void snd_soc_free_ac97_codec(struct snd_ac97 *ac97);
 
 int snd_soc_set_ac97_ops(struct snd_ac97_bus_ops *ops);
diff --git a/sound/soc/codecs/ad1980.c b/sound/soc/codecs/ad1980.c
index 3cc69a6..d9cb81d 100644
--- a/sound/soc/codecs/ad1980.c
+++ b/sound/soc/codecs/ad1980.c
@@ -240,7 +240,7 @@ static int ad1980_soc_probe(struct snd_soc_codec *codec)
 	u16 vendor_id2;
 	u16 ext_status;
 
-	ac97 = snd_soc_new_ac97_codec(codec);
+	ac97 = snd_soc_new_ac97_codec(codec, 0, 0);
 	if (IS_ERR(ac97)) {
 		ret = PTR_ERR(ac97);
 		dev_err(codec->dev, "Failed to register AC97 codec: %d\n", ret);
diff --git a/sound/soc/codecs/stac9766.c b/sound/soc/codecs/stac9766.c
index ed4cca7..c602830 100644
--- a/sound/soc/codecs/stac9766.c
+++ b/sound/soc/codecs/stac9766.c
@@ -332,7 +332,7 @@ static int stac9766_codec_probe(struct snd_soc_codec *codec)
 	struct snd_ac97 *ac97;
 	int ret = 0;
 
-	ac97 = snd_soc_new_ac97_codec(codec);
+	ac97 = snd_soc_new_ac97_codec(codec, 0, 0);
 	if (IS_ERR(ac97))
 		return PTR_ERR(ac97);
 
diff --git a/sound/soc/soc-ac97.c b/sound/soc/soc-ac97.c
index 08d7259..d40efc9 100644
--- a/sound/soc/soc-ac97.c
+++ b/sound/soc/soc-ac97.c
@@ -85,10 +85,19 @@ EXPORT_SYMBOL(snd_soc_alloc_ac97_codec);
 /**
  * snd_soc_new_ac97_codec - initailise AC97 device
  * @codec: audio codec
+ * @id: The expected device ID
+ * @id_mask: Mask that is applied to the device ID before comparing with @id
  *
  * Initialises AC97 codec resources for use by ad-hoc devices only.
+ *
+ * If @id is not 0 this function will reset the device, then read the ID from
+ * the device and check if it matches the expected ID. If it doesn't match an
+ * error will be returned and device will not be registered.
+ *
+ * Returns: A PTR_ERR() on failure or a valid snd_ac97 struct on success.
  */
-struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec)
+struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec,
+	unsigned int id, unsigned int id_mask)
 {
 	struct snd_ac97 *ac97;
 	int ret;
@@ -97,13 +106,24 @@ struct snd_ac97 *snd_soc_new_ac97_codec(struct snd_soc_codec *codec)
 	if (IS_ERR(ac97))
 		return ac97;
 
-	ret = device_add(&ac97->dev);
-	if (ret) {
-		put_device(&ac97->dev);
-		return ERR_PTR(ret);
+	if (id) {
+		ret = snd_ac97_reset(ac97, false, id, id_mask);
+		if (ret < 0) {
+			dev_err(codec->dev, "Failed to reset AC97 device: %d\n",
+				ret);
+			goto err_put_device;
+		}
 	}
 
+	ret = device_add(&ac97->dev);
+	if (ret)
+		goto err_put_device;
+
 	return ac97;
+
+err_put_device:
+	put_device(&ac97->dev);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(snd_soc_new_ac97_codec);
 
-- 
2.1.4