ASoC: core: add a helper for extended byte controls using TLV

ALSA supports arbitrary length TLVs for each kcontrol that can be used
to pass metadata about the control (e.g. volumes, enum information). The
same transport mechanism is now used for arbitrary length data by
defining a new helper.

Signed-off-by: Omair Mohammed Abdullah <omair.m.abdullah@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index b87d7d882e6d..a9ce63f634b2 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -3267,6 +3267,27 @@ int snd_soc_bytes_info_ext(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_GPL(snd_soc_bytes_info_ext);
 
+int snd_soc_bytes_tlv_callback(struct snd_kcontrol *kcontrol, int op_flag,
+                                unsigned int size, unsigned int __user *tlv)
+{
+        struct soc_bytes_ext *params = (void *)kcontrol->private_value;
+        unsigned int count = size < params->max ? size : params->max;
+        int ret = -ENXIO;
+
+        switch (op_flag) {
+        case SNDRV_CTL_TLV_OP_READ:
+                if (params->get)
+                        ret = params->get(tlv, count);
+                break;
+        case SNDRV_CTL_TLV_OP_WRITE:
+                if (params->put)
+                        ret = params->put(tlv, count);
+                break;
+        }
+        return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_bytes_tlv_callback);
+
 /**
  * snd_soc_info_xr_sx - signed multi register info callback
  * @kcontrol: mreg control