On Wed, 13 Jan 2016 12:09:49 +0100,
libin.yang@xxxxxxxxxxxxxxx wrote:
>
> From: Libin Yang <libin.yang@xxxxxxxxxxxxxxx>
>
> Add snd_hda_get_dev_select() and snd_hda_set_dev_select() functions
> for DP MST audio support.
>
> Signed-off-by: Libin Yang <libin.yang@xxxxxxxxxxxxxxx>
> ---
> sound/pci/hda/hda_codec.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
> sound/pci/hda/hda_codec.h | 2 ++
> 2 files changed, 56 insertions(+)
>
> diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
> index 8374188..95baaba 100644
> --- a/sound/pci/hda/hda_codec.c
> +++ b/sound/pci/hda/hda_codec.c
> @@ -368,6 +368,60 @@ int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid,
> return devices;
> }
>
> +/**
> + * snd_hda_get_dev_select - get device entry select on the pin
> + * @codec: the HDA codec
> + * @nid: NID of the pin to get device entry select
> + *
> + * Get the devcie entry select on the pin. Return the device entry
> + * id selected on the pin. Return 0 means the first device entry
> + * is selected or MST is not supported.
> + */
> +int snd_hda_get_dev_select(struct hda_codec *codec, hda_nid_t nid)
> +{
> + /* not support dp_mst will always return 0, using first dev_entry */
> + if (!codec->dp_mst)
> + return 0;
> +
> + return snd_hda_codec_read(codec, nid, 0, AC_VERB_GET_DEVICE_SEL, 0);
> +}
> +EXPORT_SYMBOL_GPL(snd_hda_get_dev_select);
> +
> +/**
> + * snd_hda_set_dev_select - set device entry select on the pin
> + * @codec: the HDA codec
> + * @nid: NID of the pin to set device entry select
> + * @dev_id: device entry id to be set
> + *
> + * Set the device entry select on the pin nid.
The return code isn't clearly defined.
Other than that, it looks OK. But I prefer merging this rather
together with its caller (unless a complex dependency exists).
thanks,
Takashi
> + */
> +int snd_hda_set_dev_select(struct hda_codec *codec, hda_nid_t nid, int dev_id)
> +{
> + int ret, dev;
> + unsigned long timeout;
> +
> + /* not support dp_mst will always return 0, using first dev_entry */
> + if (!codec->dp_mst)
> + return 0;
> +
> + timeout = jiffies + msecs_to_jiffies(500);
> +
> + /* make sure the device entry selection takes effect */
> + do {
> + ret = snd_hda_codec_write(codec, nid, 0,
> + AC_VERB_SET_DEVICE_SEL, dev_id);
> + udelay(20);
> +
> + dev = snd_hda_get_dev_select(codec, nid);
> + if (dev == dev_id)
> + break;
> + msleep(20);
> + } while (time_before(jiffies, timeout));
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(snd_hda_set_dev_select);
> +
> /*
> * read widget caps for each widget and store in cache
> */
> diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h
> index 373fcad..22bcad6 100644
> --- a/sound/pci/hda/hda_codec.h
> +++ b/sound/pci/hda/hda_codec.h
> @@ -349,6 +349,8 @@ int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux,
> hda_nid_t nid, int recursive);
> int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid,
> u8 *dev_list, int max_devices);
> +int snd_hda_get_dev_select(struct hda_codec *codec, hda_nid_t nid);
> +int snd_hda_set_dev_select(struct hda_codec *codec, hda_nid_t nid, int dev_id);
>
> struct hda_verb {
> hda_nid_t nid;
> --
> 1.9.1
>
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