[0/7] PinePhone BT audio bringup

Message

Samuel Holland Nov. 6, 2020, 4:15 a.m. UTC

This series makes use of the additional DAIs recently added to the
sun8i-codec driver to add hardware routing for BT SCO (headset) audio
on the PinePhone.

The BT audio connection is represented by the "dummy" bt-sco codec. The
connection to the Quectel EG-25G modem via AIF2 works as well, but I do
not include it here because there is no appropriate codec driver in
tree. We have been using an out-of-tree "dummy" codec driver similar to
bt-sco, and I'm not sure if such a driver would be desired upstream.

The modem has a similar amount of configurability as the rtl8723cs BT
chip. For the BT chip, the DAI format and PCM parameters are set in a
configuration firmware file and loaded at driver load time. For the
modem, the DAI format and PCM parameters are set by (and can be queried
from) an AT command. However, this AT command requires a modem restart
to take effect, so the parameters cannot feasibly be changed at runtime.

With a dummy driver, we pick some "standard" set of PCM parameters, e.g.
16 bit mono at 8 or 16 kHz, and assume the hardware agrees. Similarly,
we assume the DAI format pre-programmed in the remote hardware matches
what is configured in the DAI link (in this case, in the device tree).

Is that the right way to model this? Or does the modem (and maybe even
the BT chip) deserve a more featureful driver that reads and/or programs
the format and params at probe time?

Because of those unanswered questions, I'm sending BT SCO support
first/only.

Regards,
Samuel

Arnaud Ferraris (1):
  arm64: dts: allwinner: pinephone: Set audio card name

Samuel Holland (6):
  ASoC: dt-bindings: sun8i-codec: Increase #sound-dai-cells
  ARM: dts: sun8i-a33: Allow using multiple codec DAIs
  arm64: dts: allwinner: a64: Allow using multiple codec DAIs
  arm64: dts: allwinner: a64: Add pinmux nodes for AIF2/AIF3
  arm64: dts: allwinner: a64: Allow multiple DAI links
  arm64: dts: allwinner: pinephone: Add support for Bluetooth audio

 .../sound/allwinner,sun8i-a33-codec.yaml      |  2 +-
 arch/arm/boot/dts/sun8i-a33.dtsi              |  4 +-
 .../dts/allwinner/sun50i-a64-pinephone.dtsi   | 25 +++++++++++++
 arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 37 ++++++++++++++-----
 4 files changed, 55 insertions(+), 13 deletions(-)

Comments

Chen-Yu Tsai Nov. 6, 2020, 4:28 a.m. UTC | #1

Hi,

On Fri, Nov 6, 2020 at 12:15 PM Samuel Holland <[e-mail]> wrote:
>
> This series makes use of the additional DAIs recently added to the
> sun8i-codec driver to add hardware routing for BT SCO (headset) audio
> on the PinePhone.
>
> The BT audio connection is represented by the "dummy" bt-sco codec. The
> connection to the Quectel EG-25G modem via AIF2 works as well, but I do
> not include it here because there is no appropriate codec driver in
> tree. We have been using an out-of-tree "dummy" codec driver similar to
> bt-sco, and I'm not sure if such a driver would be desired upstream.
>
> The modem has a similar amount of configurability as the rtl8723cs BT
> chip. For the BT chip, the DAI format and PCM parameters are set in a
> configuration firmware file and loaded at driver load time. For the
> modem, the DAI format and PCM parameters are set by (and can be queried
> from) an AT command. However, this AT command requires a modem restart
> to take effect, so the parameters cannot feasibly be changed at runtime.
>
> With a dummy driver, we pick some "standard" set of PCM parameters, e.g.
> 16 bit mono at 8 or 16 kHz, and assume the hardware agrees. Similarly,
> we assume the DAI format pre-programmed in the remote hardware matches
> what is configured in the DAI link (in this case, in the device tree).
>
> Is that the right way to model this? Or does the modem (and maybe even
> the BT chip) deserve a more featureful driver that reads and/or programs
> the format and params at probe time?

FYI there's a "Bluetooth: Allow to use configure SCO socket codec parameters"
thread on the bluetooth mailing list which is still unresolved AFAICT.

You might want to take a look at it.

ChenYu

> Because of those unanswered questions, I'm sending BT SCO support
> first/only.
>
> Regards,
> Samuel
>
> Arnaud Ferraris (1):
>   arm64: dts: allwinner: pinephone: Set audio card name
>
> Samuel Holland (6):
>   ASoC: dt-bindings: sun8i-codec: Increase #sound-dai-cells
>   ARM: dts: sun8i-a33: Allow using multiple codec DAIs
>   arm64: dts: allwinner: a64: Allow using multiple codec DAIs
>   arm64: dts: allwinner: a64: Add pinmux nodes for AIF2/AIF3
>   arm64: dts: allwinner: a64: Allow multiple DAI links
>   arm64: dts: allwinner: pinephone: Add support for Bluetooth audio
>
>  .../sound/allwinner,sun8i-a33-codec.yaml      |  2 +-
>  arch/arm/boot/dts/sun8i-a33.dtsi              |  4 +-
>  .../dts/allwinner/sun50i-a64-pinephone.dtsi   | 25 +++++++++++++
>  arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 37 ++++++++++++++-----
>  4 files changed, 55 insertions(+), 13 deletions(-)
>
> --
> 2.26.2
>