Re: [PATCH v3 3/6] ASoC: audio-graph-card: Support setting component plls and sysclks

From: Richard Fitzgerald
Date: Mon Dec 21 2020 - 05:39:42 EST


On 18/12/2020 00:03, Kuninori Morimoto wrote:

Hi Richard

Thank you for your patch.
This is v3 patch, but I think this is the first time for me
to receive patch...

Yes sorry.
Somehow I missed you off V1 and V2 emails.


Some codecs need plls and/or sysclks to be configured using the
snd_soc_component_set_[sysclk|pll] functions. These drivers cannot
necessarily be converted to use the clock framework. If the codec is on
a I2C/SPI bus, a nested clk_get would be needed to enable the bus clock.
But the clock framework does not support nested operations and this would
deadlock.

This patch adds new dt properties that list phandles of components with
the pll/sysclk settings to be applied. Multiple settings can be given for
the same phandle to allow for components with multiple clocks and plls.
The plls and sysclks are enabled when the card bias level moves to STANDBY
and disabled when it moves to OFF.

The implementation does not attempt to handle specifying complex clock
ordering interdependencies between components. The plls and sysclks are
applied to a component as it is passed to the card set_bias_level/
set_bias_level_post callbacks. It follows from this that the order
components are configured is the order that they are passed to those
callbacks.

Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
---
include/sound/simple_card_utils.h | 25 +++
sound/soc/generic/audio-graph-card.c | 16 +-
sound/soc/generic/simple-card-utils.c | 236 ++++++++++++++++++++++++++
3 files changed, 275 insertions(+), 2 deletions(-)

I understand that you need sysclk/pll and .set_bias_level_xxx().
But I guess makes it generic code is difficult (?).
Thus, as Sameer doing on Tegra, creating custom audio-graph-card is better
idea for you ?

# Now I'm creating new audio-graph-card2 which also supports
# overwriting/customizing each/all functions.
# It is not full compatible with audio-graph-card, but almost same if you
# uses normal connection.
# I hope I can post it next year

Thank you for your help !!

Best regards
---
Kuninori Morimoto