[alsa-devel] [PATCH 2/2] ASoC: cs35l36: Add device tree documentation for CS35L36

[Mark Brown]

On Tue, Nov 13, 2018 at 12:49:17PM -0600, James Schulman wrote:

> +  - cirrus,amp-gain-zc : Boolean to determine if to use Amplifier gain-change
> +  zero-cross

Why is this a DT setting and not either enabled unconditionally or set
from userspace (many devices do the latter)?  It seems like more of a
use case dependent setting than a feature of the board.

> +  - cirrus,ldm-mode-select : Amplifier level-dependent muting enable mode selection.
> +  Configures whether the amplifier level-dependent muting is enabled for the various
> +  blocks when the selected audio source has been below the AMP_LDM_THLD for a period
> +  of time configured by AMP_LDM_DELAY. Any and all bits can be set.

Might the user not want to set these at runtime?

> +  - cirrus,pdm-ldm-exit : Boolean : Amplifier PDM mode digital volume ramp enable.
> +  When AMP_PDM_MODE = 1 controls whether the digital volume soft ramp is enabled
> +  or disabled when exiting a level-dependent muted condition. The AMP_RAMP_PDM_DN
> +  control is used to control desired ramp rate.

This also seems like a use case dependent thing.

> +  - cirrus,imon-pol-inv : Boolean to determine Amplifier will invert the
> +  polarity of outbound IMON feedback data
> +
> +  - cirrus,vmon-pol-inv : Boolean to determine Amplifier will invert the
> +  polarity of outbound VMON feedback data

Why might anyone ever want to set these?

> +  - cirrus,pdm-channel-select : PDM Channel select.
> +  0x00 (Default) : Selects Channel A data when the PDM audio input is selected.
> +  0x01 : Selects Channel B data when the PDM audio input is selected

This looks like routing control, shouldn't it be in DAPM?
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