linux-kernel - [RFC] Volume control across multiple registers

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Message-ID: <2f74b971-4a6a-016f-8121-4da941eeccef@ti.com>
Date:   Wed, 19 Feb 2020 15:11:47 -0600
From:   Dan Murphy <dmurphy@...com>
To:     <lgirdwood@...il.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>
CC:     <alsa-devel@...a-project.org>, <linux-kernel@...r.kernel.org>
Subject: [RFC] Volume control across multiple registers

Hello!

I am trying to figure out how to control the volume of a speaker device 
with full volume control spread out across 4 8bit registers.

The standard TLV calls only allow a single register for volume control.  
But I have 4 I need to touch to get a full range of volume from 0dB to 
-110dB.

I was looking at using the DAPM calls and use PGA_E and define an event 
but there really is no good way to get the current volume setting.

I don't see any example of this in any current driver.

Any guidance is appreciated.

Dan