Re: [PATCH 1/2] ASoC: codecs: wsa883x: do not set can_multi_write flag

From: Srinivas Kandagatla
Date: Wed May 24 2023 - 05:43:10 EST

On 24/05/2023 09:57, Mark Brown wrote:
On Wed, May 24, 2023 at 09:51:00AM +0100, Srinivas Kandagatla wrote:
On 23/05/2023 17:55, Mark Brown wrote:

Does the CODEC support mulitple writes? If so it seems better to leave

No, the codec itself does not support multi-write. All the codec register
level interface is via SoundWire Bus. which also does not support with the
existing code.

I'm unclear, is this a limitation of the hardware or of the current
Soundwire code?

Its both.

Codec itself does not have any private write callback to support this and AFAIU Qualcomm Soundwire controller does not have any such hw facility to program multi-registers for device at one shot.

Also to note, the current state of code soundwire regmap write callback assumes that the request to write will always have base address at the start followed by register values. This is not true for multi-register writes which comes in address-value-padding pairs.

Am confused on the multi_write feature and looking at regmap bus level write callback.

Is write callback used for both Bulk writes and multi-writes?

Is multi-write feature of regmap bus or device?