On Fri, Aug 27, 2021 at 03:03:52PM +0530, Sameer Pujar wrote:
The Master Volume Control (MVC) provides gain or attenuation to a digital signal path. It can be used in input or output signal path for per-stream volume control or it can be used as master volume control. The MVC block has one input and one output. The input digital stream can be mono or multi-channel (up to 7.1 channels) stream. An independent mute control is also included in the MVC block.
Looks like it's also got a little bit of other DSP in there (a simple EQ?). Not that it really matters.
- if (reg == TEGRA210_MVC_CTRL) {
u32 val;u8 mute_mask;
- } else {
u8 chan = (reg - TEGRA210_MVC_TARGET_VOL) / REG_SIZE;s32 val = mvc->volume[chan];
It's not clear to me why we're using the same callbacks for the volume and mute settings - there's no shared code on the read path and only a tiny bit on the write path.
- err |= regmap_update_bits(mvc->regmap, TEGRA210_MVC_SWITCH,
TEGRA210_MVC_VOLUME_SWITCH_MASK,TEGRA210_MVC_VOLUME_SWITCH_TRIGGER);+end:
- pm_runtime_put(cmpnt->dev);
- return err;
+}
_put() should return 0 if there's no change or 1 for a change.
- /* SW reset */
- regmap_write(mvc->regmap, TEGRA210_MVC_SOFT_RESET, 1);
What about all the cached values in the regmap, won't they get out of sync? Especially things like volume and mute, it looks like the mute just gets written directly to the regmap and not otherwise saved.