| Message ID | 20240613132527.46537-1-rf@opensource.cirrus.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8af49868e51ed1ba117b74728af12abe1eda82e5 |
| Headers | show |
| Series | [v2] ASoC: cs35l56: Disconnect ASP1 TX sources when ASP1 DAI is hooked up | expand |
On Thu, 13 Jun 2024 14:25:27 +0100, Richard Fitzgerald wrote: > If the ASP1 DAI is hooked up by the machine driver the ASP TX mixer > sources should be initialized to disconnected. There aren't currently > any available products using the ASP so this doesn't affect any > existing systems. > > The cs35l56 does not have any fixed default for the mixer source > registers. When the cs35l56 boots, its firmware patches these registers > to setup a system-specific routing; this is so that Windows can use > generic SDCA drivers instead of needing knowledge of chip-specific > registers. The setup varies between end-products, which each have > customized firmware, and so the default register state varies between > end-products. It can also change if the firmware on an end-product is > upgraded - for example if a change was needed to the routing for Windows > use-cases. It must be emphasized that the settings applied by the > firmware are not internal magic tuning; they are statically implementing > use-case setup that on Linux would be done via ALSA controls. > > [...] Applied to https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next Thanks! [1/1] ASoC: cs35l56: Disconnect ASP1 TX sources when ASP1 DAI is hooked up commit: 8af49868e51ed1ba117b74728af12abe1eda82e5 All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark
diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c index e89027cd40d1..27869e14e9c8 100644 --- a/sound/soc/codecs/cs35l56-shared.c +++ b/sound/soc/codecs/cs35l56-shared.c @@ -215,6 +215,10 @@ static const struct reg_sequence cs35l56_asp1_defaults[] = { REG_SEQ0(CS35L56_ASP1_FRAME_CONTROL5, 0x00020100), REG_SEQ0(CS35L56_ASP1_DATA_CONTROL1, 0x00000018), REG_SEQ0(CS35L56_ASP1_DATA_CONTROL5, 0x00000018), + REG_SEQ0(CS35L56_ASP1TX1_INPUT, 0x00000000), + REG_SEQ0(CS35L56_ASP1TX2_INPUT, 0x00000000), + REG_SEQ0(CS35L56_ASP1TX3_INPUT, 0x00000000), + REG_SEQ0(CS35L56_ASP1TX4_INPUT, 0x00000000), }; /*
If the ASP1 DAI is hooked up by the machine driver the ASP TX mixer sources should be initialized to disconnected. There aren't currently any available products using the ASP so this doesn't affect any existing systems. The cs35l56 does not have any fixed default for the mixer source registers. When the cs35l56 boots, its firmware patches these registers to setup a system-specific routing; this is so that Windows can use generic SDCA drivers instead of needing knowledge of chip-specific registers. The setup varies between end-products, which each have customized firmware, and so the default register state varies between end-products. It can also change if the firmware on an end-product is upgraded - for example if a change was needed to the routing for Windows use-cases. It must be emphasized that the settings applied by the firmware are not internal magic tuning; they are statically implementing use-case setup that on Linux would be done via ALSA controls. The driver is currently syncing the mixer controls with whatever initial state the firmware wrote to the registers, so that they report the actual audio routing. But if the ASP DAI is hooked up this can create a powered-up DAPM graph without anything intentionally setting up a path. This can lead to parts of the audio system powering up unexpectedly. For example when cs35l56 is connected to cs42l43 using a codec-codec link, this can create a complete DAPM graph which then powers-up cs42l43. But the cs42l43 can only be clocked from its SoundWire bus so this causes a bunch of errors in the kernel log where cs42l43 is unexpectedly powered-up without a clock. If the host is taking ownership of the ASP (either directly or as a codec-to-codec link) there is no need to keep the mixer settings that the firmware wrote. The driver has ALSA controls for setting these using standard Linux mechanisms. So if the machine driver hooks up the ASP the ASP mixers are initialized to "None" (no input). This prevents unintended DAPM-graph power-ups, and means the initial state of the mixers is always going to be None. Since the initial state of the mixers can vary from system to system and potentially between firmware upgrades, no use-case manager can currently assume that cs35l56 has a known initial state. The firmware could just as easily default them to "None" as to any input source. So defaulting them to "None" in the driver is not increasing the entropy of the system. Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> --- sound/soc/codecs/cs35l56-shared.c | 4 ++++ 1 file changed, 4 insertions(+)