On 29/01/2024 17:15, Pierre-Louis Bossart wrote:
On 1/29/24 17:27, Richard Fitzgerald wrote:
Patch the SDW TX mixer registers to silicon defaults.
CS35L56 is designed for SDCA and a generic SDCA driver would know nothing about these chip-specific registers. So the firmware sets up the SDW TX mixer registers to whatever audio is relevant on a specific system.
This means that the driver cannot assume the initial values of these registers. But Linux has ALSA controls to configure routing, so the registers can be patched to silicon default and the ALSA controls used to select what audio to feed back to the host capture path.
humm, which has the precedence then? a) the values set by firmware b) the default values set by the driver?
Also if the firmware touches those registers shouldn't they be marked as 'volatile'?
The firmware was designed to work with Windows, so it looks a bit strange if you are coming at it from ALSA. There's not really any defined 'precedence'. The firmware will setup the feedback monitor paths to something that satisfies SDCA and Windows expectations.
We don't care about that in Linux, the firmware on the Intel DSP probably isn't running the same algorithms for Linux, and we have ALSA controls to configure those paths. So we patch the mixers back to their silicon defaults and take over complete control of them.
The firmware only writes them during its power-up sequence so they will only change when we are rebooting the firmware or coming out of low-power standby, which is under the control of the driver. When that happens regmap will re-apply the patch and then sync up the registers again. The firmware won't touch them after boot, so we can avoid having to mark them volatile (which would mean implementing our own manual caching of the settings).
Backport note: This won't apply to kernels older than v6.6.
Signed-off-by: Richard Fitzgerald rf@opensource.cirrus.com Fixes: e49611252900 ("ASoC: cs35l56: Add driver for Cirrus Logic CS35L56")
sound/soc/codecs/cs35l56-shared.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c index 35789ffc63af..a812abf90836 100644 --- a/sound/soc/codecs/cs35l56-shared.c +++ b/sound/soc/codecs/cs35l56-shared.c @@ -12,6 +12,15 @@ #include "cs35l56.h"
static const struct reg_sequence cs35l56_patch[] = {
- /*
* Firmware can change these to non-defaults to satisfy SDCA.* Ensure that they are at known defaults.*/- { CS35L56_SWIRE_DP3_CH1_INPUT, 0x00000018 },
- { CS35L56_SWIRE_DP3_CH2_INPUT, 0x00000019 },
- { CS35L56_SWIRE_DP3_CH3_INPUT, 0x00000029 },
- { CS35L56_SWIRE_DP3_CH4_INPUT, 0x00000028 },
- /* These are not reset by a soft-reset, so patch to defaults. */ { CS35L56_MAIN_RENDER_USER_MUTE, 0x00000000 }, { CS35L56_MAIN_RENDER_USER_VOLUME, 0x00000000 },