linux-kernel - [PATCH 08/18] ASoC: cs35l56: Fix default SDW TX mixer registers

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Date: Mon, 29 Jan 2024 16:27:27 +0000
From: Richard Fitzgerald <rf@...nsource.cirrus.com>
To: <broonie@...nel.org>, <tiwai@...e.com>
CC: <alsa-devel@...a-project.org>, <linux-sound@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <patches@...nsource.cirrus.com>,
        "Richard
 Fitzgerald" <rf@...nsource.cirrus.com>
Subject: [PATCH 08/18] ASoC: cs35l56: Fix default SDW TX mixer registers

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.

Backport note:
This won't apply to kernels older than v6.6.

Signed-off-by: Richard Fitzgerald <rf@...nsource.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 },
-- 
2.39.2