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From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: <broonie@kernel.org>
CC: <alsa-devel@alsa-project.org>, <linux-sound@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <patches@opensource.cirrus.com>,
        "Richard
 Fitzgerald" <rf@opensource.cirrus.com>
Subject: [PATCH] ASoC: cs35l56: Must clear HALO_STATE before issuing SYSTEM_RESET
Date: Fri, 16 Feb 2024 14:05:35 +0000
Message-ID: <20240216140535.1434933-1-rf@opensource.cirrus.com>
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The driver must write 0 to HALO_STATE before sending the SYSTEM_RESET
command to the firmware.

HALO_STATE is in DSP memory, which is preserved across a soft reset.
The SYSTEM_RESET command does not change the value of HALO_STATE.
There is period of time while the CS35L56 is resetting, before the
firmware has started to boot, where a read of HALO_STATE will return
the value it had before the SYSTEM_RESET. If the driver does not
clear HALO_STATE, this would return BOOT_DONE status even though the
firmware has not booted.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: 8a731fd37f8b ("ASoC: cs35l56: Move utility functions to shared file")
---
 sound/soc/codecs/cs35l56-shared.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/sound/soc/codecs/cs35l56-shared.c b/sound/soc/codecs/cs35l56-shared.c
index 995d979b6d87..cb4e83126b08 100644
--- a/sound/soc/codecs/cs35l56-shared.c
+++ b/sound/soc/codecs/cs35l56-shared.c
@@ -335,6 +335,7 @@ void cs35l56_wait_min_reset_pulse(void)
 EXPORT_SYMBOL_NS_GPL(cs35l56_wait_min_reset_pulse, SND_SOC_CS35L56_SHARED);
 
 static const struct reg_sequence cs35l56_system_reset_seq[] = {
+	REG_SEQ0(CS35L56_DSP1_HALO_STATE, 0),
 	REG_SEQ0(CS35L56_DSP_VIRTUAL1_MBOX_1, CS35L56_MBOX_CMD_SYSTEM_RESET),
 };
 
-- 
2.30.2