linux-kernel - [PATCH v1 3/8] ALSA: hda: cs35l41: Assert Reset prior to de-asserting in probe and system resume

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Message-ID: <20231026150558.2105827-4-sbinding@opensource.cirrus.com>
Date:   Thu, 26 Oct 2023 16:05:53 +0100
From:   Stefan Binding <sbinding@...nsource.cirrus.com>
To:     Jaroslav Kysela <perex@...ex.cz>, Takashi Iwai <tiwai@...e.com>,
        "Mark Brown" <broonie@...nel.org>
CC:     <alsa-devel@...a-project.org>, <linux-kernel@...r.kernel.org>,
        <linux-sound@...r.kernel.org>, <patches@...nsource.cirrus.com>,
        "Stefan Binding" <sbinding@...nsource.cirrus.com>
Subject: [PATCH v1 3/8] ALSA: hda: cs35l41: Assert Reset prior to de-asserting in probe and system resume

To ensure we are in a known state, exiting from reset at the point of
probe or in system resume, assert reset before we de-assert it.

Since the BIOS may enter into a pre-boot environment to control the
amps (for example for boot beep), we need to ensure we start from a
known, reset state prior to probe or system resume.

Signed-off-by: Stefan Binding <sbinding@...nsource.cirrus.com>
---
 sound/pci/hda/cs35l41_hda.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index 919e38213975..1ac721085fb5 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -840,6 +840,7 @@ static int cs35l41_system_resume(struct device *dev)
 	}
 
 	if (cs35l41->reset_gpio) {
+		gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
 		usleep_range(2000, 2100);
 		gpiod_set_value_cansleep(cs35l41->reset_gpio, 1);
 	}
@@ -1693,6 +1694,7 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
 		}
 	}
 	if (cs35l41->reset_gpio) {
+		gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
 		usleep_range(2000, 2100);
 		gpiod_set_value_cansleep(cs35l41->reset_gpio, 1);
 	}
-- 
2.34.1