linux-kernel - [PATCH v1 1/3] ASoC: cs42l42: Ensure a reset pulse meets minimum pulse width.

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Message-ID: <20230913150012.604775-2-sbinding@opensource.cirrus.com>
Date:   Wed, 13 Sep 2023 16:00:10 +0100
From:   Stefan Binding <sbinding@...nsource.cirrus.com>
To:     Mark Brown <broonie@...nel.org>,
        Uday M Bhat <uday.m.bhat@...el.com>,
        Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
CC:     <alsa-devel@...a-project.org>, <linux-kernel@...r.kernel.org>,
        <patches@...nsource.cirrus.com>,
        Richard Fitzgerald <rf@...nsource.cirrus.com>,
        Stefan Binding <sbinding@...nsource.cirrus.com>
Subject: [PATCH v1 1/3] ASoC: cs42l42: Ensure a reset pulse meets minimum pulse width.

From: Richard Fitzgerald <rf@...nsource.cirrus.com>

The CS42L42 can accept very short reset pulses of a few microseconds
but there's no reason to force a very short pulse.
Allow a wide range for the usleep_range() so it can be relaxed about
the choice of timing source.

Signed-off-by: Richard Fitzgerald <rf@...nsource.cirrus.com>
Signed-off-by: Stefan Binding <sbinding@...nsource.cirrus.com>
---
 sound/soc/codecs/cs42l42.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
index a0de0329406a..56d2857a4f01 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -2320,6 +2320,10 @@ int cs42l42_common_probe(struct cs42l42_private *cs42l42,
 
 	if (cs42l42->reset_gpio) {
 		dev_dbg(cs42l42->dev, "Found reset GPIO\n");
+
+		/* Ensure minimum reset pulse width */
+		usleep_range(10, 500);
+
 		gpiod_set_value_cansleep(cs42l42->reset_gpio, 1);
 	}
 	usleep_range(CS42L42_BOOT_TIME_US, CS42L42_BOOT_TIME_US * 2);
-- 
2.34.1