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From:   Vitaly Rodionov <vitalyr@opensource.cirrus.com>
To:     James Schulman <james.schulman@cirrus.com>,
        David Rhodes <david.rhodes@cirrus.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>
CC:     <alsa-devel@alsa-project.org>, <patches@opensource.cirrus.com>,
        <linux-kernel@vger.kernel.org>
Subject: [PATCH] ASoC: cs42l42: make HSBIAS_SENSE_EN optional
Date:   Tue, 11 May 2021 15:52:20 +0100
Message-ID: <20210511145220.125760-1-vitalyr@opensource.cirrus.com>
MIME-Version: 1.0
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HSBIAS_SENSE_EN configures HSBIAS output current sense through
the external 2.21-k resistor. HSBIAS_SENSE is hardware feature to reduce
the potential pop noise during the headset plug out slowly. But on some
platforms ESD voltage will affect it causing test to fail, especially
with CTIA headset type. For different hardware setups, a designer might
want to tweak default behavior.

Signed-off-by: Vitaly Rodionov <vitalyr@opensource.cirrus.com>
---
 Documentation/devicetree/bindings/sound/cs42l42.txt | 7 +++++++
 sound/soc/codecs/cs42l42.c                          | 7 ++++++-
 sound/soc/codecs/cs42l42.h                          | 1 +
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/sound/cs42l42.txt b/Documentation/devicetree/bindings/sound/cs42l42.txt
index 7dfaa2ab906f..5d416fdaf023 100644
--- a/Documentation/devicetree/bindings/sound/cs42l42.txt
+++ b/Documentation/devicetree/bindings/sound/cs42l42.txt
@@ -81,6 +81,13 @@ Optional properties:
   < x1 x2 x3 x4 >
   Default = < 15 8 4 1>
 
+  - cirrus,hs-bias-sense-disable: This is boolean property. If present the
+  HSBIAS sense is disabled. Configures HSBIAS output current sense through
+  the external 2.21-k resistor. HSBIAS_SENSE is hardware feature to reduce
+  the potential pop noise during the headset plug out slowly. But on some
+  platforms ESD voltage will affect it causing test to fail, especially
+  with CTIA headset type. For different hardware setups, a designer might
+  want to tweak default behavior.
 
 Example:
 
diff --git a/sound/soc/codecs/cs42l42.c b/sound/soc/codecs/cs42l42.c
index d7fb6b38fd7c..5087c5b781f8 100644
--- a/sound/soc/codecs/cs42l42.c
+++ b/sound/soc/codecs/cs42l42.c
@@ -1033,7 +1033,7 @@ static void cs42l42_process_hs_type_detect(struct cs42l42_private *cs42l42)
 			CS42L42_AUTO_HSBIAS_HIZ_MASK |
 			CS42L42_TIP_SENSE_EN_MASK |
 			CS42L42_HSBIAS_SENSE_TRIP_MASK,
-			(1 << CS42L42_HSBIAS_SENSE_EN_SHIFT) |
+			(cs42l42->hs_bias_sense_en << CS42L42_HSBIAS_SENSE_EN_SHIFT) |
 			(1 << CS42L42_AUTO_HSBIAS_HIZ_SHIFT) |
 			(0 << CS42L42_TIP_SENSE_EN_SHIFT) |
 			(3 << CS42L42_HSBIAS_SENSE_TRIP_SHIFT));
@@ -1808,6 +1808,11 @@ static int cs42l42_handle_device_data(struct device *dev,
 			(cs42l42->hs_bias_ramp_rate <<
 			CS42L42_HSBIAS_RAMP_SHIFT));
 
+	if (device_property_read_bool(dev, "cirrus,hs-bias-sense-disable"))
+		cs42l42->hs_bias_sense_en = 0;
+	else
+		cs42l42->hs_bias_sense_en = 1;
+
 	return 0;
 }
 
diff --git a/sound/soc/codecs/cs42l42.h b/sound/soc/codecs/cs42l42.h
index 2e0d3836bd7e..24f7be228d5f 100644
--- a/sound/soc/codecs/cs42l42.h
+++ b/sound/soc/codecs/cs42l42.h
@@ -787,6 +787,7 @@ struct  cs42l42_private {
 	u8 bias_thresholds[CS42L42_NUM_BIASES];
 	u8 hs_bias_ramp_rate;
 	u8 hs_bias_ramp_time;
+	u8 hs_bias_sense_en;
 	u8 stream_use;
 };
 
-- 
2.25.1