linux-kernel - [PATCH v3 2/3] Input: aw86938 - add driver for Awinic AW86938

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Message-Id: <20260209-aw86938-driver-v3-2-5c79cff30492@fairphone.com>
Date: Mon, 09 Feb 2026 13:59:46 +0100
From: Griffin Kroah-Hartman <griffin.kroah@...rphone.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>, 
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, 
 Conor Dooley <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>, 
 Konrad Dybcio <konradybcio@...nel.org>, 
 Luca Weiss <luca.weiss@...rphone.com>
Cc: linux-input@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org, 
 Griffin Kroah-Hartman <griffin.kroah@...rphone.com>
Subject: [PATCH v3 2/3] Input: aw86938 - add driver for Awinic AW86938

Add support for the I2C-connected Awinic AW86938 LRA haptic driver.

The AW86938 has a similar but slightly different register layout. In
particular, the boost mode register values.
The AW86938 also has some extra features that aren't implemented
in this driver yet.

Signed-off-by: Griffin Kroah-Hartman <griffin.kroah@...rphone.com>
---
 drivers/input/misc/aw86927.c | 54 ++++++++++++++++++++++++++++++++++++--------
 1 file changed, 45 insertions(+), 9 deletions(-)

diff --git a/drivers/input/misc/aw86927.c b/drivers/input/misc/aw86927.c
index 8ad361239cfe3a888628b15e4dbdeed0c9ca3d1a..678526ef2bb7da654734e8f53ad8442c556f209b 100644
--- a/drivers/input/misc/aw86927.c
+++ b/drivers/input/misc/aw86927.c
@@ -43,6 +43,12 @@
 #define AW86927_PLAYCFG1_BST_VOUT_VREFSET_MASK	GENMASK(6, 0)
 #define AW86927_PLAYCFG1_BST_8500MV		0x50
 
+#define AW86938_PLAYCFG1_REG			0x06
+#define AW86938_PLAYCFG1_BST_MODE_MASK		GENMASK(5, 5)
+#define AW86938_PLAYCFG1_BST_MODE_BYPASS	0
+#define AW86938_PLAYCFG1_BST_VOUT_VREFSET_MASK	GENMASK(4, 0)
+#define AW86938_PLAYCFG1_BST_7000MV		0x11
+
 #define AW86927_PLAYCFG2_REG			0x07
 
 #define AW86927_PLAYCFG3_REG			0x08
@@ -140,6 +146,7 @@
 #define AW86927_CHIPIDH_REG			0x57
 #define AW86927_CHIPIDL_REG			0x58
 #define AW86927_CHIPID				0x9270
+#define AW86938_CHIPID				0x9380
 
 #define AW86927_TMCFG_REG			0x5b
 #define AW86927_TMCFG_UNLOCK			0x7d
@@ -173,7 +180,13 @@ enum aw86927_work_mode {
 	AW86927_RAM_MODE,
 };
 
+enum aw86927_model {
+	AW86927,
+	AW86938,
+};
+
 struct aw86927_data {
+	enum aw86927_model model;
 	struct work_struct play_work;
 	struct device *dev;
 	struct input_dev *input_dev;
@@ -377,7 +390,7 @@ static int aw86927_play_sine(struct aw86927_data *haptics)
 		return err;
 
 	/* set gain to value lower than 0x80 to avoid distorted playback */
-	err = regmap_write(haptics->regmap, AW86927_PLAYCFG2_REG, 0x7c);
+	err = regmap_write(haptics->regmap, AW86927_PLAYCFG2_REG, 0x45);
 	if (err)
 		return err;
 
@@ -565,13 +578,26 @@ static int aw86927_haptic_init(struct aw86927_data *haptics)
 	if (err)
 		return err;
 
-	err = regmap_update_bits(haptics->regmap,
-				 AW86927_PLAYCFG1_REG,
-				 AW86927_PLAYCFG1_BST_VOUT_VREFSET_MASK,
-				 FIELD_PREP(AW86927_PLAYCFG1_BST_VOUT_VREFSET_MASK,
-					    AW86927_PLAYCFG1_BST_8500MV));
-	if (err)
-		return err;
+	switch (haptics->model) {
+	case AW86927:
+		err = regmap_update_bits(haptics->regmap,
+				AW86927_PLAYCFG1_REG,
+				AW86927_PLAYCFG1_BST_VOUT_VREFSET_MASK,
+				FIELD_PREP(AW86927_PLAYCFG1_BST_VOUT_VREFSET_MASK,
+					AW86927_PLAYCFG1_BST_8500MV));
+		if (err)
+			return err;
+		break;
+	case AW86938:
+		err = regmap_update_bits(haptics->regmap,
+				AW86938_PLAYCFG1_REG,
+				AW86938_PLAYCFG1_BST_VOUT_VREFSET_MASK,
+				FIELD_PREP(AW86938_PLAYCFG1_BST_VOUT_VREFSET_MASK,
+					AW86938_PLAYCFG1_BST_7000MV));
+		if (err)
+			return err;
+		break;
+	}
 
 	err = regmap_update_bits(haptics->regmap,
 				 AW86927_PLAYCFG3_REG,
@@ -599,6 +625,9 @@ static int aw86927_ram_init(struct aw86927_data *haptics)
 				 FIELD_PREP(AW86927_SYSCTRL3_EN_RAMINIT_MASK,
 					    AW86927_SYSCTRL3_EN_RAMINIT_ON));
 
+	/* AW86938 wants a 1ms delay here */
+	usleep_range(1000, 1500);
+
 	/* Set base address for the start of the SRAM waveforms */
 	err = regmap_write(haptics->regmap,
 			   AW86927_BASEADDRH_REG, AW86927_BASEADDRH_VAL);
@@ -717,7 +746,14 @@ static int aw86927_detect(struct aw86927_data *haptics)
 
 	chip_id = be16_to_cpu(read_buf);
 
-	if (chip_id != AW86927_CHIPID) {
+	switch (chip_id) {
+	case AW86927_CHIPID:
+		haptics->model = AW86927;
+		break;
+	case AW86938_CHIPID:
+		haptics->model = AW86938;
+		break;
+	default:
 		dev_err(haptics->dev, "Unexpected CHIPID value 0x%x\n", chip_id);
 		return -ENODEV;
 	}

-- 
2.43.0