[PATCH v2 2/2] input: misc: Add PixArt PAJ7620 gesture sensor driver

[Harpreet Saini <sainiharpreet29@yahoo.com>]

This driver adds support for the PixArt PAJ7620 gesture sensor.
It implements hand gesture recognition (up, down, left, right,
etc.) and reports them as standard input key events. The driver
includes power management support via Runtime PM.

Signed-off-by: Harpreet Saini <sainiharpreet29@yahoo.com>
---
 drivers/input/misc/Kconfig   |  12 ++
 drivers/input/misc/Makefile  |   1 +
 drivers/input/misc/paj7620.c | 350 +++++++++++++++++++++++++++++++++++
 3 files changed, 363 insertions(+)
 create mode 100644 drivers/input/misc/paj7620.c

diff --git a/drivers/input/misc/Kconfig b/drivers/input/misc/Kconfig
index 94a753fcb64f..de4206c297f2 100644
--- a/drivers/input/misc/Kconfig
+++ b/drivers/input/misc/Kconfig
@@ -453,6 +453,18 @@ config INPUT_KXTJ9
 	  To compile this driver as a module, choose M here: the module will
 	  be called kxtj9.
 
+config INPUT_PAJ7620
+	tristate "PixArt PAJ7620 Gesture Sensor"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  Say Y here if you want to support the PixArt PAJ7620 gesture
+	  sensor. This sensor supports 9 hand gestures and communicates
+	  over the I2C bus.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called paj7620.
+
 config INPUT_POWERMATE
 	tristate "Griffin PowerMate and Contour Jog support"
 	depends on USB_ARCH_HAS_HCD
diff --git a/drivers/input/misc/Makefile b/drivers/input/misc/Makefile
index 415fc4e2918b..dec8b8d0cdf4 100644
--- a/drivers/input/misc/Makefile
+++ b/drivers/input/misc/Makefile
@@ -67,6 +67,7 @@ obj-$(CONFIG_INPUT_PF1550_ONKEY)	+= pf1550-onkey.o
 obj-$(CONFIG_INPUT_PM8941_PWRKEY)	+= pm8941-pwrkey.o
 obj-$(CONFIG_INPUT_PM8XXX_VIBRATOR)	+= pm8xxx-vibrator.o
 obj-$(CONFIG_INPUT_PMIC8XXX_PWRKEY)	+= pmic8xxx-pwrkey.o
+obj-$(CONFIG_INPUT_PAJ7620) 		+= paj7620.o
 obj-$(CONFIG_INPUT_POWERMATE)		+= powermate.o
 obj-$(CONFIG_INPUT_PWM_BEEPER)		+= pwm-beeper.o
 obj-$(CONFIG_INPUT_PWM_VIBRA)		+= pwm-vibra.o
diff --git a/drivers/input/misc/paj7620.c b/drivers/input/misc/paj7620.c
new file mode 100644
index 000000000000..632a77ce4085
--- /dev/null
+++ b/drivers/input/misc/paj7620.c
@@ -0,0 +1,350 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * PixArt PAJ7620 Gesture Sensor - Input driver
+ *
+ * Copyright (C) 2026 Harpreet Saini <sainiharpreet29@yahoo.com>
+ */
+
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+/* Registers */
+#define PAJ7620_REG_BANK_SEL        0xEF
+#define PAJ7620_REG_GES_RESULT1     0x43
+#define PAJ7620_REG_GES_RESULT2     0x44
+#define PAJ7620_REG_SLEEP_BANK0     0x65
+#define PAJ7620_REG_SLEEP_BANK1     0x05
+#define PAJ7620_REG_AUTO_STANDBY    0x073
+
+/* Gesture bits */
+#define PAJ_UP           BIT(0)
+#define PAJ_DOWN         BIT(1)
+#define PAJ_LEFT         BIT(2)
+#define PAJ_RIGHT        BIT(3)
+#define PAJ_FORWARD      BIT(4)
+#define PAJ_BACKWARD     BIT(5)
+#define PAJ_CLOCKWISE    BIT(6)
+#define PAJ_ANTICLOCK    BIT(7)
+#define PAJ_WAVE         BIT(8)
+
+struct paj7620_data {
+	struct i2c_client *client;
+	struct regmap *regmap;
+	struct input_dev *idev;
+	struct regulator_bulk_data supplies[3];
+};
+
+/*
+ * The following arrays contain undocumented register sequences required to
+ * initialize the sensor's internal DSP and gesture engine.
+ * These were derived from vendor reference code and verified via testing.
+ */
+static const struct reg_sequence Init_Register[] = {
+	{ 0xEF, 0x00 }, { 0x37, 0x07 }, { 0x38, 0x17 }, { 0x39, 0x06 },
+	{ 0x41, 0x00 }, { 0x42, 0x00 }, { 0x46, 0x2D }, { 0x47, 0x0F },
+	{ 0x48, 0x3C }, { 0x49, 0x00 }, { 0x4A, 0x1E }, { 0x4C, 0x20 },
+	{ 0x51, 0x10 }, { 0x5E, 0x10 }, { 0x60, 0x27 }, { 0x80, 0x42 },
+	{ 0x81, 0x44 }, { 0x82, 0x04 }, { 0x8B, 0x01 }, { 0x90, 0x06 },
+	{ 0x95, 0x0A }, { 0x96, 0x0C }, { 0x97, 0x05 }, { 0x9A, 0x14 },
+	{ 0x9C, 0x3F }, { 0xA5, 0x19 }, { 0xCC, 0x19 }, { 0xCD, 0x0B },
+	{ 0xCE, 0x13 }, { 0xCF, 0x64 }, { 0xD0, 0x21 }, { 0xEF, 0x01 },
+	{ 0x02, 0x0F }, { 0x03, 0x10 }, { 0x04, 0x02 }, { 0x25, 0x01 },
+	{ 0x27, 0x39 }, { 0x28, 0x7F }, { 0x29, 0x08 }, { 0x3E, 0xFF },
+	{ 0x5E, 0x3D }, { 0x65, 0x96 }, { 0x67, 0x97 }, { 0x69, 0xCD },
+	{ 0x6A, 0x01 }, { 0x6D, 0x2C }, { 0x6E, 0x01 }, { 0x72, 0x01 },
+	{ 0x73, 0x35 }, { 0x74, 0x00 }, { 0x77, 0x01 },
+};
+
+/*
+ * Specific configuration overrides required to enable the internal
+ * 8-gesture state machine.
+ */
+static const struct reg_sequence Init_Gesture_Array[] = {
+	{ 0xEF, 0x00 }, { 0x41, 0x00 }, { 0x42, 0x00 }, { 0xEF, 0x00 },
+	{ 0x48, 0x3C }, { 0x49, 0x00 }, { 0x51, 0x10 }, { 0x83, 0x20 },
+	{ 0x9F, 0xF9 }, { 0xEF, 0x01 }, { 0x01, 0x1E }, { 0x02, 0x0F },
+	{ 0x03, 0x10 }, { 0x04, 0x02 }, { 0x41, 0x40 }, { 0x43, 0x30 },
+	{ 0x65, 0x96 }, { 0x66, 0x00 }, { 0x67, 0x97 }, { 0x68, 0x01 },
+	{ 0x69, 0xCD }, { 0x6A, 0x01 }, { 0x6B, 0xB0 }, { 0x6C, 0x04 },
+	{ 0x6D, 0x2C }, { 0x6E, 0x01 }, { 0x74, 0x00 }, { 0xEF, 0x00 },
+	{ 0x41, 0xFF }, { 0x42, 0x01 },
+};
+
+static void paj7620_report_keys(struct input_dev *idev, int gesture)
+{
+	static const struct { int bit; int key; } map[] = {
+		{ PAJ_UP,        KEY_UP },
+		{ PAJ_DOWN,      KEY_DOWN },
+		{ PAJ_LEFT,      KEY_LEFT },
+		{ PAJ_RIGHT,     KEY_RIGHT },
+		{ PAJ_FORWARD,   KEY_ENTER },
+		{ PAJ_BACKWARD,  KEY_BACK },
+		{ PAJ_CLOCKWISE, KEY_NEXT },
+		{ PAJ_ANTICLOCK, KEY_PREVIOUS },
+		{ PAJ_WAVE,      KEY_MENU },
+	};
+	// gesture mode does not support key hold, so pulse event
+	for (int i = 0; i < ARRAY_SIZE(map); i++) {
+		if (gesture & map[i].bit) {
+			input_report_key(idev, map[i].key, 1);
+			input_sync(idev);
+			input_report_key(idev, map[i].key, 0);
+			input_sync(idev);
+		}
+	}
+}
+
+static irqreturn_t paj7620_irq_thread(int irq, void *ptr)
+{
+	struct paj7620_data *data = ptr;
+	unsigned int g1, g2;
+	int ret;
+
+	/* 2. RUNTIME PM: Force awake to read registers */
+	pm_runtime_get_sync(&data->client->dev);
+
+	regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0);
+	ret = regmap_read(data->regmap, PAJ7620_REG_GES_RESULT1, &g1);
+	ret |= regmap_read(data->regmap, PAJ7620_REG_GES_RESULT2, &g2);
+
+	if (!ret && (g1 || g2))
+		paj7620_report_keys(data->idev, (g2 << 8) | g1);
+
+	pm_runtime_mark_last_busy(&data->client->dev);
+	pm_runtime_put_autosuspend(&data->client->dev);
+
+	return IRQ_HANDLED;
+}
+
+static int paj7620_init(struct paj7620_data *data)
+{
+	int state = 0, ret, i;
+
+	/* 1. Wake-up sequence: Read register 0x00 until it returns 0x20 */
+	for (i = 0; i < 10; i++) {
+		ret = regmap_read(data->regmap, 0x00, &state);
+		if (ret >= 0 && state == 0x20)
+			break;
+		usleep_range(1000, 2000);
+	}
+
+	if (state != 0x20) {
+		dev_err(&data->client->dev, "Sensor wake-up failed (0x%02x)\n", state);
+		return -ENODEV;
+	}
+
+	/* 2. Blast full register array into PAJ7620 instantly */
+	ret = regmap_multi_reg_write(data->regmap, Init_Register,
+				     ARRAY_SIZE(Init_Register));
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Multi-reg write failed (%d)\n", ret);
+		return ret;
+	}
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x00);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_multi_reg_write(data->regmap, Init_Gesture_Array,
+				     ARRAY_SIZE(Init_Gesture_Array));
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Multi-reg write failed (%d)\n", ret);
+		return ret;
+	}
+
+	dev_info(&data->client->dev, "Gesture Sensor Registers Initialized\n");
+	return 0;
+}
+
+static int paj7620_power_down(struct paj7620_data *data)
+{
+	int ret;
+	/* Deep sleep sequence */
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x00);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_SLEEP_BANK0, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_SLEEP_BANK1, 0x01);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int paj7620_runtime_suspend(struct device *dev)
+{
+	int ret;
+	struct paj7620_data *data = dev_get_drvdata(dev);
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_AUTO_STANDBY, 0x30);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int paj7620_runtime_resume(struct device *dev)
+{
+	int ret;
+	struct paj7620_data *data = dev_get_drvdata(dev);
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x01);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_AUTO_STANDBY, 0x00);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, PAJ7620_REG_BANK_SEL, 0x00);
+	if (ret)
+		return ret;
+
+	usleep_range(1000, 2000);	// Stabilization delay (1ms minimum)
+	return 0;
+}
+
+static const struct dev_pm_ops paj7620_pm_ops = {
+	SET_RUNTIME_PM_OPS(paj7620_runtime_suspend, paj7620_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
+};
+
+static const struct regmap_config paj7620_reg_config = {
+	.reg_bits = 8, .val_bits = 8, .max_register = 0xEF,
+};
+
+static int paj7620_probe(struct i2c_client *client)
+{
+	struct paj7620_data *data;
+	int ret;
+
+	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	i2c_set_clientdata(client, data);
+
+	data->supplies[0].supply = "vdd";
+	data->supplies[1].supply = "vbus";
+	data->supplies[2].supply = "vled";
+
+	ret = devm_regulator_bulk_get(&client->dev, ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret)
+		return dev_err_probe(&client->dev, ret, "Failed to get regulators\n");
+
+	ret = regulator_bulk_enable(ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret)
+		return ret;
+
+	data->regmap = devm_regmap_init_i2c(client, &paj7620_reg_config);
+	if (IS_ERR(data->regmap))
+		return PTR_ERR(data->regmap);
+
+	ret = paj7620_init(data);
+	if (ret)
+		goto err_reg;
+
+	data->idev = devm_input_allocate_device(&client->dev);
+	if (!data->idev) {
+		ret = -ENOMEM; goto err_reg;
+	}
+
+	data->idev->name = "PAJ7620 Gesture Sensor";
+	data->idev->id.bustype = BUS_I2C;
+
+	input_set_capability(data->idev, EV_KEY, KEY_UP);
+	input_set_capability(data->idev, EV_KEY, KEY_DOWN);
+	input_set_capability(data->idev, EV_KEY, KEY_LEFT);
+	input_set_capability(data->idev, EV_KEY, KEY_RIGHT);
+	input_set_capability(data->idev, EV_KEY, KEY_ENTER);
+	input_set_capability(data->idev, EV_KEY, KEY_BACK);
+	input_set_capability(data->idev, EV_KEY, KEY_NEXT);
+	input_set_capability(data->idev, EV_KEY, KEY_PREVIOUS);
+	input_set_capability(data->idev, EV_KEY, KEY_MENU);
+
+	ret = input_register_device(data->idev);
+	if (ret)
+		goto err_reg;
+
+	pm_runtime_set_active(&client->dev);
+	pm_runtime_enable(&client->dev);
+	pm_runtime_set_autosuspend_delay(&client->dev, 2000);
+	pm_runtime_use_autosuspend(&client->dev);
+
+	ret = devm_request_threaded_irq(&client->dev, client->irq, NULL,
+					paj7620_irq_thread, IRQF_ONESHOT,
+					"paj7620", data);
+	if (ret)
+		goto err_reg;
+
+	dev_info(&client->dev, "Gesture Sensor Initialized\n");
+	return 0;
+
+err_reg:
+	dev_err_probe(&client->dev, ret, "%s: failed with error %d\n", __func__, ret);
+	if (pm_runtime_enabled(&client->dev)) {
+		pm_runtime_disable(&client->dev);
+		pm_runtime_dont_use_autosuspend(&client->dev);
+	}
+	regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
+	return ret;
+}
+
+static void paj7620_remove(struct i2c_client *client)
+{
+	int ret;
+	struct paj7620_data *data = i2c_get_clientdata(client);
+
+	pm_runtime_get_sync(&client->dev);
+	pm_runtime_disable(&client->dev);
+	pm_runtime_dont_use_autosuspend(&client->dev);
+	pm_runtime_put_noidle(&client->dev);
+
+	ret = paj7620_power_down(data);
+	if (ret)
+		dev_err(&data->client->dev, "Sensor power down failed\n");
+
+	ret = regulator_bulk_disable(ARRAY_SIZE(data->supplies), data->supplies);
+	if (ret)
+		dev_err(&data->client->dev, "Sensor regulator disable failed\n");
+}
+
+static const struct of_device_id paj7620_of_match[] = {
+	{ .compatible = "pixart,paj7620" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, paj7620_of_match);
+
+static struct i2c_driver paj7620_driver = {
+	.driver = {
+		.name = "paj7620",
+		.of_match_table = paj7620_of_match,
+		.pm = &paj7620_pm_ops,
+	},
+	.probe = paj7620_probe,
+	.remove = paj7620_remove,
+};
+module_i2c_driver(paj7620_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harpreet Saini");
+MODULE_DESCRIPTION("PAJ7620 Gesture Input Driver");
-- 
2.43.0