[PATCH v1 2/5] platform/x86: ayaneo-ec: Add hwmon support

[Antheas Kapenekakis <lkml@antheas.dev>]

Add hwmon single fan sensor reads and control for Ayaneo devices.
The register and method of access is the same for all devices.

Signed-off-by: Antheas Kapenekakis <lkml@antheas.dev>
---
 drivers/platform/x86/Kconfig     |   2 +
 drivers/platform/x86/ayaneo-ec.c | 132 +++++++++++++++++++++++++++++++
 2 files changed, 134 insertions(+)

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 6d4a33791cc1..0a7ca2c78456 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -307,6 +307,8 @@ config ASUS_TF103C_DOCK
 config AYANEO_EC
 	tristate "Ayaneo EC platform control"
 	depends on X86
+	depends on ACPI_EC
+	depends on HWMON
 	help
 	  Enables support for the platform EC of Ayaneo devices. This
 	  includes fan control, fan speed, charge limit, magic
diff --git a/drivers/platform/x86/ayaneo-ec.c b/drivers/platform/x86/ayaneo-ec.c
index 90b86527ab0d..8b1902706b81 100644
--- a/drivers/platform/x86/ayaneo-ec.c
+++ b/drivers/platform/x86/ayaneo-ec.c
@@ -7,13 +7,23 @@
  * Copyright (C) 2025 Antheas Kapenekakis <lkml@antheas.dev>
  */
 
+#include <linux/acpi.h>
 #include <linux/dmi.h>
+#include <linux/hwmon.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 
+#define AYANEO_PWM_ENABLE_REG	 0x4A
+#define AYANEO_PWM_REG		 0x4B
+#define AYANEO_PWM_MODE_AUTO	 0x00
+#define AYANEO_PWM_MODE_MANUAL	 0x01
+
+#define AYANEO_FAN_REG		 0x76
+
 struct ayaneo_ec_quirk {
+	bool has_fan_control;
 };
 
 struct ayaneo_ec_platform_data {
@@ -22,6 +32,7 @@ struct ayaneo_ec_platform_data {
 };
 
 static const struct ayaneo_ec_quirk ayaneo3 = {
+	.has_fan_control = true,
 };
 
 static const struct dmi_system_id dmi_table[] = {
@@ -35,10 +46,124 @@ static const struct dmi_system_id dmi_table[] = {
 	{},
 };
 
+/* Callbacks for hwmon interface */
+static umode_t ayaneo_ec_hwmon_is_visible(const void *drvdata,
+				       enum hwmon_sensor_types type, u32 attr,
+				       int channel)
+{
+	switch (type) {
+	case hwmon_fan:
+		return 0444;
+	case hwmon_pwm:
+		return 0644;
+	default:
+		return 0;
+	}
+}
+
+static int ayaneo_ec_read(struct device *dev, enum hwmon_sensor_types type,
+			     u32 attr, int channel, long *val)
+{
+	u8 tmp;
+	int ret;
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_input:
+			ret = ec_read(AYANEO_FAN_REG, &tmp);
+			if (ret)
+				return ret;
+			*val = tmp << 8;
+			ret = ec_read(AYANEO_FAN_REG + 1, &tmp);
+			if (ret)
+				return ret;
+			*val += tmp;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_input:
+			ret = ec_read(AYANEO_PWM_REG, &tmp);
+			if (ret)
+				return ret;
+			*val = (255 * tmp) / 100;
+			if (*val < 0 || *val > 255)
+				return -EINVAL;
+			return 0;
+		case hwmon_pwm_enable:
+			ret = ec_read(AYANEO_PWM_ENABLE_REG, &tmp);
+			if (ret)
+				return ret;
+			if (tmp == AYANEO_PWM_MODE_MANUAL)
+				*val = 1;
+			else
+				*val = 2;
+			return 0;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+	return -EOPNOTSUPP;
+}
+
+static int ayaneo_ec_write(struct device *dev, enum hwmon_sensor_types type,
+			      u32 attr, int channel, long val)
+{
+	switch (type) {
+	case hwmon_pwm:
+		switch (attr) {
+		case hwmon_pwm_enable:
+			if (val == 1)
+				return ec_write(AYANEO_PWM_ENABLE_REG,
+						AYANEO_PWM_MODE_MANUAL);
+			else if (val == 2)
+				return ec_write(AYANEO_PWM_ENABLE_REG,
+						AYANEO_PWM_MODE_AUTO);
+			else
+				return -EINVAL;
+		case hwmon_pwm_input:
+			if (val < 0 || val > 255)
+				return -EINVAL;
+			return ec_write(AYANEO_PWM_REG, (val * 100) / 255);
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+	return -EOPNOTSUPP;
+}
+
+static const struct hwmon_ops ayaneo_ec_hwmon_ops = {
+	.is_visible = ayaneo_ec_hwmon_is_visible,
+	.read = ayaneo_ec_read,
+	.write = ayaneo_ec_write,
+};
+
+static const struct hwmon_channel_info *const ayaneo_ec_sensors[] = {
+	HWMON_CHANNEL_INFO(fan, HWMON_F_INPUT),
+	HWMON_CHANNEL_INFO(pwm, HWMON_PWM_INPUT | HWMON_PWM_ENABLE),
+	NULL,
+};
+
+static const struct hwmon_chip_info ayaneo_ec_chip_info = {
+	.ops = &ayaneo_ec_hwmon_ops,
+	.info = ayaneo_ec_sensors,
+};
+
 static int ayaneo_ec_probe(struct platform_device *pdev)
 {
 	const struct dmi_system_id *dmi_entry;
 	struct ayaneo_ec_platform_data *data;
+	struct device *hwdev;
 
 	dmi_entry = dmi_first_match(dmi_table);
 	if (!dmi_entry)
@@ -52,6 +177,13 @@ static int ayaneo_ec_probe(struct platform_device *pdev)
 	data->quirks = dmi_entry->driver_data;
 	platform_set_drvdata(pdev, data);
 
+	if (data->quirks->has_fan_control) {
+		hwdev = devm_hwmon_device_register_with_info(
+			&pdev->dev, "ayaneo_ec", NULL, &ayaneo_ec_chip_info, NULL);
+		if (IS_ERR(hwdev))
+			return PTR_ERR(hwdev);
+	}
+
 	return 0;
 }
 
-- 
2.50.1