[PATCH v4 08/12] platform/x86: alienware-wmi-wmax: Add support for manual fan control

Kurt Borja
2025-03-08T20:24:02Z

All models with the "AWCC" WMAX device support a way of manually
controlling fans.

The PWM duty cycle of a fan can't be controlled directly. Instead the
AWCC interface let's us tune a fan `boost` value, which has the
following empirically discovered, aproximate behavior over the PWM
value:

pwm = pwm_base + (fan_boost / 255) * (pwm_max - pwm_base)

Where the pwm_base is the locked PWM value controlled by the FW and
fan_boost is a value between 0 and 255.

Expose this fan_boost knob as a custom HWMON attribute.

Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.com>
Cc: linux-hwmon@vger.kernel.org
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
drivers/platform/x86/dell/alienware-wmi-wmax.c | 174 ++++++++++++++++++++++++-
1 file changed, 172 insertions(+), 2 deletions(-)

diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
index f1f20db206d47f644e8cd58a6d169c850606e75b..68ff520f016d2d567cddcefe41f01bf284b4d979 100644
--- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
+++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
@@ -13,8 +13,12 @@
#include <linux/bits.h>
#include <linux/dmi.h>
#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/kstrtox.h>
+#include <linux/minmax.h>
#include <linux/moduleparam.h>
#include <linux/platform_profile.h>
+#include <linux/pm.h>
#include <linux/units.h>
#include <linux/wmi.h>
#include "alienware-wmi.h"
@@ -181,10 +185,12 @@ enum AWCC_THERMAL_INFORMATION_OPERATIONS {
AWCC_OP_GET_FAN_MIN_RPM = 0x08,
AWCC_OP_GET_FAN_MAX_RPM = 0x09,
AWCC_OP_GET_CURRENT_PROFILE = 0x0B,
+ AWCC_OP_GET_FAN_BOOST = 0x0C,
};

enum AWCC_THERMAL_CONTROL_OPERATIONS {
AWCC_OP_ACTIVATE_PROFILE = 0x01,
+ AWCC_OP_SET_FAN_BOOST = 0x02,
};

enum AWCC_GAME_SHIFT_STATUS_OPERATIONS {
@@ -248,6 +254,7 @@ struct awcc_fan_data {
const char *label;
u32 min_rpm;
u32 max_rpm;
+ u8 suspend_cache;
u8 id;
};

@@ -628,6 +635,18 @@ static inline int awcc_op_get_temperature(struct wmi_device *wdev, u8 temp_id, u
return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
}

+static inline int awcc_op_get_fan_boost(struct wmi_device *wdev, u8 fan_id, u32 *out)
+{
+ struct wmax_u32_args args = {
+ .operation = AWCC_OP_GET_FAN_BOOST,
+ .arg1 = fan_id,
+ .arg2 = 0,
+ .arg3 = 0,
+ };
+
+ return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
+}
+
static inline int awcc_op_get_current_profile(struct wmi_device *wdev, u32 *out)
{
struct wmax_u32_args args = {
@@ -653,6 +672,19 @@ static inline int awcc_op_activate_profile(struct wmi_device *wdev, u8 profile)
return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_CONTROL, &args, &out);
}

+static inline int awcc_op_set_fan_boost(struct wmi_device *wdev, u8 fan_id, u8 boost)
+{
+ struct wmax_u32_args args = {
+ .operation = AWCC_OP_SET_FAN_BOOST,
+ .arg1 = fan_id,
+ .arg2 = boost,
+ .arg3 = 0,
+ };
+ u32 out;
+
+ return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_CONTROL, &args, &out);
+}
+
/*
* HWMON
* - Provides temperature and fan speed monitoring as well as manual fan
@@ -817,6 +849,81 @@ static const struct hwmon_chip_info awcc_hwmon_chip_info = {
.info = awcc_hwmon_info,
};

+static ssize_t fan_boost_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ int index = to_sensor_dev_attr(attr)->index;
+ struct awcc_fan_data *fan = priv->fan_data[index];
+ u32 boost;
+ int ret;
+
+ ret = awcc_op_get_fan_boost(priv->wdev, fan->id, &boost);
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%u\n", boost);
+}
+
+static ssize_t fan_boost_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ int index = to_sensor_dev_attr(attr)->index;
+ struct awcc_fan_data *fan = priv->fan_data[index];
+ unsigned long val;
+ int ret;
+
+ ret = kstrtoul(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ ret = awcc_op_set_fan_boost(priv->wdev, fan->id, clamp_val(val, 0, 255));
+
+ return ret ? ret : count;
+}
+
+static SENSOR_DEVICE_ATTR_RW(fan1_boost, fan_boost, 0);
+static SENSOR_DEVICE_ATTR_RW(fan2_boost, fan_boost, 1);
+static SENSOR_DEVICE_ATTR_RW(fan3_boost, fan_boost, 2);
+static SENSOR_DEVICE_ATTR_RW(fan4_boost, fan_boost, 3);
+static SENSOR_DEVICE_ATTR_RW(fan5_boost, fan_boost, 4);
+static SENSOR_DEVICE_ATTR_RW(fan6_boost, fan_boost, 5);
+
+static umode_t fan_boost_attr_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+ struct awcc_priv *priv = dev_get_drvdata(kobj_to_dev(kobj));
+
+ return n < priv->fan_count ? attr->mode : 0;
+}
+
+static bool fan_boost_group_visible(struct kobject *kobj)
+{
+ return true;
+}
+
+DEFINE_SYSFS_GROUP_VISIBLE(fan_boost);
+
+static struct attribute *fan_boost_attrs[] = {
+ &sensor_dev_attr_fan1_boost.dev_attr.attr,
+ &sensor_dev_attr_fan2_boost.dev_attr.attr,
+ &sensor_dev_attr_fan3_boost.dev_attr.attr,
+ &sensor_dev_attr_fan4_boost.dev_attr.attr,
+ &sensor_dev_attr_fan5_boost.dev_attr.attr,
+ &sensor_dev_attr_fan6_boost.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group fan_boost_group = {
+ .attrs = fan_boost_attrs,
+ .is_visible = SYSFS_GROUP_VISIBLE(fan_boost),
+};
+
+static const struct attribute_group *awcc_hwmon_groups[] = {
+ &fan_boost_group,
+ NULL
+};
+
static int awcc_hwmon_temps_init(struct wmi_device *wdev)
{
struct awcc_priv *priv = dev_get_drvdata(&wdev->dev);
@@ -954,12 +1061,56 @@ static int awcc_hwmon_init(struct wmi_device *wdev)
if (ret)
return ret;

- priv->hwdev = devm_hwmon_device_register_with_info(&wdev->dev, "alienware_wmi", priv,
- &awcc_hwmon_chip_info, NULL);
+ priv->hwdev = devm_hwmon_device_register_with_info(&wdev->dev, "alienware_wmi",
+ priv, &awcc_hwmon_chip_info,
+ awcc_hwmon_groups);

return PTR_ERR_OR_ZERO(priv->hwdev);
}

+static void awcc_hwmon_suspend(struct device *dev)
+{
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ struct awcc_fan_data *fan;
+ unsigned int i;
+ u32 boost;
+ int ret;
+
+ for (i = 0; i < priv->fan_count; i++) {
+ fan = priv->fan_data[i];
+
+ ret = awcc_thermal_information(priv->wdev, AWCC_OP_GET_FAN_BOOST,
+ fan->id, &boost);
+ if (ret)
+ dev_err(dev, "Failed to store Fan %u boost while suspending\n", i);
+
+ fan->suspend_cache = ret ? 0 : clamp_val(boost, 0, 255);
+
+ awcc_op_set_fan_boost(priv->wdev, fan->id, 0);
+ if (ret)
+ dev_err(dev, "Failed to set Fan %u boost to 0 while suspending\n", i);
+ }
+}
+
+static void awcc_hwmon_resume(struct device *dev)
+{
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ struct awcc_fan_data *fan;
+ unsigned int i;
+ int ret;
+
+ for (i = 0; i < priv->fan_count; i++) {
+ fan = priv->fan_data[i];
+
+ if (!fan->suspend_cache)
+ continue;
+
+ ret = awcc_op_set_fan_boost(priv->wdev, fan->id, fan->suspend_cache);
+ if (ret)
+ dev_err(dev, "Failed to restore Fan %u boost while resuming\n", i);
+ }
+}
+
/*
* Thermal Profile control
* - Provides thermal profile control through the Platform Profile API
@@ -1189,6 +1340,24 @@ static int wmax_wmi_probe(struct wmi_device *wdev, const void *context)
return ret;
}

+static int wmax_wmi_suspend(struct device *dev)
+{
+ if (awcc->hwmon)
+ awcc_hwmon_suspend(dev);
+
+ return 0;
+}
+
+static int wmax_wmi_resume(struct device *dev)
+{
+ if (awcc->hwmon)
+ awcc_hwmon_resume(dev);
+
+ return 0;
+}
+
+DEFINE_SIMPLE_DEV_PM_OPS(wmax_wmi_pm_ops, wmax_wmi_suspend, wmax_wmi_resume);
+
static const struct wmi_device_id alienware_wmax_device_id_table[] = {
{ WMAX_CONTROL_GUID, NULL },
{ },
@@ -1199,6 +1368,7 @@ static struct wmi_driver alienware_wmax_wmi_driver = {
.driver = {
.name = "alienware-wmi-wmax",
.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+ .pm = pm_sleep_ptr(&wmax_wmi_pm_ops),
},
.id_table = alienware_wmax_device_id_table,
.probe = wmax_wmi_probe,

--
2.48.1