[PATCH v2 08/10] platform/x86: alienware-wmi-wmax: Add support for manual fan control

Kurt Borja
2025-02-25T22:25:25Z

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 PWM `boost` value, which has the
following empirically discovered, aproximate behavior over the PWM
value:

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

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

Expose this pwm_boost knob as a custom HWMON attribute.

Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
---
.../platform/x86/dell/alienware-wmi-wmax.c | 152 +++++++++++++++++-
1 file changed, 144 insertions(+), 8 deletions(-)

diff --git a/drivers/platform/x86/dell/alienware-wmi-wmax.c b/drivers/platform/x86/dell/alienware-wmi-wmax.c
index 818023a5b205..64818efc3a1a 100644
--- a/drivers/platform/x86/dell/alienware-wmi-wmax.c
+++ b/drivers/platform/x86/dell/alienware-wmi-wmax.c
@@ -13,8 +13,11 @@
#include <linux/bits.h>
#include <linux/dmi.h>
#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.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"
@@ -178,10 +181,12 @@ 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 {
@@ -247,6 +252,7 @@ struct awcc_fan_data {
u32 total_temps;
u32 min_rpm;
u32 max_rpm;
+ u8 suspend_cache;
u8 id;
};

@@ -560,12 +566,13 @@ static inline int awcc_thermal_information(struct wmi_device *wdev, u8 operation
return __awcc_wmi_command(wdev, AWCC_METHOD_THERMAL_INFORMATION, &args, out);
}

-static inline int awcc_thermal_control(struct wmi_device *wdev, u8 profile)
+static inline int awcc_thermal_control(struct wmi_device *wdev, u8 operation,
+ u8 arg1, u8 arg2)
{
struct wmax_u32_args args = {
- .operation = AWCC_OP_ACTIVATE_PROFILE,
- .arg1 = profile,
- .arg2 = 0,
+ .operation = operation,
+ .arg1 = arg1,
+ .arg2 = arg2,
.arg3 = 0,
};
u32 out;
@@ -815,6 +822,77 @@ static const struct hwmon_chip_info awcc_hwmon_chip_info = {
.info = awcc_hwmon_info,
};

+static ssize_t pwm_boost_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ int ret, index = to_sensor_dev_attr(attr)->index;
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ struct awcc_fan_data *data = priv->fan_data[index];
+ u32 boost;
+
+ ret = awcc_thermal_information(priv->wdev, AWCC_OP_GET_FAN_BOOST, data->id,
+ &boost);
+ if (ret)
+ return ret;
+
+ return sysfs_emit(buf, "%u\n", boost);
+}
+
+static ssize_t pwm_boost_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int ret, index = to_sensor_dev_attr(attr)->index;
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ struct awcc_fan_data *data = priv->fan_data[index];
+ unsigned long val;
+
+ ret = kstrtoul(buf, 0, &val);
+ if (ret)
+ return ret;
+
+ ret = awcc_thermal_control(priv->wdev, AWCC_OP_SET_FAN_BOOST, data->id,
+ clamp_val(val, 0, 255));
+
+ return ret ? ret : count;
+}
+
+static SENSOR_DEVICE_ATTR_RW(pwm1_boost, pwm_boost, 0);
+static SENSOR_DEVICE_ATTR_RW(pwm2_boost, pwm_boost, 1);
+static SENSOR_DEVICE_ATTR_RW(pwm3_boost, pwm_boost, 2);
+static SENSOR_DEVICE_ATTR_RW(pwm4_boost, pwm_boost, 3);
+
+static umode_t pwm_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 pwm_boost_group_visible(struct kobject *kobj)
+{
+ return true;
+}
+
+DEFINE_SYSFS_GROUP_VISIBLE(pwm_boost);
+
+static struct attribute *fan_boost_attrs[] = {
+ &sensor_dev_attr_pwm1_boost.dev_attr.attr,
+ &sensor_dev_attr_pwm2_boost.dev_attr.attr,
+ &sensor_dev_attr_pwm3_boost.dev_attr.attr,
+ &sensor_dev_attr_pwm4_boost.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group pwm_boost_group = {
+ .attrs = fan_boost_attrs,
+ .is_visible = SYSFS_GROUP_VISIBLE(pwm_boost),
+};
+
+static const struct attribute_group *awcc_hwmon_groups[] = {
+ &pwm_boost_group,
+ NULL
+};
+
static int awcc_hwmon_temps_init(struct wmi_device *wdev)
{
struct awcc_priv *priv = dev_get_drvdata(&wdev->dev);
@@ -948,12 +1026,51 @@ 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)
+ fan->suspend_cache = 0;
+ else
+ fan->suspend_cache = clamp_val(boost, 0, 255);
+
+ awcc_thermal_control(priv->wdev, AWCC_OP_SET_FAN_BOOST, fan->id, 0);
+ }
+}
+
+static void awcc_hwmon_resume(struct device *dev)
+{
+
+ struct awcc_priv *priv = dev_get_drvdata(dev);
+ struct awcc_fan_data *fan;
+ unsigned int i;
+
+ for (i = 0; i < priv->fan_count; i++) {
+ fan = priv->fan_data[i];
+
+ if (fan->suspend_cache)
+ awcc_thermal_control(priv->wdev, AWCC_OP_SET_FAN_BOOST,
+ fan->id, fan->suspend_cache);
+ }
+}
+
/*
* Thermal Profile control
* - Provides thermal profile control through the Platform Profile API
@@ -1018,8 +1135,8 @@ static int awcc_platform_profile_set(struct device *dev,
}
}

- return awcc_thermal_control(priv->wdev,
- priv->supported_profiles[profile]);
+ return awcc_thermal_control(priv->wdev, AWCC_OP_ACTIVATE_PROFILE,
+ priv->supported_profiles[profile], 0);
}

static int awcc_platform_profile_probe(void *drvdata, unsigned long *choices)
@@ -1187,6 +1304,24 @@ 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 },
{ },
@@ -1197,6 +1332,7 @@ 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