Most newer ASUS laptops supports settings a maximum charging percentage,
which help prolonging the battery life.
Tested on a Zenbook UX430UNR.
Signed-off-by: Kristian Klausen <kristian@xxxxxxxxxx>
---
V2:
Add sysfs documentation.
Reorder ASUS_WMI_CHARGE_THRESHOLD and rename to ASUS_WMI_DEVID_RSOC.
Add a comment explaining the charge_threshold variable.
Rephrase the commit message (charge threshold -> maximum charging
percentage).
The sysfs knob is still called "charge_threshold", as
maximum_charging_percentage seems a bit long.
I did look on some of the other platform modules, the LG module
use battery_care_limit and the Samsung module use
battery_life_extender.
.../ABI/testing/sysfs-platform-asus-wmi | 8 +++
drivers/platform/x86/asus-wmi.c | 49 +++++++++++++++++++
include/linux/platform_data/x86/asus-wmi.h | 3 ++
3 files changed, 60 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-platform-asus-wmi b/Documentation/ABI/testing/sysfs-platform-asus-wmi
index 9e99f2909612..21730e7ccd47 100644
--- a/Documentation/ABI/testing/sysfs-platform-asus-wmi
+++ b/Documentation/ABI/testing/sysfs-platform-asus-wmi
@@ -46,3 +46,11 @@ Description:
* 0 - normal,
* 1 - overboost,
* 2 - silent
+
+What: /sys/devices/platform/<platform>/charge_threshold
+Date: Aug 2019
+KernelVersion: 5.3
+Contact: "Kristian Klausen" <kristian@xxxxxxxxxx>
+Description:
+ Control the maximum charging percentage.
+ Accepted values are 0-100.
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 34dfbed65332..c4e6cc1e3b74 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -195,6 +195,9 @@ struct asus_wmi {
u8 fan_boost_mode_mask;
u8 fan_boost_mode;
+ /* The battery maximum charging percentage */
+ int charge_threshold;
+
struct hotplug_slot hotplug_slot;
struct mutex hotplug_lock;
struct mutex wmi_lock;
@@ -2075,6 +2078,43 @@ static ssize_t cpufv_store(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR_WO(cpufv);
+
+static ssize_t charge_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct asus_wmi *asus = dev_get_drvdata(dev);
+ int value, ret, rv;
+
+ ret = kstrtouint(buf, 10, &value);
+
+ if (!count || ret != 0)
+ return -EINVAL;
+ if (value < 0 || value > 100)
+ return -EINVAL;
+
+ asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, value, &rv);
+
+ if (rv != 1)
+ return -EIO;
+
+ /* There isn't any method in the DSDT to read the threshold, so we
+ * save the threshold.
+ */
+ asus->charge_threshold = value;
+ return count;
+}
+
+static ssize_t charge_threshold_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct asus_wmi *asus = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", asus->charge_threshold);
+}
+
+static DEVICE_ATTR_RW(charge_threshold);
+
static struct attribute *platform_attributes[] = {
&dev_attr_cpufv.attr,
&dev_attr_camera.attr,
@@ -2083,6 +2123,7 @@ static struct attribute *platform_attributes[] = {
&dev_attr_lid_resume.attr,
&dev_attr_als_enable.attr,
&dev_attr_fan_boost_mode.attr,
+ &dev_attr_charge_threshold.attr,
NULL
};
@@ -2106,6 +2147,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
devid = ASUS_WMI_DEVID_ALS_ENABLE;
else if (attr == &dev_attr_fan_boost_mode.attr)
ok = asus->fan_boost_mode_available;
+ else if (attr == &dev_attr_charge_threshold.attr)
+ devid = ASUS_WMI_DEVID_RSOC;
if (devid != -1)
ok = !(asus_wmi_get_devstate_simple(asus, devid) < 0);
@@ -2434,6 +2477,12 @@ static int asus_wmi_add(struct platform_device *pdev)
}
asus_wmi_debugfs_init(asus);
+ /* The charge threshold is only reset when the system is power cycled,
+ * and we can't get the current threshold so let set it to 100% on
+ * module load.
+ */
+ asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
+ asus->charge_threshold = 100;
return 0;
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 409e16064f4b..60249e22e844 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -81,6 +81,9 @@
/* Deep S3 / Resume on LID open */
#define ASUS_WMI_DEVID_LID_RESUME 0x00120031
+/* Maximum charging percentage */
+#define ASUS_WMI_DEVID_RSOC 0x00120057
+
/* DSTS masks */
#define ASUS_WMI_DSTS_STATUS_BIT 0x00000001
#define ASUS_WMI_DSTS_UNKNOWN_BIT 0x00000002
--
2.22.0
