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>
---
I can't pass the asus struct to asus_wmi_battery_{add,remove}, so I use a
global variable. Is there any better way to do it?
I think the implementation of asus_wmi_battery_{init,exit} could be
improved, any ideas?
V3:
Refactor to use the new battery hooking API[1] and knobs[2].
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fa93854f7a7ed63d054405bf3779247d5300edd3
[2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=813cab8f3994250e136819ae48fbd1c95d980466
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.
drivers/platform/x86/asus-wmi.c | 91 ++++++++++++++++++++++
include/linux/platform_data/x86/asus-wmi.h | 3 +
2 files changed, 94 insertions(+)
diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 34dfbed65332..06c830c1c04f 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -26,6 +26,7 @@
#include <linux/rfkill.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
+#include <linux/power_supply.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/debugfs.h>
@@ -36,6 +37,7 @@
#include <linux/acpi.h>
#include <linux/dmi.h>
#include <acpi/video.h>
+#include <acpi/battery.h>
#include "asus-wmi.h"
@@ -368,6 +370,92 @@ static bool asus_wmi_dev_is_present(struct asus_wmi *asus, u32 dev_id)
return status == 0 && (retval & ASUS_WMI_DSTS_PRESENCE_BIT);
}
+/* Battery ********************************************************************/
+
+/* The battery maximum charging percentage */
+static int charge_end_threshold;
+
+static ssize_t charge_control_end_threshold_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ 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.
+ */
+ charge_end_threshold = value;
+ return count;
+}
+
+static ssize_t charge_control_end_threshold_show(struct device *device,
+ struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%d\n", charge_end_threshold);
+}
+
+static DEVICE_ATTR_RW(charge_control_end_threshold);
+
+static int asus_wmi_battery_add(struct power_supply *battery)
+{
+ /* The WMI method does not provide a way to specific a battery, so we
+ * just assume it is the first battery.
+ */
+ if (!strcmp(battery->desc->name, "BAT0") == 0)
+ return -ENODEV;
+
+ if (device_create_file(&battery->dev,
+ &dev_attr_charge_control_end_threshold))
+ return -ENODEV;
+
+ /* 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% when
+ * a battery is added.
+ */
+ asus_wmi_set_devstate(ASUS_WMI_DEVID_RSOC, 100, NULL);
+ charge_end_threshold = 100;
+
+ return 0;
+}
+
+static int asus_wmi_battery_remove(struct power_supply *battery)
+{
+ device_remove_file(&battery->dev,
+ &dev_attr_charge_control_end_threshold);
+ return 0;
+}
+
+static struct acpi_battery_hook battery_hook = {
+ .add_battery = asus_wmi_battery_add,
+ .remove_battery = asus_wmi_battery_remove,
+ .name = "ASUS Battery Extension",
+};
+
+static void asus_wmi_battery_init(struct asus_wmi *asus)
+{
+ if (asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_RSOC) >= 0)
+ battery_hook_register(&battery_hook);
+}
+
+static void asus_wmi_battery_exit(struct asus_wmi *asus)
+{
+ if (asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_RSOC) >= 0)
+ battery_hook_unregister(&battery_hook);
+}
+
/* LEDs ***********************************************************************/
/*
@@ -2433,6 +2521,8 @@ static int asus_wmi_add(struct platform_device *pdev)
goto fail_wmi_handler;
}
+ asus_wmi_battery_init(asus);
+
asus_wmi_debugfs_init(asus);
return 0;
@@ -2468,6 +2558,7 @@ static int asus_wmi_remove(struct platform_device *device)
asus_wmi_debugfs_exit(asus);
asus_wmi_sysfs_exit(asus->platform_device);
asus_fan_set_auto(asus);
+ asus_wmi_battery_exit(asus);
kfree(asus);
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
