Commit 76f7eba3 authored by Tim Crawford's avatar Tim Crawford Committed by Hans de Goede
Browse files

platform/x86: system76_acpi: Add battery charging thresholds 



System76 laptops running open source EC firmware support configuring
charging thresholds through ACPI methods. Expose this functionality
through the standard sysfs entries charge_control_{start,end}_threshold.

Signed-off-by: default avatarTim Crawford <tcrawford@system76.com>
Link: https://lore.kernel.org/r/20211006202202.7479-4-tcrawford@system76.com


Reviewed-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
parent 0de30fc6

drivers/platform/x86/system76_acpi.c

+157 −0
Original line number Diff line number Diff line
@@ -18,8 +18,12 @@ 
#include <linux/leds.h>

#include <linux/module.h>

#include <linux/pci_ids.h>

#include <linux/power_supply.h>

#include <linux/sysfs.h>

#include <linux/types.h>



#include <acpi/battery.h>



struct system76_data {

	struct acpi_device *acpi_dev;

	struct led_classdev ap_led;
@@ -143,6 +147,154 @@ static int system76_set(struct system76_data *data, char *method, int value) 
		return -1;

}



#define BATTERY_THRESHOLD_INVALID	0xFF



enum {

	THRESHOLD_START,

	THRESHOLD_END,

};



static ssize_t battery_get_threshold(int which, char *buf)

{

	struct acpi_object_list input;

	union acpi_object param;

	acpi_handle handle;

	acpi_status status;

	unsigned long long ret = BATTERY_THRESHOLD_INVALID;



	handle = ec_get_handle();

	if (!handle)

		return -ENODEV;



	input.count = 1;

	input.pointer = &param;

	// Start/stop selection

	param.type = ACPI_TYPE_INTEGER;

	param.integer.value = which;



	status = acpi_evaluate_integer(handle, "GBCT", &input, &ret);

	if (ACPI_FAILURE(status))

		return -EIO;

	if (ret == BATTERY_THRESHOLD_INVALID)

		return -EINVAL;



	return sysfs_emit(buf, "%d\n", (int)ret);

}



static ssize_t battery_set_threshold(int which, const char *buf, size_t count)

{

	struct acpi_object_list input;

	union acpi_object params[2];

	acpi_handle handle;

	acpi_status status;

	unsigned int value;

	int ret;



	handle = ec_get_handle();

	if (!handle)

		return -ENODEV;



	ret = kstrtouint(buf, 10, &value);

	if (ret)

		return ret;



	if (value > 100)

		return -EINVAL;



	input.count = 2;

	input.pointer = params;

	// Start/stop selection

	params[0].type = ACPI_TYPE_INTEGER;

	params[0].integer.value = which;

	// Threshold value

	params[1].type = ACPI_TYPE_INTEGER;

	params[1].integer.value = value;



	status = acpi_evaluate_object(handle, "SBCT", &input, NULL);

	if (ACPI_FAILURE(status))

		return -EIO;



	return count;

}



static ssize_t charge_control_start_threshold_show(struct device *dev,

	struct device_attribute *attr, char *buf)

{

	return battery_get_threshold(THRESHOLD_START, buf);

}



static ssize_t charge_control_start_threshold_store(struct device *dev,

	struct device_attribute *attr, const char *buf, size_t count)

{

	return battery_set_threshold(THRESHOLD_START, buf, count);

}



static DEVICE_ATTR_RW(charge_control_start_threshold);



static ssize_t charge_control_end_threshold_show(struct device *dev,

	struct device_attribute *attr, char *buf)

{

	return battery_get_threshold(THRESHOLD_END, buf);

}



static ssize_t charge_control_end_threshold_store(struct device *dev,

	struct device_attribute *attr, const char *buf, size_t count)

{

	return battery_set_threshold(THRESHOLD_END, buf, count);

}



static DEVICE_ATTR_RW(charge_control_end_threshold);



static struct attribute *system76_battery_attrs[] = {

	&dev_attr_charge_control_start_threshold.attr,

	&dev_attr_charge_control_end_threshold.attr,

	NULL,

};



ATTRIBUTE_GROUPS(system76_battery);



static int system76_battery_add(struct power_supply *battery)

{

	// System76 EC only supports 1 battery

	if (strcmp(battery->desc->name, "BAT0") != 0)

		return -ENODEV;



	if (device_add_groups(&battery->dev, system76_battery_groups))

		return -ENODEV;



	return 0;

}



static int system76_battery_remove(struct power_supply *battery)

{

	device_remove_groups(&battery->dev, system76_battery_groups);

	return 0;

}



static struct acpi_battery_hook system76_battery_hook = {

	.add_battery = system76_battery_add,

	.remove_battery = system76_battery_remove,

	.name = "System76 Battery Extension",

};



static void system76_battery_init(void)

{

	acpi_handle handle;



	handle = ec_get_handle();

	if (handle && acpi_has_method(handle, "GBCT"))

		battery_hook_register(&system76_battery_hook);

}



static void system76_battery_exit(void)

{

	acpi_handle handle;



	handle = ec_get_handle();

	if (handle && acpi_has_method(handle, "GBCT"))

		battery_hook_unregister(&system76_battery_hook);

}



// Get the airplane mode LED brightness

static enum led_brightness ap_led_get(struct led_classdev *led)

{
@@ -581,6 +733,8 @@ static int system76_add(struct acpi_device *acpi_dev) 
	if (err)

		goto error;



	system76_battery_init();



	return 0;



error:
@@ -596,6 +750,9 @@ static int system76_remove(struct acpi_device *acpi_dev) 
	struct system76_data *data;



	data = acpi_driver_data(acpi_dev);



	system76_battery_exit();



	if (data->kb_color >= 0)

		device_remove_file(data->kb_led.dev, &kb_led_color_dev_attr);