platform/x86: asus-wmi: add WMI method to show if egpu connected

Exposes the WMI method which tells if the eGPU is properly connected
on the devices that support it.
Signed-off-by: Luke D. Jones <luke@ljones.dev>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230630053552.976579-5-luke@ljones.devSigned-off-by: Hans de Goede <hdegoede@redhat.com>

Documentation/ABI/testing/sysfs-platform-asus-wmi

@@ -107,4 +107,13 @@ Description:
 		Get the current charging mode being used:
 			* 1 - Barrel connected charger,
 			* 2 - USB-C charging
-			* 3 - Both connected, barrel used for charging
\ No newline at end of file
+			* 3 - Both connected, barrel used for charging
+
+What:		/sys/devices/platform/<platform>/egpu_connected
+Date:		Jun 2023
+KernelVersion:	6.5
+Contact:	"Luke Jones" <luke@ljones.dev>
+Description:
+		Show if the egpu (XG Mobile) is correctly connected:
+			* 0 - False,
+			* 1 - True

drivers/platform/x86/asus-wmi.c

@@ -243,6 +243,7 @@ struct asus_wmi {
 
 	bool charge_mode_available;
 	bool egpu_enable_available;
+	bool egpu_connect_available;
 	bool dgpu_disable_available;
 	bool gpu_mux_mode_available;
 
@@ -709,6 +710,22 @@ static ssize_t egpu_enable_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(egpu_enable);
 
+/* Is eGPU connected? *********************************************************/
+static ssize_t egpu_connected_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+	int result;
+
+	result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_EGPU_CONNECTED);
+	if (result < 0)
+		return result;
+
+	return sysfs_emit(buf, "%d\n", result);
+}
+
+static DEVICE_ATTR_RO(egpu_connected);
+
 /* gpu mux switch *************************************************************/
 static ssize_t gpu_mux_mode_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
@@ -3645,6 +3662,7 @@ static struct attribute *platform_attributes[] = {
 	&dev_attr_touchpad.attr,
 	&dev_attr_charge_mode.attr,
 	&dev_attr_egpu_enable.attr,
+	&dev_attr_egpu_connected.attr,
 	&dev_attr_dgpu_disable.attr,
 	&dev_attr_gpu_mux_mode.attr,
 	&dev_attr_lid_resume.attr,
@@ -3677,6 +3695,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
 		ok = asus->charge_mode_available;
 	else if (attr == &dev_attr_egpu_enable.attr)
 		ok = asus->egpu_enable_available;
+	else if (attr == &dev_attr_egpu_connected.attr)
+		ok = asus->egpu_connect_available;
 	else if (attr == &dev_attr_dgpu_disable.attr)
 		ok = asus->dgpu_disable_available;
 	else if (attr == &dev_attr_gpu_mux_mode.attr)
@@ -3943,6 +3963,7 @@ static int asus_wmi_add(struct platform_device *pdev)
 
 	asus->charge_mode_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_CHARGE_MODE);
 	asus->egpu_enable_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_EGPU);
+	asus->egpu_connect_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_EGPU_CONNECTED);
 	asus->dgpu_disable_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_DGPU);
 	asus->gpu_mux_mode_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_GPU_MUX);
 	asus->kbd_rgb_mode_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_TUF_RGB_MODE);

include/linux/platform_data/x86/asus-wmi.h

@@ -100,7 +100,9 @@
 /* Charging mode - 1=Barrel, 2=USB */
 #define ASUS_WMI_DEVID_CHARGE_MODE	0x0012006C
 
-/* dgpu on/off */
+/* epu is connected? 1 == true */
+#define ASUS_WMI_DEVID_EGPU_CONNECTED	0x00090018
+/* egpu on/off */
 #define ASUS_WMI_DEVID_EGPU		0x00090019
 
 /* dgpu on/off */