[PATCH] platform/x86: asus-wmi: disable USB0 hub on ROG Ally before suspend

["Luke D. Jones" <luke@ljones.dev>]

ASUS have worked around an issue in XINPUT in Windows by tweaking the MCU
firmware to disable the USB0 hub on screen disable when suspending.

The issue we have with this however is one of timing - the call the tells
the MCU to this isn't able to complete before suspend is done so we call
this in a prepare() and add a small msleep() to ensure it is done.

Without this the MCU is unable to initialise itself correctly on resume.

Signed-off-by: Luke D. Jones <luke@ljones.dev>
---
 drivers/platform/x86/asus-wmi.c | 43 +++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 6a79f16233ab..c28829d45fb5 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -16,6 +16,7 @@
 #include <linux/acpi.h>
 #include <linux/backlight.h>
 #include <linux/debugfs.h>
+#include <linux/delay.h>
 #include <linux/dmi.h>
 #include <linux/fb.h>
 #include <linux/hwmon.h>
@@ -132,6 +133,9 @@ module_param(fnlock_default, bool, 0444);
 #define ASUS_SCREENPAD_BRIGHT_MAX 255
 #define ASUS_SCREENPAD_BRIGHT_DEFAULT 60
 
+/* Controls the power state of the USB0 hub on ROG Ally which input is on */
+#define ASUS_USB0_PWR_SB_PCI0_SBRG_EC0_CSEE "\\_SB.PCI0.SBRG.EC0.CSEE"
+
 static const char * const ashs_ids[] = { "ATK4001", "ATK4002", NULL };
 
 static int throttle_thermal_policy_write(struct asus_wmi *);
@@ -300,6 +304,9 @@ struct asus_wmi {
 
 	bool fnlock_locked;
 
+	/* The ROG Ally device requires the USB hub to be disabled before suspend */
+	bool pre_suspend_ec0_csee_disable;
+
 	struct asus_wmi_debug debug;
 
 	struct asus_wmi_driver *driver;
@@ -4488,6 +4495,8 @@ static int asus_wmi_add(struct platform_device *pdev)
 	asus->nv_temp_tgt_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_NV_THERM_TARGET);
 	asus->panel_overdrive_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_PANEL_OD);
 	asus->mini_led_mode_available = asus_wmi_dev_is_present(asus, ASUS_WMI_DEVID_MINI_LED_MODE);
+	asus->pre_suspend_ec0_csee_disable = acpi_has_method(NULL, ASUS_USB0_PWR_SB_PCI0_SBRG_EC0_CSEE)
+						&& dmi_match(DMI_BOARD_NAME, "RC71L");
 
 	err = fan_boost_mode_check_present(asus);
 	if (err)
@@ -4654,6 +4663,38 @@ static int asus_hotk_resume(struct device *device)
 		asus_wmi_fnlock_update(asus);
 
 	asus_wmi_tablet_mode_get_state(asus);
+
+	return 0;
+}
+
+static int asus_hotk_resume_early(struct device *device)
+{
+	struct asus_wmi *asus = dev_get_drvdata(device);
+	acpi_status status;
+
+	if (asus->pre_suspend_ec0_csee_disable) {
+		status = acpi_execute_simple_method(NULL, ASUS_USB0_PWR_SB_PCI0_SBRG_EC0_CSEE, 0xB8);
+		if (ACPI_FAILURE(status)) {
+			pr_warn("failed to set USB hub power on\n");
+			return 1;
+		}
+	}
+	return 0;
+}
+
+static int asus_hotk_prepare(struct device *device)
+{
+	struct asus_wmi *asus = dev_get_drvdata(device);
+	acpi_status status;
+
+	if (asus->pre_suspend_ec0_csee_disable) {
+		status = acpi_execute_simple_method(NULL, ASUS_USB0_PWR_SB_PCI0_SBRG_EC0_CSEE, 0xB7);
+		msleep(500); /* sleep required to ensure n-key is disabled before sleep continues */
+		if (ACPI_FAILURE(status)) {
+			pr_warn("failed to set USB hub power off\n");
+			// return 1;
+		}
+	}
 	return 0;
 }
 
@@ -4701,6 +4742,8 @@ static const struct dev_pm_ops asus_pm_ops = {
 	.thaw = asus_hotk_thaw,
 	.restore = asus_hotk_restore,
 	.resume = asus_hotk_resume,
+	.resume_early = asus_hotk_resume_early,
+	.prepare = asus_hotk_prepare,
 };
 
 /* Registration ***************************************************************/
-- 
2.43.0