[PATCH] platform/x86: asus-wmi: add keystone dongle support

Dariusz Figzał posted 1 patch 1 week, 5 days ago
There is a newer version of this series
drivers/platform/x86/asus-wmi.c            | 75 ++++++++++++++++++++++
include/linux/platform_data/x86/asus-wmi.h |  7 ++
2 files changed, 82 insertions(+)
[PATCH] platform/x86: asus-wmi: add keystone dongle support
Posted by Dariusz Figzał 1 week, 5 days ago
The ASUS Keystone is a physical NFC-like dongle that slots into supported
ASUS laptops. The EC fires WMI notify code 0xB4 on insert/remove events.

Expose the current insert state via a sysfs attribute by querying WMI
device ID 0x00120091 (DSTS). This devid does not follow the standard DSTS
convention: PRESENCE_BIT (0x00010000) encodes the insert state rather than
feature presence, and STATUS_BIT is never set. Presence of a keystone slot
is detected by a successful DSTS call (any result other than -ENODEV).

Signed-off-by: Dariusz Figzał <dariuszfigzal@gmail.com>
---
 drivers/platform/x86/asus-wmi.c            | 75 ++++++++++++++++++++++
 include/linux/platform_data/x86/asus-wmi.h |  7 ++
 2 files changed, 82 insertions(+)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 80144c412b90..a3fa3921aef3 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -70,6 +70,7 @@ module_param(fnlock_default, bool, 0444);
 #define NOTIFY_KBD_TTP			0xae
 #define NOTIFY_LID_FLIP			0xfa
 #define NOTIFY_LID_FLIP_ROG		0xbd
+#define NOTIFY_KEYSTONE			0xb4
 
 #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
 
@@ -279,6 +280,8 @@ struct asus_wmi {
 	u32 tablet_switch_dev_id;
 	bool tablet_switch_inverted;
 
+	bool keystone_detected;
+
 	enum fan_type fan_type;
 	enum fan_type gpu_fan_type;
 	enum fan_type mid_fan_type;
@@ -646,6 +649,66 @@ static bool asus_wmi_dev_is_present(struct asus_wmi *asus, u32 dev_id)
 	return status == 0 && (retval & ASUS_WMI_DSTS_PRESENCE_BIT);
 }
 
+/* Keystone *******************************************************************/
+
+static ssize_t keystone_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+	u32 retval;
+	int err;
+
+	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
+	if (err)
+		return err;
+
+	return sysfs_emit(buf, "%d\n", !!(retval & ASUS_WMI_DSTS_PRESENCE_BIT));
+}
+
+static DEVICE_ATTR_RO(keystone);
+
+static void asus_wmi_keystone_notify(struct asus_wmi *asus)
+{
+	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "keystone");
+}
+
+static int asus_wmi_keystone_init(struct asus_wmi *asus)
+{
+	u32 retval;
+	int err;
+
+	/*
+	 * Use a raw devstate call rather than asus_wmi_dev_is_present().
+	 * For this devid, PRESENCE_BIT encodes current insert state, not
+	 * feature presence, so asus_wmi_dev_is_present() would return false
+	 * whenever the dongle is absent at boot, even on machines that have
+	 * a keystone slot.
+	 * -ENODEV means the firmware doesn't know this devid at all.
+	 * retval is not examined here, only the return code matters.
+	 */
+	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
+	if (err == -ENODEV)
+		return 0;
+	if (err)
+		return err;
+
+	err = device_create_file(&asus->platform_device->dev, &dev_attr_keystone);
+	if (err)
+		return err;
+
+	asus->keystone_detected = true;
+	return 0;
+}
+
+static void asus_wmi_keystone_exit(struct asus_wmi *asus)
+{
+	if (!asus->keystone_detected)
+		return;
+
+	device_remove_file(&asus->platform_device->dev, &dev_attr_keystone);
+	asus->keystone_detected = false;
+}
+
 /* Input **********************************************************************/
 static void asus_wmi_tablet_sw_report(struct asus_wmi *asus, bool value)
 {
@@ -4575,6 +4638,12 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
 		return;
 	}
 
+	if (code == NOTIFY_KEYSTONE) {
+		if (asus->keystone_detected)
+			asus_wmi_keystone_notify(asus);
+		return;
+	}
+
 	if (code == NOTIFY_KBD_FBM || code == NOTIFY_KBD_TTP) {
 		if (asus->fan_boost_mode_available)
 			fan_boost_mode_switch_next(asus);
@@ -5085,6 +5154,10 @@ static int asus_wmi_add(struct platform_device *pdev)
 	if (err)
 		goto fail_sysfs;
 
+	err = asus_wmi_keystone_init(asus);
+	if (err)
+		dev_warn(&pdev->dev, "Keystone initialization failed: %d\n", err);
+
 	err = asus_wmi_input_init(asus);
 	if (err)
 		goto fail_input;
@@ -5170,6 +5243,7 @@ static int asus_wmi_add(struct platform_device *pdev)
 fail_hwmon:
 	asus_wmi_input_exit(asus);
 fail_input:
+	asus_wmi_keystone_exit(asus);
 	asus_wmi_sysfs_exit(asus->platform_device);
 fail_sysfs:
 fail_custom_fan_curve:
@@ -5191,6 +5265,7 @@ static void asus_wmi_remove(struct platform_device *device)
 	asus_wmi_backlight_exit(asus);
 	asus_screenpad_exit(asus);
 	asus_wmi_input_exit(asus);
+	asus_wmi_keystone_exit(asus);
 	asus_wmi_led_exit(asus);
 	asus_wmi_rfkill_exit(asus);
 	asus_wmi_debugfs_exit(asus);
diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
index 554f41b827e1..c29962d5baac 100644
--- a/include/linux/platform_data/x86/asus-wmi.h
+++ b/include/linux/platform_data/x86/asus-wmi.h
@@ -147,6 +147,13 @@
 #define ASUS_WMI_DEVID_GPU_MUX		0x00090016
 #define ASUS_WMI_DEVID_GPU_MUX_VIVO	0x00090026
 
+/* Keystone dongle insert/remove state.
+ * PRESENCE_BIT (0x00010000) encodes insert state:
+ * 0x00010000 = inserted, 0x00000000 = absent. STATUS_BIT is never set.
+ * 0xFFFFFFFE means no keystone slot on this machine.
+ */
+#define ASUS_WMI_DEVID_KEYSTONE		0x00120091
+
 /* TUF laptop RGB modes/colours */
 #define ASUS_WMI_DEVID_TUF_RGB_MODE	0x00100056
 #define ASUS_WMI_DEVID_TUF_RGB_MODE2	0x0010005A
-- 
2.54.0

Re: [PATCH] platform/x86: asus-wmi: add keystone dongle support
Posted by Denis Benato 1 week, 4 days ago
On 5/26/26 23:44, Dariusz Figzał wrote:
> The ASUS Keystone is a physical NFC-like dongle that slots into supported
> ASUS laptops. The EC fires WMI notify code 0xB4 on insert/remove events.
>
> Expose the current insert state via a sysfs attribute by querying WMI
> device ID 0x00120091 (DSTS). This devid does not follow the standard DSTS
> convention: PRESENCE_BIT (0x00010000) encodes the insert state rather than
> feature presence, and STATUS_BIT is never set. Presence of a keystone slot
> is detected by a successful DSTS call (any result other than -ENODEV).
Thanks for this!

Ilpo might have some suggestions on how to make the code better,
As we discussed a fair bit about this I say LGTM.

Reviewed-by: Denis Benato <denis.benato@linux.dev>
> Signed-off-by: Dariusz Figzał <dariuszfigzal@gmail.com>
> ---
>  drivers/platform/x86/asus-wmi.c            | 75 ++++++++++++++++++++++
>  include/linux/platform_data/x86/asus-wmi.h |  7 ++
>  2 files changed, 82 insertions(+)
>
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 80144c412b90..a3fa3921aef3 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -70,6 +70,7 @@ module_param(fnlock_default, bool, 0444);
>  #define NOTIFY_KBD_TTP			0xae
>  #define NOTIFY_LID_FLIP			0xfa
>  #define NOTIFY_LID_FLIP_ROG		0xbd
> +#define NOTIFY_KEYSTONE			0xb4
>  
>  #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
>  
> @@ -279,6 +280,8 @@ struct asus_wmi {
>  	u32 tablet_switch_dev_id;
>  	bool tablet_switch_inverted;
>  
> +	bool keystone_detected;
> +
>  	enum fan_type fan_type;
>  	enum fan_type gpu_fan_type;
>  	enum fan_type mid_fan_type;
> @@ -646,6 +649,66 @@ static bool asus_wmi_dev_is_present(struct asus_wmi *asus, u32 dev_id)
>  	return status == 0 && (retval & ASUS_WMI_DSTS_PRESENCE_BIT);
>  }
>  
> +/* Keystone *******************************************************************/
> +
> +static ssize_t keystone_show(struct device *dev,
> +			     struct device_attribute *attr, char *buf)
> +{
> +	struct asus_wmi *asus = dev_get_drvdata(dev);
> +	u32 retval;
> +	int err;
> +
> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
> +	if (err)
> +		return err;
> +
> +	return sysfs_emit(buf, "%d\n", !!(retval & ASUS_WMI_DSTS_PRESENCE_BIT));
> +}
> +
> +static DEVICE_ATTR_RO(keystone);
> +
> +static void asus_wmi_keystone_notify(struct asus_wmi *asus)
> +{
> +	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "keystone");
> +}
> +
> +static int asus_wmi_keystone_init(struct asus_wmi *asus)
> +{
> +	u32 retval;
> +	int err;
> +
> +	/*
> +	 * Use a raw devstate call rather than asus_wmi_dev_is_present().
> +	 * For this devid, PRESENCE_BIT encodes current insert state, not
> +	 * feature presence, so asus_wmi_dev_is_present() would return false
> +	 * whenever the dongle is absent at boot, even on machines that have
> +	 * a keystone slot.
> +	 * -ENODEV means the firmware doesn't know this devid at all.
> +	 * retval is not examined here, only the return code matters.
> +	 */
> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
> +	if (err == -ENODEV)
> +		return 0;
> +	if (err)
> +		return err;
> +
> +	err = device_create_file(&asus->platform_device->dev, &dev_attr_keystone);
> +	if (err)
> +		return err;
> +
> +	asus->keystone_detected = true;
> +	return 0;
> +}
> +
> +static void asus_wmi_keystone_exit(struct asus_wmi *asus)
> +{
> +	if (!asus->keystone_detected)
> +		return;
> +
> +	device_remove_file(&asus->platform_device->dev, &dev_attr_keystone);
> +	asus->keystone_detected = false;
> +}
> +
>  /* Input **********************************************************************/
>  static void asus_wmi_tablet_sw_report(struct asus_wmi *asus, bool value)
>  {
> @@ -4575,6 +4638,12 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
>  		return;
>  	}
>  
> +	if (code == NOTIFY_KEYSTONE) {
> +		if (asus->keystone_detected)
> +			asus_wmi_keystone_notify(asus);
> +		return;
> +	}
> +
>  	if (code == NOTIFY_KBD_FBM || code == NOTIFY_KBD_TTP) {
>  		if (asus->fan_boost_mode_available)
>  			fan_boost_mode_switch_next(asus);
> @@ -5085,6 +5154,10 @@ static int asus_wmi_add(struct platform_device *pdev)
>  	if (err)
>  		goto fail_sysfs;
>  
> +	err = asus_wmi_keystone_init(asus);
> +	if (err)
> +		dev_warn(&pdev->dev, "Keystone initialization failed: %d\n", err);
> +
>  	err = asus_wmi_input_init(asus);
>  	if (err)
>  		goto fail_input;
> @@ -5170,6 +5243,7 @@ static int asus_wmi_add(struct platform_device *pdev)
>  fail_hwmon:
>  	asus_wmi_input_exit(asus);
>  fail_input:
> +	asus_wmi_keystone_exit(asus);
>  	asus_wmi_sysfs_exit(asus->platform_device);
>  fail_sysfs:
>  fail_custom_fan_curve:
> @@ -5191,6 +5265,7 @@ static void asus_wmi_remove(struct platform_device *device)
>  	asus_wmi_backlight_exit(asus);
>  	asus_screenpad_exit(asus);
>  	asus_wmi_input_exit(asus);
> +	asus_wmi_keystone_exit(asus);
>  	asus_wmi_led_exit(asus);
>  	asus_wmi_rfkill_exit(asus);
>  	asus_wmi_debugfs_exit(asus);
> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> index 554f41b827e1..c29962d5baac 100644
> --- a/include/linux/platform_data/x86/asus-wmi.h
> +++ b/include/linux/platform_data/x86/asus-wmi.h
> @@ -147,6 +147,13 @@
>  #define ASUS_WMI_DEVID_GPU_MUX		0x00090016
>  #define ASUS_WMI_DEVID_GPU_MUX_VIVO	0x00090026
>  
> +/* Keystone dongle insert/remove state.
> + * PRESENCE_BIT (0x00010000) encodes insert state:
> + * 0x00010000 = inserted, 0x00000000 = absent. STATUS_BIT is never set.
> + * 0xFFFFFFFE means no keystone slot on this machine.
> + */
> +#define ASUS_WMI_DEVID_KEYSTONE		0x00120091
> +
>  /* TUF laptop RGB modes/colours */
>  #define ASUS_WMI_DEVID_TUF_RGB_MODE	0x00100056
>  #define ASUS_WMI_DEVID_TUF_RGB_MODE2	0x0010005A
Re: [PATCH] platform/x86: asus-wmi: add keystone dongle support
Posted by Ilpo Järvinen 1 week, 4 days ago
On Thu, 28 May 2026, Denis Benato wrote:

> 
> On 5/26/26 23:44, Dariusz Figzał wrote:
> > The ASUS Keystone is a physical NFC-like dongle that slots into supported
> > ASUS laptops. The EC fires WMI notify code 0xB4 on insert/remove events.
> >
> > Expose the current insert state via a sysfs attribute by querying WMI
> > device ID 0x00120091 (DSTS). This devid does not follow the standard DSTS
> > convention: PRESENCE_BIT (0x00010000) encodes the insert state rather than
> > feature presence, and STATUS_BIT is never set. Presence of a keystone slot
> > is detected by a successful DSTS call (any result other than -ENODEV).
> Thanks for this!
> 
> Ilpo might have some suggestions on how to make the code better,
> As we discussed a fair bit about this I say LGTM.
> 
> Reviewed-by: Denis Benato <denis.benato@linux.dev>
> > Signed-off-by: Dariusz Figzał <dariuszfigzal@gmail.com>
> > ---
> >  drivers/platform/x86/asus-wmi.c            | 75 ++++++++++++++++++++++
> >  include/linux/platform_data/x86/asus-wmi.h |  7 ++
> >  2 files changed, 82 insertions(+)
> >
> > diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> > index 80144c412b90..a3fa3921aef3 100644
> > --- a/drivers/platform/x86/asus-wmi.c
> > +++ b/drivers/platform/x86/asus-wmi.c
> > @@ -70,6 +70,7 @@ module_param(fnlock_default, bool, 0444);
> >  #define NOTIFY_KBD_TTP			0xae
> >  #define NOTIFY_LID_FLIP			0xfa
> >  #define NOTIFY_LID_FLIP_ROG		0xbd
> > +#define NOTIFY_KEYSTONE			0xb4
> >  
> >  #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
> >  
> > @@ -279,6 +280,8 @@ struct asus_wmi {
> >  	u32 tablet_switch_dev_id;
> >  	bool tablet_switch_inverted;
> >  
> > +	bool keystone_detected;
> > +
> >  	enum fan_type fan_type;
> >  	enum fan_type gpu_fan_type;
> >  	enum fan_type mid_fan_type;
> > @@ -646,6 +649,66 @@ static bool asus_wmi_dev_is_present(struct asus_wmi *asus, u32 dev_id)
> >  	return status == 0 && (retval & ASUS_WMI_DSTS_PRESENCE_BIT);
> >  }
> >  
> > +/* Keystone *******************************************************************/
> > +
> > +static ssize_t keystone_show(struct device *dev,
> > +			     struct device_attribute *attr, char *buf)
> > +{
> > +	struct asus_wmi *asus = dev_get_drvdata(dev);
> > +	u32 retval;
> > +	int err;
> > +
> > +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
> > +	if (err)
> > +		return err;
> > +
> > +	return sysfs_emit(buf, "%d\n", !!(retval & ASUS_WMI_DSTS_PRESENCE_BIT));
> > +}
> > +
> > +static DEVICE_ATTR_RO(keystone);
> > +
> > +static void asus_wmi_keystone_notify(struct asus_wmi *asus)
> > +{
> > +	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "keystone");
> > +}
> > +
> > +static int asus_wmi_keystone_init(struct asus_wmi *asus)
> > +{
> > +	u32 retval;
> > +	int err;
> > +
> > +	/*
> > +	 * Use a raw devstate call rather than asus_wmi_dev_is_present().
> > +	 * For this devid, PRESENCE_BIT encodes current insert state, not
> > +	 * feature presence, so asus_wmi_dev_is_present() would return false
> > +	 * whenever the dongle is absent at boot, even on machines that have
> > +	 * a keystone slot.
> > +	 * -ENODEV means the firmware doesn't know this devid at all.
> > +	 * retval is not examined here, only the return code matters.
> > +	 */
> > +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
> > +	if (err == -ENODEV)
> > +		return 0;
> > +	if (err)
> > +		return err;
> > +
> > +	err = device_create_file(&asus->platform_device->dev, &dev_attr_keystone);
> > +	if (err)
> > +		return err;
> > +
> > +	asus->keystone_detected = true;
> > +	return 0;
> > +}

The visibility of this should be controlled using .is_visible and the 
attribute should be placed into the normal attribute array.

> > +static void asus_wmi_keystone_exit(struct asus_wmi *asus)
> > +{
> > +	if (!asus->keystone_detected)
> > +		return;
> > +
> > +	device_remove_file(&asus->platform_device->dev, &dev_attr_keystone);
> > +	asus->keystone_detected = false;
> > +}
> > +
> >  /* Input **********************************************************************/
> >  static void asus_wmi_tablet_sw_report(struct asus_wmi *asus, bool value)
> >  {
> > @@ -4575,6 +4638,12 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
> >  		return;
> >  	}
> >  
> > +	if (code == NOTIFY_KEYSTONE) {
> > +		if (asus->keystone_detected)
> > +			asus_wmi_keystone_notify(asus);
> > +		return;
> > +	}
> > +
> >  	if (code == NOTIFY_KBD_FBM || code == NOTIFY_KBD_TTP) {
> >  		if (asus->fan_boost_mode_available)
> >  			fan_boost_mode_switch_next(asus);
> > @@ -5085,6 +5154,10 @@ static int asus_wmi_add(struct platform_device *pdev)
> >  	if (err)
> >  		goto fail_sysfs;
> >  
> > +	err = asus_wmi_keystone_init(asus);
> > +	if (err)
> > +		dev_warn(&pdev->dev, "Keystone initialization failed: %d\n", err);
> > +
> >  	err = asus_wmi_input_init(asus);
> >  	if (err)
> >  		goto fail_input;
> > @@ -5170,6 +5243,7 @@ static int asus_wmi_add(struct platform_device *pdev)
> >  fail_hwmon:
> >  	asus_wmi_input_exit(asus);
> >  fail_input:
> > +	asus_wmi_keystone_exit(asus);
> >  	asus_wmi_sysfs_exit(asus->platform_device);
> >  fail_sysfs:
> >  fail_custom_fan_curve:
> > @@ -5191,6 +5265,7 @@ static void asus_wmi_remove(struct platform_device *device)
> >  	asus_wmi_backlight_exit(asus);
> >  	asus_screenpad_exit(asus);
> >  	asus_wmi_input_exit(asus);
> > +	asus_wmi_keystone_exit(asus);
> >  	asus_wmi_led_exit(asus);
> >  	asus_wmi_rfkill_exit(asus);
> >  	asus_wmi_debugfs_exit(asus);
> > diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
> > index 554f41b827e1..c29962d5baac 100644
> > --- a/include/linux/platform_data/x86/asus-wmi.h
> > +++ b/include/linux/platform_data/x86/asus-wmi.h
> > @@ -147,6 +147,13 @@
> >  #define ASUS_WMI_DEVID_GPU_MUX		0x00090016
> >  #define ASUS_WMI_DEVID_GPU_MUX_VIVO	0x00090026
> >  
> > +/* Keystone dongle insert/remove state.
> > + * PRESENCE_BIT (0x00010000) encodes insert state:
> > + * 0x00010000 = inserted, 0x00000000 = absent. STATUS_BIT is never set.
> > + * 0xFFFFFFFE means no keystone slot on this machine.
> > + */
> > +#define ASUS_WMI_DEVID_KEYSTONE		0x00120091
> > +
> >  /* TUF laptop RGB modes/colours */
> >  #define ASUS_WMI_DEVID_TUF_RGB_MODE	0x00100056
> >  #define ASUS_WMI_DEVID_TUF_RGB_MODE2	0x0010005A
> 

-- 
 i.
Re: [PATCH] platform/x86: asus-wmi: add keystone dongle support
Posted by Dariusz Figzał 1 week, 4 days ago

On 5/28/26 11:06 AM, Ilpo Järvinen wrote:
> On Thu, 28 May 2026, Denis Benato wrote:
> 
>>
>> On 5/26/26 23:44, Dariusz Figzał wrote:
>>> The ASUS Keystone is a physical NFC-like dongle that slots into supported
>>> ASUS laptops. The EC fires WMI notify code 0xB4 on insert/remove events.
>>>
>>> Expose the current insert state via a sysfs attribute by querying WMI
>>> device ID 0x00120091 (DSTS). This devid does not follow the standard DSTS
>>> convention: PRESENCE_BIT (0x00010000) encodes the insert state rather than
>>> feature presence, and STATUS_BIT is never set. Presence of a keystone slot
>>> is detected by a successful DSTS call (any result other than -ENODEV).
>> Thanks for this!
>>
>> Ilpo might have some suggestions on how to make the code better,
>> As we discussed a fair bit about this I say LGTM.
>>
>> Reviewed-by: Denis Benato <denis.benato@linux.dev>
>>> Signed-off-by: Dariusz Figzał <dariuszfigzal@gmail.com>
>>> ---
>>>   drivers/platform/x86/asus-wmi.c            | 75 ++++++++++++++++++++++
>>>   include/linux/platform_data/x86/asus-wmi.h |  7 ++
>>>   2 files changed, 82 insertions(+)
>>>
>>> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
>>> index 80144c412b90..a3fa3921aef3 100644
>>> --- a/drivers/platform/x86/asus-wmi.c
>>> +++ b/drivers/platform/x86/asus-wmi.c
>>> @@ -70,6 +70,7 @@ module_param(fnlock_default, bool, 0444);
>>>   #define NOTIFY_KBD_TTP			0xae
>>>   #define NOTIFY_LID_FLIP			0xfa
>>>   #define NOTIFY_LID_FLIP_ROG		0xbd
>>> +#define NOTIFY_KEYSTONE			0xb4
>>>   
>>>   #define ASUS_WMI_FNLOCK_BIOS_DISABLED	BIT(0)
>>>   
>>> @@ -279,6 +280,8 @@ struct asus_wmi {
>>>   	u32 tablet_switch_dev_id;
>>>   	bool tablet_switch_inverted;
>>>   
>>> +	bool keystone_detected;
>>> +
>>>   	enum fan_type fan_type;
>>>   	enum fan_type gpu_fan_type;
>>>   	enum fan_type mid_fan_type;
>>> @@ -646,6 +649,66 @@ static bool asus_wmi_dev_is_present(struct asus_wmi *asus, u32 dev_id)
>>>   	return status == 0 && (retval & ASUS_WMI_DSTS_PRESENCE_BIT);
>>>   }
>>>   
>>> +/* Keystone *******************************************************************/
>>> +
>>> +static ssize_t keystone_show(struct device *dev,
>>> +			     struct device_attribute *attr, char *buf)
>>> +{
>>> +	struct asus_wmi *asus = dev_get_drvdata(dev);
>>> +	u32 retval;
>>> +	int err;
>>> +
>>> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
>>> +	if (err)
>>> +		return err;
>>> +
>>> +	return sysfs_emit(buf, "%d\n", !!(retval & ASUS_WMI_DSTS_PRESENCE_BIT));
>>> +}
>>> +
>>> +static DEVICE_ATTR_RO(keystone);
>>> +
>>> +static void asus_wmi_keystone_notify(struct asus_wmi *asus)
>>> +{
>>> +	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "keystone");
>>> +}
>>> +
>>> +static int asus_wmi_keystone_init(struct asus_wmi *asus)
>>> +{
>>> +	u32 retval;
>>> +	int err;
>>> +
>>> +	/*
>>> +	 * Use a raw devstate call rather than asus_wmi_dev_is_present().
>>> +	 * For this devid, PRESENCE_BIT encodes current insert state, not
>>> +	 * feature presence, so asus_wmi_dev_is_present() would return false
>>> +	 * whenever the dongle is absent at boot, even on machines that have
>>> +	 * a keystone slot.
>>> +	 * -ENODEV means the firmware doesn't know this devid at all.
>>> +	 * retval is not examined here, only the return code matters.
>>> +	 */
>>> +	err = asus_wmi_get_devstate(asus, ASUS_WMI_DEVID_KEYSTONE, &retval);
>>> +	if (err == -ENODEV)
>>> +		return 0;
>>> +	if (err)
>>> +		return err;
>>> +
>>> +	err = device_create_file(&asus->platform_device->dev, &dev_attr_keystone);
>>> +	if (err)
>>> +		return err;
>>> +
>>> +	asus->keystone_detected = true;
>>> +	return 0;
>>> +}
> 
> The visibility of this should be controlled using .is_visible and the
> attribute should be placed into the normal attribute array.
>

Thanks for the review. I'll fix this in v2.

>>> +static void asus_wmi_keystone_exit(struct asus_wmi *asus)
>>> +{
>>> +	if (!asus->keystone_detected)
>>> +		return;
>>> +
>>> +	device_remove_file(&asus->platform_device->dev, &dev_attr_keystone);
>>> +	asus->keystone_detected = false;
>>> +}
>>> +
>>>   /* Input **********************************************************************/
>>>   static void asus_wmi_tablet_sw_report(struct asus_wmi *asus, bool value)
>>>   {
>>> @@ -4575,6 +4638,12 @@ static void asus_wmi_handle_event_code(int code, struct asus_wmi *asus)
>>>   		return;
>>>   	}
>>>   
>>> +	if (code == NOTIFY_KEYSTONE) {
>>> +		if (asus->keystone_detected)
>>> +			asus_wmi_keystone_notify(asus);
>>> +		return;
>>> +	}
>>> +
>>>   	if (code == NOTIFY_KBD_FBM || code == NOTIFY_KBD_TTP) {
>>>   		if (asus->fan_boost_mode_available)
>>>   			fan_boost_mode_switch_next(asus);
>>> @@ -5085,6 +5154,10 @@ static int asus_wmi_add(struct platform_device *pdev)
>>>   	if (err)
>>>   		goto fail_sysfs;
>>>   
>>> +	err = asus_wmi_keystone_init(asus);
>>> +	if (err)
>>> +		dev_warn(&pdev->dev, "Keystone initialization failed: %d\n", err);
>>> +
>>>   	err = asus_wmi_input_init(asus);
>>>   	if (err)
>>>   		goto fail_input;
>>> @@ -5170,6 +5243,7 @@ static int asus_wmi_add(struct platform_device *pdev)
>>>   fail_hwmon:
>>>   	asus_wmi_input_exit(asus);
>>>   fail_input:
>>> +	asus_wmi_keystone_exit(asus);
>>>   	asus_wmi_sysfs_exit(asus->platform_device);
>>>   fail_sysfs:
>>>   fail_custom_fan_curve:
>>> @@ -5191,6 +5265,7 @@ static void asus_wmi_remove(struct platform_device *device)
>>>   	asus_wmi_backlight_exit(asus);
>>>   	asus_screenpad_exit(asus);
>>>   	asus_wmi_input_exit(asus);
>>> +	asus_wmi_keystone_exit(asus);
>>>   	asus_wmi_led_exit(asus);
>>>   	asus_wmi_rfkill_exit(asus);
>>>   	asus_wmi_debugfs_exit(asus);
>>> diff --git a/include/linux/platform_data/x86/asus-wmi.h b/include/linux/platform_data/x86/asus-wmi.h
>>> index 554f41b827e1..c29962d5baac 100644
>>> --- a/include/linux/platform_data/x86/asus-wmi.h
>>> +++ b/include/linux/platform_data/x86/asus-wmi.h
>>> @@ -147,6 +147,13 @@
>>>   #define ASUS_WMI_DEVID_GPU_MUX		0x00090016
>>>   #define ASUS_WMI_DEVID_GPU_MUX_VIVO	0x00090026
>>>   
>>> +/* Keystone dongle insert/remove state.
>>> + * PRESENCE_BIT (0x00010000) encodes insert state:
>>> + * 0x00010000 = inserted, 0x00000000 = absent. STATUS_BIT is never set.
>>> + * 0xFFFFFFFE means no keystone slot on this machine.
>>> + */
>>> +#define ASUS_WMI_DEVID_KEYSTONE		0x00120091
>>> +
>>>   /* TUF laptop RGB modes/colours */
>>>   #define ASUS_WMI_DEVID_TUF_RGB_MODE	0x00100056
>>>   #define ASUS_WMI_DEVID_TUF_RGB_MODE2	0x0010005A
>>
>