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 > > Signed-off-by: Dariusz Figzał > > --- > > 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.