[PATCH 0/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[PATCH 0/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

This patch adds Logitech Bolt receiver support for Logitech HID++
devices so Bolt-connected HID++ peripherals can expose battery
information through the kernel power_supply path with the correct device
model.

Tested with:
- Logitech MX Keys for Business via Bolt receiver

Erik Håkansson (1):
  HID: logitech: add Bolt receiver support for Logitech HID++ devices

 drivers/hid/hid-logitech-dj.c    | 10 +++++++
 drivers/hid/hid-logitech-hidpp.c | 47 ++++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 3 deletions(-)


base-commit: 44696aa3a489d2baf58efa61b37833f100072bee
-- 
2.55.0

[PATCH 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

Add Logitech Bolt receiver support to the Logitech HID receiver and
HID++ drivers.

Handle Bolt receiver notifications in hid-logitech-dj and add a
Bolt-specific initialization path in hid-logitech-hidpp, separate from
the existing Unifying receiver path.

This allows Bolt-connected HID++ devices to expose battery information
through the kernel power_supply path, so userspace tools can report
their battery status with the correct device model.

Tested with:
- Logitech MX Keys for Business via Bolt receiver

Signed-off-by: Erik Håkansson <erikhakan@gmail.com>
---
 drivers/hid/hid-logitech-dj.c    | 10 +++++++
 drivers/hid/hid-logitech-hidpp.c | 48 ++++++++++++++++++++++++++++++--
 2 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 9c574ab8b60b..518a9ee662b0 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -121,6 +121,7 @@ enum recvr_type {
 	recvr_type_27mhz,
 	recvr_type_bluetooth,
 	recvr_type_dinovo,
+	recvr_type_bolt,
 };
 
 struct dj_report {
@@ -1156,6 +1157,10 @@ static void logi_hidpp_recv_queue_notif(struct hid_device *hdev,
 		logi_hidpp_dev_conn_notif_equad(hdev, hidpp_report, &workitem);
 		workitem.reports_supported |= STD_KEYBOARD;
 		break;
+	case 0x10:
+		device_type = "Bolt";
+		logi_hidpp_dev_conn_notif_equad(hdev, hidpp_report, &workitem);
+		break;
 	}
 
 	/* custom receiver device (eg. powerplay) */
@@ -1894,6 +1899,7 @@ static int logi_dj_probe(struct hid_device *hdev,
 	case recvr_type_27mhz:		no_dj_interfaces = 2; break;
 	case recvr_type_bluetooth:	no_dj_interfaces = 2; break;
 	case recvr_type_dinovo:		no_dj_interfaces = 2; break;
+	case recvr_type_bolt:		no_dj_interfaces = 3; break;
 	}
 	if (hid_is_usb(hdev)) {
 		intf = to_usb_interface(hdev->dev.parent);
@@ -2103,6 +2109,10 @@ static const struct hid_device_id logi_dj_receivers[] = {
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_3),
 	 .driver_data = recvr_type_gaming_hidpp_ls_1_3},
+	{ /* Logitech Bolt receiver (0xc548) */
+	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+			 USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER),
+	 .driver_data = recvr_type_bolt},
 	{ /* Logitech lightspeed receiver (0xc54d) */
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_4),
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 90b0184df777..0b5d0a322ae8 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -4161,8 +4161,50 @@ static int hidpp_initialize_battery(struct hidpp_device *hidpp)
 	return ret;
 }
 
+static bool hidpp_is_bolt_child(struct hid_device *hdev)
+{
+	struct device *parent = hdev->dev.parent;
+	struct hid_device *receiver_hdev;
+
+	if (!parent)
+		return false;
+
+	receiver_hdev = to_hid_device(parent);
+	return receiver_hdev->vendor == USB_VENDOR_ID_LOGITECH &&
+	       receiver_hdev->product == USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER;
+}
+
+static int hidpp_bolt_init(struct hidpp_device *hidpp)
+{
+	struct hid_device *hdev = hidpp->hid_dev;
+	char *name;
+	int ret;
+
+	ret = hidpp_serial_init(hidpp);
+	if (ret)
+		return ret;
+
+	name = hidpp_get_device_name(hidpp);
+	if (!name)
+		return -EIO;
+
+	snprintf(hdev->name, sizeof(hdev->name), "%s", name);
+	dbg_hid("HID++ Bolt: Got name: %s\n", name);
+
+	kfree(name);
+	return 0;
+}
+
+static int hidpp_receiver_init(struct hidpp_device *hidpp)
+{
+	if (hidpp_is_bolt_child(hidpp->hid_dev))
+		return hidpp_bolt_init(hidpp);
+
+	return hidpp_unifying_init(hidpp);
+}
+
 /* Get name + serial for USB and Bluetooth HID++ devices */
-static void hidpp_non_unifying_init(struct hidpp_device *hidpp)
+static void hidpp_non_receiver_init(struct hidpp_device *hidpp)
 {
 	struct hid_device *hdev = hidpp->hid_dev;
 	char *name;
@@ -4510,9 +4552,9 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	/* Get name + serial, store in hdev->name + hdev->uniq */
 	if (id->group == HID_GROUP_LOGITECH_DJ_DEVICE)
-		hidpp_unifying_init(hidpp);
+		hidpp_receiver_init(hidpp);
 	else
-		hidpp_non_unifying_init(hidpp);
+		hidpp_non_receiver_init(hidpp);
 
 	if (hidpp->quirks & HIDPP_QUIRK_DELAYED_INIT)
 		connect_mask &= ~HID_CONNECT_HIDINPUT;

base-commit: 44696aa3a489d2baf58efa61b37833f100072bee
-- 
2.55.0

Re: [PATCH 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Kateřina Medvědová]

Hello Erik,
I tested your patch on my hardware and found two issues:

1. Both keyboard and mouse inputs stop working correctly. The mouse 
becomes very sensitive and creates events that shouldn't happen 
(sometimes scrolls on its own) and the keyboard's keys are scrambled. I 
verified on my hardware that if you pass the first two of Bolt's 
interfaces (0 boot keyboard and 1 boot mouse) to the generic HID driver 
and only handle interface 2 in the DJ driver, you can keep the extra 
functionality (like battery reporting) without affecting inputs. The 
existing bInterfaceNumber >= no_dj_interfaces check never triggers for 
Bolt. no_dj_interfaces = 3, but the receiver's highest interface number 
is 2, so interfaces 0 and 1 fall through to the DJ path. Here's what 
fixed it:


if (id->driver_data == recvr_type_bolt && intf &&
     intf->altsetting->desc.bInterfaceNumber !=
				LOGITECH_DJ_INTERFACE_NUMBER) {
	hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
	return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
}


2. Bolt devices stay behind after unpairing in userspace (using Solaar). 
The existing driver code doesn't handle Bolt's unpair events so devices 
stay visible after unpairing. Here's how I handled it:

if (djrcv_dev->type == recvr_type_bolt &&
     hidpp_report->report_id == REPORT_ID_HIDPP_SHORT &&
     hidpp_report->sub_id == REPORT_TYPE_NOTIF_DEVICE_UNPAIRED) {
	struct dj_workitem workitem = {
		.device_index = device_index,
		.type = WORKITEM_TYPE_UNPAIRED,
	};

	kfifo_in(&djrcv_dev->notif_fifo, &workitem, sizeof(workitem));
	schedule_work(&djrcv_dev->work);
	spin_unlock_irqrestore(&djrcv_dev->lock, flags);
	return false;
}

Hardware tested:
- Logi Bolt receiver (046d:c548)
- Logi POP Icon Keys
- Logi Lift Vertical
- Logi K650

Happy to do more testing.

Regards,
Kateřina Medvědová

Re: [PATCH 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

Hi,

Thank you for testing this.

I could not reproduce issue 1 locally with my MX Keys for Business, but
I applied your fix since it also works on my hardware. Either the
different keyboard models behave differently, or something differs
between our setups. I folded it into the existing interface handling to
keep the code smaller.

I also noticed that my older Lightspeed receiver exposes interfaces 0
and 1 as boot keyboard and mouse interfaces too, while only interfaces
>= 3 are treated as generic HID. So Bolt appears to need different
interface handling from the existing Lightspeed receiver path.

Issue 2 was easy to reproduce, and I applied your fix more or less
verbatim.

I will send a v2 patch shortly. I would be very grateful if you could
test it again.

Regards,
Erik

[PATCH v2 0/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

This patch adds Logitech Bolt receiver support for Logitech HID++
devices so Bolt-connected HID++ peripherals can expose battery
information through the kernel power_supply path with the correct device
model.

Changes in v2:
- Handle only the Bolt receiver/control interface in hid-logitech-dj and
  leave the other Bolt receiver interfaces to generic HID handling.
- Handle Bolt HID++ unpair notifications so child HID devices are removed
  after unpairing.

Thanks to Kateřina Medvědová for testing v1 on additional Bolt hardware
and identifying that Bolt interfaces 0 and 1 must remain handled by the
generic HID path, and that Bolt unpair notifications need explicit
handling.

Reported by Kateřina Medvědová.

Tested with:
- Logitech MX Keys for Business via Bolt receiver

Erik Håkansson (1):
  HID: logitech: add Bolt receiver support for Logitech HID++ devices

 drivers/hid/hid-logitech-dj.c    | 48 +++++++++++++++++++++++++++++---
 drivers/hid/hid-logitech-hidpp.c | 48 ++++++++++++++++++++++++++++++--
 2 files changed, 89 insertions(+), 7 deletions(-)


base-commit: 44696aa3a489d2baf58efa61b37833f100072bee
-- 
2.55.0

[PATCH v2 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

Add Logitech Bolt receiver support to the Logitech HID receiver and
HID++ drivers.

Handle Bolt receiver notifications in hid-logitech-dj and add a
Bolt-specific initialization path in hid-logitech-hidpp, separate from
the existing Unifying receiver path.

This allows Bolt-connected HID++ devices to expose battery information
through the kernel power_supply path, so userspace tools can report
their battery status with the correct device model.

Tested with:
- Logitech MX Keys for Business via Bolt receiver

Reported-by: Kateřina Medvědová <k8ie@mcld.eu>
Link: https://lore.kernel.org/linux-input/345f7347-30a8-4568-a7a6-c70f54a52a8d@mcld.eu/
Signed-off-by: Erik Håkansson <erikhakan@gmail.com>
---
Changes in v2:
- Handle only the Bolt receiver/control interface in hid-logitech-dj and
  leave the other Bolt receiver interfaces to generic HID handling.
- Handle Bolt HID++ unpair notifications so child HID devices are removed
  after unpairing.

 drivers/hid/hid-logitech-dj.c    | 48 +++++++++++++++++++++++++++++---
 drivers/hid/hid-logitech-hidpp.c | 48 ++++++++++++++++++++++++++++++--
 2 files changed, 89 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-logitech-dj.c b/drivers/hid/hid-logitech-dj.c
index 9c574ab8b60b..571d5caa5bb5 100644
--- a/drivers/hid/hid-logitech-dj.c
+++ b/drivers/hid/hid-logitech-dj.c
@@ -121,6 +121,7 @@ enum recvr_type {
 	recvr_type_27mhz,
 	recvr_type_bluetooth,
 	recvr_type_dinovo,
+	recvr_type_bolt,
 };
 
 struct dj_report {
@@ -1156,6 +1157,10 @@ static void logi_hidpp_recv_queue_notif(struct hid_device *hdev,
 		logi_hidpp_dev_conn_notif_equad(hdev, hidpp_report, &workitem);
 		workitem.reports_supported |= STD_KEYBOARD;
 		break;
+	case 0x10:
+		device_type = "Bolt";
+		logi_hidpp_dev_conn_notif_equad(hdev, hidpp_report, &workitem);
+		break;
 	}
 
 	/* custom receiver device (eg. powerplay) */
@@ -1745,6 +1750,24 @@ static int logi_dj_hidpp_event(struct hid_device *hdev,
 
 	dj_dev = djrcv_dev->paired_dj_devices[device_index];
 
+	/*
+	 * Bolt receivers send explicit unpair notifications as HID++ events;
+	 * queue device removal when we receive one.
+	 */
+	if (djrcv_dev->type == recvr_type_bolt &&
+	    hidpp_report->report_id == REPORT_ID_HIDPP_SHORT &&
+	    hidpp_report->sub_id == REPORT_TYPE_NOTIF_DEVICE_UNPAIRED) {
+		struct dj_workitem workitem = {
+			.device_index = device_index,
+			.type = WORKITEM_TYPE_UNPAIRED,
+		};
+
+		kfifo_in(&djrcv_dev->notif_fifo, &workitem, sizeof(workitem));
+		schedule_work(&djrcv_dev->work);
+		spin_unlock_irqrestore(&djrcv_dev->lock, flags);
+		return false;
+	}
+
 	/*
 	 * With 27 MHz receivers, we do not get an explicit unpair event,
 	 * remove the old device if the user has paired a *different* device.
@@ -1884,6 +1907,9 @@ static int logi_dj_probe(struct hid_device *hdev,
 	 * treat these as logitech-dj interfaces then this causes input events
 	 * reported through this extra interface to not be reported correctly.
 	 * To avoid this, we treat these as generic-hid devices.
+	 *
+	 * Bolt receivers only use LOGITECH_DJ_INTERFACE_NUMBER for receiver
+	 * reporting. Treat all other Bolt interfaces as generic-hid devices.
 	 */
 	switch (id->driver_data) {
 	case recvr_type_dj:		no_dj_interfaces = 3; break;
@@ -1897,10 +1923,20 @@ static int logi_dj_probe(struct hid_device *hdev,
 	}
 	if (hid_is_usb(hdev)) {
 		intf = to_usb_interface(hdev->dev.parent);
-		if (intf && intf->altsetting->desc.bInterfaceNumber >=
-							no_dj_interfaces) {
-			hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
-			return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+		if (intf) {
+			bool generic_hid_interface;
+
+			if (id->driver_data == recvr_type_bolt)
+				generic_hid_interface =
+					intf->altsetting->desc.bInterfaceNumber !=
+					LOGITECH_DJ_INTERFACE_NUMBER;
+			else
+				generic_hid_interface =
+					intf->altsetting->desc.bInterfaceNumber >= no_dj_interfaces;
+			if (generic_hid_interface) {
+				hdev->quirks |= HID_QUIRK_INPUT_PER_APP;
+				return hid_hw_start(hdev, HID_CONNECT_DEFAULT);
+			}
 		}
 	}
 
@@ -2103,6 +2139,10 @@ static const struct hid_device_id logi_dj_receivers[] = {
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_3),
 	 .driver_data = recvr_type_gaming_hidpp_ls_1_3},
+	{ /* Logitech Bolt receiver (0xc548) */
+	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
+			 USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER),
+	 .driver_data = recvr_type_bolt},
 	{ /* Logitech lightspeed receiver (0xc54d) */
 	  HID_USB_DEVICE(USB_VENDOR_ID_LOGITECH,
 		USB_DEVICE_ID_LOGITECH_NANO_RECEIVER_LIGHTSPEED_1_4),
diff --git a/drivers/hid/hid-logitech-hidpp.c b/drivers/hid/hid-logitech-hidpp.c
index 90b0184df777..0b5d0a322ae8 100644
--- a/drivers/hid/hid-logitech-hidpp.c
+++ b/drivers/hid/hid-logitech-hidpp.c
@@ -4161,8 +4161,50 @@ static int hidpp_initialize_battery(struct hidpp_device *hidpp)
 	return ret;
 }
 
+static bool hidpp_is_bolt_child(struct hid_device *hdev)
+{
+	struct device *parent = hdev->dev.parent;
+	struct hid_device *receiver_hdev;
+
+	if (!parent)
+		return false;
+
+	receiver_hdev = to_hid_device(parent);
+	return receiver_hdev->vendor == USB_VENDOR_ID_LOGITECH &&
+	       receiver_hdev->product == USB_DEVICE_ID_LOGITECH_BOLT_RECEIVER;
+}
+
+static int hidpp_bolt_init(struct hidpp_device *hidpp)
+{
+	struct hid_device *hdev = hidpp->hid_dev;
+	char *name;
+	int ret;
+
+	ret = hidpp_serial_init(hidpp);
+	if (ret)
+		return ret;
+
+	name = hidpp_get_device_name(hidpp);
+	if (!name)
+		return -EIO;
+
+	snprintf(hdev->name, sizeof(hdev->name), "%s", name);
+	dbg_hid("HID++ Bolt: Got name: %s\n", name);
+
+	kfree(name);
+	return 0;
+}
+
+static int hidpp_receiver_init(struct hidpp_device *hidpp)
+{
+	if (hidpp_is_bolt_child(hidpp->hid_dev))
+		return hidpp_bolt_init(hidpp);
+
+	return hidpp_unifying_init(hidpp);
+}
+
 /* Get name + serial for USB and Bluetooth HID++ devices */
-static void hidpp_non_unifying_init(struct hidpp_device *hidpp)
+static void hidpp_non_receiver_init(struct hidpp_device *hidpp)
 {
 	struct hid_device *hdev = hidpp->hid_dev;
 	char *name;
@@ -4510,9 +4552,9 @@ static int hidpp_probe(struct hid_device *hdev, const struct hid_device_id *id)
 
 	/* Get name + serial, store in hdev->name + hdev->uniq */
 	if (id->group == HID_GROUP_LOGITECH_DJ_DEVICE)
-		hidpp_unifying_init(hidpp);
+		hidpp_receiver_init(hidpp);
 	else
-		hidpp_non_unifying_init(hidpp);
+		hidpp_non_receiver_init(hidpp);
 
 	if (hidpp->quirks & HIDPP_QUIRK_DELAYED_INIT)
 		connect_mask &= ~HID_CONNECT_HIDINPUT;
-- 
2.55.0

Re: [PATCH v2 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Kateřina Medvědová]

Hi,

I tested your V2 and both issues were resolved.

Not sure what caused issue number 1 on my system. I can try to dig 
deeper if it would help.

I have 3 Bolt receivers on hand. Two of them have much newer firmware 
(5.3.20, revision 3). The other one is on 5.0.9. Unfortunately I'm not 
sure which of them I was testing on.
AFAIK the only way to get this information is through Options+.

I'm so glad you're taking this on! I'll keep this on my system for daily 
driving, I love that the battery reporting works!

Thanks,
Kateřina Medvědová

Re: [PATCH v2 1/1] HID: logitech: add Bolt receiver support for Logitech HID++ devices

[Erik Håkansson]

Hi,

Thank you very much for your help.

Unfortunately I don't have a Windows system easily accessible, so I
can't check my firmware version in Options+.
fwupdmgr says:
> Current version:    MPR05.03_B0020
so perhaps that means 5.03.20.

Let me know if anything pops up if you dig some more,
Thanks,
Erik