Received-SPF: softfail (google.com: domain of transitioning linux-kernel-owner@vger.kernel.org does not designate 23.128.96.19 as permitted sender) client-ip=23.128.96.19;
Date:   Tue,  5 Apr 2022 14:39:53 -0400
Message-Id: <20220405183953.2094007-1-pceballos@google.com>
Mime-Version: 1.0
Subject: [PATCH] HID: Driver for Google Hangouts Meet Speakermic
From:   Pablo Ceballos <pceballos@google.com>
To:     jikos@kernel.org, benjamin.tissoires@redhat.com,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org
Cc:     Pablo Ceballos <pceballos@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

This driver works around a problem with the HID usage sent by this
device for the mute button. It prevents key events from being generated
for that HID usage since they would be incorrect.

Signed-off-by: Pablo Ceballos <pceballos@google.com>
---
 drivers/hid/Kconfig            | 12 ++++++++
 drivers/hid/Makefile           |  1 +
 drivers/hid/hid-google-atrus.c | 55 ++++++++++++++++++++++++++++++++++
 drivers/hid/hid-ids.h          |  1 +
 4 files changed, 69 insertions(+)
 create mode 100644 drivers/hid/hid-google-atrus.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index f5544157576c..d4b6be827d15 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -403,6 +403,18 @@ config HOLTEK_FF
 	  Say Y here if you have a Holtek On Line Grip based game controller
 	  and want to have force feedback support for it.
 
+config HID_GOOGLE_ATRUS
+	tristate "Google Hangouts Meet Speakermic"
+	depends on USB_HID
+	help
+	This selects a driver for the Google Hangouts Meet Speakermic.
+
+	This driver works around a problem with the HID usage sent by this
+	device for the mute button. It prevents key events from being generated
+	for that HID usage since they would be incorrect.
+
+	Say Y here if you have a Google Hangouts Meet Speakermic.
+
 config HID_GOOGLE_HAMMER
 	tristate "Google Hammer Keyboard"
 	depends on USB_HID && LEDS_CLASS && CROS_EC
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 6d3e630e81af..2ee446b5b953 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -50,6 +50,7 @@ obj-$(CONFIG_HID_FT260)		+= hid-ft260.o
 obj-$(CONFIG_HID_GEMBIRD)	+= hid-gembird.o
 obj-$(CONFIG_HID_GFRM)		+= hid-gfrm.o
 obj-$(CONFIG_HID_GLORIOUS)  += hid-glorious.o
+obj-$(CONFIG_HID_GOOGLE_ATRUS)  += hid-google-atrus.o
 obj-$(CONFIG_HID_GOOGLE_HAMMER)	+= hid-google-hammer.o
 obj-$(CONFIG_HID_VIVALDI)	+= hid-vivaldi.o
 obj-$(CONFIG_HID_GT683R)	+= hid-gt683r.o
diff --git a/drivers/hid/hid-google-atrus.c b/drivers/hid/hid-google-atrus.c
new file mode 100644
index 000000000000..e136c70e9425
--- /dev/null
+++ b/drivers/hid/hid-google-atrus.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  HID driver for Google Hangouts Meet Speakermic
+ *
+ *  Copyright 2022 Google LLC.
+ */
+
+#include <linux/hid.h>
+#include <linux/module.h>
+
+#include "hid-ids.h"
+
+/*
+ * This driver handles the telephony phone mute HID usage by ignoring it. This
+ * avoids the default handling by the hid-input driver which is to map this to
+ * a KEY_MICMUTE event. The issue is that this device implements the phone mute
+ * HID usage as a toggle switch, where 1 indicates muted, and 0 indicates
+ * unmuted. However, for an EV_KEY event 1 indicates the key has been pressed
+ * and 0 indicates it has been released.
+ */
+
+static int atrus_event(struct hid_device *hid, struct hid_field *field,
+		       struct hid_usage *usage, __s32 value)
+{
+	/*
+	 * Return 1 to indicate no further processing should be done for this
+	 * usage.
+	 */
+	return 1;
+}
+
+static const struct hid_device_id atrus_devices[] = {
+	{ HID_DEVICE(BUS_USB, HID_GROUP_GENERIC,
+		     USB_VENDOR_ID_GOOGLE, USB_DEVICE_ID_GOOGLE_ATRUS) },
+	{ }
+};
+MODULE_DEVICE_TABLE(hid, atrus_devices);
+
+static const struct hid_usage_id atrus_usages[] = {
+	/* Handle only the Telephony Phone Mute usage. */
+	{ HID_UP_TELEPHONY | 0x2f, EV_KEY, HID_ANY_ID },
+	{ HID_TERMINATOR, HID_TERMINATOR, HID_TERMINATOR }
+};
+
+static struct hid_driver atrus_driver = {
+	.name = "atrus",
+	.id_table = atrus_devices,
+	.usage_table = atrus_usages,
+	.event = atrus_event,
+};
+module_hid_driver(atrus_driver);
+
+MODULE_AUTHOR("Pablo Ceballos <pcebalos@google.com>");
+MODULE_DESCRIPTION("Google Hangouts Meet Speakermic USB HID Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
index 85975031389b..9f6fc5cfbeb9 100644
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -506,6 +506,7 @@
 #define USB_DEVICE_ID_GOOGLE_MOONBALL	0x5044
 #define USB_DEVICE_ID_GOOGLE_DON	0x5050
 #define USB_DEVICE_ID_GOOGLE_EEL	0x5057
+#define USB_DEVICE_ID_GOOGLE_ATRUS	0x8001
 
 #define USB_VENDOR_ID_GOTOP		0x08f2
 #define USB_DEVICE_ID_SUPER_Q2		0x007f
-- 
2.35.1.1094.g7c7d902a7c-goog