Index: sys/dev/acpi_support/acpi_cros_kblt.c
===================================================================
--- /dev/null
+++ sys/dev/acpi_support/acpi_cros_kblt.c
@@ -0,0 +1,159 @@
+/*-
+ * Copyright (c) 2019 Greg V <greg@unrelenting.technology>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include "opt_acpi.h"
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/bus.h>
+#include <sys/sysctl.h>
+#include <machine/cpufunc.h>
+
+#include <contrib/dev/acpica/include/acpi.h>
+#include <contrib/dev/acpica/include/accommon.h>
+
+#include "acpi_if.h"
+#include <sys/module.h>
+#include <dev/acpica/acpivar.h>
+
+ACPI_MODULE_NAME("CROS_KBLT")
+
+struct acpi_cros_kblt_softc {
+	device_t	dev;
+	ACPI_HANDLE	handle;
+	int		val;
+
+	struct sysctl_ctx_list	*sysctl_ctx;
+	struct sysctl_oid	*sysctl_tree;
+};
+
+static int
+acpi_cros_kblt_sysctl(SYSCTL_HANDLER_ARGS)
+{
+	struct acpi_cros_kblt_softc	*sc =
+		(struct acpi_cros_kblt_softc*)oidp->oid_arg1;
+	int err = 0;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	if (ACPI_FAILURE(acpi_GetInteger(sc->handle, "KBQC", &sc->val))) {
+		device_printf(sc->dev, "ACPI failure\n");
+		return (ENXIO);
+	}
+
+	err = sysctl_handle_int(oidp, &sc->val, 0, req);
+	if (err != 0 || req->newptr == NULL)
+		return (err);
+
+	if (sc->val > 100)
+		return (EINVAL);
+
+	if (ACPI_FAILURE(acpi_SetInteger(sc->handle, "KBCM", sc->val))) {
+		device_printf(sc->dev, "ACPI failure\n");
+		return (ENXIO);
+	}
+
+	return (err);
+}
+
+static int
+acpi_cros_kblt_resume(device_t dev)
+{
+	struct acpi_cros_kblt_softc *sc = device_get_softc(dev);
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	if (ACPI_FAILURE(acpi_SetInteger(sc->handle, "KBCM", sc->val))) {
+		device_printf(sc->dev, "ACPI failure\n");
+		return (ENXIO);
+	}
+
+	return (0);
+}
+
+static char *cros_kblt_ids[] = {"GOOG0002", NULL};
+
+static int
+acpi_cros_kblt_probe(device_t dev)
+{
+	int err;
+
+	if (acpi_disabled("cros_kblt") ||
+	    device_get_unit(dev) != 0)
+		return (ENXIO);
+
+	err = ACPI_ID_PROBE(device_get_parent(dev), dev, cros_kblt_ids, NULL);
+
+	if (err <= 0)
+		device_set_desc(dev, "Google Keyboard Backlight Control");
+
+	return (err);
+}
+
+static int
+acpi_cros_kblt_attach(device_t dev)
+{
+	struct acpi_cros_kblt_softc	*sc;
+
+	ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+	sc = device_get_softc(dev);
+	sc->dev = dev;
+	sc->handle = acpi_get_handle(dev);
+	sc->sysctl_ctx = device_get_sysctl_ctx(dev);
+	sc->sysctl_tree = device_get_sysctl_tree(dev);
+
+	SYSCTL_ADD_PROC(sc->sysctl_ctx,
+	    SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO,
+	    "level", CTLTYPE_INT | CTLFLAG_RW,
+	    sc, 0, acpi_cros_kblt_sysctl, "I",
+	    "Keyboard backlight level (0-100)");
+
+	return (0);
+}
+
+static device_method_t acpi_cros_kblt_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe, acpi_cros_kblt_probe),
+	DEVMETHOD(device_attach, acpi_cros_kblt_attach),
+	DEVMETHOD(device_resume, acpi_cros_kblt_resume),
+
+	DEVMETHOD_END
+};
+
+static driver_t	acpi_cros_kblt_driver = {
+	"acpi_cros_kblt",
+	acpi_cros_kblt_methods,
+	sizeof(struct acpi_cros_kblt_softc),
+};
+
+static devclass_t acpi_cros_kblt_devclass;
+
+DRIVER_MODULE(acpi_cros_kblt, acpi, acpi_cros_kblt_driver,
+		acpi_cros_kblt_devclass, 0, 0);
+MODULE_DEPEND(acpi_cros_kblt, acpi, 1, 1, 1);
Index: sys/modules/acpi/acpi_cros_kblt/Makefile
===================================================================
--- /dev/null
+++ sys/modules/acpi/acpi_cros_kblt/Makefile
@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+.PATH:		${SRCTOP}/sys/dev/acpi_support
+KMOD=		acpi_cros_kblt
+SRCS=		acpi_cros_kblt.c opt_acpi.h device_if.h bus_if.h acpi_if.h
+
+.include <bsd.kmod.mk>