git: 105869a2c78d - main - acpi_system76: Add backlight(9) support for keyboard
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Date: Mon, 09 Mar 2026 09:21:50 UTC
The branch main has been updated by pouria:
URL: https://cgit.FreeBSD.org/src/commit/?id=105869a2c78d21f310a8f271eaa510acea045805
commit 105869a2c78d21f310a8f271eaa510acea045805
Author: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
AuthorDate: 2026-03-07 22:40:21 +0000
Commit: Pouria Mousavizadeh Tehrani <pouria@FreeBSD.org>
CommitDate: 2026-03-09 09:12:01 +0000
acpi_system76: Add backlight(9) support for keyboard
Reviewed by: wulf
Differential Revision: https://reviews.freebsd.org/D55716
---
sys/dev/acpi_support/acpi_system76.c | 145 ++++++++++++++++++++++++++++++++
sys/modules/acpi/acpi_system76/Makefile | 1 +
2 files changed, 146 insertions(+)
diff --git a/sys/dev/acpi_support/acpi_system76.c b/sys/dev/acpi_support/acpi_system76.c
index 9ae7d116be0b..a4ac848a0fec 100644
--- a/sys/dev/acpi_support/acpi_system76.c
+++ b/sys/dev/acpi_support/acpi_system76.c
@@ -38,6 +38,9 @@
#include <dev/acpica/acpivar.h>
#include <sys/sysctl.h>
+#include <dev/backlight/backlight.h>
+#include "backlight_if.h"
+
#define _COMPONENT ACPI_OEM
ACPI_MODULE_NAME("system76")
@@ -60,11 +63,16 @@ struct acpi_system76_softc {
struct sysctl_ctx_list sysctl_ctx;
struct sysctl_oid *sysctl_tree;
+ struct cdev *kbb_bkl;
+ uint8_t backlight_level;
};
static int acpi_system76_probe(device_t);
static int acpi_system76_attach(device_t);
static int acpi_system76_detach(device_t);
+static int acpi_system76_suspend(device_t);
+static int acpi_system76_resume(device_t);
+static int acpi_system76_shutdown(device_t);
static void acpi_system76_init(struct acpi_system76_softc *);
static struct acpi_ctrl *
acpi_system76_ctrl_map(struct acpi_system76_softc *, int);
@@ -72,6 +80,12 @@ static int acpi_system76_update(struct acpi_system76_softc *, int, bool);
static int acpi_system76_sysctl_handler(SYSCTL_HANDLER_ARGS);
static void acpi_system76_notify_handler(ACPI_HANDLE, uint32_t, void *);
static void acpi_system76_check(struct acpi_system76_softc *);
+static int acpi_system76_backlight_update_status(device_t dev,
+ struct backlight_props *props);
+static int acpi_system76_backlight_get_status(device_t dev,
+ struct backlight_props *props);
+static int acpi_system76_backlight_get_info(device_t dev,
+ struct backlight_info *info);
/* methods */
enum {
@@ -125,9 +139,18 @@ static const struct s76_ctrl_table s76_sysctl_table[] = {
};
static device_method_t acpi_system76_methods[] = {
+ /* Device interface */
DEVMETHOD(device_probe, acpi_system76_probe),
DEVMETHOD(device_attach, acpi_system76_attach),
DEVMETHOD(device_detach, acpi_system76_detach),
+ DEVMETHOD(device_suspend, acpi_system76_suspend),
+ DEVMETHOD(device_resume, acpi_system76_resume),
+ DEVMETHOD(device_shutdown, acpi_system76_shutdown),
+
+ /* Backlight interface */
+ DEVMETHOD(backlight_update_status, acpi_system76_backlight_update_status),
+ DEVMETHOD(backlight_get_status, acpi_system76_backlight_get_status),
+ DEVMETHOD(backlight_get_info, acpi_system76_backlight_get_info),
DEVMETHOD_END
};
@@ -145,6 +168,33 @@ static driver_t acpi_system76_driver = {
sizeof(struct acpi_system76_softc)
};
+static const uint32_t acpi_system76_backlight_levels[] = {
+ 0, 6, 12, 18, 24, 30, 36, 42,
+ 48, 54, 60, 66, 72, 78, 84, 100
+};
+
+static inline uint32_t
+devstate_to_backlight(uint32_t val)
+{
+ return (acpi_system76_backlight_levels[val >> 4 & 0xf]);
+}
+
+static inline uint32_t
+backlight_to_devstate(uint32_t bkl)
+{
+ int i;
+ uint32_t val;
+
+ for (i = 0; i < nitems(acpi_system76_backlight_levels); i++) {
+ if (bkl < acpi_system76_backlight_levels[i])
+ break;
+ }
+ val = (i - 1) * 16;
+ if (val > 224)
+ val = 255;
+ return (val);
+}
+
/*
* Returns corresponding acpi_ctrl of softc from method
*/
@@ -244,6 +294,9 @@ acpi_system76_notify_update(void *arg)
acpi_system76_update(sc, method, false);
}
ACPI_SERIAL_END(system76);
+
+ if (sc->kbb_bkl != NULL)
+ sc->backlight_level = devstate_to_backlight(sc->kbb.val);
}
static void
@@ -335,6 +388,8 @@ acpi_system76_sysctl_handler(SYSCTL_HANDLER_ARGS)
case S76_CTRL_KBB:
if (val > UINT8_MAX || val < 0)
return (EINVAL);
+ if (sc->kbb_bkl != NULL)
+ sc->backlight_level = devstate_to_backlight(val);
break;
case S76_CTRL_KBC:
if (val >= (1 << 24) || val < 0)
@@ -386,6 +441,14 @@ acpi_system76_init(struct acpi_system76_softc *sc)
if (!ctrl->exists)
continue;
+ if (method == S76_CTRL_KBB) {
+ sc->kbb_bkl = backlight_register("system76_keyboard", sc->dev);
+ if (sc->kbb_bkl == NULL)
+ device_printf(sc->dev, "Can not register backlight\n");
+ else
+ sc->backlight_level = devstate_to_backlight(sc->kbb.val);
+ }
+
SYSCTL_ADD_PROC(&sc->sysctl_ctx,
SYSCTL_CHILDREN(sc->sysctl_tree), OID_AUTO, s76_sysctl_table[method].name,
CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_ANYBODY | CTLFLAG_MPSAFE,
@@ -393,6 +456,45 @@ acpi_system76_init(struct acpi_system76_softc *sc)
}
}
+static int
+acpi_system76_backlight_update_status(device_t dev, struct backlight_props
+ *props)
+{
+ struct acpi_system76_softc *sc;
+
+ sc = device_get_softc(dev);
+ if (sc->kbb.val != backlight_to_devstate(props->brightness)) {
+ sc->kbb.val = backlight_to_devstate(props->brightness);
+ acpi_system76_update(sc, S76_CTRL_KBB, true);
+ }
+ sc->backlight_level = props->brightness;
+
+ return (0);
+}
+
+static int
+acpi_system76_backlight_get_status(device_t dev, struct backlight_props *props)
+{
+ struct acpi_system76_softc *sc;
+
+ sc = device_get_softc(dev);
+ props->brightness = sc->backlight_level;
+ props->nlevels = nitems(acpi_system76_backlight_levels);
+ memcpy(props->levels, acpi_system76_backlight_levels,
+ sizeof(acpi_system76_backlight_levels));
+
+ return (0);
+}
+
+static int
+acpi_system76_backlight_get_info(device_t dev, struct backlight_info *info)
+{
+ info->type = BACKLIGHT_TYPE_KEYBOARD;
+ strlcpy(info->name, "System76 Keyboard", BACKLIGHTMAXNAMELENGTH);
+
+ return (0);
+}
+
static int
acpi_system76_attach(device_t dev)
{
@@ -423,9 +525,51 @@ acpi_system76_detach(device_t dev)
if (sysctl_ctx_free(&sc->sysctl_ctx) != 0)
return (EBUSY);
+ AcpiRemoveNotifyHandler(sc->handle, ACPI_SYSTEM_NOTIFY,
+ acpi_system76_notify_handler);
+
+ if (sc->kbb_bkl != NULL)
+ backlight_destroy(sc->kbb_bkl);
+
return (0);
}
+static int
+acpi_system76_suspend(device_t dev)
+{
+ struct acpi_system76_softc *sc;
+ struct acpi_ctrl *ctrl;
+
+ sc = device_get_softc(dev);
+ if ((ctrl = acpi_system76_ctrl_map(sc, S76_CTRL_KBB)) != NULL) {
+ ctrl->val = 0;
+ acpi_system76_update(sc, S76_CTRL_KBB, true);
+ }
+
+ return (0);
+}
+
+static int
+acpi_system76_resume(device_t dev)
+{
+ struct acpi_system76_softc *sc;
+ struct acpi_ctrl *ctrl;
+
+ sc = device_get_softc(dev);
+ if ((ctrl = acpi_system76_ctrl_map(sc, S76_CTRL_KBB)) != NULL) {
+ ctrl->val = backlight_to_devstate(sc->backlight_level);
+ acpi_system76_update(sc, S76_CTRL_KBB, true);
+ }
+
+ return (0);
+}
+
+static int
+acpi_system76_shutdown(device_t dev)
+{
+ return (acpi_system76_detach(dev));
+}
+
static int
acpi_system76_probe(device_t dev)
{
@@ -444,3 +588,4 @@ acpi_system76_probe(device_t dev)
DRIVER_MODULE(acpi_system76, acpi, acpi_system76_driver, 0, 0);
MODULE_VERSION(acpi_system76, 1);
MODULE_DEPEND(acpi_system76, acpi, 1, 1, 1);
+MODULE_DEPEND(acpi_system76, backlight, 1, 1, 1);
diff --git a/sys/modules/acpi/acpi_system76/Makefile b/sys/modules/acpi/acpi_system76/Makefile
index 86d2c91e712d..76bee091dfca 100644
--- a/sys/modules/acpi/acpi_system76/Makefile
+++ b/sys/modules/acpi/acpi_system76/Makefile
@@ -3,5 +3,6 @@
KMOD= acpi_system76
CFLAGS+=-I${SRCTOP}/sys/dev/acpi_support
SRCS= acpi_system76.c opt_acpi.h acpi_if.h device_if.h bus_if.h
+SRCS+= backlight_if.h
.include <bsd.kmod.mk>