Add gpiobl(4), a driver for gpio controlled display backlights. This will

allow us to turn off the screen on Apple Silicon laptops until we have a
proper display controller driver.

ok kettenis@ patrick@

2 files changed, 132 insertions, 1 deletions

diff --git a/sys/dev/fdt/files.fdt b/sys/dev/fdt/files.fdt
index 2855c761ece..f01a350b87a 100644
--- a/sys/dev/fdt/files.fdt
+++ b/sys/dev/fdt/files.fdt
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.167 2022/11/06 15:36:13 patrick Exp $
+#	$OpenBSD: files.fdt,v 1.168 2022/11/08 19:06:57 tobhe Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -601,6 +601,10 @@ device	dapmic
 attach	dapmic at i2c
 file	dev/fdt/dapmic.c		dapmic
 
+device	gpiobl
+attach	gpiobl at fdt
+file	dev/fdt/gpiobl.c		gpiobl
+
 device	gpiocharger
 attach	gpiocharger at fdt
 file	dev/fdt/gpiocharger.c		gpiocharger
diff --git a/sys/dev/fdt/gpiobl.c b/sys/dev/fdt/gpiobl.c
new file mode 100644
index 00000000000..9c218694ccb
--- /dev/null
+++ b/sys/dev/fdt/gpiobl.c
@@ -0,0 +1,127 @@
+/*	$OpenBSD: gpiobl.c,v 1.1 2022/11/08 19:06:57 tobhe Exp $	*/
+/*
+ * Copyright (c) 2022 Tobias Heider <tobhe@openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/device.h>
+#include <sys/malloc.h>
+#include <sys/task.h>
+
+#include <machine/fdt.h>
+#include <machine/bus.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_gpio.h>
+#include <dev/ofw/ofw_misc.h>
+
+#include <dev/wscons/wsconsio.h>
+#include <dev/wscons/wsdisplayvar.h>
+
+struct gpiobl_softc {
+	struct device		sc_dev;
+	int			sc_on;
+	uint32_t		sc_gpio[3];
+	struct task		sc_task;
+};
+
+struct gpiobl_softc *sc_gpiobl;
+
+int	gpiobl_match(struct device *, void *, void *);
+void	gpiobl_attach(struct device *, struct device *, void *);
+
+const struct cfattach gpiobl_ca = {
+	sizeof(struct gpiobl_softc), gpiobl_match, gpiobl_attach
+};
+
+struct cfdriver gpiobl_cd = {
+	NULL, "gpiobl", DV_DULL
+};
+
+void gpiobl_task(void *);
+int gpiobl_get_param(struct wsdisplay_param *);
+int gpiobl_set_param(struct wsdisplay_param *);
+
+int
+gpiobl_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "gpio-backlight");
+}
+
+
+void
+gpiobl_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct gpiobl_softc *sc = (struct gpiobl_softc *)self;
+	struct fdt_attach_args *faa = aux;
+	size_t len;
+
+	len = OF_getproplen(faa->fa_node, "gpios");
+	if (len <= 0)
+		return;
+	OF_getpropintarray(faa->fa_node, "gpios", sc->sc_gpio, len);
+	gpio_controller_config_pin(sc->sc_gpio, GPIO_CONFIG_OUTPUT);
+
+	sc->sc_on = OF_getpropbool(faa->fa_node, "default-on");
+	sc_gpiobl = sc;
+
+	task_set(&sc->sc_task, gpiobl_task, sc);
+	ws_get_param = gpiobl_get_param;
+	ws_set_param = gpiobl_set_param;
+	printf("\n");
+}
+
+void
+gpiobl_task(void *args)
+{
+	struct gpiobl_softc *sc = args;
+	gpio_controller_set_pin(&sc->sc_gpio[0], sc->sc_on);
+}
+
+int
+gpiobl_get_param(struct wsdisplay_param *dp)
+{
+	struct gpiobl_softc *sc = (struct gpiobl_softc *)sc_gpiobl;
+
+	switch (dp->param) {
+	case WSDISPLAYIO_PARAM_BRIGHTNESS:
+		dp->min = 0;
+		dp->max = 1;
+		dp->curval = sc->sc_on;
+		return 0;
+	default:
+		return -1;
+	}
+}
+
+int
+gpiobl_set_param(struct wsdisplay_param *dp)
+{
+	struct gpiobl_softc *sc = (struct gpiobl_softc *)sc_gpiobl;
+
+	switch (dp->param) {
+	case WSDISPLAYIO_PARAM_BRIGHTNESS:
+		if (dp->curval == sc->sc_on)
+			return 0;
+		sc->sc_on = !sc->sc_on;
+		task_add(systq, &sc->sc_task);
+		return 0;
+	default:
+		return -1;
+	}
+}