Add pwmleds(4), a driver for PWM controlled LEDs.

For now this only implements keyboard backlight support.

ok kn@

2 files changed, 166 insertions, 1 deletions

diff --git a/sys/dev/fdt/files.fdt b/sys/dev/fdt/files.fdt
index 7e0781ca413..93c8f7de922 100644
--- a/sys/dev/fdt/files.fdt
+++ b/sys/dev/fdt/files.fdt
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.171 2022/11/10 12:12:53 patrick Exp $
+#	$OpenBSD: files.fdt,v 1.172 2022/11/23 23:43:08 kettenis Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -231,6 +231,10 @@ device	pwmfan
 attach	pwmfan at fdt
 file	dev/fdt/pwmfan.c		pwmfan
 
+device	pwmleds
+attach	pwmleds at fdt
+file	dev/fdt/pwmleds.c		pwmleds
+
 device	pwmreg
 attach	pwmreg at fdt
 file	dev/fdt/pwmreg.c		pwmreg
diff --git a/sys/dev/fdt/pwmleds.c b/sys/dev/fdt/pwmleds.c
new file mode 100644
index 00000000000..24d2fe054c6
--- /dev/null
+++ b/sys/dev/fdt/pwmleds.c
@@ -0,0 +1,161 @@
+/*	$OpenBSD: pwmleds.c,v 1.1 2022/11/23 23:43:08 kettenis Exp $	*/
+/*
+ * Copyright (c) 2022 Mark Kettenis <kettenis@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 <machine/bus.h>
+#include <machine/fdt.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_misc.h>
+#include <dev/ofw/fdt.h>
+
+#include <dev/wscons/wsconsio.h>
+
+extern int (*wskbd_get_backlight)(struct wskbd_backlight *);
+extern int (*wskbd_set_backlight)(struct wskbd_backlight *);
+
+struct pwmleds_softc {
+	struct device	sc_dev;
+
+	/* Keyboard backlight. */
+	uint32_t	*sc_pwm;
+	int		sc_pwm_len;
+	uint32_t	sc_max_brightness;
+};
+
+int	pwmleds_match(struct device *, void *, void *);
+void	pwmleds_attach(struct device *, struct device *, void *);
+
+const struct cfattach pwmleds_ca = {
+	sizeof (struct pwmleds_softc), pwmleds_match, pwmleds_attach
+};
+
+struct cfdriver pwmleds_cd = {
+	NULL, "pwmleds", DV_DULL
+};
+
+int pwmleds_get_kbd_backlight(struct wskbd_backlight *);
+int pwmleds_set_kbd_backlight(struct wskbd_backlight *);
+
+int
+pwmleds_match(struct device *parent, void *match, void *aux)
+{
+	const struct fdt_attach_args	*faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "pwm-leds");
+}
+
+void
+pwmleds_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct pwmleds_softc *sc = (struct pwmleds_softc *)self;
+	struct fdt_attach_args	*faa = aux;
+	char *function;
+	int len, node;
+
+	printf("\n");
+
+	for (node = OF_child(faa->fa_node); node; node = OF_peer(node)) {
+		len = OF_getproplen(node, "function");
+		if (len <= 0)
+			continue;
+
+		function = malloc(len, M_TEMP, M_WAITOK);
+		OF_getprop(node, "function", function, len);
+		if (strcmp(function, "kbd_backlight") != 0) {
+			free(function, M_TEMP, len);
+			continue;
+		}
+		free(function, M_TEMP, len);
+
+		len = OF_getproplen(node, "pwms");
+		if (len <= 0)
+			continue;
+
+		sc->sc_pwm = malloc(len, M_DEVBUF, M_WAITOK);
+		OF_getpropintarray(node, "pwms", sc->sc_pwm, len);
+		sc->sc_pwm_len = len;
+
+		sc->sc_max_brightness =
+		    OF_getpropint(node, "max-brightness", 0);
+		wskbd_get_backlight = pwmleds_get_kbd_backlight;
+		wskbd_set_backlight = pwmleds_set_kbd_backlight;
+	}
+}
+
+struct pwmleds_softc *
+pwmleds_kbd_backlight(void)
+{
+	struct pwmleds_softc *sc;
+	int i;
+
+	for (i = 0; i < pwmleds_cd.cd_ndevs; i++) {
+		sc = pwmleds_cd.cd_devs[i];
+		if (sc == NULL)
+			continue;
+		if (sc->sc_max_brightness > 0)
+			return sc;
+	}
+
+	return NULL;
+}
+
+int
+pwmleds_get_kbd_backlight(struct wskbd_backlight *kbl)
+{
+	struct pwmleds_softc *sc;
+	struct pwm_state ps;
+	int error;
+
+	sc = pwmleds_kbd_backlight();
+	if (sc == NULL)
+		return ENOTTY;
+
+	error = pwm_get_state(sc->sc_pwm, &ps);
+	if (error)
+		return error;
+
+	kbl->min = 0;
+	kbl->max = sc->sc_max_brightness;
+	kbl->curval = (ps.ps_enabled) ?
+	    ((uint64_t)ps.ps_pulse_width * kbl->max) / ps.ps_period : 0;
+	return 0;
+}
+
+int
+pwmleds_set_kbd_backlight(struct wskbd_backlight *kbl)
+{
+	struct pwmleds_softc *sc;
+	struct pwm_state ps;
+
+	sc = pwmleds_kbd_backlight();
+	if (sc == NULL)
+		return ENOTTY;
+
+	if (kbl->curval < 0 || kbl->curval > sc->sc_max_brightness)
+		return EINVAL;
+
+	pwm_init_state(sc->sc_pwm, &ps);
+	ps.ps_pulse_width =
+	    ((uint64_t)kbl->curval * ps.ps_period) / sc->sc_max_brightness;
+	ps.ps_enabled = (ps.ps_pulse_width > 0);
+	return pwm_set_state(sc->sc_pwm, &ps);
+}