Add a generic LED driver for flashing lamps.

The hardware driver decides the name under /dev/led and provides
the function to turn the lamp on/off.

All leds are serviced by a single timeout which runs at a basic rate
of hz/10.

The LED is controlled by ascii strings as follows.

0	Turn off.
1	Turn on.
f	Flash: _-
f2	Flash: __--
f3	Flash: ___---
f4...f9 etc.
d%d	Digits.  "d12": -__________-_-______________________________
s%s	String, roll your own:
	'a-j' gives on for (1...10)/10 sec.
	'A-J' gives on for (1...10)/10 sec.
	'sAaAbBa': _-_--__-
m%s	Morse
	'.' dot
	'-' dash
	' ' letter space
	'\n' word space

My mdoc skills do not reach to express that.

2 files changed, 279 insertions, 0 deletions

diff --git a/sys/dev/led/led.c b/sys/dev/led/led.c
new file mode 100644
index 0000000..2f89e2e
--- /dev/null
+++ b/sys/dev/led/led.c
@@ -0,0 +1,258 @@
+/*-
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ *
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/conf.h>
+#include <sys/kernel.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+#include <sys/ctype.h>
+#include <sys/sbuf.h>
+#include <sys/queue.h>
+#include <dev/led/led.h>
+#include <sys/uio.h>
+
+struct ledsc {
+	LIST_ENTRY(ledsc)	list;
+	void			*private;
+	led_t			*func;
+	dev_t			dev;
+	struct sbuf		*spec;
+	char			*str;
+	char			*ptr;
+	int			count;
+};
+
+static unsigned next_minor;
+static struct mtx led_mtx;
+static LIST_HEAD(, ledsc) led_list = LIST_HEAD_INITIALIZER(&led_list);
+
+MALLOC_DEFINE(M_LED, "LED", "LED driver");
+
+static void
+led_timeout(void *p)
+{
+	struct ledsc	*sc;
+
+	mtx_lock(&led_mtx);
+	LIST_FOREACH(sc, &led_list, list) {
+		if (sc->ptr == NULL)
+			continue;
+		if (sc->count > 0) {
+			sc->count--;
+			continue;
+		}
+		sc->func(sc->private, sc->ptr[0] >= 'a' ? 1 : 0);
+		sc->count = sc->ptr[0] & 0xf;
+		if (*(++sc->ptr) == '\0')
+			sc->ptr = sc->str;
+	}
+	mtx_unlock(&led_mtx);
+	timeout(led_timeout, p, hz / 10);
+	return;
+}
+
+static int
+led_write(dev_t dev, struct uio *uio, int ioflag)
+{
+	int error;
+	char *s;
+	struct ledsc *sc;
+	struct sbuf *sb;
+	struct sbuf *sb2;
+	int i;
+
+	sc = dev->si_drv1;
+
+	if (uio->uio_resid > 512)
+		return (EINVAL);
+	s = malloc(uio->uio_resid + 1, M_DEVBUF, M_WAITOK);
+	if (s == NULL)
+		return (ENOMEM);
+	s[uio->uio_resid] = '\0';
+	error = uiomove(s, uio->uio_resid, uio);
+	if (error) {
+		free(s, M_DEVBUF);
+		return (error);
+	}
+
+	/*
+	 * Handle "on" and "off" immediately so people can flash really
+	 * fast from userland if they want to
+	 */
+	if (*s == '0' || *s == '1') {
+		mtx_lock(&led_mtx);
+		sb2 = sc->spec;
+		sc->spec = NULL;
+		sc->str = NULL;
+		sc->ptr = NULL;
+		sc->count = 0;
+		sc->func(sc->private, *s & 1);
+		mtx_unlock(&led_mtx);
+		if (sb2 != NULL)
+			sbuf_delete(sb2);
+		free(s, M_DEVBUF);
+		return(0);
+	}
+
+	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
+	if (sb == NULL) {
+		free(s, M_DEVBUF);
+		return (ENOMEM);
+	}
+		
+	switch(s[0]) {
+		/*
+		 * Flash, default is 100msec/100msec.
+		 * 'f2' sets 200msec/200msec etc.
+		 */
+		case 'f':
+			if (s[1] >= '1' && s[1] <= '9')
+				i = s[1] - '1';
+			else
+				i = 0;
+			sbuf_printf(sb, "%c%c", 'a' + i, 'A' + i);
+			break;
+		/*
+		 * Digits, flashes out numbers.
+		 * 'd12' becomes -__________-_-______________________________
+		 */
+		case 'd':
+			for(s++; *s; s++) {
+				if (!isdigit(*s))
+					continue;
+				i = *s - '0';
+				if (i == 0)
+					i = 10;
+				for (; i > 1; i--) 
+					sbuf_cat(sb, "aA");
+				sbuf_cat(sb, "aJ");
+			}
+			sbuf_cat(sb, "JJ");
+			break;
+		/*
+		 * String, roll your own.
+		 * 'A-J' gives "off" for n/10 sec.
+		 * 'a-j' gives "on" for n/10 sec.
+		 * no delay before repeat
+		 * 'sAaAbBa' becomes _-_--__-
+		 */
+		case 's':
+			for(s++; *s; s++) {
+				if ((*s & 0x0f) > 10)
+					continue;
+				if ((*s & 0xf0) < ' ')
+					continue;
+				sbuf_bcat(sb, s, 1);
+			}
+			break;
+		/*
+		 * Morse.
+		 * '.' becomes _-
+		 * '-' becomes _---
+		 * ' ' becomes __
+		 * '\n' becomes ____
+		 * 1sec pause between repeats
+		 * '... --- ...' -> _-_-_-___---_---_---___-_-_-__________
+		 */
+		case 'm':
+			for(s++; *s; s++) {
+				if (*s == '.')
+					sbuf_cat(sb, "Aa");
+				else if (*s == '-')
+					sbuf_cat(sb, "Ac");
+				else if (*s == ' ')
+					sbuf_cat(sb, "B");
+			}
+			sbuf_cat(sb, "J");
+			break;
+		default:
+			break;
+	}
+	sbuf_finish(sb);
+	free(s, M_DEVBUF);
+	if (sbuf_overflowed(sb)) {
+		sbuf_delete(sb);
+		return (ENOMEM);
+	}
+	if (sbuf_len(sb) == 0) {
+		sbuf_delete(sb);
+		return (0);
+	}
+
+	mtx_lock(&led_mtx);
+	sb2 = sc->spec;
+	sc->spec = sb;
+	sc->str = sbuf_data(sb);
+	sc->ptr = sc->str;
+	sc->count = 0;
+	mtx_unlock(&led_mtx);
+	if (sb2 != NULL)
+		sbuf_delete(sb2);
+	return(0);
+}
+
+static struct cdevsw led_cdevsw = {
+        .d_write =      led_write,
+        .d_name =       "LED",
+};
+
+dev_t
+led_create(led_t *func, void *priv, char const *name)
+{
+	struct ledsc	*sc;
+	struct sbuf *sb;
+
+	if (next_minor == 0) {
+		mtx_init(&led_mtx, "LED mtx", MTX_DEF, 0);
+		timeout(led_timeout, NULL, hz / 10);
+	}
+
+	sb = sbuf_new(NULL, NULL, SPECNAMELEN, SBUF_FIXEDLEN);
+	if (sb == NULL)
+		return (NODEV);
+	sbuf_cpy(sb, "led/");
+	sbuf_cat(sb, name);
+	sbuf_finish(sb);
+	if (sbuf_overflowed(sb)) {
+		sbuf_delete(sb);
+		return (NODEV);
+	}
+		
+	sc = malloc(sizeof *sc, M_LED, M_WAITOK | M_ZERO);
+	sc->private = priv;
+	sc->func = func;
+	sc->dev = make_dev(&led_cdevsw, unit2minor(next_minor),
+	    UID_ROOT, GID_WHEEL, 0600, sbuf_data(sb));
+	sc->dev->si_drv1 = sc;
+	next_minor++;
+	sbuf_delete(sb);
+	mtx_lock(&led_mtx);
+	LIST_INSERT_HEAD(&led_list, sc, list);
+	mtx_unlock(&led_mtx);
+	return (sc->dev);
+}
+
+void
+led_destroy(dev_t dev)
+{
+	struct ledsc *sc;
+
+	sc = dev->si_drv1;
+	mtx_lock(&led_mtx);
+	LIST_REMOVE(sc, list);
+	mtx_unlock(&led_mtx);
+	sbuf_delete(sc->spec);
+	destroy_dev(dev);
+	free(sc, M_LED);
+}
diff --git a/sys/dev/led/led.h b/sys/dev/led/led.h
new file mode 100644
index 0000000..70655af
--- /dev/null
+++ b/sys/dev/led/led.h
@@ -0,0 +1,21 @@
+/*-
+ * ----------------------------------------------------------------------------
+ * "THE BEER-WARE LICENSE" (Revision 42):
+ * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
+ * can do whatever you want with this stuff. If we meet some day, and you think
+ * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
+ * ----------------------------------------------------------------------------
+ *
+ */
+
+#ifndef _DEV_LED_H
+#define _DEV_LED_H
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+typedef	void led_t(void *, int);
+dev_t led_create(led_t *func, void *priv, char const *name);
+void led_destroy(dev_t);
+
+#endif /* _DEV_LED_H */