Add pwmfan(4), a driver for PWM-regulated fans.

ok kurt@

sys/arch/arm64/conf/GENERIC

@@ -1,4 +1,4 @@
-# $OpenBSD: GENERIC,v 1.134 2019/12/03 09:08:48 patrick Exp $
+# $OpenBSD: GENERIC,v 1.135 2019/12/03 09:12:46 patrick Exp $
 #
 # GENERIC machine description file
 #
@@ -90,6 +90,7 @@ pluart*		at fdt?
 psci*		at fdt? early 1
 pwmreg*		at fdt? early 1
 syscon*		at fdt? early 1
+pwmfan*		at fdt?
 
 virtio*		at fdt?
 virtio*		at pci?

sys/arch/arm64/conf/RAMDISK

@@ -1,4 +1,4 @@
-# $OpenBSD: RAMDISK,v 1.108 2019/12/03 09:08:48 patrick Exp $
+# $OpenBSD: RAMDISK,v 1.109 2019/12/03 09:12:46 patrick Exp $
 #
 # GENERIC machine description file
 #
@@ -96,6 +96,7 @@ plrtc*		at fdt?
 pluart*		at fdt?
 psci*		at fdt? early 1
 syscon*		at fdt? early 1
+pwmfan*		at fdt?
 
 virtio*		at fdt?
 virtio*		at pci?

sys/dev/fdt/files.fdt

@@ -1,4 +1,4 @@
-#	$OpenBSD: files.fdt,v 1.105 2019/12/03 09:08:48 patrick Exp $
+#	$OpenBSD: files.fdt,v 1.106 2019/12/03 09:12:45 patrick Exp $
 #
 # Config file and device description for machine-independent FDT code.
 # Included by ports that need it.
@@ -144,6 +144,10 @@ device	pwmbl
 attach	pwmbl at fdt
 file	dev/fdt/pwmbl.c			pwmbl
 
+device	pwmfan
+attach	pwmfan at fdt
+file	dev/fdt/pwmfan.c		pwmfan
+
 device	pwmreg
 attach	pwmreg at fdt
 file	dev/fdt/pwmreg.c		pwmreg

sys/dev/fdt/pwmfan.c

@@ -0,0 +1,131 @@
+/*	$OpenBSD: pwmfan.c,v 1.1 2019/12/03 09:12:45 patrick Exp $	*/
+/*
+ * Copyright (c) 2019 Krystian Lewandowski
+ * Copyright (c) 2019 Mark Kettenis <kettenis@openbsd.org>
+ * Copyright (c) 2019 Patrick Wildt <patrick@blueri.se>
+ *
+ * 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/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/ofw/ofw_thermal.h>
+
+struct pwmfan_softc {
+	struct device		sc_dev;
+	uint32_t		*sc_pwm;
+	int			sc_pwm_len;
+	uint32_t		*sc_levels;
+	int			sc_nlevels;
+	int			sc_curlevel;
+
+	struct cooling_device	sc_cd;
+};
+
+int	pwmfan_match(struct device *, void *, void *);
+void	pwmfan_attach(struct device *, struct device *, void *);
+
+struct cfattach pwmfan_ca = {
+	sizeof(struct pwmfan_softc), pwmfan_match, pwmfan_attach
+};
+
+struct cfdriver pwmfan_cd = {
+	NULL, "pwmfan", DV_DULL
+};
+
+uint32_t pwmfan_get_cooling_level(void *, uint32_t *);
+void	pwmfan_set_cooling_level(void *, uint32_t *, uint32_t);
+
+int
+pwmfan_match(struct device *parent, void *match, void *aux)
+{
+	struct fdt_attach_args *faa = aux;
+
+	return OF_is_compatible(faa->fa_node, "pwm-fan");
+}
+
+void
+pwmfan_attach(struct device *parent, struct device *self, void *aux)
+{
+	struct pwmfan_softc *sc = (struct pwmfan_softc *)self;
+	struct fdt_attach_args *faa = aux;
+	int len;
+
+	len = OF_getproplen(faa->fa_node, "pwms");
+	if (len < 0) {
+		printf(": no pwm\n");
+		return;
+	}
+
+	sc->sc_pwm = malloc(len, M_DEVBUF, M_WAITOK);
+	OF_getpropintarray(faa->fa_node, "pwms", sc->sc_pwm, len);
+	sc->sc_pwm_len = len;
+
+	len = OF_getproplen(faa->fa_node, "cooling-levels");
+	if (len < 0) {
+		free(sc->sc_pwm, M_DEVBUF, sc->sc_pwm_len);
+		printf(": no cooling levels\n");
+		return;
+	}
+
+	sc->sc_levels = malloc(len, M_DEVBUF, M_WAITOK);
+	OF_getpropintarray(faa->fa_node, "cooling-levels",
+	    sc->sc_levels, len);
+	sc->sc_nlevels = len / sizeof(uint32_t);
+
+	printf("\n");
+
+	sc->sc_cd.cd_node = faa->fa_node;
+	sc->sc_cd.cd_cookie = sc;
+	sc->sc_cd.cd_get_level = pwmfan_get_cooling_level;
+	sc->sc_cd.cd_set_level = pwmfan_set_cooling_level;
+	cooling_device_register(&sc->sc_cd);
+}
+
+uint32_t
+pwmfan_get_cooling_level(void *cookie, uint32_t *cells)
+{
+	struct pwmfan_softc *sc = cookie;
+
+	return sc->sc_curlevel;
+}
+
+void
+pwmfan_set_cooling_level(void *cookie, uint32_t *cells, uint32_t level)
+{
+	struct pwmfan_softc *sc = cookie;
+	struct pwm_state ps;
+
+	if (level == sc->sc_curlevel || level > sc->sc_nlevels ||
+	    sc->sc_levels[level] > 255)
+		return;
+
+	if (pwm_init_state(sc->sc_pwm, &ps))
+		return;
+
+	sc->sc_curlevel = level;
+	level = sc->sc_levels[level];
+
+	ps.ps_enabled = level ? 1 : 0;
+	ps.ps_pulse_width = (ps.ps_period * level) / 255;
+	pwm_set_state(sc->sc_pwm, &ps);
+}