Add a basic driver for X-Powers AXP813 and AXP818 power management ICs.

This driver simply installs a shutdown event handler for handling
RB_POWEROFF at shutdown. Tested on a Sinovoip BananaPi BPI-M3.

sys/arm/allwinner/axp81x.c

@@ -0,0 +1,180 @@
+/*-
+ * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * X-Powers AXP813/818 PMU for Allwinner SoCs
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/eventhandler.h>
+#include <sys/bus.h>
+#include <sys/rman.h>
+#include <sys/kernel.h>
+#include <sys/reboot.h>
+#include <sys/module.h>
+#include <machine/bus.h>
+
+#include <dev/iicbus/iicbus.h>
+#include <dev/iicbus/iiconf.h>
+
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+#include "iicbus_if.h"
+
+#define	AXP_ICTYPE		0x03
+#define	AXP_POWERBAT		0x32
+#define	 AXP_POWERBAT_SHUTDOWN	(1 << 7)
+
+static struct ofw_compat_data compat_data[] = {
+	{ "x-powers,axp813",			1 },
+	{ "x-powers,axp818",			1 },
+	{ NULL,					0 }
+};
+
+struct axp81x_softc {
+	uint16_t		addr;
+	struct intr_config_hook	enum_hook;
+};
+
+static int
+axp81x_read(device_t dev, uint8_t reg, uint8_t *data, uint8_t size)
+{
+	struct axp81x_softc *sc;
+	struct iic_msg msg[2];
+
+	sc = device_get_softc(dev);
+
+	msg[0].slave = sc->addr;
+	msg[0].flags = IIC_M_WR;
+	msg[0].len = 1;
+	msg[0].buf = &reg;
+
+	msg[1].slave = sc->addr;
+	msg[1].flags = IIC_M_RD;
+	msg[1].len = size;
+	msg[1].buf = data;
+
+	return (iicbus_transfer(dev, msg, 2));
+}
+
+static int
+axp81x_write(device_t dev, uint8_t reg, uint8_t val)
+{
+	struct axp81x_softc *sc;
+	struct iic_msg msg[2];
+
+	sc = device_get_softc(dev);
+
+	msg[0].slave = sc->addr;
+	msg[0].flags = IIC_M_WR;
+	msg[0].len = 1;
+	msg[0].buf = &reg;
+
+	msg[1].slave = sc->addr;
+	msg[1].flags = IIC_M_WR;
+	msg[1].len = 1;
+	msg[1].buf = &val;
+
+	return (iicbus_transfer(dev, msg, 2));
+}
+
+static void
+axp81x_shutdown(void *devp, int howto)
+{
+	device_t dev;
+
+	if ((howto & RB_POWEROFF) == 0)
+		return;
+
+	dev = devp;
+
+	if (bootverbose)
+		device_printf(dev, "Shutdown AXP81x\n");
+
+	axp81x_write(dev, AXP_POWERBAT, AXP_POWERBAT_SHUTDOWN);
+}
+
+static int
+axp81x_probe(device_t dev)
+{
+	if (!ofw_bus_status_okay(dev))
+		return (ENXIO);
+
+	if (ofw_bus_search_compatible(dev, compat_data)->ocd_data == 0)
+		return (ENXIO);
+
+	device_set_desc(dev, "X-Powers AXP81x Power Management Unit");
+
+	return (BUS_PROBE_DEFAULT);
+}
+
+static int
+axp81x_attach(device_t dev)
+{
+	struct axp81x_softc *sc;
+	uint8_t chip_id;
+
+	sc = device_get_softc(dev);
+
+	sc->addr = iicbus_get_addr(dev);
+
+	if (bootverbose) {
+		axp81x_read(dev, AXP_ICTYPE, &chip_id, 1);
+		device_printf(dev, "chip ID 0x%02x\n", chip_id);
+	}
+
+	EVENTHANDLER_REGISTER(shutdown_final, axp81x_shutdown, dev,
+	    SHUTDOWN_PRI_LAST);
+
+	return (0);
+}
+
+static device_method_t axp81x_methods[] = {
+	/* Device interface */
+	DEVMETHOD(device_probe,		axp81x_probe),
+	DEVMETHOD(device_attach,	axp81x_attach),
+
+	DEVMETHOD_END
+};
+
+static driver_t axp81x_driver = {
+	"axp81x_pmu",
+	axp81x_methods,
+	sizeof(struct axp81x_softc),
+};
+
+static devclass_t axp81x_devclass;
+
+DRIVER_MODULE(axp81x, iicbus, axp81x_driver, axp81x_devclass, 0, 0);
+MODULE_VERSION(axp81x, 1);
+MODULE_DEPEND(axp81x, iicbus, 1, 1, 1);