i2c driver for Analog Devices AD7418

MFC after:	1 month

1 files changed, 234 insertions, 0 deletions

diff --git a/sys/dev/iicbus/ad7418.c b/sys/dev/iicbus/ad7418.c
new file mode 100644
index 0000000..ec68fc1
--- /dev/null
+++ b/sys/dev/iicbus/ad7418.c
@@ -0,0 +1,234 @@
+/*-
+ * Copyright (c) 2006 Sam Leffler.  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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+/*
+ * Analog Devices AD7418 chip sitting on the I2C bus.
+ */
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/lock.h>
+#include <sys/module.h>
+#include <sys/mutex.h>
+#include <sys/bus.h>
+#include <sys/resource.h>
+#include <sys/rman.h>
+#include <sys/sysctl.h>
+
+#include <machine/bus.h>
+#include <machine/cpu.h>
+#include <machine/cpufunc.h>
+#include <machine/frame.h>
+#include <machine/resource.h>
+#include <machine/intr.h>
+
+#include <dev/iicbus/iiconf.h>
+
+#include "iicbus_if.h"
+
+#define	IIC_M_WR	0	/* write operation */
+
+#define	AD7418_ADDR	0x50	/* slave address */
+
+#define	AD7418_TEMP	0	/* Temperature Value (r/o) */
+#define	AD7418_CONF	1	/* Config Register (r/w) */
+#define	AD7418_CONF_SHUTDOWN	0x01
+#define	AD7418_CONF_CHAN	0xe0	/* channel select mask */
+#define	AD7418_CHAN_TEMP	0x00	/* temperature channel */
+#define	AD7418_CHAN_VOLT	0x80	/* voltage channel */
+#define	AD7418_THYST	2	/* Thyst Setpoint (r/o) */
+#define	AD7418_TOTI	3	/* Toti Setpoint */
+#define	AD7418_VOLT	4	/* ADC aka Voltage (r/o) */
+#define	AD7418_CONF2	5	/* Config2 Register (r/w) */
+
+struct ad7418_softc {
+	device_t	sc_dev;
+	struct mtx	sc_mtx;
+	int		sc_curchan;	/* current channel */
+	int		sc_curtemp;
+	int		sc_curvolt;
+	int		sc_lastupdate;	/* in ticks */
+};
+
+static void ad7418_update(struct ad7418_softc *);
+static int ad7418_read_1(device_t dev, int reg);
+static int ad7418_write_1(device_t dev, int reg, int v);
+
+static int
+ad7418_probe(device_t dev)
+{
+	/* XXX really probe? */
+	device_set_desc(dev, "Analog Devices AD7418 ADC");
+	return (0);
+}
+
+static int
+ad7418_sysctl_temp(SYSCTL_HANDLER_ARGS)
+{
+	struct ad7418_softc *sc = arg1;
+	int temp;
+
+	ad7418_update(sc);
+	temp = (sc->sc_curtemp / 64) * 25;
+	return sysctl_handle_int(oidp, &temp, 0, req);
+}
+
+static int
+ad7418_sysctl_voltage(SYSCTL_HANDLER_ARGS)
+{
+	struct ad7418_softc *sc = arg1;
+	int volt;
+
+	ad7418_update(sc);
+	volt = (sc->sc_curvolt >> 6) * 564 / 10;
+	return sysctl_handle_int(oidp, &volt, 0, req);
+}
+
+static int
+ad7418_attach(device_t dev)
+{
+	struct ad7418_softc *sc = device_get_softc(dev);
+	struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(dev);
+	struct sysctl_oid *tree = device_get_sysctl_tree(dev);
+	int conf;
+
+	sc->sc_dev = dev;
+	mtx_init(&sc->sc_mtx, "ad7418", "ad7418", MTX_DEF);
+
+	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
+		"temp", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
+		ad7418_sysctl_temp, "I", "operating temperature");
+	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
+		"volt", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
+		ad7418_sysctl_voltage, "I", "input voltage");
+
+	/* enable chip if configured in shutdown mode */
+	conf = ad7418_read_1(dev, AD7418_CONF);
+	if (conf >= 0 && (conf & AD7418_CONF_SHUTDOWN))
+		ad7418_write_1(dev, AD7418_CONF, conf &~ AD7418_CONF_SHUTDOWN);
+
+	return (0);
+}
+
+static int
+ad7418_read_1(device_t dev, int reg) 
+{
+	uint8_t addr = reg;
+	uint8_t data[1];
+	struct iic_msg msgs[2] = {
+	     { AD7418_ADDR, IIC_M_WR, 1, &addr },
+	     { AD7418_ADDR, IIC_M_RD, 1, data },
+	};
+	return iicbus_transfer(dev, msgs, 2) != 0 ? -1 : data[0];
+}
+
+static int
+ad7418_write_1(device_t dev, int reg, int v) 
+{
+	/* NB: register pointer precedes actual data */
+	uint8_t data[2];
+	struct iic_msg msgs[1] = {
+	     { AD7418_ADDR, IIC_M_WR, 2, data },
+	};
+	data[0] = reg;
+	data[1] = v & 0xff;
+	return iicbus_transfer(dev, msgs, 1);
+}
+
+static void
+ad7418_set_channel(struct ad7418_softc *sc, int chan)
+{
+	if (sc->sc_curchan == chan)
+		return;
+	ad7418_write_1(sc->sc_dev, AD7418_CONF, 
+	    (ad7418_read_1(sc->sc_dev, AD7418_CONF) &~ AD7418_CONF_CHAN)|chan);
+	sc->sc_curchan = chan;
+#if 0
+	/*
+	 * NB: Linux driver delays here but chip data sheet
+	 *     says nothing and things appear to work fine w/o
+	 *     a delay on channel change.  If this is enabled
+	 *     be sure to account for losing the mutex below
+	 *     in ad7418_update.
+	 */
+	mtx_assert(&sc->sc_mtx, MA_OWNED);
+	/* let channel change settle, 1 tick should be 'nuf (need ~1ms) */
+	msleep(sc, &sc->sc_mtx, 0, "ad7418", 1);
+#endif
+}
+
+static int
+ad7418_read_2(device_t dev, int reg) 
+{
+	uint8_t addr = reg;
+	uint8_t data[2];
+	struct iic_msg msgs[2] = {
+	     { AD7418_ADDR, IIC_M_WR, 1, &addr },
+	     { AD7418_ADDR, IIC_M_RD, 2, data },
+	};
+	/* NB: D15..D8 precede D7..D0 per data sheet (Fig 12) */
+	return iicbus_transfer(dev, msgs, 2) != 0 ?
+		-1 : ((data[0] << 8) | data[1]);
+}
+
+static void
+ad7418_update(struct ad7418_softc *sc)
+{
+	int v;
+
+	mtx_lock(&sc->sc_mtx);
+	/* NB: no point in updating any faster than the chip */
+	if (ticks - sc->sc_lastupdate > hz) {
+		ad7418_set_channel(sc, AD7418_CHAN_TEMP);
+		v = ad7418_read_2(sc->sc_dev, AD7418_TEMP);
+		if (v >= 0)
+			sc->sc_curtemp = v;
+		ad7418_set_channel(sc, AD7418_CHAN_VOLT);
+		v = ad7418_read_2(sc->sc_dev, AD7418_VOLT);
+		if (v >= 0)
+			sc->sc_curvolt = v;
+		sc->sc_lastupdate = ticks;
+	}
+	mtx_unlock(&sc->sc_mtx);
+}
+
+static device_method_t ad7418_methods[] = {
+	DEVMETHOD(device_probe,		ad7418_probe),
+	DEVMETHOD(device_attach,	ad7418_attach),
+
+	{0, 0},
+};
+
+static driver_t ad7418_driver = {
+	"ad7418",
+	ad7418_methods,
+	sizeof(struct ad7418_softc),
+};
+static devclass_t ad7418_devclass;
+
+DRIVER_MODULE(ad7418, iicbus, ad7418_driver, ad7418_devclass, 0, 0);
+MODULE_VERSION(ad7418, 1);
+MODULE_DEPEND(ad7418, iicbus, 1, 1, 1);