jedec_ts: a driver for thermal sensors on memory modules

The driver currently supports chips that are fully compliant with the
JEDEC SPD / EEPROM / TS standard (JEDEC Standard 21-C,
TSE2002 Specification, frequenlty referred to as JEDEC JC 42.4).

Additionally some chips from STMicroelectronics are supported as well.
They are compliant except for their Device ID pattern.

Given the continued lack of any common sensor infrastructure, the driver
uses an ad-hoc sysctl to report the temperature.

Reviewed by:	wblock (documentation)
MFC after:	2 weeks
Relnotes:	yes
Differential Revision: https://reviews.freebsd.org/D8174

5 files changed, 193 insertions, 1 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index afc521518978..af8bf72cabb8 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -2527,7 +2527,12 @@ device		ismt
 
 device		smb
 
+# SMBus peripheral devices
 #
+# jedec_ts	Temperature Sensor compliant with JEDEC Standard 21-C
+#
+device		jedec_ts
+
 # I2C Bus
 #
 # Philips i2c bus support is provided by the `iicbus' device.
diff --git a/sys/conf/files b/sys/conf/files
index ef6ac4b6de5d..a430fb4ca308 100644
--- a/sys/conf/files
+++ b/sys/conf/files
@@ -2062,6 +2062,7 @@ dev/ixgbe/ixgbe_dcb_82598.c	optional ix inet | ixv inet \
 	compile-with "${NORMAL_C} -I$S/dev/ixgbe"
 dev/ixgbe/ixgbe_dcb_82599.c	optional ix inet | ixv inet \
 	compile-with "${NORMAL_C} -I$S/dev/ixgbe"
+dev/jedec_ts/jedec_ts.c		optional jedec_ts smbus
 dev/jme/if_jme.c		optional jme pci
 dev/joy/joy.c			optional joy
 dev/joy/joy_isa.c		optional joy isa
diff --git a/sys/dev/jedec_ts/jedec_ts.c b/sys/dev/jedec_ts/jedec_ts.c
new file mode 100644
index 000000000000..b65ef789173f
--- /dev/null
+++ b/sys/dev/jedec_ts/jedec_ts.c
@@ -0,0 +1,179 @@
+/*-
+ * Copyright (c) 2016 Andriy Gapon <avg@FreeBSD.org>
+ * 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("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/bus.h>
+#include <sys/endian.h>
+#include <sys/module.h>
+#include <sys/rman.h>
+#include <sys/sysctl.h>
+#include <sys/systm.h>
+
+#include <dev/smbus/smbconf.h>
+#include <dev/smbus/smbus.h>
+
+#include "smbus_if.h"
+
+
+/*
+ * SMBus specification defines little-endian byte order,
+ * but it seems that the JEDEC devices expect it to
+ * be big-endian.
+ */
+static int
+ts_readw_be(device_t dev, uint8_t reg, uint16_t *val)
+{
+	device_t bus = device_get_parent(dev);
+	uint8_t addr = smbus_get_addr(dev);
+	int err;
+
+	err = smbus_readw(bus, addr, reg, val);
+	if (err != 0)
+		return (err);
+	*val = be16toh(*val);
+	return (0);
+}
+
+static int
+ts_temp_sysctl(SYSCTL_HANDLER_ARGS)
+{
+	device_t dev = arg1;
+	int err;
+	int temp;
+	uint16_t val;
+
+	err = ts_readw_be(dev, 5, &val);
+	if (err != 0)
+		return (EIO);
+
+	/*
+	 * Convert the reading to temperature in 0.0001 Kelvins.
+	 * Three most significant bits are flags, the next
+	 * most significant bit is a sign bit.
+	 * Each step is 0.0625 degrees.
+	 */
+	temp = val & 0xfff;
+	if ((val & 0x1000) != 0)
+		temp = -temp;
+	temp = temp * 625 + 2731500;
+	err = sysctl_handle_int(oidp, &temp, 0, req);
+	return (err);
+}
+
+static int
+ts_probe(device_t dev)
+{
+	device_set_desc(dev, "DIMM memory sensor");
+	return (BUS_PROBE_DEFAULT);
+}
+
+static int
+ts_attach(device_t dev)
+{
+	struct sysctl_ctx_list *ctx;
+	struct sysctl_oid_list *tree;
+	int err;
+	uint16_t vendorid;
+	uint16_t devid;
+	uint8_t addr;
+
+	addr = smbus_get_addr(dev);
+	if ((addr & 0x30) != 0x30) {
+		/* Up to 8 slave devices starting at 0x30. */
+		return (ENXIO);
+	}
+
+	err = ts_readw_be(dev, 6, &vendorid);
+	if (err != 0) {
+		device_printf(dev, "failed to read Manufacturer ID\n");
+		return (ENXIO);
+	}
+	err = ts_readw_be(dev, 6, &devid);
+	if (err != 0) {
+		device_printf(dev, "failed to read Device ID\n");
+		return (ENXIO);
+	}
+	if ((devid & 0xff00) == 0x2200) {
+		/*
+		 * Defined by JEDEC Standard No. 21-C, Release 26,
+		 * Page 4.1.6 – 24
+		 */
+	} else if (vendorid == 0x104a) {
+		/*
+		 * STMicroelectronics datasheets say that
+		 * device ID and revision can vary.
+		 * E.g. STT424E02, Doc ID 13448 Rev 8,
+		 * section 4.6, page 26.
+		 */
+	} else {
+		if (bootverbose) {
+			device_printf(dev, "Unknown Manufacturer and Device IDs"
+			    ", 0x%x and 0x%x\n", vendorid, devid);
+		}
+		return (ENXIO);
+	}
+
+	ctx = device_get_sysctl_ctx(dev);
+	tree = SYSCTL_CHILDREN(device_get_sysctl_tree(dev));
+
+	SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temp",
+	    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, 0,
+	    ts_temp_sysctl, "IK4", "Current temperature");
+
+	return (0);
+}
+
+static int
+ts_detach(device_t dev)
+{
+	return (0);
+}
+
+
+static device_method_t jedec_ts_methods[] = {
+	/* Methods from the device interface */
+	DEVMETHOD(device_probe,		ts_probe),
+	DEVMETHOD(device_attach,	ts_attach),
+	DEVMETHOD(device_detach,	ts_detach),
+
+	/* Terminate method list */
+	{ 0, 0 }
+};
+
+static driver_t jedec_ts_driver = {
+	"jedec_ts",
+	jedec_ts_methods,
+	0	/* no softc */
+};
+
+static devclass_t jedec_ts_devclass;
+
+DRIVER_MODULE(jedec_ts, smbus, jedec_ts_driver, jedec_ts_devclass, 0, 0);
+MODULE_DEPEND(jedec_ts, smbus, SMBUS_MINVER, SMBUS_PREFVER, SMBUS_MAXVER);
+MODULE_VERSION(jedec_ts, 1);
diff --git a/sys/modules/i2c/Makefile b/sys/modules/i2c/Makefile
index a2199f561051..8e9bdf982cb6 100644
--- a/sys/modules/i2c/Makefile
+++ b/sys/modules/i2c/Makefile
@@ -1,6 +1,6 @@
 # $FreeBSD$
 
 SUBDIR =
-SUBDIR += controllers if_ic smbus iicbus iicbb iicsmb iic cyapa smb isl
+SUBDIR += controllers if_ic smbus iicbus iicbb iicsmb iic cyapa smb isl jedec_ts
 
 .include <bsd.subdir.mk>
diff --git a/sys/modules/i2c/jedec_ts/Makefile b/sys/modules/i2c/jedec_ts/Makefile
new file mode 100644
index 000000000000..66e620619fd5
--- /dev/null
+++ b/sys/modules/i2c/jedec_ts/Makefile
@@ -0,0 +1,7 @@
+# $FreeBSD$
+
+.PATH:		${.CURDIR}/../../../dev/jedec_ts
+KMOD		= jedec_ts
+SRCS		= jedec_ts.c bus_if.h device_if.h smbus_if.h
+
+.include <bsd.kmod.mk>