Date: Fri, 29 Nov 2013 17:28:20 -0200 From: Luiz Otavio O Souza <loos.br@gmail.com> To: freebsd-embedded@freebsd.org Subject: [patch] LM75 kernel driver Message-ID: <69CF7423-FD5B-44B3-8B90-E76BA96BB31A@gmail.com>
next in thread | raw e-mail | index | archive | help
--Apple-Mail=_13A74922-970E-4308-9EC5-22D6556CBCE5
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain;
charset=windows-1252
Hi,
I=92ve written a kernel driver for lm75 (i2c temperature sensor).
It=92s a very simple, convenient and cheap way to verify an i2c bus.
This driver provides full control of the lm75 registers (configuration =
bits, over temperature and hysteresis settings) and so provides basic =
read and write test abilities.
The high resolution version (lm75b - 11 bits) isn=92t supported ATM, but =
i have plans to do so.
On my RPi i=92ve added this to sys/boot/fdt/dts/rpi.dts:
bsc0 {
lm750 {
compatible =3D "lm75";
i2c-address =3D <0x96>;
};
lm751 {
compatible =3D "lm75";
i2c-address =3D <0x9e>;
};
};
And =91device lm75=92 to RPI-B kernel file (after apply the attached =
patch).
Here is the result:
iichb0: <BCM2708/2835 BSC controller> mem 0x20205000-0x2020501f irq 61 =
on simplebus0
iicbus1: <OFW I2C bus> on iichb0
iic1: <I2C generic I/O> on iicbus1
lm751: <LM75 temperature sensor> at addr 0x96 on iicbus1
lm752: <LM75 temperature sensor> at addr 0x9e on iicbus1
# sysctl dev.lm75.1
dev.lm75.1.%desc: LM75 temperature sensor
dev.lm75.1.%driver: lm75
dev.lm75.1.%location: addr=3D0x96
dev.lm75.1.%pnpinfo: name=3Dlm750 compat=3Dlm75
dev.lm75.1.%parent: iicbus1
dev.lm75.1.temperature: 30.0C
dev.lm75.1.thyst: 75.0C
dev.lm75.1.tos: 80.0C
dev.lm75.1.conf.faults: 1
dev.lm75.1.conf.mode: comparator
dev.lm75.1.conf.polarity: active-low
dev.lm75.1.conf.shutdown: 0
# sysctl dev.lm75.2
dev.lm75.2.%desc: LM75 temperature sensor
dev.lm75.2.%driver: lm75
dev.lm75.2.%location: addr=3D0x9e
dev.lm75.2.%pnpinfo: name=3Dlm751 compat=3Dlm75
dev.lm75.2.%parent: iicbus1
dev.lm75.2.temperature: 29.5C
dev.lm75.2.thyst: 60.0C
dev.lm75.2.tos: 80.0C
dev.lm75.2.conf.faults: 2
dev.lm75.2.conf.mode: interrupt
dev.lm75.2.conf.polarity: active-low
dev.lm75.2.conf.shutdown: 0
I hope this may be useful for someone else.
Luiz
--Apple-Mail=_13A74922-970E-4308-9EC5-22D6556CBCE5
Content-Disposition: attachment;
filename=lm75.diff
Content-Type: application/octet-stream;
name="lm75.diff"
Content-Transfer-Encoding: 7bit
Index: sys/conf/files
===================================================================
--- sys/conf/files (revision 258680)
+++ sys/conf/files (working copy)
@@ -1472,6 +1472,7 @@
dev/iicbus/iicsmb.c optional iicsmb \
dependency "iicbus_if.h"
dev/iicbus/iicoc.c optional iicoc
+dev/iicbus/lm75.c optional lm75
dev/iicbus/pcf8563.c optional pcf8563
dev/iicbus/s35390a.c optional s35390a
dev/iir/iir.c optional iir
--- /dev/null 2013-11-29 15:00:00.000000000 -0200
+++ sys/dev/iicbus/lm75.c 2013-11-29 14:58:31.174941027 -0200
@@ -0,0 +1,510 @@
+/*-
+ * Copyright (c) 2010 Andreas Tobler.
+ * Copyright (c) 2013 Luiz Otavio O Souza <loos@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/bus.h>
+#include <sys/callout.h>
+#include <sys/endian.h>
+#include <sys/kernel.h>
+#include <sys/module.h>
+#include <sys/sysctl.h>
+#include <sys/systm.h>
+
+#include <machine/bus.h>
+
+#include <dev/iicbus/iicbus.h>
+#include <dev/iicbus/iiconf.h>
+
+#include <dev/ofw/openfirm.h>
+#include <dev/ofw/ofw_bus.h>
+#include <dev/ofw/ofw_bus_subr.h>
+
+/* LM75 registers */
+#define LM75_TEMP 0x0
+#define LM75_CONF 0x1
+#define LM75_CONF_FSHIFT 3
+#define LM75_CONF_FAULT 0x18
+#define LM75_CONF_POL 0x04
+#define LM75_CONF_MODE 0x02
+#define LM75_CONF_SHUTD 0x01
+#define LM75_CONF_MASK 0x1f
+#define LM75_THYST 0x2
+#define LM75_TOS 0x3
+
+/* LM75 constants */
+#define LM75_MIN_TEMP -55
+#define LM75_MAX_TEMP 125
+#define LM75_LSB 0x80
+#define LM75_MSB 0x8000
+#define LM75_NEG_BIT LM75_MSB
+#define TZ_ZEROC 2732
+
+/* Regular bus attachment functions */
+static int lm75_probe(device_t);
+static int lm75_attach(device_t);
+
+struct lm75_softc {
+ device_t sc_dev;
+ struct intr_config_hook enum_hook;
+ uint32_t sc_addr;
+ uint32_t sc_conf;
+};
+
+int lm75_faults[4] = { 1, 2, 4, 6 };
+
+/* Utility functions */
+static int lm75_conf_read(struct lm75_softc *);
+static int lm75_conf_write(struct lm75_softc *);
+static int lm75_temp_read(struct lm75_softc *, uint8_t, int *);
+static int lm75_temp_write(struct lm75_softc *, uint8_t, int);
+static void lm75_start(void *);
+static int lm75_read(device_t, uint32_t, uint8_t, uint8_t *, size_t);
+static int lm75_write(device_t, uint32_t, uint8_t *, size_t);
+static int lm75_str_mode(char *);
+static int lm75_str_pol(char *);
+static int lm75_temp_sysctl(SYSCTL_HANDLER_ARGS);
+static int lm75_faults_sysctl(SYSCTL_HANDLER_ARGS);
+static int lm75_mode_sysctl(SYSCTL_HANDLER_ARGS);
+static int lm75_pol_sysctl(SYSCTL_HANDLER_ARGS);
+static int lm75_shutdown_sysctl(SYSCTL_HANDLER_ARGS);
+
+static device_method_t lm75_methods[] = {
+ /* Device interface */
+ DEVMETHOD(device_probe, lm75_probe),
+ DEVMETHOD(device_attach, lm75_attach),
+
+ DEVMETHOD_END
+};
+
+static driver_t lm75_driver = {
+ "lm75",
+ lm75_methods,
+ sizeof(struct lm75_softc)
+};
+
+static devclass_t lm75_devclass;
+
+DRIVER_MODULE(lm75, iicbus, lm75_driver, lm75_devclass, 0, 0);
+
+static int
+lm75_read(device_t dev, uint32_t addr, uint8_t reg, uint8_t *data, size_t len)
+{
+ int try;
+
+ struct iic_msg msg[2] = {
+ { addr, IIC_M_WR | IIC_M_NOSTOP, 1, ® },
+ { addr, IIC_M_RD, len, data },
+ };
+
+ try = 0;
+ for (;;) {
+ if (iicbus_transfer(dev, msg, 2) != 0)
+ goto retry;
+
+ return (0);
+ retry:
+ if (++try > 5) {
+ device_printf(dev, "iicbus read failed\n");
+ return (-1);
+ }
+ pause("lm75_read", hz);
+ }
+}
+
+static int
+lm75_write(device_t dev, uint32_t addr, uint8_t *data, size_t len)
+{
+ int try;
+
+ struct iic_msg msg[1] = {
+ { addr, IIC_M_WR, len, data },
+ };
+
+ try = 0;
+ for (;;) {
+ if (iicbus_transfer(dev, msg, 1) != 0)
+ goto retry;
+
+ return (0);
+ retry:
+ if (++try > 5) {
+ device_printf(dev, "iicbus write failed\n");
+ return (-1);
+ }
+ pause("lm75_write", hz);
+ }
+}
+
+static int
+lm75_probe(device_t dev)
+{
+
+ if (!ofw_bus_is_compatible(dev, "lm75"))
+ return (ENXIO);
+
+ device_set_desc(dev, "LM75 temperature sensor");
+
+ return (BUS_PROBE_GENERIC);
+}
+
+static int
+lm75_attach(device_t dev)
+{
+ struct lm75_softc *sc;
+
+ sc = device_get_softc(dev);
+ sc->sc_dev = dev;
+ sc->sc_addr = iicbus_get_addr(dev);
+
+ sc->enum_hook.ich_func = lm75_start;
+ sc->enum_hook.ich_arg = dev;
+
+ /*
+ * We have to wait until interrupts are enabled. I2C read and write
+ * only works if the interrupts are available.
+ */
+ if (config_intrhook_establish(&sc->enum_hook) != 0)
+ return (ENOMEM);
+
+ return (0);
+}
+
+static void
+lm75_start(void *xdev)
+{
+ device_t dev;
+ struct lm75_softc *sc;
+ struct sysctl_ctx_list *ctx;
+ struct sysctl_oid *conf_node, *tree_node;
+ struct sysctl_oid_list *conf_tree, *tree;
+
+ dev = (device_t)xdev;
+ sc = device_get_softc(dev);
+ ctx = device_get_sysctl_ctx(dev);
+ tree_node = device_get_sysctl_tree(dev);
+ tree = SYSCTL_CHILDREN(tree_node);
+
+ config_intrhook_disestablish(&sc->enum_hook);
+
+ /* Read the configuration register. */
+ if (lm75_conf_read(sc) != 0) {
+ device_printf(dev, "cannot read the configuration register.\n");
+ return;
+ }
+
+ SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "temperature",
+ CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, dev, LM75_TEMP,
+ lm75_temp_sysctl, "IK", "Current temperature");
+ SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "thyst",
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, dev, LM75_THYST,
+ lm75_temp_sysctl, "IK", "Hysteresis temperature");
+ SYSCTL_ADD_PROC(ctx, tree, OID_AUTO, "tos",
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, dev, LM75_TOS,
+ lm75_temp_sysctl, "IK", "Overtemperature");
+
+ conf_node = SYSCTL_ADD_NODE(ctx, tree, OID_AUTO, "conf",
+ CTLFLAG_RD, NULL, "LM75 configuration");
+ conf_tree = SYSCTL_CHILDREN(conf_node);
+
+ SYSCTL_ADD_PROC(ctx, conf_tree, OID_AUTO, "faults",
+ CTLFLAG_RW | CTLTYPE_UINT, dev, 0,
+ lm75_faults_sysctl, "IU", "LM75 fault queue");
+ SYSCTL_ADD_PROC(ctx, conf_tree, OID_AUTO, "mode",
+ CTLFLAG_RW | CTLTYPE_STRING, dev, 0,
+ lm75_mode_sysctl, "A", "LM75 mode");
+ SYSCTL_ADD_PROC(ctx, conf_tree, OID_AUTO, "polarity",
+ CTLFLAG_RW | CTLTYPE_STRING, dev, 0,
+ lm75_pol_sysctl, "A", "LM75 OS polarity");
+ SYSCTL_ADD_PROC(ctx, conf_tree, OID_AUTO, "shutdown",
+ CTLFLAG_RW | CTLTYPE_UINT, dev, 0,
+ lm75_shutdown_sysctl, "IU", "LM75 shutdown");
+}
+
+static int
+lm75_conf_read(struct lm75_softc *sc)
+{
+ uint8_t buf8;
+
+ if (lm75_read(sc->sc_dev, sc->sc_addr, LM75_CONF, &buf8, 1) < 0)
+ return (-1);
+
+ sc->sc_conf = (uint32_t)buf8;
+
+ return (0);
+}
+
+static int
+lm75_conf_write(struct lm75_softc *sc)
+{
+ uint8_t buf8[2];
+
+ buf8[0] = LM75_CONF;
+ buf8[1] = (uint8_t)sc->sc_conf & LM75_CONF_MASK;
+
+ if (lm75_write(sc->sc_dev, sc->sc_addr, buf8, 2) < 0)
+ return (-1);
+
+ return (0);
+}
+
+static int
+lm75_temp_read(struct lm75_softc *sc, uint8_t reg, int *temp)
+{
+ uint8_t buf8[2];
+ uint16_t buf;
+
+ if (lm75_read(sc->sc_dev, sc->sc_addr, reg, buf8, 2) < 0)
+ return (-1);
+
+ buf = (buf8[0] << 8) | (buf8[1] & 0xff);
+
+ /*
+ * LM75 has 9 bit ADC with resolution of 0.5 C per bit. Temperature is
+ * stored with two's complement.
+ */
+ if (buf & LM75_NEG_BIT)
+ buf = ~buf + 1;
+ *temp = ((int16_t)buf >> 8) * 10;
+ if (buf & LM75_LSB)
+ *temp += 5;
+ if (buf & LM75_NEG_BIT)
+ *temp = -(*temp);
+ *temp += TZ_ZEROC;
+
+ return (0);
+}
+
+static int
+lm75_temp_write(struct lm75_softc *sc, uint8_t reg, int temp)
+{
+ uint8_t buf8[3];
+ uint16_t buf;
+
+ if (temp > LM75_MAX_TEMP)
+ temp = LM75_MAX_TEMP;
+ if (temp < LM75_MIN_TEMP)
+ temp = LM75_MIN_TEMP;
+
+ buf = (uint16_t)temp;
+ buf <<= 8;
+
+ buf8[0] = reg;
+ buf8[1] = buf >> 8;
+ buf8[2] = buf & 0xff;
+
+ if (lm75_write(sc->sc_dev, sc->sc_addr, buf8, 3) < 0)
+ return (-1);
+
+ return (0);
+}
+
+static int
+lm75_str_mode(char *buf)
+{
+ int len, rtrn;
+
+ rtrn = -1;
+ len = strlen(buf);
+ if (len > 2 && strncasecmp("interrupt", buf, len) == 0)
+ rtrn = 1;
+ else if (len > 2 && strncasecmp("comparator", buf, len) == 0)
+ rtrn = 0;
+
+ return (rtrn);
+}
+static int
+lm75_str_pol(char *buf)
+{
+ int len, rtrn;
+
+ rtrn = -1;
+ len = strlen(buf);
+ if (len > 1 && strncasecmp("high", buf, len) == 0)
+ rtrn = 1;
+ else if (len > 1 && strncasecmp("low", buf, len) == 0)
+ rtrn = 0;
+ else if (len > 8 && strncasecmp("active-high", buf, len) == 0)
+ rtrn = 1;
+ else if (len > 8 && strncasecmp("active-low", buf, len) == 0)
+ rtrn = 0;
+
+ return (rtrn);
+}
+
+static int
+lm75_temp_sysctl(SYSCTL_HANDLER_ARGS)
+{
+ device_t dev;
+ int error, temp;
+ struct lm75_softc *sc;
+ uint8_t reg;
+
+ dev = arg1;
+ reg = arg2;
+ sc = device_get_softc(dev);
+
+ if (lm75_temp_read(sc, reg, &temp) != 0)
+ return (EIO);
+
+ error = sysctl_handle_int(oidp, &temp, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ if (lm75_temp_write(sc, reg, temp) != 0)
+ return (EIO);
+
+ return (error);
+}
+
+static int
+lm75_faults_sysctl(SYSCTL_HANDLER_ARGS)
+{
+ device_t dev;
+ int error, faults, i, newf, tmp;
+ struct lm75_softc *sc;
+
+ dev = arg1;
+ sc = device_get_softc(dev);
+ tmp = (sc->sc_conf & LM75_CONF_FAULT) >> LM75_CONF_FSHIFT;
+ if (tmp > nitems(lm75_faults))
+ tmp = nitems(lm75_faults);
+ faults = lm75_faults[tmp];
+
+ error = sysctl_handle_int(oidp, &faults, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ if (faults != lm75_faults[tmp]) {
+ newf = 0;
+ for (i = 0; i < nitems(lm75_faults); i++)
+ if (faults >= lm75_faults[i])
+ newf = i;
+ sc->sc_conf &= ~LM75_CONF_FAULT;
+ sc->sc_conf |= newf << LM75_CONF_FSHIFT;
+ if (lm75_conf_write(sc) != 0)
+ return (EIO);
+ }
+
+ return (error);
+}
+
+static int
+lm75_mode_sysctl(SYSCTL_HANDLER_ARGS)
+{
+ char buf[16];
+ device_t dev;
+ int error, mode, newm;
+ struct lm75_softc *sc;
+
+ dev = arg1;
+ sc = device_get_softc(dev);
+ if (sc->sc_conf & LM75_CONF_MODE) {
+ mode = 1;
+ strlcpy(buf, "interrupt", sizeof(buf));
+ } else {
+ mode = 0;
+ strlcpy(buf, "comparator", sizeof(buf));
+ }
+
+ error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ newm = lm75_str_mode(buf);
+ if (newm != -1 && mode != newm) {
+ sc->sc_conf &= ~LM75_CONF_MODE;
+ if (newm == 1)
+ sc->sc_conf |= LM75_CONF_MODE;
+ if (lm75_conf_write(sc) != 0)
+ return (EIO);
+ }
+
+ return (error);
+}
+
+static int
+lm75_pol_sysctl(SYSCTL_HANDLER_ARGS)
+{
+ char buf[16];
+ device_t dev;
+ int error, newp, pol;
+ struct lm75_softc *sc;
+
+ dev = arg1;
+ sc = device_get_softc(dev);
+ if (sc->sc_conf & LM75_CONF_POL) {
+ pol = 1;
+ strlcpy(buf, "active-high", sizeof(buf));
+ } else {
+ pol = 0;
+ strlcpy(buf, "active-low", sizeof(buf));
+ }
+
+ error = sysctl_handle_string(oidp, buf, sizeof(buf), req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ newp = lm75_str_pol(buf);
+ if (newp != -1 && pol != newp) {
+ sc->sc_conf &= ~LM75_CONF_POL;
+ if (newp == 1)
+ sc->sc_conf |= LM75_CONF_POL;
+ if (lm75_conf_write(sc) != 0)
+ return (EIO);
+ }
+
+ return (error);
+}
+
+static int
+lm75_shutdown_sysctl(SYSCTL_HANDLER_ARGS)
+{
+ device_t dev;
+ int error, shutdown, tmp;
+ struct lm75_softc *sc;
+
+ dev = arg1;
+ sc = device_get_softc(dev);
+ tmp = shutdown = (sc->sc_conf & LM75_CONF_SHUTD) ? 1 : 0;
+
+ error = sysctl_handle_int(oidp, &shutdown, 0, req);
+ if (error != 0 || req->newptr == NULL)
+ return (error);
+
+ if (shutdown != tmp) {
+ sc->sc_conf &= ~LM75_CONF_SHUTD;
+ if (shutdown)
+ sc->sc_conf |= LM75_CONF_SHUTD;
+ if (lm75_conf_write(sc) != 0)
+ return (EIO);
+ }
+
+ return (error);
+}
--Apple-Mail=_13A74922-970E-4308-9EC5-22D6556CBCE5--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?69CF7423-FD5B-44B3-8B90-E76BA96BB31A>