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>
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[-- Attachment #1 --]
Hi,
I’ve written a kernel driver for lm75 (i2c temperature sensor).
It’s 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’t supported ATM, but i have plans to do so.
On my RPi i’ve added this to sys/boot/fdt/dts/rpi.dts:
bsc0 {
lm750 {
compatible = "lm75";
i2c-address = <0x96>;
};
lm751 {
compatible = "lm75";
i2c-address = <0x9e>;
};
};
And ‘device lm75’ 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=0x96
dev.lm75.1.%pnpinfo: name=lm750 compat=lm75
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=0x9e
dev.lm75.2.%pnpinfo: name=lm751 compat=lm75
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
[-- Attachment #2 --]
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);
+}
help
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