batt_smbus: driver for smart battery

src/drivers/batt_smbus/batt_smbus.cpp

@@ -0,0 +1,438 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012, 2013 PX4 Development Team. All rights reserved.
+ *   Author: Randy Mackay <rmackay9@yahoo.com>
+ *
+ * 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.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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
+ * COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file batt_smbus.cpp
+ *
+ * Driver for a battery monitor connected via SMBus (I2C).
+ *
+ */
+
+#include <nuttx/config.h>
+
+#include <sys/types.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <semaphore.h>
+#include <string.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <errno.h>
+#include <stdio.h>
+#include <math.h>
+#include <unistd.h>
+#include <ctype.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/clock.h>
+
+#include <board_config.h>
+
+#include <systemlib/perf_counter.h>
+#include <systemlib/err.h>
+#include <systemlib/systemlib.h>
+
+#include <uORB/uORB.h>
+#include <uORB/topics/subsystem_info.h>
+#include <uORB/topics/battery_status.h>
+
+#include <float.h>
+
+#include <drivers/device/i2c.h>
+#include <drivers/drv_hrt.h>
+#include <drivers/drv_batt_smbus.h>
+#include <drivers/device/ringbuffer.h>
+
+#define BATT_SMBUS_I2C_BUS				PX4_I2C_BUS_EXPANSION
+#define BATT_SMBUS_ADDR					0x0B	/* I2C address */
+#define BATT_SMBUS_TEMP					0x08	/* temperature register */
+#define BATT_SMBUS_VOLTAGE				0x09	/* voltage register */
+#define BATT_SMBUS_DESIGN_CAPACITY		0x18	/* design capacity register */
+#define BATT_SMBUS_DESIGN_VOLTAGE		0x19	/* design voltage register */
+#define BATT_SMBUS_SERIALNUM			0x1c	/* serial number register */
+#define BATT_SMBUS_MANUFACTURE_INFO		0x25	/* cell voltage register */
+#define BATT_SMBUS_CURRENT				0x2a	/* current register */
+#define BATT_SMBUS_MEASUREMENT_INTERVAL_MS	(1000000 / 10)	/* time in microseconds, measure at 10hz */
+
+#ifndef CONFIG_SCHED_WORKQUEUE
+# error This requires CONFIG_SCHED_WORKQUEUE.
+#endif
+
+class BATT_SMBUS : public device::I2C
+{
+public:
+	BATT_SMBUS(int bus = PX4_I2C_BUS_EXPANSION, uint16_t batt_smbus_addr = BATT_SMBUS_ADDR);
+	virtual ~BATT_SMBUS();
+
+	virtual int		init();
+	virtual int		test();
+
+protected:
+	virtual int		probe();		// check if the device can be contacted
+
+private:
+
+	// start periodic reads from the battery
+	void			start();
+
+	// stop periodic reads from the battery
+	void			stop();
+
+	// static function that is called by worker queue
+	static void		cycle_trampoline(void *arg);
+
+	// perform a read from the battery
+	void			cycle();
+
+	// read_reg - read a word from specified register
+	int				read_reg(uint8_t reg, uint16_t &val);
+
+	// read_block - returns number of characters read if successful, zero if unsuccessful
+	uint8_t			read_block(uint8_t reg, uint8_t* data, uint8_t max_len, bool append_zero);
+
+	// internal variables
+	work_s			_work;			// work queue for scheduling reads
+	RingBuffer		*_reports;		// buffer of recorded voltages, currents
+	struct battery_status_s _last_report;	// last published report, used for test()
+	orb_advert_t	_batt_topic;
+	orb_id_t		_batt_orb_id;
+};
+
+/* for now, we only support one BATT_SMBUS */
+namespace
+{
+BATT_SMBUS *g_batt_smbus;
+}
+
+void batt_smbus_usage();
+
+extern "C" __EXPORT int batt_smbus_main(int argc, char *argv[]);
+
+// constructor
+BATT_SMBUS::BATT_SMBUS(int bus, uint16_t batt_smbus_addr) :
+	I2C("batt_smbus", BATT_SMBUS_DEVICE_PATH, bus, batt_smbus_addr, 400000),
+	_work{},
+	_reports(nullptr),
+	_batt_topic(-1),
+	_batt_orb_id(nullptr)
+{
+	// work_cancel in the dtor will explode if we don't do this...
+	memset(&_work, 0, sizeof(_work));
+}
+
+// destructor
+BATT_SMBUS::~BATT_SMBUS()
+{
+	/* make sure we are truly inactive */
+	stop();
+
+	if (_reports != nullptr) {
+		delete _reports;
+	}
+}
+
+int
+BATT_SMBUS::init()
+{
+	int ret = ENOTTY;
+
+	// attempt to initialise I2C bus
+	ret = I2C::init();
+
+	if (ret != OK) {
+		errx(1,"failed to init I2C");
+		return ret;
+	} else {
+		/* allocate basic report buffers */
+		_reports = new RingBuffer(2, sizeof(struct battery_status_s));
+		if (_reports == nullptr) {
+			ret = ENOTTY;
+		} else {
+			// start work queue
+			start();
+		}
+	}
+
+	// init orb id
+	_batt_orb_id = ORB_ID(battery_status);
+
+	return ret;
+}
+
+int
+BATT_SMBUS::test()
+{
+	int sub = orb_subscribe(ORB_ID(battery_status));
+	bool updated = false;
+	struct battery_status_s status;
+	uint64_t start_time = hrt_absolute_time();
+
+	// loop for 5 seconds
+	while ((hrt_absolute_time() - start_time) < 5000000) {
+
+		// display new info that has arrived from the orb
+		orb_check(sub, &updated);
+		if (updated) {
+			if (orb_copy(ORB_ID(battery_status), sub, &status) == OK) {
+				warnx("V=%4.2f C=%4.2f", status.voltage_v, status.current_a);
+			}
+		}
+
+		// sleep for 0.05 seconds
+		usleep(50000);
+	}
+
+	return OK;
+}
+
+int
+BATT_SMBUS::probe()
+{
+	// always return OK to ensure device starts
+	return OK;
+}
+
+// start periodic reads from the battery
+void
+BATT_SMBUS::start()
+{
+	/* reset the report ring and state machine */
+	_reports->flush();
+
+	/* schedule a cycle to start things */
+	work_queue(HPWORK, &_work, (worker_t)&BATT_SMBUS::cycle_trampoline, this, 1);
+}
+
+// stop periodic reads from the battery
+void
+BATT_SMBUS::stop()
+{
+	work_cancel(HPWORK, &_work);
+}
+
+// static function that is called by worker queue
+void
+BATT_SMBUS::cycle_trampoline(void *arg)
+{
+	BATT_SMBUS *dev = (BATT_SMBUS *)arg;
+
+	dev->cycle();
+}
+
+// perform a read from the battery
+void
+BATT_SMBUS::cycle()
+{
+	// read data from sensor
+	struct battery_status_s new_report;
+
+	// set time of reading
+	new_report.timestamp = hrt_absolute_time();
+
+	// read voltage
+	uint16_t tmp;
+	if (read_reg(BATT_SMBUS_VOLTAGE, tmp) == OK) {
+		// initialise new_report
+		memset(&new_report, 0, sizeof(new_report));
+
+		// convert millivolts to volts
+		new_report.voltage_v = ((float)tmp) / 1000.0f;
+
+		// To-Do: read current as block from BATT_SMBUS_CURRENT register
+
+		// publish to orb
+		if (_batt_topic != -1) {
+			orb_publish(_batt_orb_id, _batt_topic, &new_report);
+		} else {
+			_batt_topic = orb_advertise(_batt_orb_id, &new_report);
+			if (_batt_topic < 0) {
+				errx(1, "ADVERT FAIL");
+			}
+		}
+
+		// copy report for test()
+		_last_report = new_report;
+
+		/* post a report to the ring */
+		_reports->force(&new_report);
+
+		/* notify anyone waiting for data */
+		poll_notify(POLLIN);
+	}
+
+	/* schedule a fresh cycle call when the measurement is done */
+	work_queue(HPWORK, &_work, (worker_t)&BATT_SMBUS::cycle_trampoline, this, USEC2TICK(BATT_SMBUS_MEASUREMENT_INTERVAL_MS));
+}
+
+int
+BATT_SMBUS::read_reg(uint8_t reg, uint16_t &val)
+{
+	uint8_t buff[2];
+
+	// short sleep to improve reliability in cases of two consecutive reads
+	usleep(1);
+
+	// read from register
+    int ret = transfer(&reg, 1, buff, 2);
+	if (ret == OK) {
+		val = (uint16_t)buff[1] << 8 | (uint16_t)buff[0];
+	}
+
+	// return success or failure
+	return ret;
+}
+
+// read_block - returns number of characters read if successful, zero if unsuccessful
+uint8_t BATT_SMBUS::read_block(uint8_t reg, uint8_t* data, uint8_t max_len, bool append_zero)
+{
+	uint8_t buff[max_len+1];    // buffer to hold results
+
+	usleep(1);
+
+	// read bytes
+	int ret = transfer(&reg, 1,buff, max_len+1);
+
+	// return zero on failure
+	if (ret != OK) {
+		return 0;
+	}
+
+	// get length
+	uint8_t bufflen = buff[0];
+
+	// sanity check length returned by smbus
+	if (bufflen == 0 || bufflen > max_len) {
+		return 0;
+	}
+
+	// copy data
+	memcpy(data, &buff[1], bufflen);
+
+	// optionally add zero to end
+	if (append_zero) {
+		data[bufflen] = '\0';
+	}
+
+	// return success
+	return bufflen;
+}
+
+///////////////////////// shell functions ///////////////////////
+
+void
+batt_smbus_usage()
+{
+	warnx("missing command: try 'start', 'test', 'stop'");
+	warnx("options:");
+		warnx("    -b i2cbus (%d)", BATT_SMBUS_I2C_BUS);
+		warnx("    -a addr (0x%x)", BATT_SMBUS_ADDR);
+}
+
+int
+batt_smbus_main(int argc, char *argv[])
+{
+	int i2cdevice = BATT_SMBUS_I2C_BUS;
+	int batt_smbusadr = BATT_SMBUS_ADDR; /* 7bit */
+
+	int ch;
+
+	/* jump over start/off/etc and look at options first */
+	while ((ch = getopt(argc, argv, "a:b:")) != EOF) {
+		switch (ch) {
+		case 'a':
+			batt_smbusadr = strtol(optarg, NULL, 0);
+			break;
+
+		case 'b':
+			i2cdevice = strtol(optarg, NULL, 0);
+			break;
+
+		default:
+			batt_smbus_usage();
+			exit(0);
+		}
+	}
+
+	if (optind >= argc) {
+		batt_smbus_usage();
+		exit(1);
+	}
+
+	const char *verb = argv[optind];
+
+	if (!strcmp(verb, "start")) {
+		if (g_batt_smbus != nullptr) {
+			errx(1, "already started");
+		} else {
+			// create new global object
+			g_batt_smbus = new BATT_SMBUS(i2cdevice, batt_smbusadr);
+
+			if (g_batt_smbus == nullptr) {
+				errx(1, "new failed");
+			}
+
+			if (OK != g_batt_smbus->init()) {
+				delete g_batt_smbus;
+				g_batt_smbus = nullptr;
+				errx(1, "init failed");
+			}
+		}
+
+		exit(0);
+	}
+
+	/* need the driver past this point */
+	if (g_batt_smbus == nullptr) {
+		warnx("not started");
+		batt_smbus_usage();
+		exit(1);
+	}
+
+	if (!strcmp(verb, "test")) {
+		g_batt_smbus->test();
+		exit(0);
+	}
+
+	if (!strcmp(verb, "stop")) {
+		delete g_batt_smbus;
+		g_batt_smbus = nullptr;
+		exit(0);
+	}
+
+	batt_smbus_usage();
+	exit(0);
+}

src/drivers/batt_smbus/module.mk

@@ -0,0 +1,8 @@
+#
+# driver for SMBus smart batteries
+#
+
+MODULE_COMMAND	 = batt_smbus
+SRCS		 = batt_smbus.cpp
+
+MAXOPTIMIZATION	 = -Os

src/drivers/drv_batt_smbus.h

@@ -0,0 +1,50 @@
+/****************************************************************************
+ *
+ *   Copyright (C) 2012-2013 PX4 Development Team. 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.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "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
+ * COPYRIGHT OWNER OR CONTRIBUTORS 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file drv_batt_smbus.h
+ *
+ * SMBus battery monitor device API
+ */
+
+#pragma once
+
+#include <stdint.h>
+#include <sys/ioctl.h>
+#include "drv_orb_dev.h"
+
+/* device path */
+#define BATT_SMBUS_DEVICE_PATH "/dev/batt_smbus"
+
+/* ObjDev tag for battery data */
+ORB_DECLARE(battery_status);