Initial scd30 driver

.gitignore

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+*.o
+/release
+/scd30/scd_git_version.c
+/scd30/scd30_example_usage_hw_i2c
+/scd30/scd30_example_usage_sw_i2c

Makefile

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+drivers=scd30
+clean_drivers=$(foreach d, $(drivers), clean_$(d))
+release_drivers=$(foreach d, $(drivers), release/$(d))
+
+.PHONY: FORCE all $(release_drivers) $(clean_drivers)
+
+all: $(drivers)
+
+$(drivers): scd30/scd_git_version.c FORCE
+	cd $@ && $(MAKE) $(MFLAGS)
+
+scd30/scd_git_version.c: FORCE
+	git describe --always --dirty | \
+		awk 'BEGIN \
+		{print "/* THIS FILE IS AUTOGENERATED */"} \
+		{print "#include \"scd_git_version.h\""} \
+		{print "const char * SCD_DRV_VERSION_STR = \"" $$0"\";"} \
+		END {}' > $@
+
+$(release_drivers): scd30/scd_git_version.c
+	export rel=$@ && \
+	export driver=$${rel#release/} && \
+	export tag="$$(git describe --always --dirty)" && \
+	export pkgname="$${driver}-$${tag}" && \
+	export pkgdir="release/$${pkgname}" && \
+	rm -rf "$${pkgdir}" && mkdir -p "$${pkgdir}" && \
+	cp -r embedded-common/* "$${pkgdir}" && \
+	cp -r $${driver}/* "$${pkgdir}" && \
+	perl -pi -e 's/^sensirion_common_dir :=.*$$/sensirion_common_dir := ./' "$${pkgdir}/Makefile" && \
+	cd "$${pkgdir}" && $(MAKE) $(MFLAGS) && $(MAKE) clean $(MFLAGS) && cd - && \
+	cd release && zip -r "$${pkgname}.zip" "$${pkgname}" && cd - && \
+	ln -sf $${pkgname} $@
+
+release: clean $(release_drivers)
+
+$(clean_drivers):
+	export rel=$@ && \
+	export driver=$${rel#clean_} && \
+	cd $${driver} && $(MAKE) clean $(MFLAGS) && cd -
+
+clean: $(clean_drivers)
+	rm -rf release scd30/scd_git_version.c

scd30/Makefile

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+sensirion_common_dir := ../embedded-common
+scd_common_dir := .
+sw_i2c_dir := ${sensirion_common_dir}/sw_i2c
+hw_i2c_dir := ${sensirion_common_dir}/hw_i2c
+
+CFLAGS := -Os -Wall -Werror -I. -I${sensirion_common_dir}
+
+sensirion_common_objects := sensirion_common.o
+scd_common_objects := scd_git_version.o
+scd30_binaries := scd30_example_usage_sw_i2c scd30_example_usage_hw_i2c
+scd_binaries += ${scd30_binaries}
+
+sw_objects := sensirion_sw_i2c.o sensirion_sw_i2c_implementation.o
+hw_objects := sensirion_hw_i2c_implementation.o
+all_objects := ${sensirion_common_objects} ${scd_common_objects} ${hw_objects} ${sw_objects} scd30.o
+
+.PHONY: all
+
+all: ${scd_binaries}
+
+scd_git_version.o: ${scd_common_dir}/scd_git_version.c
+	$(CC) $(CFLAGS) -c -o $@ $^
+sensirion_common.o: ${sensirion_common_dir}/sensirion_common.c
+	$(CC) $(CFLAGS) -c -o $@ $^
+sensirion_sw_i2c_implementation.o: ${sw_i2c_dir}/sample-implementations/linux_user_space/sensirion_sw_i2c_implementation.c
+	$(CC) -I${sw_i2c_dir} $(CFLAGS) -c -o $@ $^
+sensirion_hw_i2c_implementation.o: ${hw_i2c_dir}/sensirion_hw_i2c_implementation.c
+	$(CC) $(CFLAGS) -c -o $@ $^
+
+sensirion_sw_i2c.o: ${sw_i2c_dir}/sensirion_sw_i2c.c
+	$(CC) -I${sw_i2c_dir} $(CFLAGS) -c -o $@ $^
+
+scd30.o: ${sensirion_common_dir}/sensirion_arch_config.h ${sensirion_common_dir}/sensirion_i2c.h ${scd_common_dir}/scd_git_version.c scd30.h scd30.c
+
+scd30_example_usage_sw_i2c: ${sensirion_common_objects} ${scd_common_objects} ${sw_objects} scd30.o
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LOADLIBES) $(LDLIBS) scd30_example_usage.c
+
+scd30_example_usage_hw_i2c: ${sensirion_common_objects} ${scd_common_objects} ${hw_objects} scd30.o
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^ $(LOADLIBES) $(LDLIBS) scd30_example_usage.c
+
+clean:
+	$(RM) ${all_objects} ${scd_binaries}

scd30/scd30.c

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+/*
+ * Copyright (c) 2018, Sensirion AG
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * * Redistributions of source code must retain the above copyright notice, this
+ *   list of conditions and the following disclaimer.
+ *
+ * * 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.
+ *
+ * * Neither the name of Sensirion AG 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 HOLDER 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.
+ */
+
+#include "sensirion_arch_config.h"
+#include "sensirion_i2c.h"
+#include "sensirion_common.h"
+#include "scd_git_version.h"
+#include "scd30.h"
+
+
+#ifdef SCD_ADDRESS
+static const u8 SCD_I2C_ADDRESS = SCD_ADDRESS;
+#else
+static const u8 SCD_I2C_ADDRESS = 0x61;
+#endif
+
+#define SCD_CMD_START_PERIODIC_MEASUREMENT  0x0010
+#define SCD_CMD_STOP_PERIODIC_MEASUREMENT   0x0104
+#define SCD_CMD_READ_MEASUREMENT            0x0300
+#define SCD_CMD_SET_MEASUREMENT_INTERVAL    0x4600
+#define SCD_CMD_GET_DATA_READY              0x0202
+#define SCD_CMD_SET_TEMPERATURE_OFFSET      0x5403
+#define SCD_CMD_SET_ALTITUDE                0x5102
+
+#define SCD_WORD_LEN     2
+#define SCD_COMMAND_LEN  2
+#define SCD_MAX_BUFFER_WORDS 24
+
+
+/**
+ * scd_i2c_read_words() - read data words from sensor
+ * @data:       Allocated buffer to store the read data.
+ *              The buffer may also have been modified on STATUS_FAIL return.
+ * @data_words: Number of data words to read (without CRC bytes)
+ *
+ * Return:      STATUS_OK on success, an error code otherwise
+ */
+static s16 scd_i2c_read_words(u16 *data, u16 data_words) {
+    s16 ret;
+    u16 i, j;
+    u16 size = data_words * (SCD_WORD_LEN + CRC8_LEN);
+    u16 word_buf[SCD_MAX_BUFFER_WORDS];
+    u8 * const buf8 = (u8 *)word_buf;
+
+    ret = sensirion_i2c_read(SCD_I2C_ADDRESS, buf8, size);
+    if (ret != STATUS_OK)
+        return ret;
+
+    /* check the CRC for each word */
+    for (i = 0, j = 0;
+         i < size;
+         i += SCD_WORD_LEN + CRC8_LEN, j += SCD_WORD_LEN) {
+
+        if (sensirion_common_check_crc(&buf8[i], SCD_WORD_LEN,
+                                       buf8[i + SCD_WORD_LEN]) == STATUS_FAIL) {
+            return STATUS_FAIL;
+        }
+        ((u8 *)data)[j]     = buf8[i];
+        ((u8 *)data)[j + 1] = buf8[i + 1];
+    }
+
+    return STATUS_OK;
+}
+
+
+/**
+ * scd_fill_cmd_send_buf() - create the i2c send buffer for a command and a set
+ *                           of argument words.
+ *                           The output buffer interleaves argument words with
+ *                           their checksums.
+ * @buf:        The generated buffer to send over i2c. Then buffer length must
+ *              be at least SCD_COMMAND_LEN + num_args * (SCD_WORD_LEN +
+ *              CRC8_LEN).
+ * @cmd:        The i2c command to send. It already includes a checksum.
+ * @args:       The arguments to the command. Can be NULL if none.
+ * @num_args:   The number of word arguments in args.
+ */
+static void scd_fill_cmd_send_buf(u8 *buf, u16 cmd, const u16 *args,
+                                  u8 num_args) {
+    u16 word;
+    u8 crc;
+    u8 i;
+    u8 idx = 0;
+
+    buf[idx++] = (u8)((cmd & 0xFF00) >> 8);
+    buf[idx++] = (u8)((cmd & 0x00FF) >> 0);
+
+    for (i = 0; i < num_args; ++i) {
+        word = be16_to_cpu(args[i]);
+        crc = sensirion_common_generate_crc((u8 *)&word, SCD_WORD_LEN);
+
+        buf[idx++] = (u8)((word & 0x00FF) >> 0);
+        buf[idx++] = (u8)((word & 0xFF00) >> 8);
+        buf[idx++] = crc;
+    }
+}
+
+
+/**
+ * scd_i2c_write() - writes to the sensor
+ * @command:    Sensor command
+ *
+ * Return:      STATUS_OK on success, an error code otherwise
+ */
+static s16 scd_i2c_write(u16 command) {
+    u8 buf[SCD_COMMAND_LEN];
+
+    scd_fill_cmd_send_buf(buf, command, NULL, 0);
+    return sensirion_i2c_write(SCD_I2C_ADDRESS, buf, SCD_COMMAND_LEN);
+}
+
+
+/**
+ * scd_i2c_read_words_from_cmd() - reads data words from the sensor after a
+ *                                 command has been issued
+ * @cmd:        Command
+ * @data_words: Allocated buffer to store the read data
+ * @num_words:  Data words to read (without CRC bytes)
+ *
+ * Return:      STATUS_OK on success, an error code otherwise
+ */
+static s16 scd_i2c_read_words_from_cmd(u16 cmd, u16 *data_words,
+                                       u16 num_words) {
+
+    s16 ret = scd_i2c_write(cmd);
+
+    if (ret != STATUS_OK)
+        return ret;
+
+    return scd_i2c_read_words(data_words, num_words);
+}
+
+
+s16 scd_start_periodic_measurement(u16 ambient_pressure_mbar) {
+    const u16 BUF_SIZE = SCD_COMMAND_LEN + SCD_WORD_LEN + CRC8_LEN;
+    u8 buf[BUF_SIZE];
+
+    if (ambient_pressure_mbar && (ambient_pressure_mbar < 700 ||
+                                  ambient_pressure_mbar > 1400)) {
+        /* out of allowable range */
+        return STATUS_FAIL;
+    }
+
+    scd_fill_cmd_send_buf(buf, SCD_CMD_START_PERIODIC_MEASUREMENT,
+                          &ambient_pressure_mbar,
+                          sizeof(ambient_pressure_mbar) / SCD_WORD_LEN);
+
+    return sensirion_i2c_write(SCD_I2C_ADDRESS, buf, BUF_SIZE);
+}
+
+
+s16 scd_stop_periodic_measurement() {
+    return scd_i2c_write(SCD_CMD_STOP_PERIODIC_MEASUREMENT);
+}
+
+
+s16 scd_read_measurement(f32 *co2_ppm, f32 *temperature, f32 *humidity) {
+    s16 ret;
+    u16 word_buf[6]; /* 2 words for each co2, temperature, humidity */
+    union {
+        u32 raw;
+        f32 float32;
+    } tmp;
+
+    ret = scd_i2c_read_words_from_cmd(SCD_CMD_READ_MEASUREMENT, word_buf,
+                                      sizeof(word_buf) / SCD_WORD_LEN);
+    if (ret != STATUS_OK)
+        return ret;
+
+    tmp.raw = (((u32)be16_to_cpu(word_buf[0])) << 16) |
+               ((u32)be16_to_cpu(word_buf[1]));
+    *co2_ppm = tmp.float32;
+
+    tmp.raw = (((u32)be16_to_cpu(word_buf[2])) << 16) |
+               ((u32)be16_to_cpu(word_buf[3]));
+    *temperature = tmp.float32;
+
+    tmp.raw = (((u32)be16_to_cpu(word_buf[4])) << 16) |
+               ((u32)be16_to_cpu(word_buf[5]));
+    *humidity = tmp.float32;
+
+    return STATUS_OK;
+}
+
+
+s16 scd_set_measurement_interval(u16 interval_sec) {
+    const u16 BUF_SIZE = SCD_COMMAND_LEN + SCD_WORD_LEN + CRC8_LEN;
+    u8 buf[BUF_SIZE];
+
+    if (interval_sec < 2 || interval_sec > 1800) {
+        /* out of allowable range */
+        return STATUS_FAIL;
+    }
+
+    scd_fill_cmd_send_buf(buf, SCD_CMD_SET_MEASUREMENT_INTERVAL, &interval_sec,
+                          sizeof(interval_sec) / SCD_WORD_LEN);
+
+    return sensirion_i2c_write(SCD_I2C_ADDRESS, buf, BUF_SIZE);
+}
+
+
+s16 scd_get_data_ready(u16 *data_ready) {
+    return scd_i2c_read_words_from_cmd(SCD_CMD_GET_DATA_READY, data_ready,
+                                       sizeof(*data_ready) / SCD_WORD_LEN);
+}
+
+
+s16 scd_set_temperature_offset(u16 temperature_offset) {
+    const u16 BUF_SIZE = SCD_COMMAND_LEN + SCD_WORD_LEN + CRC8_LEN;
+    u8 buf[BUF_SIZE];
+
+    scd_fill_cmd_send_buf(buf, SCD_CMD_SET_TEMPERATURE_OFFSET,
+                          &temperature_offset,
+                          sizeof(temperature_offset) / SCD_WORD_LEN);
+
+    return sensirion_i2c_write(SCD_I2C_ADDRESS, buf, BUF_SIZE);
+}
+
+
+s16 scd_set_altitude(u16 altitude) {
+    const u16 BUF_SIZE = SCD_COMMAND_LEN + SCD_WORD_LEN + CRC8_LEN;
+    u8 buf[BUF_SIZE];
+
+    scd_fill_cmd_send_buf(buf, SCD_CMD_SET_ALTITUDE, &altitude,
+                          sizeof(altitude) / SCD_WORD_LEN);
+
+    return sensirion_i2c_write(SCD_I2C_ADDRESS, buf, BUF_SIZE);
+}
+
+
+/**
+ * scd_get_driver_version() - Return the driver version
+ * Return:  Driver version string
+ */
+const char *scd_get_driver_version()
+{
+    return SCD_DRV_VERSION_STR;
+}
+
+
+/**
+ * scd_get_configured_address() - returns the configured I2C address
+ *
+ * Return:      u8 I2C address
+ */
+u8 scd_get_configured_address() {
+    return SCD_I2C_ADDRESS;
+}
+
+
+/**
+ * scd_probe() - check if sensor is available
+ *
+ * Return:  STATUS_OK on success, an error code otherwise
+ */
+s16 scd_probe() {
+    u16 data_ready;
+
+    /* Initialize I2C */
+    sensirion_i2c_init();
+
+    /* try to read data-ready state */
+    return scd_get_data_ready(&data_ready);
+}