Add initial generated driver

.clang-format

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+---
+Language: Cpp
+BasedOnStyle: LLVM
+IndentWidth: 4
+AlignAfterOpenBracket: Align
+AllowShortBlocksOnASingleLine: false
+AllowShortCaseLabelsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: false
+IndentCaseLabels: true
+SpacesBeforeTrailingComments: 2
+PointerAlignment: Left
+AlignEscapedNewlines: Left
+ForEachMacros: ['TEST_GROUP', 'TEST']
+...

.gitignore

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+/scd4x_i2c_example_usage

.gitlab-ci.yml

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+stages:
+  - validate
+  - build
+  - test
+
+syntax_check:
+  stage: validate
+  image:
+      name: registry.gitlab.sensirion.lokal/mso-sw/drivers/docker-driver-generator:0.1.0
+  tags: [linux, docker]
+  script:
+    - find . -type f -iregex ".*\.\(c\|h\|cpp\|ino\)" -exec clang-format-6.0 -i -style=file {} \; && git diff --exit-code
+
+
+cppcheck:
+  stage: validate
+  image:
+      name: registry.gitlab.sensirion.lokal/mso-sw/drivers/docker-driver-generator:0.1.0
+  tags: [linux, docker]
+  script:
+    - cppcheck --std=c89 --language=c --error-exitcode=1 --enable=warning,style,performance,portability -i sample-implementations/ .
+
+build:
+  stage: build
+  image:
+    name: sensirion/embedded-ci:2.3.0
+  tags: [linux, docker]
+  script:
+    - make
+
+test:
+  stage: test
+  image: registry.gitlab.sensirion.lokal/sensirion/docker/docker-rpi-testbed:1.2.0
+  tags: [mso-sw-testbed-2]
+  script:
+    - git clone -b 3.0.0 https://gitlab-ci-token:${CI_JOB_TOKEN}@gitlab/MSO-SW/drivers/testbed/i2c-mux-testbed.git
+    - cd tests/
+    - make test

LICENSE

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+BSD 3-Clause License
+
+Copyright (c) 2021, 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:
+
+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 of the copyright holder 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.

Makefile

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+common_sources = sensirion_config.h sensirion_common.h sensirion_common.c
+i2c_sources = sensirion_i2c_hal.h sensirion_i2c.h sensirion_i2c.c
+scd4x_sources = scd4x_i2c.h scd4x_i2c.c
+
+i2c_implementation ?= sensirion_i2c_hal.c
+
+CFLAGS = -Os -Wall -fstrict-aliasing -Wstrict-aliasing=1 -Wsign-conversion -fPIC -I.
+
+ifdef CI
+    CFLAGS += -Werror
+endif
+
+.PHONY: all clean
+
+all: scd4x_i2c_example_usage
+
+scd4x_i2c_example_usage: clean
+	$(CC) $(CFLAGS) -o $@  ${scd4x_sources} ${i2c_sources} \
+		${i2c_implementation} ${common_sources} scd4x_i2c_example_usage.c
+
+clean:
+	$(RM) scd4x_i2c_example_usage

README.md

@@ -1,3 +1,99 @@
-# embedded-scd4x
+# Getting started
 
-Embedded driver for the SCD4x sensor family.
+To get the embedded driver for your Sensirion Sensor working there are now
+only a few steps missing. These steps are needed since our driver is made
+in a way that it is possible to run it on different hardware platforms.
+So we need to adjust two files according to your platform.
+The first one is `sensirion_i2c_hal.c`.
+This file contains the implementation of the sensor communication
+(how to send requests to it). Therefore, how this is done depends on your
+hardware platform. For this reason we can't provide just one version of this
+code. The default version of this file is an unimplemented template, where you
+can implement it yourself. For some common platforms we provide an
+implementation in the `sample-implementations` folder.
+If you are using for example a Linux based platform like Raspberry Pi
+you can just replace the unimplemented HAL template with the provided
+implementation in `sample-implementations/linux_user_space/` by replacing
+the template with the actual implementation:
+
+```
+cp sample-implementations/linux_user_space/sensirion_i2c_hal.c ./
+```
+
+If you are on a different platform just use one of the other sample
+implementations or implement `sensirion_i2c_hal.c` yourself.
+The second file is `sensirion_config.h`.
+If you are on a Linux based platform you can skip this part since
+everything is already correctly setup for you.
+Otherwise you need to check if the libraries `<stdint.h>` and
+`<stdlib.h>` are provided by your toolchain, compiler or are available
+on your system. If you have no idea on how to do that you can skip this
+step for now and come back when you get errors including these names when
+trying to compile your driver.
+The features we use out of those libraries is standard integer sizes
+from `<stdint.h>` and `NULL` from `<stdlib.h>`. If they are not available
+you need to specify the following integer types yourself:
+* `int64_t` = signed 64bit integer
+* `uint64_t` = unsigned 64bit integer
+* `int32_t` = signed 32bit integer
+* `uint32_t` = unsigned 32bit integer
+* `int16_t` = signed 16bit integer
+* `uint16_t` = unsigned 16bit integer
+* `int8_t` = signed 8bit integer
+* `uint8_t` = unsigned 8bit integer
+
+In addition to that you will need to specify `NULL`.
+For both we have a commented template where just need to fill in
+your system specific values.
+Now we are ready to compile and run the example usage for your sensor.
+This is again specific to your platform. Since this step can vary quite
+a lot we here just explain how to do it on Linux based platforms. In
+general you now just need to take all the `.c` and `.h` files directly in
+this folder pass them to your favorite C compiler and run the resulting
+binary. For Linux systems this is done by following these steps:
+
+1. Open up a terminal.
+2. Navigate the directory where this README is located.
+3. Run `make`, this compiles all the code here to one binary.
+4. Run `./[SENSORNAME]_example_usage`, where you replace `[SENSORNAME]`
+   with your sensors name. This will run your newly compiled binary.
+5. Now you should see the first measurement values appear in your terminal.
+   As a next step you can adjust the example usage file or write your own
+   main function to use the sensor.
+
+We hope this tutorial was helpful and you are now able to use the embedded drivers
+to communicate with your Sensirion sensor.
+
+# Background
+
+## Files
+
+### sensirion\_i2c.[ch]
+
+In these files you can find the implementation of the I2C protocol used by Sensirion
+sensors. The functions in these files are used by the embedded driver to build the
+correct frame out of data to be sent to the sensor or receive a frame of data from
+the sensor and convert is back to data readable by your machine. The functions in
+here calculate and check CRCs, reorder bytes for different byte orders and build the
+correct formatted frame for your sensor.
+
+### sensirion\_i2c\_hal.[ch]
+
+In these files you can find the implementation of the hardware abstraction layer used
+by Sensirion I2C embedded drivers. This part of the code is specific to the underlying
+hardware platform, therefore multiple implementations exist. We also provide an
+unimplemented template for the user to implement.
+In the `sample-implementations/` folder we provide implementations for the most common
+platforms.
+
+### sensirion\_config.h
+
+In this file we keep all the included libraries for our drivers and global defines.
+Next to `sensirion_i2c_hal.c` *it's the only file you should need to edit to get your
+driver working.*
+
+### sensirion\_common.[ch]
+
+In these files you can find some helper functions used by Sensirion embedded drivers.
+It mostly contains byte order conversions for different variable types. These functions
+are also used by the UART embedded drivers therefore they are keep in their own file.

sample-implementations/Atmel_SAMD2_series/sensirion_i2c_hal.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 <delay.h>
+#include <i2c_master.h>
+
+#include "sensirion_common.h"
+#include "sensirion_config.h"
+#include "sensirion_i2c_hal.h"
+
+struct i2c_master_module i2c_master_instance;
+
+void sensirion_i2c_hal_init(void) {
+    /* initialize config structure and software module */
+    struct i2c_master_config config_i2c_master;
+    i2c_master_get_config_defaults(&config_i2c_master);
+
+    /* change buffer timeout to something longer */
+    config_i2c_master.buffer_timeout = 10000;
+
+    /* initialize and enable device with config. */
+    i2c_master_init(&i2c_master_instance, SERCOM2, &config_i2c_master);
+    i2c_master_enable(&i2c_master_instance);
+}
+
+/**
+ * Release all resources initialized by sensirion_i2c_hal_init().
+ */
+void sensirion_i2c_hal_free(void) {
+}
+
+int8_t sensirion_i2c_hal_read(uint8_t address, uint8_t* data, uint16_t count) {
+    struct i2c_master_packet packet = {
+        .address = address,
+        .data_length = count,
+        .data = (uint8_t*)data,
+        .ten_bit_address = false,
+        .high_speed = false,
+    };
+    return i2c_master_read_packet_wait(&i2c_master_instance, &packet);
+}
+
+int8_t sensirion_i2c_hal_write(uint8_t address, const uint8_t* data,
+                               uint16_t count) {
+    struct i2c_master_packet packet = {
+        .address = address,
+        .data_length = count,
+        .data = (uint8_t*)data,
+        .ten_bit_address = false,
+        .high_speed = false,
+    };
+    return i2c_master_write_packet_wait_no_stop(&i2c_master_instance, &packet);
+}
+
+void sensirion_i2c_hal_sleep_usec(uint32_t useconds) {
+    delay_us(useconds);
+}

sample-implementations/GPIO_bit_banging/README.md

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+# GPIO based Software I2C
+
+This implementation of the I2C HAL uses bit banging on GPIOs to run
+the I2C communication. It is different from other sample-implementations.
+It uses an additional pair of `.c` and `.h` file to make the implementation
+generic, in a way that GPIO bitbanging can be performed on any system providing
+access to GPIOs. Note that in this case the pull-up resistors in the electric
+circuit are still needed, or need to be enabled manually if your microprocessor
+provides this option. These files are called `sensirion_i2c_gpio.[ch]`.
+Similar to the I2C HAL, we provide an unimplemented template in this  in this
+folder to implement yourself for your platform and sample implementations in the
+so called folder.
+
+## Getting started
+
+To use this I2C HAL copy `sensirion_i2c_hal.c` and `sensirion_i2c_gpio.h`
+from this folder to the main folder of your driver. Then either choose a
+sample implementation or implement `sensirion_i2c_gpio.c` and copy
+it to the main driver folder as well.