How to add new i2c based sensor device to ncs\v1.3.0\zephyr\drivers\sensor

[ChandraSR K]

How to add new i2c based sensor device to ncs\v1.3.0\zephyr\drivers\sensor.

Can you suggest any tutorial to do so as i want to use sensor subsystem which in turn uses i2c driver.

Thanks

Chandra

[Simon]

I tried to look around but could not find any such guides. However I have provided an answer for this earlier, take a look at it here.

Down below I've provided a short guide how to add a custom sensor to Zephyr

• Start with a senor most similar to your sensor and use it as a reference
• Create a binding in zephyr\dts\bindings\sensor\<compatible string>.yaml
  • E.g. copy zephyr\dts\bindings\sensor\adi,adxl362.yaml, change the name and modify it according to your sensor
• Create the driver in zephyr\drivers\sensor
  • E.g. copy zephyr\drivers\sensor\adxl362, change the name and modify it according to your sensor
• In \zephyr\drivers\sensor\CMakeLists.txt add the following line

add_subdirectory_ifdef(CONFIG_<name of sensor> <sensor directory>)

• In \zephyr\drivers\sensor\Kconfig add the following line

source "drivers/sensor/<sensor directory>/Kconfig"

• Create a sample in zephyr\samples\sensor, to test if it works as expected

Best regards,

Simon

[ChandraSR K]

Hi

Thanks for the info and this is verymuch useful.

I have followed all the steps.

in  the sensor  c file, i have some like below:

#if defined(DT_VENDOR_CHIPNAME_BUS_SPI)
    chip_spi_init(dev);
#elif defined(DT_VENDOR_CHIPNAME_BUS_I2C)
    chip_i2c_init(dev);
#else
    #error "BUS MACRO NOT DEFINED IN DTS"
#endif

These macros are not getting defined. This is some things to do with zephyr system, but any pointers that would greatly help to proceed.

[ChandraSR K]

Hi

zephyr\dts\bindings\sensor\<compatible string>.yaml  -----> Contains tdk,icm20948-i2c.yaml , tdk,icm20948-spi.yaml

tdk,icm20948-spi.yaml

description: |
  ICM-20948 Nine Axis I2C/SPI MEMS
  This is a representation of the ICM-20948 Three Axis High-g I2C/SPI accelerometer

compatible: "tdk,icm20948"

include: spi-device.yaml

#inherits:
#  !include i2c-device.yaml

properties:
    int1-gpios:
      type: phandle-array
      required: false
      description: |
        The INT1 signal defaults to active high as produced by the
        sensor.  The property value should ensure the flags properly
        describe the signal that is presented to the driver.

tdk,icm20948-i2c.yaml

description: |
  ICM-20948 Nine Axis I2C/SPI MEMS
  This is a representation of the ICM-20948 Three Axis High-g I2C/SPI accelerometer

compatible: "tdk,icm20948"

include: i2c-device.yaml

#inherits:
#  !include i2c-device.yaml

properties:
    int1-gpios:
      type: phandle-array
      required: false
      description: |
        The INT1 signal defaults to active high as produced by the
        sensor.  The property value should ensure the flags properly
        describe the signal that is presented to the driver.

zephyr\samples\sensor\<your sensor>\boards\<board name>.overlay --> I donot have this file. but I have overlay file in my application:nrf9160dk_nrf9160ns.overlay

/* 	uart0 reserved for debug prints
	uart1 reserved for modem traces
*/

/*		status = "okay"; disable usart2 to use I2C_2 for ICM20948 */

&uart2 {
	status = "disabled";
};

&i2c2 {
	compatible = "nordic,nrf-twim";
	status = "okay";
	sda-pin = <11>;
	scl-pin = <12>;
	clock-frequency = <I2C_BITRATE_STANDARD>; 

        /* The I2C address could be one of two, here 0x68 is assumed */
	icm20948@68 {
		compatible = "tdk,icm20948";
		reg = <0x68>;
		label = "ICM20948";
	};
};

[Simon]

Try to do this:

// You need this in order for DT_ANY_INST_ON_BUS_STATUS_OKAY to work
#define DT_DRV_COMPAT tdk_icm20948 

// code
// code
// code


#if DT_ANY_INST_ON_BUS_STATUS_OKAY(spi)
    //Do stuff
#elif DT_ANY_INST_ON_BUS_STATUS_OKAY(i2c)
    //Do stuff
#else
#error "BUS MACRO NOT DEFINED IN DTS"
#endif

Take a look at the zephyr/include/devicetree.h for more information about the macro DT_ANY_INST_ON_BUS_STATUS_OKAY.

Best regards,

Simon

[ChandraSR K]

This part i got it. it works for me early this week.

but i have following code in driver.

#if defined(DT_TDK_ICM20948_BUS_SPI)
    icm20948_spi_init(dev);
#elif defined(DT_TDK_ICM20948_BUS_I2C)
    icm20948_i2c_init(dev);
#else
    #error "BUS MACRO NOT DEFINED IN DTS"
#endif

DT_TDK_ICM20948_BUS_SPI, DT_TDK_ICM20948_BUS_I2C: what are these?

I just repalced these with DT_ANY_INST_ON_BUS_STATUS_OKAY(spi) and DT_ANY_INST_ON_BUS_STATUS_OKAY(I2C).

How to enable these macros : DT_TDK_ICM20948_BUS_SPI ,DT_TDK_ICM20948_BUS_I2C? we can just ignore.

[Simon]

I'm not sure where you get those DTS defines from, and why you think those should be generated. Could you give me some pointers?

I think you should be fine using DT_ANY_INST_ON_BUS_STATUS_OKAY and DT_ANY_INST_ON_BUS_STATUS_OKAY, that is what all the other sensor drives in NCS v1.3.0 are using:

https://github.com/nrfconnect/sdk-zephyr/blob/v2.3.0-rc1-ncs2/drivers/sensor/iis3dhhc/iis3dhhc.c#L235

https://github.com/nrfconnect/sdk-zephyr/blob/v2.3.0-rc1-ncs1/drivers/sensor/lps22hh/lps22hh.c#L210-L225

https://github.com/nrfconnect/sdk-zephyr/blob/v2.3.0-rc1-ncs1/drivers/sensor/stts751/stts751.c#L207

https://github.com/nrfconnect/sdk-zephyr/blob/v2.3.0-rc1-ncs1/drivers/sensor/lsm6dso/lsm6dso.c#L755

Best regards,

Simon

[ChandraSR K]

OK thanks for all the clarifications. Thank you very much.

I could succeed with DT_ANY_INST_ON_BUS_STATUS_OKAY , could communicate with sensor.

Need to improve sensor driver.

for now I am going to close this ticket.

Thanks
Chandra