Linux/INA223: Linux kernel driver & application for INA223

Hello Siva,

We do not have any linux drivers. Although you can most likely find linux code to communicate with the INA223 or other devices online. I found this source code online using a quick and simple search.

code.woboq.org/.../ina2xx.c.html

This is for the INA226, INA219, and others, but all of our digital current shunt monitors are very similar with their I2C communication protocol. Hope this helps.

Sincerely,
Peter Iliya
Current Sensing Applications

Siva,

We have driver code at our website, see link belw. Seems like the same thing compared to what I sent earlier.

www.ti.com/.../ina2xxsw-linux

Sincerely,
Peter Iliya
Current Sensing Applications

Hi Peter,

Thanks for your input. 

I tried to cross compile the same code. But i get  the following error

drivers/hwmon/ina2xx.c: In function ‘ina2xx_probe’:

drivers/hwmon/ina2xx.c:447:27: error: implicit declaration of function ‘of_device_get_match_data’; did you mean ‘of_device_get_modalias’? [-Werror=implicit-function-declaration]
chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);

If you are aware of this error earlier. Please do let me know in first place.

Looks like needs some modification in the code of adding a header or so..

Thanks,

Siva

 

Actually, the code that you provided earlier through google search doesn't support the device tress
But the code provided in the latest post supports the device tress.
My linux kernel v4 is based on device tress to detect the devices.

This doesn't support device tress

Getting the compilation errors !!!
drivers/hwmon/ina2xx.c: In function ‘ina2xx_probe’:

drivers/hwmon/ina2xx.c:447:27: error: implicit declaration of function ‘of_device_get_match_data’; did you mean ‘of_device_get_modalias’? [-Werror=implicit-function-declaration]
chip = (enum ina2xx_ids)of_device_get_match_data(&client->dev);

Siva,

I am sorry to read of your problem. I am no linux expert, but when I look through the library "<linux/of_device.h>" online I do not see a function called "of_device_get_match_data". Maybe try replacing this function with following options until the code compiles:

of_device_get_modalias
of_driver_match_device

Additionally, this driver source code was not made to include INA233, but INA233 I2C is very similar to our other devices (INA226, INA219, etc) so there may be some minor modification needed for the source code like making sure register locations are correct and adding INA233 to the "MODULE_DEVICE_TABLE".

I hope this helps.
Sincerely,
Peter Iliya
Current Sensing Applications

Hi Peter,

Thanks for your support.

Now, I Succesfully compile the driver with proper changes to device_id  and the module inserted succesfully. 

But I donot see the corresponding folder created under /sys/class/hwmon/

In my case, hwmon0 is the temperature zone. I can only see that folder.

Am I in right path in usage of this driver ?

I am not sure how to read the register values or the voltage/current values by using the driver. 

I am able to see the device with I2C address 0x41 when I probe with i2cdetect -y 3

Let me know  if you need more inputs, I can share the code for your reference.

Looking forward for your help

Thanks,

Siva

Thanks,

Siva

Hi Siva,

What folder are you looking for in /sys/class/hwmon? I would recommend to try sending individual read/writing commands similar to your "i2cdetect -y 3" over a command-line-interface. Whatever I2C library you are using must have i2c read and write commands.

Best,
Peter Iliya
Current Sensing Applications

Hi Peter,

I am not sure about the register address(configuration register) to read from i2cget

The i2cdump gives the following values
root@imx7d-pcm-061-2111101e:~# i2cdump 3 0x41 b
WARNING! This program can confuse your I2C bus, cause data loss and worse!
I will probe file /dev/i2c-3, address 0x41, mode byte
Continue? [Y/n] y
0 1 2 3 4 5 6 7 8 9 a b c d e f 0123456789abcdef
00: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
10: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
20: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
30: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
40: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
50: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
60: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
70: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
80: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
90: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
a0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
b0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
c0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
d0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
e0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..
f0: 00 00 00 00 05 1e 00 00 00 00 00 00 05 1e 00 00 ....??......??..

I am not able to find the register address from the data sheet.
So could you please provide me the configuration register address then i will read that address from i2cget.

Basic question if i am able to handle the device from i2ctools in userspace then what's the purpose of this INA2XX driver here ?


Thanks,
Siva

Hey Siva,

The configuration register address is 0x00. This is because this is the only register in the device. You will write to this register (0x00) in order to set gains for shunt and bus voltage measurements and to set the output mode settings (Table 1 in datasheet). Since there is only one register in the device, once the pointer is set a 0x00, then you can obtain measurements with 3-byte read commands as shown with Figure 40.

The i2c-tools library in Linux provides a basic library to communicate with devices over the command line. The Linux driver is there to provide device-specific functions in the memory of whatever your system may be. This will make the writing firmware easier.

Sincerely,
Peter Iliya
Current Sensing Applications

Hi Peter,

Now I am able to see the ina223 device under

# cat /sys/class/hwmon/hwmon0/name

ina223
# cat /sys/class/hwmon/hwmon0/curr1_input
352
# cat /sys/class/hwmon/hwmon0/in0_input
0
# cat /sys/class/hwmon/hwmon0/name
ina223
~# cat /sys/class/hwmon/hwmon0/power1_input
0

in the dmesg, I can see the 

~# dmesg | grep ina223
[ 0.246615] i2c i2c-3: of_i2c: register /soc/aips-bus@30800000/i2c@30a50000/ina223@41
[ 0.246772] i2c i2c-3: client [ina223] registered with bus id 3-0041
[ 1.871869] ina223 3-0041: probe
[ 1.872693] ina223 3-0041: power monitor ina223 (Rshunt = 10000 uOhm)
[ 1.877880] i2c-core: driver [ina223] registered
[ 4.551582] ina223 3-0041: uevent
[ 4.635567] ina223 3-0041: uevent
[ 4.635820] ina223 3-0041: uevent
[ 4.636053] ina223 3-0041: uevent

Now at this stage, I am not sure how to read the current & voltage readings from the driver populated sys filesystem. Could you please assist.

How can i change the configuration register value from the sysfs using the ina223 driver.

Please provide me your inputs on this topic. Looking forward for your response

Best Regards,

Siva

Hi Andrew,

Thanks for the inputs. I am using the linux driver and lmsensor application to read the values. Below is the output

# sensors

ina223-i2c-0-41
Adapter: 30a20000.i2c
in0: +0.00 V
in1: +0.00 V
power1: 0.00 W
curr1: +1.21 A

The linux driver is for ina226. But the device on the board is ina223 . I am not sure whether i need to do any modifications in the driver to get the correct values.

The shunt resistor value is 50000 microohms

From the above output. It shows 0 values for in0, in1 & power1. Could you please provide your inputs where I am missing. 

Thanking you in advance for your quick response.

Best Regards,

Siva

I am not using the i2ctools to access the device rather I am using the linux driver which takes cares of the samples.

The INA223 is not compatible with the INA226 driver. The INA223 cannot output the voltage or current over I2C as, unlike the INA226, it has no internal ADC. It does not matter what driver or tools you use the device will not give you the current or voltage over I2C. If you need to read the current or voltage over I2C use the INA226.

Andrew

Hi Andrew,

From the earlier posts of this thread its suggested that we can read this device through simple i2c tools and also with the linux driver. 

But from the latest posts from you gives that we are not in right direction to access this device.

At this stage if i want to progress with INA223 device to measure the current & Voltage readings. Do I need to connect the analog output to any ADC ?

If so could you please point to some application note specific to INA223 device. 

Thanking you in advance for your help. 

Best Regards,

Siva

Hi Siva,

Yes is does look like there was some confusion in the early thread in regards to the driver compatibility.

You are correct in that you will need to connect the analog output to an ADC. Which one you chose is depedent on your application, for instance if a lot of application processors and micro-controllers have one built in that you can attach to and read from there. If you do not have an ADC available then using an external dedicated one is probably more trouble that it is worth and you should just use the INA226 which has one built in, they are only a couple cents more.

Thanks,
Andrew