[lm-sensors] Ina219 with linux kernel driver

[lm-sensors] Ina219 with linux kernel driver

[Pierre Kancir]

Hi,

I am trying to use ina219 sensor (http://www.adafruit.com/products/904)
with linux kernel driver on beaglebone black.

I want to use device tree overlay to use the sensor. I follow kernel
indications (
http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/i2c/ina2xx.txt)
and the sensor works as expected.

But adafruit board use 0.1ohms and default driver value for shunt-resistor
is 10mOhms so return value are wrong.

I want to modify value in device tree as indicated

ina219@40 {
          compatible = "ti,ina219";
          reg = <0x40>;
          shunt-resistor = <100000>;
 };

but changing shunt-resistor value does nothing. The sensor is always create
with 10mOhms value

ina2xx 1-0040: power monitor ina219 (Rshunt = 10000 uOhm)

How can i change the shunt-resistor value to get the proper return?

thanks,

Pierre
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Re: [lm-sensors] Ina219 with linux kernel driver

[Guenter Roeck]

On 04/08/2014 06:29 AM, Pierre Kancir wrote:
> Hi,
>
> I am trying to use ina219 sensor (http://www.adafruit.com/products/904)
> with linux kernel driver on beaglebone black.
>
> I want to use device tree overlay to use the sensor. I follow kernel
> indications (
> http://lxr.free-electrons.com/source/Documentation/devicetree/bindings/i2c/ina2xx.txt)
> and the sensor works as expected.
>
> But adafruit board use 0.1ohms and default driver value for shunt-resistor
> is 10mOhms so return value are wrong.
>
> I want to modify value in device tree as indicated
>
> ina219@40 {
>            compatible = "ti,ina219";
>            reg = <0x40>;
>            shunt-resistor = <100000>;
>   };
>
> but changing shunt-resistor value does nothing. The sensor is always create
> with 10mOhms value
>
> ina2xx 1-0040: power monitor ina219 (Rshunt = 10000 uOhm)
>
> How can i change the shunt-resistor value to get the proper return?
>

Good question. This functionality was added mid-2013. What is your kernel version ?

Guenter


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Re: [lm-sensors] Ina219 with linux kernel driver

[Pierre Kancir]

Hi,

I am using beaglebone black default kernel, here is its informations :
Linux arm 3.8.13-bone40 #1 SMP Fri Jan 31 10:36:05 UTC 2014 armv7l
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=13.10
DISTRIB_CODENAME=saucy
DISTRIB_DESCRIPTION="Ubuntu 13.10"

I modify devicetree as follow : in /boot/dtbs/

# generate the dts from the dtb
dtc -I dtb -O dts -o am335x-boneblack.dts am335x-boneblack.dtb

# modify the dts with a text editor  :

i add after cape_eeprom3@57 ( in i2c3 lines i2c@4819c000)

ina219@40 {
          compatible = "ti,ina219";
          reg = <0x40>;
          shunt-resistor = <100000>;
 };

# generate the dtb from the modified dts
dtc -I dts -O dtb -o am335x-boneblack.dtb am335x-boneblack.dts

#reboot the beaglebone black to load the new device tree

#use sensors
ubuntu@arm:~$ sensors
am335x-bandgap-isa-0000
Adapter: ISA adapter
temp1:        +53.0°C

ina219-i2c-1-40
Adapter: OMAP I2C adapter
in0:          +0.03 V
in1:          +4.94 V
power1:       12.74 W <- wrong value since not the good shunt resistor
value...
curr1:        +2.56 A  <- wrong value since not the good shunt resistor
value..



 *Kancir Pierre*
pierre.kancir@gmail.com
LinkedIn <http://www.linkedin.com/pub/pierre-kancir/4b/a1a/32a> |
Viadeo<http://www.viadeo.com/fr/profile/pierre.kancir>


2014-04-08 15:50 GMT+02:00 Guenter Roeck <linux@roeck-us.net>:

> On 04/08/2014 06:29 AM, Pierre Kancir wrote:
>
>> Hi,
>>
>> I am trying to use ina219 sensor (http://www.adafruit.com/products/904)
>> with linux kernel driver on beaglebone black.
>>
>> I want to use device tree overlay to use the sensor. I follow kernel
>> indications (
>> http://lxr.free-electrons.com/source/Documentation/
>> devicetree/bindings/i2c/ina2xx.txt)
>> and the sensor works as expected.
>>
>> But adafruit board use 0.1ohms and default driver value for shunt-resistor
>> is 10mOhms so return value are wrong.
>>
>> I want to modify value in device tree as indicated
>>
>> ina219@40 {
>>            compatible = "ti,ina219";
>>            reg = <0x40>;
>>            shunt-resistor = <100000>;
>>   };
>>
>> but changing shunt-resistor value does nothing. The sensor is always
>> create
>> with 10mOhms value
>>
>> ina2xx 1-0040: power monitor ina219 (Rshunt = 10000 uOhm)
>>
>> How can i change the shunt-resistor value to get the proper return?
>>
>>
> Good question. This functionality was added mid-2013. What is your kernel
> version ?
>
> Guenter
>
>
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Re: [lm-sensors] Ina219 with linux kernel driver

[Guenter Roeck]

On Tue, Apr 08, 2014 at 04:13:00PM +0200, Pierre Kancir wrote:
> Hi,
> 
> I am using beaglebone black default kernel, here is its informations :
> Linux arm 3.8.13-bone40 #1 SMP Fri Jan 31 10:36:05 UTC 2014 armv7l
> DISTRIB_ID=Ubuntu
> DISTRIB_RELEASE\x13.10
> DISTRIB_CODENAME=saucy
> DISTRIB_DESCRIPTION="Ubuntu 13.10"
> 
Devicetree support was only added to the ina2xx driver with
kernel version 3.11. You would have to back-port commit 31e7ad7
into your kernel to get it.

Guenter

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Re: [lm-sensors] Ina219 with linux kernel driver

[Pierre Kancir]

ok! thank you!

Is there another way to use ina2xx driver without devicetree?


 *Kancir Pierre*
pierre.kancir@gmail.com
LinkedIn <http://www.linkedin.com/pub/pierre-kancir/4b/a1a/32a> |
Viadeo<http://www.viadeo.com/fr/profile/pierre.kancir>


2014-04-08 17:08 GMT+02:00 Guenter Roeck <linux@roeck-us.net>:

> On Tue, Apr 08, 2014 at 04:13:00PM +0200, Pierre Kancir wrote:
> > Hi,
> >
> > I am using beaglebone black default kernel, here is its informations :
> > Linux arm 3.8.13-bone40 #1 SMP Fri Jan 31 10:36:05 UTC 2014 armv7l
> > DISTRIB_ID=Ubuntu
> > DISTRIB_RELEASE\x13.10
> > DISTRIB_CODENAME=saucy
> > DISTRIB_DESCRIPTION="Ubuntu 13.10"
> >
> Devicetree support was only added to the ina2xx driver with
> kernel version 3.11. You would have to back-port commit 31e7ad7
> into your kernel to get it.
>
> Guenter
>
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Re: [lm-sensors] Ina219 with linux kernel driver

[Guenter Roeck]

On Tue, Apr 08, 2014 at 05:57:03PM +0200, Pierre Kancir wrote:
> ok! thank you!
> 
Please don't top-post.

> Is there another way to use ina2xx driver without devicetree?
> 
You should be able to use it as-is and correct the reported values in
the sensors configuration file. Another option would be to provide
the shunt resistor value with platform data. Since that would mean
patching your kernel, it might be easier to back-port the missing patch.

Guenter

> 
>  *Kancir Pierre*
> pierre.kancir@gmail.com
> LinkedIn <http://www.linkedin.com/pub/pierre-kancir/4b/a1a/32a> |
> Viadeo<http://www.viadeo.com/fr/profile/pierre.kancir>
> 
> 
> 2014-04-08 17:08 GMT+02:00 Guenter Roeck <linux@roeck-us.net>:
> 
> > On Tue, Apr 08, 2014 at 04:13:00PM +0200, Pierre Kancir wrote:
> > > Hi,
> > >
> > > I am using beaglebone black default kernel, here is its informations :
> > > Linux arm 3.8.13-bone40 #1 SMP Fri Jan 31 10:36:05 UTC 2014 armv7l
> > > DISTRIB_ID=Ubuntu
> > > DISTRIB_RELEASE\x13.10
> > > DISTRIB_CODENAME=saucy
> > > DISTRIB_DESCRIPTION="Ubuntu 13.10"
> > >
> > Devicetree support was only added to the ina2xx driver with
> > kernel version 3.11. You would have to back-port commit 31e7ad7
> > into your kernel to get it.
> >
> > Guenter
> >

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