Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-08 Thread Laxman Dewangan 


On Wednesday 08 June 2016 08:34 PM, Andrew F. Davis wrote:

On 06/07/2016 05:30 PM, Guenter Roeck wrote:

On Fri, Jun 03, 2016 at 10:17:55AM -0500, Andrew F. Davis wrote:

On 06/03/2016 09:14 AM, Laxman Dewangan wrote:

On Friday 03 June 2016 06:59 PM, Guenter Roeck wrote:

On 06/03/2016 03:06 AM, Jonathan Cameron wrote:

On 01/06/16 13:34, Laxman Dewangan wrote:

The INA3221 is a three-channel, high-side current and bus voltage
monitor
with an I2C interface from Texas Instruments. The INA3221 monitors both
shunt voltage drops and bus supply voltages in addition to having
programmable conversion times and averaging modes for these signals.
The INA3221 offers both critical and warning alerts to detect multiple
programmable out-of-range conditions for each channel.

Add support for INA3221 SW driver via IIO ADC interface. The device is
register as iio-device and provides interface for voltage/current
and power
monitor. Also provide interface for setting oneshot/continuous mode and
critical/warning threshold for the shunt voltage drop.

Signed-off-by: Laxman Dewangan 

Hi Laxman,

As ever with any driver lying on the border of IIO and hwmon, please
include
a short justification of why you need an IIO driver and also cc the
hwmon list + maintainers. (cc'd on this reply).

I simply won't take a driver where the hwmon maintainers aren't happy.
As it stands I'm not seeing obvious reasons in the code for why this
should be an IIO device.


Me not either.

I have a hwmon driver for the same chip pending from Andrew Davis (TI)
which I am just about to accept. We had directed Andrew back in April
to write a hwmon driver for the chip, which he did.


Thanks Guenter,  I found the series

[PATCH v2 0/2] Add support for INA3221 Triple Current/Voltage Monitors
Looks fine to me. I can use the hwmon.


If you search even further back you can see I originally went with an
IIO driver as well, comparing the IIO and hwmon version for the simple
use cases I needed the hwmod version turned out much simpler, so it was
probably the right framework for now.


However, some of the stuff from my patch are not there which I will add
later once original patch applied:
- Dynamic mode changes for continuous and one-shot from sysfs.
- In one shot, when try to read voltage data, do conversion and then read.


My attempt is rather minimal, to be honest I like your stab at this
driver better in some ways, especially relating to DT putting each
channel in its own node with labels, I think this is a bit more clean
and will be more extendable if/when new multi-channel monitor chips are
made.


Not sure whether exporting the following will help or not. Can you
please confirm?
- Oversampling time i.e. average sample
- conversion time for bus voltage and shunt voltage if default is not
suited for system.



These can always be added as needed, but the DT changes are not as easy.
I would like it if this got in this cycle but if you think something
will be needed to help your improvements, that can not be added
incrementally, it would probably be best to get them into the initial DT
binding doc now.


Andrew,

with this, the hwmon driver is pretty much on hold. What do you want me to do ?
Should I wait for DT updates ?


If Laxman would like to commit to making these changes I do not problem
waiting a bit to get this right the first time.

If we don't hear back soon then I'd just take it as is and anything
needing to be fixed can be later.




I will be able to post the patch tomorrow.
I think this series can be applied and then on top of it, I will post 
the dt changes and other my changes.


As this is new driver and no one using now, it will be fine to have dt 
changes if everything complete in one cycle.


I will work from the tree on which this applied to post my patches.

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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-08 Thread Andrew F. Davis 
On 06/07/2016 05:30 PM, Guenter Roeck wrote:
> On Fri, Jun 03, 2016 at 10:17:55AM -0500, Andrew F. Davis wrote:
>> On 06/03/2016 09:14 AM, Laxman Dewangan wrote:
>>>
>>> On Friday 03 June 2016 06:59 PM, Guenter Roeck wrote:
 On 06/03/2016 03:06 AM, Jonathan Cameron wrote:
> On 01/06/16 13:34, Laxman Dewangan wrote:
>> The INA3221 is a three-channel, high-side current and bus voltage
>> monitor
>> with an I2C interface from Texas Instruments. The INA3221 monitors both
>> shunt voltage drops and bus supply voltages in addition to having
>> programmable conversion times and averaging modes for these signals.
>> The INA3221 offers both critical and warning alerts to detect multiple
>> programmable out-of-range conditions for each channel.
>>
>> Add support for INA3221 SW driver via IIO ADC interface. The device is
>> register as iio-device and provides interface for voltage/current
>> and power
>> monitor. Also provide interface for setting oneshot/continuous mode and
>> critical/warning threshold for the shunt voltage drop.
>>
>> Signed-off-by: Laxman Dewangan 
> Hi Laxman,
>
> As ever with any driver lying on the border of IIO and hwmon, please
> include
> a short justification of why you need an IIO driver and also cc the
> hwmon list + maintainers. (cc'd on this reply).
>
> I simply won't take a driver where the hwmon maintainers aren't happy.
> As it stands I'm not seeing obvious reasons in the code for why this
> should be an IIO device.
>

 Me not either.

 I have a hwmon driver for the same chip pending from Andrew Davis (TI)
 which I am just about to accept. We had directed Andrew back in April
 to write a hwmon driver for the chip, which he did.

>>>
>>> Thanks Guenter,  I found the series
>>>
>>> [PATCH v2 0/2] Add support for INA3221 Triple Current/Voltage Monitors
>>> Looks fine to me. I can use the hwmon.
>>>
>>
>> If you search even further back you can see I originally went with an
>> IIO driver as well, comparing the IIO and hwmon version for the simple
>> use cases I needed the hwmod version turned out much simpler, so it was
>> probably the right framework for now.
>>
>>>
>>> However, some of the stuff from my patch are not there which I will add
>>> later once original patch applied:
>>> - Dynamic mode changes for continuous and one-shot from sysfs.
>>> - In one shot, when try to read voltage data, do conversion and then read.
>>>
>>
>> My attempt is rather minimal, to be honest I like your stab at this
>> driver better in some ways, especially relating to DT putting each
>> channel in its own node with labels, I think this is a bit more clean
>> and will be more extendable if/when new multi-channel monitor chips are
>> made.
>>
>>> Not sure whether exporting the following will help or not. Can you
>>> please confirm?
>>> - Oversampling time i.e. average sample
>>> - conversion time for bus voltage and shunt voltage if default is not
>>> suited for system.
>>>
>>>
>>
>> These can always be added as needed, but the DT changes are not as easy.
>> I would like it if this got in this cycle but if you think something
>> will be needed to help your improvements, that can not be added
>> incrementally, it would probably be best to get them into the initial DT
>> binding doc now.
>>
> Andrew,
> 
> with this, the hwmon driver is pretty much on hold. What do you want me to do 
> ?
> Should I wait for DT updates ?
> 

If Laxman would like to commit to making these changes I do not problem
waiting a bit to get this right the first time.

If we don't hear back soon then I'd just take it as is and anything
needing to be fixed can be later.

Andrew
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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Andrew F. Davis 
On 06/03/2016 09:14 AM, Laxman Dewangan wrote:
> 
> On Friday 03 June 2016 06:59 PM, Guenter Roeck wrote:
>> On 06/03/2016 03:06 AM, Jonathan Cameron wrote:
>>> On 01/06/16 13:34, Laxman Dewangan wrote:
 The INA3221 is a three-channel, high-side current and bus voltage
 monitor
 with an I2C interface from Texas Instruments. The INA3221 monitors both
 shunt voltage drops and bus supply voltages in addition to having
 programmable conversion times and averaging modes for these signals.
 The INA3221 offers both critical and warning alerts to detect multiple
 programmable out-of-range conditions for each channel.

 Add support for INA3221 SW driver via IIO ADC interface. The device is
 register as iio-device and provides interface for voltage/current
 and power
 monitor. Also provide interface for setting oneshot/continuous mode and
 critical/warning threshold for the shunt voltage drop.

 Signed-off-by: Laxman Dewangan 
>>> Hi Laxman,
>>>
>>> As ever with any driver lying on the border of IIO and hwmon, please
>>> include
>>> a short justification of why you need an IIO driver and also cc the
>>> hwmon list + maintainers. (cc'd on this reply).
>>>
>>> I simply won't take a driver where the hwmon maintainers aren't happy.
>>> As it stands I'm not seeing obvious reasons in the code for why this
>>> should be an IIO device.
>>>
>>
>> Me not either.
>>
>> I have a hwmon driver for the same chip pending from Andrew Davis (TI)
>> which I am just about to accept. We had directed Andrew back in April
>> to write a hwmon driver for the chip, which he did.
>>
> 
> Thanks Guenter,  I found the series
> 
> [PATCH v2 0/2] Add support for INA3221 Triple Current/Voltage Monitors
> Looks fine to me. I can use the hwmon.
> 

If you search even further back you can see I originally went with an
IIO driver as well, comparing the IIO and hwmon version for the simple
use cases I needed the hwmod version turned out much simpler, so it was
probably the right framework for now.

> 
> However, some of the stuff from my patch are not there which I will add
> later once original patch applied:
> - Dynamic mode changes for continuous and one-shot from sysfs.
> - In one shot, when try to read voltage data, do conversion and then read.
> 

My attempt is rather minimal, to be honest I like your stab at this
driver better in some ways, especially relating to DT putting each
channel in its own node with labels, I think this is a bit more clean
and will be more extendable if/when new multi-channel monitor chips are
made.

> Not sure whether exporting the following will help or not. Can you
> please confirm?
> - Oversampling time i.e. average sample
> - conversion time for bus voltage and shunt voltage if default is not
> suited for system.
> 
> 

These can always be added as needed, but the DT changes are not as easy.
I would like it if this got in this cycle but if you think something
will be needed to help your improvements, that can not be added
incrementally, it would probably be best to get them into the initial DT
binding doc now.

Thanks,
Andrew

> 
> 
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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Laxman Dewangan 


On Friday 03 June 2016 06:59 PM, Guenter Roeck wrote:

On 06/03/2016 03:06 AM, Jonathan Cameron wrote:

On 01/06/16 13:34, Laxman Dewangan wrote:
The INA3221 is a three-channel, high-side current and bus voltage 
monitor

with an I2C interface from Texas Instruments. The INA3221 monitors both
shunt voltage drops and bus supply voltages in addition to having
programmable conversion times and averaging modes for these signals.
The INA3221 offers both critical and warning alerts to detect multiple
programmable out-of-range conditions for each channel.

Add support for INA3221 SW driver via IIO ADC interface. The device is
register as iio-device and provides interface for voltage/current 
and power

monitor. Also provide interface for setting oneshot/continuous mode and
critical/warning threshold for the shunt voltage drop.

Signed-off-by: Laxman Dewangan 

Hi Laxman,

As ever with any driver lying on the border of IIO and hwmon, please 
include

a short justification of why you need an IIO driver and also cc the
hwmon list + maintainers. (cc'd on this reply).

I simply won't take a driver where the hwmon maintainers aren't happy.
As it stands I'm not seeing obvious reasons in the code for why this
should be an IIO device.



Me not either.

I have a hwmon driver for the same chip pending from Andrew Davis (TI)
which I am just about to accept. We had directed Andrew back in April
to write a hwmon driver for the chip, which he did.



Thanks Guenter,  I found the series

[PATCH v2 0/2] Add support for INA3221 Triple Current/Voltage Monitors
Looks fine to me. I can use the hwmon.


However, some of the stuff from my patch are not there which I will add later 
once original patch applied:
- Dynamic mode changes for continuous and one-shot from sysfs.
- In one shot, when try to read voltage data, do conversion and then read.

Not sure whether exporting the following will help or not. Can you please 
confirm?
- Oversampling time i.e. average sample
- conversion time for bus voltage and shunt voltage if default is not suited 
for system.




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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Laxman Dewangan 


On Friday 03 June 2016 05:34 PM, Jonathan Cameron wrote:

On 03/06/16 12:31, Laxman Dewangan wrote:

On Friday 03 June 2016 03:46 PM, Jonathan Cameron wrote:

On 03/06/16 11:06, Jonathan Cameron wrote:

Code looks good, bu these more fundamental bits need sorting.

Another minor point - why do the power calculations in driver?
no hardware support for it, so why not just leave it to userspace?

Device supports the bus and shunt voltage monitoring. So even no current. Also 
the warning/critical limit is for the voltage across shunt.

So should we only expose the shunt/bus voltage, no power/current?

I am thinking that user space should not know the platform and hence shunt 
resistance and so exposing the current and power on bus is better option.


I'd go for current and voltage rather than current and power, but
otherwise agree.


OK, I will have the voltage (bus voltage) and current (on bus).
User space can get power out of this.

Thanks for suggestion.

The critical limits will be still in current. And it should be 
customized sysfs instead of the iio_chan_spec i.e. iio_device attribute 
interface.





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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Laxman Dewangan 


On Friday 03 June 2016 03:36 PM, Jonathan Cameron wrote:

On 01/06/16 13:34, Laxman Dewangan wrote:

Add support for INA3221 SW driver via IIO ADC interface. The device is
register as iio-device and provides interface for voltage/current and power
monitor. Also provide interface for setting oneshot/continuous mode and
critical/warning threshold for the shunt voltage drop.

Signed-off-by: Laxman Dewangan 

Hi Laxman,

As ever with any driver lying on the border of IIO and hwmon, please include
a short justification of why you need an IIO driver and also cc the
hwmon list + maintainers. (cc'd on this reply).

I simply won't take a driver where the hwmon maintainers aren't happy.
As it stands I'm not seeing obvious reasons in the code for why this
should be an IIO device.


I thought that all ADC or monitors are going to be part of IIO device 
framework. I saw the ina2xx which is same (single channel) which was my 
reference point.




Funily enough I know this datasheet a little as was evaluating
it for use on some boards at the day job a week or so ago.

Various comments inline. Major points are:
* Don't use 'fake' channels to control events. If the events infrastructure
doesn't handle your events, then fix that rather than working around it.
* There is a lot of ABI in here concerned with oneshot vs continuous.
This seems to me to be more than it should be. We wouldn't expect to
see stuff changing as a result of switching between these modes other
than wrt to when the data shows up.  So I'd expect to not see this
directly exposed at all - but rather sit in oneshot unless either:
1) Buffered mode is running (not currently supported)
2) Alerts are on - which I think requires it to be in continuous mode.

Other question to my mind is whether we should be reporting vshunt or
(using device tree to pass resistance) current.


This is bus and shunt voltage  device for power monitoring. In our 
platforms, we use this device for bus current and so  power monitor.


We have two usecases, one is one shot, read when it needs it. And other 
continuous when we have multiple core running then continuous mode to 
get the power consumption by rail.


Yaah, alert is used only on continuous mode and mainly used for 
throttling when rail power goes beyond some limit.


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Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Jonathan Cameron 
On 03/06/16 11:06, Jonathan Cameron wrote:
> On 01/06/16 13:34, Laxman Dewangan wrote:
>> The INA3221 is a three-channel, high-side current and bus voltage monitor
>> with an I2C interface from Texas Instruments. The INA3221 monitors both
>> shunt voltage drops and bus supply voltages in addition to having
>> programmable conversion times and averaging modes for these signals.
>> The INA3221 offers both critical and warning alerts to detect multiple
>> programmable out-of-range conditions for each channel.
>>
>> Add support for INA3221 SW driver via IIO ADC interface. The device is
>> register as iio-device and provides interface for voltage/current and power
>> monitor. Also provide interface for setting oneshot/continuous mode and
>> critical/warning threshold for the shunt voltage drop.
>>
>> Signed-off-by: Laxman Dewangan 
> Hi Laxman,
> 
> As ever with any driver lying on the border of IIO and hwmon, please include
> a short justification of why you need an IIO driver and also cc the
> hwmon list + maintainers. (cc'd on this reply).
> 
> I simply won't take a driver where the hwmon maintainers aren't happy.
> As it stands I'm not seeing obvious reasons in the code for why this
> should be an IIO device.
> 
> Funily enough I know this datasheet a little as was evaluating
> it for use on some boards at the day job a week or so ago.
> 
> Various comments inline. Major points are:
> * Don't use 'fake' channels to control events. If the events infrastructure
> doesn't handle your events, then fix that rather than working around it.
> * There is a lot of ABI in here concerned with oneshot vs continuous.
> This seems to me to be more than it should be. We wouldn't expect to
> see stuff changing as a result of switching between these modes other
> than wrt to when the data shows up.  So I'd expect to not see this
> directly exposed at all - but rather sit in oneshot unless either:
> 1) Buffered mode is running (not currently supported)
> 2) Alerts are on - which I think requires it to be in continuous mode.
> 
> Other question to my mind is whether we should be reporting vshunt or
> (using device tree to pass resistance) current.
> 
> Code looks good, bu these more fundamental bits need sorting.
Another minor point - why do the power calculations in driver?
no hardware support for it, so why not just leave it to userspace?
> 
> Thanks,
> 
> Jonathan
>> ---
>>  drivers/iio/adc/Kconfig   |   12 +
>>  drivers/iio/adc/Makefile  |1 +
>>  drivers/iio/adc/ina3221.c | 1175 
>> +
>>  3 files changed, 1188 insertions(+)
>>  create mode 100644 drivers/iio/adc/ina3221.c
>>
>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>> index 25378c5..65f3c27 100644
>> --- a/drivers/iio/adc/Kconfig
>> +++ b/drivers/iio/adc/Kconfig
>> @@ -223,6 +223,18 @@ config INA2XX_ADC
>>Say yes here to build support for TI INA2xx family of Power Monitors.
>>This driver is mutually exclusive with the HWMON version.
>>  
>> +config INA3221
>> +tristate "TI INA3221 3-Channel Shunt and Bus Voltage Monitor"
>> +depends on I2C
>> +select REGMAP_I2C
>> +help
>> +  INA3221 is Triple-Channel, High-Side Measurement, Shunt and Bus
>> +  Voltage Monitor device from TI. This driver support the reading
>> +  of all channel's voltage/current and power via IIO interface.
>> +  Say yes here to build support for TI INA3221. To compile this
>> +  driver as a module, choose M here: the module will be called
>> +  ina3221.
>> +
>>  config IMX7D_ADC
>>  tristate "IMX7D ADC driver"
>>  depends on ARCH_MXC || COMPILE_TEST
>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>> index 38638d4..c24f455 100644
>> --- a/drivers/iio/adc/Makefile
>> +++ b/drivers/iio/adc/Makefile
>> @@ -24,6 +24,7 @@ obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
>>  obj-$(CONFIG_HI8435) += hi8435.o
>>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
>> +obj-$(CONFIG_INA3221) += ina3221.o
>>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>>  obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
>>  obj-$(CONFIG_MAX1027) += max1027.o
>> diff --git a/drivers/iio/adc/ina3221.c b/drivers/iio/adc/ina3221.c
>> new file mode 100644
>> index 000..a17f688
>> --- /dev/null
>> +++ b/drivers/iio/adc/ina3221.c
>> @@ -0,0 +1,1175 @@
>> +/*
>> + * IIO driver for INA3221
>> + *
>> + * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +#include 
>> +
>> +/* INA3221 registers definition */
>> +#define INA3221_CONFIG  0x00
>> +#define INA3221_SHUNT_VOL_CHAN1 0x01
>>

Re: [PATCH 2/3] iio: adc: ina3221: Add support for IIO ADC driver for TI INA3221

2016-06-03 Thread Jonathan Cameron 
On 01/06/16 13:34, Laxman Dewangan wrote:
> The INA3221 is a three-channel, high-side current and bus voltage monitor
> with an I2C interface from Texas Instruments. The INA3221 monitors both
> shunt voltage drops and bus supply voltages in addition to having
> programmable conversion times and averaging modes for these signals.
> The INA3221 offers both critical and warning alerts to detect multiple
> programmable out-of-range conditions for each channel.
> 
> Add support for INA3221 SW driver via IIO ADC interface. The device is
> register as iio-device and provides interface for voltage/current and power
> monitor. Also provide interface for setting oneshot/continuous mode and
> critical/warning threshold for the shunt voltage drop.
> 
> Signed-off-by: Laxman Dewangan 
Hi Laxman,

As ever with any driver lying on the border of IIO and hwmon, please include
a short justification of why you need an IIO driver and also cc the
hwmon list + maintainers. (cc'd on this reply).

I simply won't take a driver where the hwmon maintainers aren't happy.
As it stands I'm not seeing obvious reasons in the code for why this
should be an IIO device.

Funily enough I know this datasheet a little as was evaluating
it for use on some boards at the day job a week or so ago.

Various comments inline. Major points are:
* Don't use 'fake' channels to control events. If the events infrastructure
doesn't handle your events, then fix that rather than working around it.
* There is a lot of ABI in here concerned with oneshot vs continuous.
This seems to me to be more than it should be. We wouldn't expect to
see stuff changing as a result of switching between these modes other
than wrt to when the data shows up.  So I'd expect to not see this
directly exposed at all - but rather sit in oneshot unless either:
1) Buffered mode is running (not currently supported)
2) Alerts are on - which I think requires it to be in continuous mode.

Other question to my mind is whether we should be reporting vshunt or
(using device tree to pass resistance) current.

Code looks good, bu these more fundamental bits need sorting.

Thanks,

Jonathan
> ---
>  drivers/iio/adc/Kconfig   |   12 +
>  drivers/iio/adc/Makefile  |1 +
>  drivers/iio/adc/ina3221.c | 1175 
> +
>  3 files changed, 1188 insertions(+)
>  create mode 100644 drivers/iio/adc/ina3221.c
> 
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 25378c5..65f3c27 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -223,6 +223,18 @@ config INA2XX_ADC
> Say yes here to build support for TI INA2xx family of Power Monitors.
> This driver is mutually exclusive with the HWMON version.
>  
> +config INA3221
> + tristate "TI INA3221 3-Channel Shunt and Bus Voltage Monitor"
> + depends on I2C
> + select REGMAP_I2C
> + help
> +   INA3221 is Triple-Channel, High-Side Measurement, Shunt and Bus
> +   Voltage Monitor device from TI. This driver support the reading
> +   of all channel's voltage/current and power via IIO interface.
> +   Say yes here to build support for TI INA3221. To compile this
> +   driver as a module, choose M here: the module will be called
> +   ina3221.
> +
>  config IMX7D_ADC
>   tristate "IMX7D ADC driver"
>   depends on ARCH_MXC || COMPILE_TEST
> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
> index 38638d4..c24f455 100644
> --- a/drivers/iio/adc/Makefile
> +++ b/drivers/iio/adc/Makefile
> @@ -24,6 +24,7 @@ obj-$(CONFIG_FSL_MX25_ADC) += fsl-imx25-gcq.o
>  obj-$(CONFIG_HI8435) += hi8435.o
>  obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
>  obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
> +obj-$(CONFIG_INA3221) += ina3221.o
>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>  obj-$(CONFIG_LPC18XX_ADC) += lpc18xx_adc.o
>  obj-$(CONFIG_MAX1027) += max1027.o
> diff --git a/drivers/iio/adc/ina3221.c b/drivers/iio/adc/ina3221.c
> new file mode 100644
> index 000..a17f688
> --- /dev/null
> +++ b/drivers/iio/adc/ina3221.c
> @@ -0,0 +1,1175 @@
> +/*
> + * IIO driver for INA3221
> + *
> + * Copyright (C) 2016 NVIDIA CORPORATION. All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +#include 
> +
> +/* INA3221 registers definition */
> +#define INA3221_CONFIG   0x00
> +#define INA3221_SHUNT_VOL_CHAN1  0x01
> +#define INA3221_BUS_VOL_CHAN10x02
> +#define INA3221_SHUNT_VOL_CHAN2  0x03
> +#define INA3221_BUS_VOL_CHAN20x04
> +#define INA3221_SHUNT_VOL_CHAN3  0x05
> +#define INA3221_BUS_VOL_CHAN30x06
>