Re: MCP9808 iio or hwmon

[Alison Schofield <amsfield22@gmail.com>]

On Fri, Jun 24, 2016 at 07:11:45PM -0700, Guenter Roeck wrote:
> On 06/24/2016 05:36 PM, Alison Schofield wrote:
> >On Tue, Jun 21, 2016 at 04:42:46PM -0700, Guenter Roeck wrote:
> >>On Tue, Jun 21, 2016 at 03:26:11PM -0700, Alison Schofield wrote:
> >>>On Tue, Jun 14, 2016 at 06:27:50AM -0700, Guenter Roeck wrote:
> >>>>On 06/14/2016 01:22 AM, Daniel Baluta wrote:
> >>>>>[fixing IIO, hwmon lists emails]
> >>>>>
> >>>>>On Tue, Jun 14, 2016 at 11:20 AM, Daniel Baluta <daniel.baluta@gmail.com> wrote:
> >>>>>>On Tue, Jun 14, 2016 at 1:08 AM, Alison Schofield <amsfield22@gmail.com> wrote:
> >>>>>>>
> >>>>>>>I was working on an iio driver for MCP9808 when Jonathan took notice
> >>>>>>>and suggested we have the iio or hwmon discussion.
> >>>>>>>
> >>>>>>>So, where should this sensor driver reside?
> >>>>>>>
> >>>>>>>http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
> >>>>>>>
> >>>>>>>It's a digital temp sensor with user programmable registers for
> >>>>>>>sensing applications.  Supports shutdown, low power modes,
> >>>>>>>specifying of event & critical output boundaries.  Can support
> >>>>>>>8 sensors on a single serial bus. Touted as 'ideal for sophisticated
> >>>>>>>multi-zone temperature-monitoring applications.'
> >>>>>>
> >>>>>>This is debatable, looking to the datasheet this driver could reside
> >>>>>>in both places.
> >>>>>>
> >>>>>>Because this sensor has Industrial utility (e.g freezers, refrigerators) I
> >>>>>>am inclined to say we should support it in IIO.
> >>>>>>
> >>>>
> >>>>Literally every sensor has that utility.
> >>>>
> >>>>Alternatively, you might consider adding its device ID to the jc42 driver.
> >>>>If you want to be fancy, you could add optional support for resolution
> >>>>selection to the driver.
> >>>>
> >>>>Guenter
> >>>
> >>>Hi Guenter,
> >>>I'm using the mcp9808 with the jc42 driver by instantiating it.
> >>>
> >>>I've added the device ID info so that the .detect callback can recognize
> >>>it, but can't figure out how to test that.  When/how does that .detect
> >>>get called?  I am using the Diolan.
> >>>
> >>Not sure if it works, but try to load the the jc42 driver using modprobe
> >>first, and _then_ insert the diolan adapter.
> >>
> >>Guenter
> >
> >Finally got it!  I had to add I2C_CLASS_SPD (jc42's class) to Diolan and
> >then follow the order you suggested.
> >
> 
> Great. Can you send a patch for the jc42 driver ?
> 
> Thanks,
> Guenter
> 
Guenther,

I have the patch, but am stumbling on the changelog.

I hoped to simply state in the changelog that MCP9808 is a jc-42
compliant sensor, but I don't think it's 100% true, and I'm not
sure of where it falls short of compliance.

jc42 currently supports these Microchip sensors:
MCP9804, MCP9805, MCP98242, MCP98243, MCP98244, MCP9843

All, with the exception of 9804 (and my 9808), clearly state they
are jc-42 compliant in their datasheet.

9804 is 9808's twin and I've tested with 9808.

Wondering if the non-compliance has to do with the lack of a capability
register for 9804 & 9808, which doesn't affect the drivers functioning.

Appreciate your advice on how to submit this correctly. Thanks!

alisons