On 02/21/2015 12:52 AM, Guenter Roeck wrote:

On 02/20/2015 12:15 PM, Cedric Le Goater wrote:

quoted

On 02/20/2015 05:52 PM, Guenter Roeck wrote:

quoted

On Fri, Feb 20, 2015 at 04:07:34PM +0100, Cédric Le Goater wrote:

quoted

Hello !

These patches rework the ibmpowernv driver to support the new device
tree as proposed by this patchset on the skiboot mailing list :

   https://lists.ozlabs.org/pipermail/skiboot/2015-February/000457.html

They are based on Linux 3.19 and were tested on IBM Power and Open Power
systems running trusty.

The main issue is that the new device tree is incompatible with the
previous ibmpowernv drivers. The consequence is no powernv sensors
on systems with such a opal/linux configuration.

I don't think that would be acceptable. There must be lots of such
systems out there. Why does it have to be incompatible ?
Can't it support both the old and new versions ?

I should have provided more explanation in the Linux patchset. Sorry
for that. Here is the rationale behind this brutal code change.

The initial ibmpowernv driver was designed in the early days of the
powernv platform and the device tree it is using to expose the sensors
has some limitations that makes it difficult to add new ones. The current
layout of the device tree is also tightly coupled to IBM Power systems
and their service processor (FSP). Open Power systems are different and
need a different solution.

It is to get more sensors out the P8 (and there are quite a few) that
the OPAL patchset [1] proposes a new device tree. On the Linux side, it
feels simpler to make a jump forward and break the compatibility than
to maintain multiple branches of code just to keep alive an early v1
of the ibmpowernv driver.

Would it possibly be appropriate to write a different driver for the new
device tree ?

Sure. That is an option. 

There are no conflicts between the trees so we can live with two drivers 
using the same sensors/ root node. With time we will deprecate the initial
one.

Is that the preferred option ? How would we name the new driver ? 

	1. powernv
	2. powernv-hwmon
	3. openpowernv
	4. ibmpowernv2 

Thanks,

C.