Hi Martin,Philipp,
On 10/8/2019 3:53 AM, Martin Blumenstingl wrote:
Hi Philipp,
On Thu, Oct 3, 2019 at 4:19 PM Philipp Zabel <pza@xxxxxxxxxxxxxx> wrote:
[...]
because the register layout was greatly simplified for the newer SoCs
(for which there is reset-intel) compared to the older ones
(reset-lantiq).
Dilip's suggestion (in my own words) is that you take his new
reset-intel driver, then we will work on porting reset-lantiq over to
that so in the end we can drop the reset-lantiq driver.
Just to be sure, you are suggesting to add support for the current
lantiq,reset binding to the reset-intel driver at a later point? I
see no reason not to do that, but I'm also not quite sure what the
benefit will be over just keeping reset-lantiq as is?
according to Chuan and Dilip the current reset-lantiq implementation
is wrong [0].
my understanding is that the Lantiq and Intel LGM reset controllers
are identical except:
- the Lantiq variant uses a weird register layout (reset and status
registers not at consecutive offsets)
- the bits of the reset and status registers sometimes don't match on
the Lantiq variant
- the Intel variant has a dedicated registers area for the reset
controller registers, while the Lantiq variant mixes them with various
other functionality (for example: USB2 PHYs)
This approach means more work for me (as I am probably the one who
then has to do the work to port reset-lantiq over to reset-intel).
More work than what alternative?
compared to "fixing" the existing reset-lantiq driver (reset callback)
and then (instead of adding a new driver) integrating Intel LGM
support into reset-lantiq
Integrating Intel LGM support into reset-lantiq boils down to re-writing
reset-lantiq driver as intel-reset driver and adding Lantiq variant
support. Why because reset-lantiq driver is not according to hardware
design[1].
I see the final best solution is to integrate Lantiq variant driver to
intel-reset driver.[1]
I hope you guys are ok with it. Please let me know your view.
Regards,
Dilip
[1]: https://www.spinics.net/lists/devicetree/msg308930.html
I'm happy to do that work if you think that it's worth following this
approach. So I want your opinion on this before I spend any effort on
porting reset-lantiq over to reset-intel.
Reset drivers are typically so simple, I'm not quite sure whether it is
worth to integrate multiple drivers if it complicates matters too much.
In this case though I expect it would just be adding support for a
custom .of_xlate and lantiq specific register property parsing?
yes, that's how I understand the Lantiq and Intel reset controllers:
- reset/status/assert/deassert callbacks would be shared across all variants
- register parsing and of_xlate are SoC specific
Martin
[0] https://www.spinics.net/lists/devicetree/msg305951.html
