Messages in this thread | | | Subject | Re: [PATCH v2 2/2] reset: Reset controller driver for Intel LGM SoC | From | Dilip Kota <> | Date | Tue, 8 Oct 2019 10:47:03 +0800 |
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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@pengutronix.de> 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
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