gpioiic FDT overlays for sun8i-h3

[Emmanuel Vadot]

On Fri, 29 Nov 2019 15:54:31 +0200
Nick Kostirya <nikolay.kostirya at i11.co> wrote:

> From: Nick Kostirya <nikolay.kostirya at i11.co>
> To: Milan Obuch <milan at obuch.sk>
> Subject: Re: gpioiic FDT overlays for sun8i-h3
> Date: Fri, 29 Nov 2019 15:53:05 +0200
> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i386-portbld-freebsd12.0)
> 
> On Fri, 29 Nov 2019 14:43:16 +0100
> Milan Obuch <milan at obuch.sk> wrote:
> 
> > On Fri, 29 Nov 2019 15:37:54 +0200
> > Nick Kostirya via freebsd-arm <freebsd-arm at freebsd.org> wrote:
> >   
> > > On Thu, 28 Nov 2019 06:21:49 +0100
> > > Emmanuel Vadot <manu at bidouilliste.com> wrote:
> > >     
> > > >  Try this but I haven't even compiled it :
> > > > 
> > > > /dts-v1/;
> > > > /plugin/;
> > > > 
> > > > / {
> > > >     compatible = "allwinner,sun8i-h3";
> > > > };
> > > > 
> > > > &{/soc/pinctrl at 1c20800} {
> > > >         gpioiic0 {
> > > >             compatible    = "gpioiic";
> > > >             scl = <0>; /*    GPIO pin 00 (PA0) */
> > > >             sda = <2>; /*    GPIO pin 02 (PA2) */
> > > > 
> > > >     };
> > > > };      
> > > 
> > > Maybe I must rebuild all u-boot with this overlay?
> > > 
> > > Because the overlay do not help when it is in /boot/dtb/overlays/ and
> > > /boot/msdos/dtb/overlays/.
> > >    
> > 
> > Did you add in /boot/loader.conf line like
> > 
> > fdt_overlays="gpioiic"  
> 
> Yes.
> I have 
> fdt_overlays="sun8i-h3-sid,sun8i-h3-ths,sun8i-h3-opp,sun8i-h3-gpio-iic0"
> 
> where sun8i-h3-gpio-iic0 if gpioiic overlay.
> 
> I see gpioiic in ofwdump -a output. 

 Which means that the overlays was applied.
 I've spent a few hours yesterday to find how to use this module and
the result is we can't. The reason is that the driver is at an higher
bus pass number than the parent (gpiobus) so the driver isn't probed
and is removed from the child list of gpiobus, meaning that it's never
added later.
  ian@ and I agreed that it the driver would need to be rewritten
because of this and because you cannot use gpio from different banks as
it needs to be a children of one gpio controller.
 So the TLDR is : right now this driver is useless (at least on FDT
system).

> 
> > 
> > (gpioiic is name of your module in /boot/dtb/overlays)? Overlays are
> > processed by loader of ours (freeBSD), not u-boot, AFAIK...  
> 
> By the way why do we need /boot/msdos/dtb/overlays/?

 Nope it's not needed, overlays are processed by loader(8).

-- 
Emmanuel Vadot <manu at bidouilliste.com> <manu at freebsd.org>