lkml.org 
[lkml]   [2016]   [Sep]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2 2/6] ARM: dts: bcm283x: Define standard pinctrl groups in the gpio node.
From
Date
  Hi,

> > > + emmc_gpio48: emmc_gpio48 {
> > > + brcm,pins = <48 49 50 51 52 53>;
> > > + brcm,function = <BCM2835_FSEL_ALT3>;
> > > + };
> >
> > Sorry, i didn't notice this before. The naming of these groups suggest 3 muxes
> > for the same eMMC interface. I thought there is a eMMC interface and a SD host
> > interface with different DMA channels.
> >
> > > +
> > > ...
> > > +
> > > + sdhost_gpio48: sdhost_gpio48 {
> > > + brcm,pins = <48 49 50 51 52 53>;
> > > + brcm,function = <BCM2835_FSEL_ALT0>;
> > > + };
> >
> > I think this incorrect. There is no function ALT0 for these pins, only ALT3.
>
> please forget my last 2 comments. According to this page [1] eMMC is selected by
> ALT3 and sdhost is selected by ALT0.
>
> Do you know a reliable source where all muxes for both interface are documented?
> The datasheet isn't very helpful here.

No, I don't know any source better than the datasheet @ github.
Yes, I tried to double-check things with the sheet too.

IIRC Eric mentioned a while back in some mail or patch that he checked
something for the rpi device tree with non-public docs, not fully sure
though whenever it was emmc/sdhost or something else. But I'm basically
trusting Eric here ...

cheers,
Gerd

PS: This is exactly why I think it us useful to have all those entries
in the dt file even if unused: To serve as documentation.

\
 
 \ /
  Last update: 2016-09-17 09:59    [W:0.209 / U:0.020 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site