[Buildroot] [PATCH v5 2/6] board/raspberrypicm4io: enable RTC and USB overlays
Peter Seiderer
ps.report at gmx.net
Sun Oct 17 20:54:22 UTC 2021
Hello Yann,
On Sun, 17 Oct 2021 22:27:17 +0200, "Yann E. MORIN" <yann.morin.1998 at free.fr> wrote:
> Peter, All,
>
> On 2021-09-21 22:21 +0200, Peter Seiderer spake thusly:
> > - add RTC and USB dtoverlay entries to config_cm4io.txt
>
> Why specifically the RTC and USB? And why only on the CM, and not the
> other boards?
The config is not for the CM4 standalone, but specific to the
CM4 IO Board, equipped (as the only RPi original one) with an
RTC chip....
>
> IIRC, dwc2 is an OTG chip, too, and it is also wired on the rpi0. Well,
> by experience, I know that the rpi0 *can* do USB slave/OTG.
And as far as I know the USB is enabled with all RPi's with
exception of the CM4: 'The USB interface is disabled to save power by
default on the CM4' (see [1] page 5)
According to [2]:
Name: dwc-otg
Info: Selects the dwc_otg USB controller driver which has fiq support. This
is the default on all except the Pi Zero which defaults to dwc2.
Load: dtoverlay=dwc-otg
Params: <None>
Name: dwc2
Info: Selects the dwc2 USB controller driver
Load: dtoverlay=dwc2,<param>=<val>
Params: dr_mode Dual role mode: "host", "peripheral" or "otg"
g-rx-fifo-size Size of rx fifo size in gadget mode
g-np-tx-fifo-size Size of non-periodic tx fifo size in gadget
mode
Would interpret 'defaults to dwc2' on Pi Zero as enabled by default...
Regards,
Peter
[1] https://datasheets.raspberrypi.com/cm4io/cm4io-datasheet.pdf
[2] https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README
>
>
> Regards,
> Yann E. MORIN.
>
> > Signed-off-by: Peter Seiderer <ps.report at gmx.net>
> > ---
> > Changes v4 -> v5:
> > - new patch
> > ---
> > board/raspberrypi/config_cm4io.txt | 7 +++++++
> > 1 file changed, 7 insertions(+)
> >
> > diff --git a/board/raspberrypi/config_cm4io.txt b/board/raspberrypi/config_cm4io.txt
> > index 01f60395b3..cf7e6df1a1 100644
> > --- a/board/raspberrypi/config_cm4io.txt
> > +++ b/board/raspberrypi/config_cm4io.txt
> > @@ -24,3 +24,10 @@ gpu_mem_1024=100
> >
> > # fixes rpi (3B, 3B+, 3A+, 4B and Zero W) ttyAMA0 serial console
> > dtoverlay=miniuart-bt
> > +
> > +# enable RTC
> > +dtparam=i2c_vc=on
> > +dtoverlay=i2c-rtc,pcf85063a,i2c_csi_dsi
> > +
> > +# enable dwc2 USB controller (USB 2.0)
> > +dtoverlay=dwc2,dr_mode=host
> > --
> > 2.33.0
> >
> > _______________________________________________
> > buildroot mailing list
> > buildroot at lists.buildroot.org
> > https://lists.buildroot.org/mailman/listinfo/buildroot
>
More information about the buildroot
mailing list