[PATCH V2 RFC 6/6] ARM: dts: bcm2835: Add Raspberry Pi Zero

[Stefan Wahren]

Hi Stephen,

> Stephen Warren <swarren at wwwdotorg.org> hat am 2. August 2016 um 19:19
> geschrieben:
> 
> 
> On 07/26/2016 12:53 PM, Stefan Wahren wrote:
> > The Raspberry Pi Zero is a minified version of model A+. It's
> > notable there is no PWR LED and the ACT LED is inverted.
> 
> Patches 3-6,
> Acked-by: Stephen Warren <swarren at nvidia.com>
> 
> > diff --git a/arch/arm/boot/dts/bcm2835-rpi-zero.dts
> > b/arch/arm/boot/dts/bcm2835-rpi-zero.dts
> 
> The following comment format is a bit strange, but I'm not sure there's 
> anything objectively better...

the idea behind that was to provide valid values for every dr_mode with minimum
effort. I see 2 alternative solutions:
  a) add different dr_mode examples to the dwc2 => doesn't work for all
platforms
  b) add comments to drivers/usb/dwc2/platform.c => harder to find

At the end the solution here is already obsolete. This patch series doesn't
contain an update for the bcm2835_defconfig which should set the following:

CONFIG_NOP_USB_XCEIV=y
CONFIG_USB_GADGET=y

After enabling these options another issue is revealed. Currently the dr_mode
for all the other bcm283x boards isn't defined, which means "otg" instead of
intended "host". But the dwc2 driver ignores this as long as CONFIG_USB_GADGET
is not defined. So we need to define the dr_mode for all bcm283x boards. In
order to avoid such massive copy & paste, we better define 3 dtsi files for each
dr_mode.  The only catch about this solution is the modes "otg" and "peripheral"
wouldn't be referenced.

I'll wait for John's feedback before sending a new version.

Stefan

> 
> > +&usb {
> > +	dr_mode = "host";
> > +	h-rx-fifo-size = <774>;
> > +	h-np-tx-fifo-size = <256>;
> > +	h-tx-fifo-size = <512>;
> > +/*
> > + * Settings for otg
> > + *
> > +	dr_mode = "otg";
> > +	h-rx-fifo-size = <774>;
> > +	h-np-tx-fifo-size = <32>;
> > +	h-tx-fifo-size = <0>;
> > +	g-np-tx-fifo-size = <16>;
> > +	g-rx-fifo-size = <256>;
> > +	g-tx-fifo-size = <256 128 128 64 64 64 32>;
> > + *
> > + * Settings for peripheral
> > + *
> > +	dr_mode = "peripheral";
> > +	h-rx-fifo-size = <774>;
> > +	h-np-tx-fifo-size = <0>;
> > +	h-tx-fifo-size = <0>;
> > +	g-np-tx-fifo-size = <16>;
> > +	g-rx-fifo-size = <256>;
> > +	g-tx-fifo-size = <256 128 128 64 64 64 32>;
> > + */
> > +};
>