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

[John Youn <John.Youn-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>]

On 7/26/2016 11:54 AM, 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.
> 
> Signed-off-by: Stefan Wahren <stefan.wahren-eS4NqCHxEME@public.gmane.org>
> ---
>  arch/arm/boot/dts/Makefile             |    3 +-
>  arch/arm/boot/dts/bcm2835-rpi-zero.dts |   57 ++++++++++++++++++++++++++++++++
>  2 files changed, 59 insertions(+), 1 deletion(-)
>  create mode 100644 arch/arm/boot/dts/bcm2835-rpi-zero.dts
> 
> diff --git a/arch/arm/boot/dts/Makefile b/arch/arm/boot/dts/Makefile
> index e38e7c9..cafa3b1 100644
> --- a/arch/arm/boot/dts/Makefile
> +++ b/arch/arm/boot/dts/Makefile
> @@ -69,7 +69,8 @@ dtb-$(CONFIG_ARCH_BCM2835) += \
>  	bcm2835-rpi-b-rev2.dtb \
>  	bcm2835-rpi-b-plus.dtb \
>  	bcm2835-rpi-a-plus.dtb \
> -	bcm2836-rpi-2-b.dtb
> +	bcm2836-rpi-2-b.dtb \
> +	bcm2835-rpi-zero.dtb
>  dtb-$(CONFIG_ARCH_BCM_5301X) += \
>  	bcm4708-asus-rt-ac56u.dtb \
>  	bcm4708-asus-rt-ac68u.dtb \
> diff --git a/arch/arm/boot/dts/bcm2835-rpi-zero.dts b/arch/arm/boot/dts/bcm2835-rpi-zero.dts
> new file mode 100644
> index 0000000..12bc82d
> --- /dev/null
> +++ b/arch/arm/boot/dts/bcm2835-rpi-zero.dts
> @@ -0,0 +1,57 @@
> +/dts-v1/;
> +#include "bcm2835.dtsi"
> +#include "bcm2835-rpi.dtsi"
> +
> +/ {
> +	compatible = "raspberrypi,model-zero", "brcm,bcm2835";
> +	model = "Raspberry Pi Zero";
> +
> +	leds {
> +		act {
> +			gpios = <&gpio 47 GPIO_ACTIVE_HIGH>;
> +		};
> +	};
> +};
> +
> +
> +&usb {
> +	dr_mode = "host";
> +	h-rx-fifo-size = <774>;
> +	h-np-tx-fifo-size = <256>;
> +	h-tx-fifo-size = <512>;

It seems like these last two are the same as the default values
reported in the registers. So they should already be set that way
without needing to specify them. If not, there may be some problem in
the driver.

> +/*
> + * Settings for otg
> + *
> +	dr_mode = "otg";
> +	h-rx-fifo-size = <774>;
> +	h-np-tx-fifo-size = <32>;
> +	h-tx-fifo-size = <0>;

This seems odd. It should be non-zero for use when operating as host.

> +	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>;

You should be able to omit the host params if dr_mode == peripheral.

> +	g-np-tx-fifo-size = <16>;
> +	g-rx-fifo-size = <256>;
> +	g-tx-fifo-size = <256 128 128 64 64 64 32>;
> + */
> +};

Regards,
John
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