Re: [PATCH 3/3] ARM: at91: dt: at91sam9n12ek: enable udp

[Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>]

Hello Bo,

On Mon, Feb 09, 2015 at 05:02:52PM +0800, Bo Shen wrote:
> Enable usb device port on at91sam9n12ek board.
> 
> Signed-off-by: Bo Shen <voice.shen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>
> ---
> 
>  arch/arm/boot/dts/at91sam9n12ek.dts | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm/boot/dts/at91sam9n12ek.dts b/arch/arm/boot/dts/at91sam9n12ek.dts
> index 13bb24e..3e572e5 100644
> --- a/arch/arm/boot/dts/at91sam9n12ek.dts
> +++ b/arch/arm/boot/dts/at91sam9n12ek.dts
> @@ -120,6 +120,11 @@
>  				};
>  			};
>  
> +			usb1: gadget@f803c000 {
> +				atmel,vbus-gpio = <&pioB 16 GPIO_ACTIVE_HIGH>;
> +				status = "okay";
> +			};
> +

There is an external resistor divider on PB16, acting like a pull-down 
(R22+R23). PB16 reset state is input, pull-up, schmitt trigger, you need 
to disable the pull-up in pinctrl this way:

usb1: gadget@f803c000 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_board_usb1>;
	…
}

pinctrl … {
	usb1 {
		pinctrl_board_usb1: usb1-board {
			atmel,pins = <AT91_PIOB 16 AT91_PERIPH_GPIO AT91_PINCTRL_DEGLITCH>;    /* PB16, no pull up and deglitch */
		};
	};
};


Sylvain
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