Re: [PATCH 2/2] arm64: dts: broadcom: bcm2712-rpi-5-b: add spi0 interface

[Gregor Herburger]

On Thu, Sep 03, 2026 at 06:26:19PM +0200, Andrea della Porta wrote:
> Hi Gregor,
> 
> On 18:04 Tue 11 Aug     , Gregor Herburger wrote:
> > The Raspberry Pi 5 routes the spi0 of the rp1 chip to the pin header.
> > Add the rp1_spi0 node and its pinctrl node to the devicetree to enable
> > the spi interface.
> > 
> > Signed-off-by: Gregor Herburger <gregor.herburger@xxxxxxxxxxxxx>
> > ---
> >  arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts | 16 ++++++++++++++++
> >  1 file changed, 16 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> > index 0fc57e72632ed..81aec81c5ce12 100644
> > --- a/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> > +++ b/arch/arm64/boot/dts/broadcom/bcm2712-rpi-5-b.dts
> > @@ -69,6 +69,14 @@ usb_vbus_default_state: usb-vbus-default-state {
> >  		groups = "vbus1";
> >  	};
> >  
> > +	rp1_spi0_default_state: rp1-spi0-default-state {
> > +		function = "spi0";
> > +		groups = "spi0";
> > +		bias-disable;
> > +		drive-strength = <12>;
> > +		slew-rate = <1>;
> > +	};
> > +
> >  	rp1_i2c4_default_state: rp1-i2c4-default-state {
> >  		function = "i2c4";
> >  		groups = "i2c4_2";
> > @@ -94,6 +102,14 @@ &rp1_i2c6 {
> >  	pinctrl-names = "default";
> >  };
> >  
> > +&rp1_spi0 {
> > +	pinctrl-0 = <&rp1_spi0_default_state>;
> 
> Is there any reason to avoid defining the CS pins as pulled-up gpios
> in the rp1_gpio node and then referencing it in pinctrl-0?
No there is no reason for this. I will try it and send a new version.
> Something like thie following:
> 
> rp1_spi0_cs_default_state: rp1-spi0-cs-default-state {
> 	function = "gpio";
> 	pins = "gpio7", "gpio8";
> 	bias-pull-up;
> };
> 
> &rp1_spi0 {
> 	...
> 	pinctrl-0 = <&rp1_spi0_default_state &rp1_spi0_cs_default_state>;
> 	...
> };
> 
> 
> Many thanks,
> Andrea
> 
> > +	pinctrl-names = "default";
> > +
> > +	num-cs = <2>;
> > +	cs-gpios = <&rp1_gpio 8 GPIO_ACTIVE_LOW &rp1_gpio 7 GPIO_ACTIVE_LOW>;
> > +};
> > +
> >  &rp1_usb0 {
> >  	pinctrl-0 = <&usb_vbus_default_state>;
> >  	pinctrl-names = "default";
> > 
> > -- 
> > 2.47.3
> > 

-- 
Gregor Herburger
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