[PATCH 5/7] arm64: dts: broadcom: bcm2712: Add one more GPIO node

Ivan T. Ivanov iivanov at suse.de
Thu Aug 1 00:19:08 PDT 2024


On 07-31 15:11, Florian Fainelli wrote:
> > +
> > +		gio: gpio at 7d508500 {
> > +			compatible = "brcm,brcmstb-gpio";
> > +			reg = <0x7d508500 0x40>;
> > +			interrupt-parent = <&main_irq>;
> > +			interrupts = <0>;
> > +			gpio-controller;
> > +			#gpio-cells = <2>;
> > +			interrupt-controller;
> > +			#interrupt-cells = <2>;
> > +			brcm,gpio-bank-widths = <32 22>;
> > +			brcm,gpio-direct;
> 
> Undocumented and unsupported property upstream, what does it do? Other than
> that, LGTM.

Doh. Something used for banging GPIO's from user-space via "/dev/gpiomem".

I will remove it in next patch version.

Thanks,
Ivan


[1]
 "...
    gpio: mmio: Add DIRECT mode for shared access

    The generic MMIO GPIO library uses shadow registers for efficiency,
    but this breaks attempts by raspi-gpio to change other GPIOs in the
    same bank. Add a DIRECT mode that makes fewer assumptions about the
    existing register contents, but note that genuinely simultaneous
    accesses are likely to lose updates.
 ... "



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