[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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