Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 26 Mar 2018 12:22:24 +0200 | Subject | Re: [PATCH v3 05/11] dt-bindings: i3c: Document core bindings |
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Hi Boris,
On Fri, Mar 23, 2018 at 12:00 PM, Boris Brezillon <boris.brezillon@bootlin.com> wrote: > From: Boris Brezillon <boris.brezillon@free-electrons.com> > > A new I3C subsystem has been added and a generic description has been > created to represent the I3C bus and the devices connected on it. > > Document this generic representation. > > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Thanks for your patch!
> --- /dev/null > +++ b/Documentation/devicetree/bindings/i3c/i3c.txt > @@ -0,0 +1,140 @@
> +I3C devices > +=========== > + > +All I3C devices are supposed to support DAA (Dynamic Address Assignment), and > +are thus discoverable. So, by default, I3C devices do not have to be described > +in the device tree.
But if they're described, they should have a compatible value, no?
> +This being said, one might want to attach extra resources to these devices, > +and those resources may have to be described in the device tree, which in turn > +means we have to describe I3C devices. > + > +Another use case for describing an I3C device in the device tree is when this > +I3C device has a static address and we want to assign it a specific dynamic > +address before the DAA takes place (so that other devices on the bus can't > +take this dynamic address). > + > +The I3C device should be names <device-type>@<static-address>,<i3c-pid>,
named
So the i3c-pid in the unit address is represented as a 64-bit number, not as two comma-separated 32-bit numbers?
> +Example: > + > + i3c-master@d040000 { > + compatible = "cdns,i3c-master"; > + clocks = <&coreclock>, <&i3csysclock>; > + clock-names = "pclk", "sysclk"; > + interrupts = <3 0>; > + reg = <0x0d040000 0x1000>; > + #address-cells = <3>; > + #size-cells = <0>; > + > + status = "okay"; > + i2c-scl-frequency = <100000>; > + > + /* I2C device. */ > + nunchuk: nunchuk@52 {
@52,8000001000000000?
> + compatible = "nintendo,nunchuk"; > + reg = <0x52 0x80000010 0x0>; > + }; > + > + /* I3C device with a static address. */ > + thermal_sensor: sensor@68,39200144004 {
No compatible value?
> + reg = <0x68 0x392 0x144004>; > + assigned-address = <0xa>; > + }; > + > + /* > + * I3C device without a static address but requiring resources > + * described in the DT. > + */ > + sensor@0,39200154004 {
No compatible value?
> + reg = <0x0 0x392 0x154004>; > + clocks = <&clock_provider 0>; > + }; > + };
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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