On 09:34 Fri 04 May , Tony Lindgren wrote:
> * Jean-Christophe PLAGNIOL-VILLARD <plagnioj@xxxxxxxxxxxx> [120504 08:58]:
> > On 08:03 Fri 04 May , Tony Lindgren wrote:
> > > >
> > > > so I was thinking to do like on gpio
> > > >
> > > > uart {
> > > > pin = < &pioA 12 {pararms} >
> > > >
> > > > }
> > >
> > > Hmm I assume the "12" above the gpio number?
> > no pin number in the bank because it could not be gpio
>
> Yes OK, but pin number 12 in the gpio bank, not in the mux register.
> Got it.
>
> > pioD: gpio@fffff800 {
> > compatible = "atmel,at91rm9200-gpio";
> > reg = <0xfffff800 0x100>;
> > interrupts = <5 4>;
> > #gpio-cells = <2>;
> > gpio-controller;
> > interrupt-controller;
> > };
> >
> > pioE: gpio@fffffa00 {
> > compatible = "atmel,at91rm9200-gpio";
> > reg = <0xfffffa00 0x100>;
> > interrupts = <5 4>;
> > #gpio-cells = <2>;
> > gpio-controller;
> > interrupt-controller;
> > };
> >
> > dbgu {
> > pins = < &pioB 12 0 0
> > &pioB 13 0 2 >;
> > /* with macro */
> > pins = < &pioB 12 MUX_A NO_PULL_UP
> > &pioB 13 MUX_A PULL_UP >;
> > };
>
> I could change to use this too no problem. The only concern I have is
> that is "&pioB 12" immutable for all gpio controllers?
>
> Grepping the *.dts* files, at least exynos is using the following
> for gpios:
>
> gpios = <&gpx2 0 0 0 2>;
>
> If we can conclude that phandle to the gpio controller instance and
> the register offset is always enough here, then I'm OK changing to
> that format. It would actually save some parsing in most cases.
I would said yes but we could use the same notion to create pin-bank
the idea is to refer to the bank and then the pin inside
after if a driver need more argumement as on exynos they will have to
implement their own xlate
as we did on at91 for the irq xlate
>
> > /* and also the notion of linked group
> > * as on uart of network you have often the same subset of pin use.
> > *
> > * As example on uart rxd/txd is use for the group without rts/cts
> > * and the one with it
> > * on ethernet the RMII pin are use also on MII
> > */
> >
> > uart0_rxd_txd {
> > pins = < &pioB 19 MUX_A PULL_UP /* rxd */
> > &pioB 18 MUX_A NO_PULL_UP >; /* txd */
> > };
> >
> > uart0_rts_cts {
> > groups = < &uart0_rxd_txd >;
> > pins = < &pioB 17 MUX_B NO_PULL_UP /* rts */
> > &pioB 15 MUX_B NO_PULL_UP >; /* cts */
> > };
> >
> > uart0_rts_cts_external_pull_up {
> > groups = < &uart0_rts_cts >;
> > gpios = <&pioC 1 0>;
> > };
> > };
> >
> > The idea is to avoid duplication the xlate for pins will be driver specific
> > with maybe a common implementation
> >
> > the 3 or 4 first fix as done on gpio
>
> Yeah sounds doable to me, but can probably be added later?
for the sub-group stuff yes agreed
>
> Regarding grouping, basically for most cases it makes sense to have
> three states: default, active, idle instead of just active and idle.
> The reason is that for most cases the default pins only need to be
> set once for each devices. Only few pins need to toggle between
> active and idle states.
yeah agreed
Best Regards,
J.
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