Guys:
Ok, I have gpio_to_irq() more-or-less showing signs of life for the
MPC5200. But I'm having some trouble using it the way I want to.
Recall that I have a rotary encoder that's tied to IRQ2 and
GPIO_WKUP_7. I want to be able to describe it something like this:
rotary-encoder {
compatible = "linux,rotary-encoder","rotary-encoder";
interrupts = <&mpc5200_pic 2 3 &gpio_wkup 0 1>; // "IRQ2 on the
MPC5200 PIC,
// and pin 0 on GPIO_WKUP"
type = <1>; // what event signal to generate
val-ccw = <0x4a>; // what code to use for counter-clockwise rotation
val-cw = <78>; // what code to use for clockwise rotation
};
I've had some limited success with this, but not for any good reason.
It turns out that the explanation for why I was getting a valid number
for the first interrupt specification was because the device tree
compiler was assuming that the interrupt-parent was the mpc5200_pic; my
reference to the node in that list was utterly meaningless. The dtc
also appears to have ignored the &gpio_wkup word, and interpreted the
following zero as being the zero-th interrupt channel in the
mpc5200_pic. Or something like that. Clearly, I don't understand the
device tree syntax at all yet.
Anyway, when I change the statement to this:
rotary-encoder {
compatible = "linux,rotary-encoder","rotary-encoder";
interrupt-parent = <&gpio_wkup>;
interrupts = <0 0>;
type = <1>;
val-ccw = <0x4a>;
val-cw = <78>;
};
... then the magic number that the dtc comes up with is causing my new
chained interrupt handler for the gpio_wkup peripheral to come alive.
(Of course it doesn't actually work yet, but that's not the point!)
So here's my question: does the device tree compiler/syntax limit you to
only one interrupt parent?
I think the answer is no, because what I'm trying to do doesn't seem
that much different from how one specifies GPIO pins coming from
different controllers.
Any suggestions?
b.g.
--
Bill Gatliff
b...@billgatliff.com
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
