On Fri, Sep 12, 2008 at 04:43:22PM -0400, Jon Smirl wrote:
> I need to implement some more of the mpc5200's gpio capabilities.
>
> Right now we have:
> gpios = <&gpio_wkup 0 0>;
> first cell is index into the bank, and second is unused.
>
> What do we need to fully describe a mpc5200 gpio?
>
> 1) open drain: 1 enable
This can be described in the gpios = <> property via second cell.
> 2) interrupt: 0 no int, 1 simple, 2 wakeup, 3 both
> 3) interrupt type: 0 any transition, 1 rising, 2 falling, 3 pulse
These we describe via interrupts = <> proprty, so..
> A gpio pin would then have four cells?
>
> Or should all of this be encoded into a single cell so that the
> existing two cell syntax can be preserved?
It is still possible to preserve two cells syntax and encode
irq-specific information there, but this isn't pretty.
I think that interrupts and their information could be encoded in
the "interrupts" property... something like (QE example):
qe_pio_e: [EMAIL PROTECTED] {
#gpio-cells = <2>;
compatible = "fsl,mpc8360-qe-pario-bank",
"fsl,mpc8323-qe-pario-bank";
reg = <0x1460 0x18>;
interrupts = <0 1 2 3 4 5 6 7 8 9 ...>;
interrupt-parent = <&qeic>;
gpio-controller;
};
qeic: [EMAIL PROTECTED] {
#address-cells = <0>;
#interrupt-cells = <1>;
compatible = "fsl,qe-ic";
interrupt-controller;
reg = <0x80 0x80>;
big-endian;
interrupts = <32 8 33 8>;
interrupt-parent = <&ipic>;
};
That way it is easy to implement gpio_to_irq() call, and we won't
need to bother with interrupt-specific information in the gpios = <>.
It also correctly describes the hardware, there are really two
distinct hw units: interrupt controller and gpio controller.
Also, I think that gpio_to_irq() call would be a rare case, since
you can always specify interrupts directly, i.e.
device {
gpios = <&qe_pio_e 0 0>;
interrupts = <0>;
interrupt-parent = <&qeic>;
};
--
Anton Vorontsov
email: [EMAIL PROTECTED]
irc://irc.freenode.net/bd2
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