Re: [RFC 1/2] powerpc/5200: add general purpose timer API for the MPC5200

[Grant Likely <grant.likely@secretlab.ca>]

On Fri, Mar 6, 2009 at 2:29 PM, Jon Smirl <jonsmirl@gmail.com> wrote:
> I'm using a GPT pin in input capture mode to implement IR. I attached
> my GPT driver code. I can convert to your API. That's a really cheap
> way to do IR, just IR sensor, resistor and a cap.

The driver I posted can't do input capture mode yet, but it shouldn't
be too difficult to add.  Just another api function for setting the
mode I think.  I don't have a use for that yet, so I haven't thought
much about it.  Feel free to suggest what you think the API should
look like.

> This is my old device tree, what should the new one look like?
>
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0ir0@670 { /* General Purpose Timer 6 in In=
put mode */
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0compatible =3D "gpt-ir";
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0cell-index =3D <7>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0reg =3D <0x670 0x10>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupts =3D <0x1 0x10 0=
x0>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0interrupt-parent =3D <&mpc=
5200_pic>;
> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0};

You'd want a node for the IR device which uses the GPT node as its
interrupt controller.

so:
    gpt7: gpt@670 {
        compatible =3D "fsl,mpc5200b-gpt"
        reg =3D <0x670 0x10>;
        interrupt =3D <1 16 0>;
        interrupt-controller;
        #interrupt-cells =3D <1>;
    };

Then elsewhere:
    ir {
        compatible =3D "digispeaker,ir";  // or whatever best matches your =
board
        interrupt-parent =3D <&gpt>;
        interrupts =3D <0>;  // IIRC, '0' means irq on both edges for
the GPT irq controller
    };

g.

--=20
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.