Hi!
I'm working on a custom Freescale 8544-based board and having some
trouble with getting the device tree right. In particular, we have a
setup which looks like this:
* We have an FPGA which contains a few serial ports, an interrupt
controller and some other devices
* The serial ports are "normal" 16550s and interrupt the FPGA interrupt
controller
* The interrupt controller is in turn cascaded to the 8544 OpenPIC
(mpic).
My problem is that I can't figure out how to express this correctly in
the device tree for the board. My device tree looks like this ("isf" is
the name of the FPGA):
i...@c0020000 {
#address-cells = <1>;
#size-cells = <1>;
reg = <c0020000 00020000>;
isf_pic: isf_...@4000 {
device_type = "isf-pic";
compatible = "isf-pic";
interrupt-controller;
clock-frequency = <0>;
#address-cells = <0>;
#interrupt-cells = <2>;
reg = <4000 100>;
built-in;
interrupts = <4 1>;
interrupt-parent = <&mpic>;
};
serial2: isf-ser...@4200 {
device_type = "serial";
compatible = "ns16550";
reg = <4200 100>;
clock-frequency = <13ab6680>; /* 330Mhz */
interrupts = <0 1>;
interrupt-parent = <&isf_pic>;
};
<... and a few more serial ports which look the same >
Following the example set in mpc85xx_ds.c, I lookup the interrupt
controller manually in the platform setup code (init_IRQ). Basically
np = of_find_compatible_node(NULL, "isf-pic", "isf-pic");
if (np == NULL) {
printk(KERN_ERR "Could not find ISF PIC\n");
return;
}
and thereafter calling a custom setup function for the FPGA interrupt
controller. That appears to work fine, but I'm wondering how to get the
serial ports detected properly by of_serial.
I suppose I can do something similar in code to what is done in
arch/powerpc/kernel/legacy_serial.c:find_legacy_serial_ports, but I
thought I could do without that with the device trees. Is it so, or do
I have to add code to walk through and setup the rest of the serial
ports?
Thanks in advance,
// Simon
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