Re: need help getting SPI controller working on 405EX
From: Lorenz Kolb <hidden>
Date: 2009-08-09 14:08:19
Nathan French wrote:
quoted hunk
Hi, I am trying to add support for the 405EX's SPI controller on a Kilauea board. I've added the below to the device tree (under plb/opb/): [nfrench@nfrench-laptop linux-2.6-denx]$ diff -C2 arch/powerpc/boot/dts/kilauea.dts spi.dts *** arch/powerpc/boot/dts/kilauea.dts 2009-05-05 15:56:16.000000000 -0700--- spi.dts 2009-08-06 08:42:19.000000000 -0700*************** *** 207,210 ****--- 207,221 ---- #size-cells = <0>; }; + + SPI0: spi@ef600600 { + cell-index = <0>; + compatible = "ibm,spi-405ex", "ibm,spi"; + reg = <ef600600 6>; + interrupts = <8 4>; + interrupt-parent = <&UIC0>; + mode = "cpu"; + }; RGMII0: emac-rgmii@ef600b00 {
That entry within the device tree will generally make the spi-"bus" known to Linux, that's ok so far.
I've also compiled my kernel with the following enabled:
CONFIG_SPI=y
CONFIG_SPI_MASTER=y
CONFIG_SPI_SPIDEV=y
I see this make it into the device tree after boot:
[root@10.2.3.28 /]$ find /proc/device-tree/ | grep spi
/proc/device-tree/plb/opb/spi@ef600600
/proc/device-tree/plb/opb/spi@ef600600/name
/proc/device-tree/plb/opb/spi@ef600600/mode
/proc/device-tree/plb/opb/spi@ef600600/interrupt-parent
/proc/device-tree/plb/opb/spi@ef600600/interrupts
/proc/device-tree/plb/opb/spi@ef600600/reg
/proc/device-tree/plb/opb/spi@ef600600/compatible
/proc/device-tree/plb/opb/spi@ef600600/cell-index
But I don't see any /dev/spidev* devices created or any mention of SPI
at boot time. I'm starting to suspect that I don't have the kernel
configured right, otherwise I would see at least the SPI driver
complaining about something, right?
For getting spidev devices you have to add entries for an spidev device
to your newly created spi-"bus". So what you are currently missing are
the spidev child-nodes in the device tree.
As I'm currently cut off from some device to test, no guaranty that it
will work, but your dts entry should look something like:
SPI0: spi@ef600600 {
cell-index = <0>;
compatible = "ibm,spi-405ex", "ibm,spi";
reg = <ef600600 6>;
interrupts = <8 4>;
interrupt-parent = <&UIC0>;
mode = "cpu";
yourdevice@0 {
compatible = "spidev";
spi-max-frequency = <1000000>; /* what ever your
max-freq. is */
reg = <0>; /* Chipselect-address */
};
};
Thanks, Nathan French
At least something similar worked for me some months ago (before we switched to a "real" driver for some custom peripheral). Regards, Lorenz