>>>>> "Bruce" == Bruce Leonard <[EMAIL PROTECTED]> writes:
Hi,
Bruce> I'm seriously confused by how things are supposed to work now
Bruce> with device trees on the PowerPC arch. I'm bringing up our
Bruce> custom HW which is bassed on the mpc8347e, with an m41t00 RTC
Bruce> hanging off the i2c bus, U-boot is 1.2.0, kernel is 2.6.22.
Bruce> My problem is I can't get the kernel to access the RTC. It
Bruce> works fine in U-boot, but nothing in the kernel.
Bruce> I've searched through all the device tree files that come with
Bruce> the kernel
Bruce> and I can't find any that explicitly show an external device
Bruce> as a child node to a SoC I2C controller but it sure seems to
Bruce> me that the purpose of the device tree is to describe to the
Bruce> kernel all the hardware in the system. Therefore it seems to
Bruce> me that there should be something like the following in the
Bruce> device tree:
Bruce> <snip>
Bruce> [EMAIL PROTECTED] {
Bruce> device_type = "i2c";
Bruce> compatible = "fsl-i2c";
Bruce> reg = <3000 100>;
Bruce> interrupts = <e 8>;
Bruce> interrupt-parent = < &ipic >;
Bruce> dfsrr;
You need to add #address/size-cells to the I2C node, E.G.:
+ #address-cells = <1>;
+ #size-cells = <0>;
Bruce> [EMAIL PROTECTED] {
Bruce> device_type = "rtc";
Bruce> something;
Bruce> something;
Bruce> something;
Bruce> }
Bruce> }
Bruce> <snip>
You need to set compatible and reg, E.G.
[EMAIL PROTECTED] {
device_type = "rtc";
compatible = "stm,m41t00";
reg = <54>;
};
And it should get picked up automatically by
fsl_soc.c:of_find_i2c_driver().
Notice that you will need to use galak's git tree
(git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc.git) or
apply the following patch:
http://ozlabs.org/pipermail/linuxppc-dev/2007-September/042896.html
As it isn't in mainline yet.
--
Bye, Peter Korsgaard
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