I know that this post is quite old and I hope you got it fixed. I use
kernel 3.12.10 and I can make the can device up without any problem.
However I can't get any can mesaages from another board which I am %100
sure that it is working properly. I use candump utility to check received
packets. I am suspicious about the changes I made in am335x-boneblack.dts
file. Here are the lines I added in the file.
dcan0_pins: dcan0_pins {
pinctrl-single,pins = <
0x178 0x12/*(SLEWCTRL_FAST | PIN_INPUT_PULLUP | MUX_MODE2)
0x17C 0x32/*(SLEWCTRL_FAST | PIN_INPUT_PULLUP | MUX_MODE2)
>;
};
&dcan0 {
#address-cells = <1>;
#size-cells = <0>;
pinctrl-names = "default";
pinctrl-0 = <&dcan0_pins>;
status = "okay";
};
This is the node in am33xx.dtsi file,
dcan0: d_can@481cc000 {
compatible = "bosch,d_can";
ti,hwmods = "d_can0";
clocks = <&dcan0_fck>;
clock-names = "fck";
reg = <0x481cc000 0x2000
0x44e10644 0x4>;
interrupts = <52>;
status = "disabled";
};
Can you share your changes in am335x-boneblack.dts file?
15 Kasım 2013 Cuma 02:45:06 UTC+2 tarihinde AndrewTaneGlen yazdı:
>
> Using the new 3.12 mainline kernel and Robert C Nelson's Ubuntu rootfs
> I've managed to get both CAN devices working. However, it get a warning
> when the device boots:
>
> c_can_platform 481d0000.d_can: can't request region for resource [mem
> 0x44e10644-0x44e10647]
>
> What this is referring to is the fact that in the device tree definitions
> for each of the two can devices, the same register address is being
> requested. They are defined in 'am33xx.dtsi
> <https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am33xx.dtsi?id=refs/tags/v3.12>'
>
> as follows:
>
> dcan0: d_can@481cc000 {
> compatible = "bosch,d_can";
> ti,hwmods = "d_can0";
> reg = <0x481cc000 0x2000
> 0x44e10644 0x4>;
> interrupts = <52>;
> status = "disabled";
> };
>
> dcan1: d_can@481d0000 {
> compatible = "bosch,d_can";
> ti,hwmods = "d_can1";
> reg = <0x481d0000 0x2000
> 0x44e10644 0x4>;
> interrupts = <55>;
> status = "disabled";
> };
>
> For both items the address '0x44e10644 0x4', referring to the register
> 'dcan_raminit'
> (Pg 793 of spruh73h.pdf <http://www.ti.com/lit/ug/spruh73h/spruh73h.pdf>),
> is being reserved for use. The new devicetree interpreter considers any
> overlap between device register memory mappings as a problem, hence the
> message seen on boot.
>
> The register 'dcan_raminit' is in fact used by both can devices, so it
> does make sense for both to have access to it. It appears however, that
> this register is only used in the d_can driver which does not appear to be
> in use with this latest kernel release. In any case, both device work
> flawlessly (as far as I can tell) regardless of the error message.
>
> I thought I'd have a go at tidying this part of the 'am33xx.dtsi
> <https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am33xx.dtsi?id=refs/tags/v3.12>'
>
> devicetree file up a bit to get rid of this message - and this is where my
> question comes in. I thought I could make a single parent node for d_can
> with this shared register defined at the top level, and then add the two
> can devices to it as child nodes. I came up with something like this:
>
> dcan {
> #address-cells = <1>;
> #size-cells = <1>;
> reg = <0x44e10644 0x4>;
>
> dcan0: d_can@481cc000 {
> compatible = "bosch,d_can";
> ti,hwmods = "d_can0";
> reg = <0x481cc000 0x2000>;
> interrupts = <52>;
> status = "disabled";
> };
>
> dcan1: d_can@481d0000 {
> compatible = "bosch,d_can";
> ti,hwmods = "d_can1";
> reg = <0x481d0000 0x2000>;
> interrupts = <55>;
> status = "disabled";
> };
> };
>
> I tried various iterations along this line (and modified the
> am335x-boneblack.dts
> <https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/am335x-boneblack.dts?id=refs/tags/v3.12>
> file
> with the corresponding 'status = 'okay' entries for these devices), all
> of which would compile fine, and the dvice would boot with no error
> messages, but for whatever reason the devices would never show up as they
> had previously.
>
> I was wonder if anyone with a better understanding of devicetree syntax
> could suggest the correct structure for the parent/child nodes I am trying
> to create.
>
> Any help or suggestions would be greatly appreciated.
>
>
> Regards,
> Andrew Glen.
>
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