[Buildroot] [dtc] Compiling a .dts overlay
Oscar Gomez Fuente
oscargomezf at gmail.com
Mon May 9 09:57:02 UTC 2016
Hi everyone,
The dtb overlay loaded fine. I've checked this with the command: vcdbg log
msg
...
001402.187: Loading 'bcm2710-rpi-3-b.dtb' from SD card
001468.661: dtparam: uart0_clkrate=48000000
001488.609: Loaded overlay 'pi3-disable-bt'
001523.385: Loaded overlay 'tca6424a'
...
Now I can see the device: /sys/call/gpiochip488
I can access to the 24 pins of my TCA6424A IC [488 to 511]
# echo 488 > /sys/class/gpio/export
# echo "out" > /sys/class/gpio/gpio488/direction
# echo 1 > /sys/class/gpio/gpio488/value
But I couldn't see the interrupt in /proc/interrupts:
# cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3
16: 0 0 0 0 ARMCTRL 16 Edge
bcm2708_fb dma
20: 0 0 0 0 ARMCTRL 20 Edge
DMA IRQ
21: 0 0 0 0 ARMCTRL 21 Edge
DMA IRQ
24: 0 0 0 0 ARMCTRL 24 Edge
DMA IRQ
32: 424138 0 0 0 ARMCTRL 32 Edge
dwc_otg, dwc_otg_pcd, dwc_otg_hcd:usb1
49: 0 0 0 0 ARMCTRL 49 Edge
3f200000.gpio:bank0
50: 0 0 0 0 ARMCTRL 50 Edge
3f200000.gpio:bank1
65: 14 0 0 0 ARMCTRL 65 Edge
3f00b880.mailbox
66: 2 0 0 0 ARMCTRL 66 Edge
VCHIQ doorbell
75: 1 0 0 0 ARMCTRL 75 Edge
77: 554 0 0 0 ARMCTRL 77 Edge
DMA IRQ
79: 6148 0 0 0 ARMCTRL 79 Edge
3f804000.i2c
80: 0 0 0 0 ARMCTRL 80 Edge
3f204000.spi
82: 136 0 0 0 ARMCTRL 82 Edge
mmc0
83: 10895 0 0 0 ARMCTRL 83 Edge
uart-pl011
84: 9475 0 0 0 ARMCTRL 84 Edge
mmc1
96: 0 0 0 0 ARMCTRL 96 Edge
arch_timer
97: 10595 8874 3133 458 ARMCTRL 97 Edge
arch_timer
...
According to my .dts file, I've configured the pin GPIO04 as an input
[interrupt]. I think I had to see an interrupt related to tca6424a, didn't
I? but it didn't appear. I've read the kernel log and I've seen this
suspicious message:
# dmesg
..
[ 3.633230] pca953x 1-0022: interrupt support not compiled in
..
So I was surfing on the internet and It seems to be you have to select in
the kernel the option:
Device Drivers > GPIO Support > I2C GPIO expanders > [*] GPIO_PCA953X_IRQ
But If you want to select this option you can't select the driver:
PCA95[357]x, PCA9698, TCA64xx, and MAX7310 I/O ports like a module. (I
don't have any idea why?)
Eventually, everything works fine.
So this is my final tca6424a-overlay.dts [i2c1 and INT pin connected to
GPI04] working fine on my raspberry pi 3B.
---
// Definitions for TCA6424A IO Expander from Texas Instruments
/dts-v1/;
/plugin/;
/ {
compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
fragment at 0 {
target = <&i2c1>;
__overlay__ {
status = "okay";
};
};
fragment at 1 {
target = <&gpio>;
__overlay__ {
tca6424_pins: tca6424_pins {
brcm,pins = <4>;
brcm,function = <0>;
};
};
};
fragment at 2 {
target = <&i2c1>;
__overlay__ {
#address-cells = <1>;
#size-cells = <0>;
tca6424 at 22 {
compatible = "ti,tca6424";
reg = <0x22>;
pinctrl-names = "default";
pinctrl-0 = <&tca6424_pins>;
interrupt-parent = <&gpio>;
interrupts = <4 2>;
};
};
};
};
---
I would like to place this overlay dts file in
https://github.com/raspberrypi/linux.git/arch/arm/boot/dts/overlays
Does anyone know how to apply for uploading this overlay dts file, to the
person in charge of https://github.com/raspberrypi/linux?
Best regards.
On 9 May 2016 at 08:37, Oscar Gomez Fuente <oscargomezf at gmail.com> wrote:
> Hi,
>
>
> I've tried what told me Peter Seiderer, and it compiled fine: "using
> interrupts = <23 2>;". Now I'm going to check if the .dtb file works fine.
>
> Thank you very much.
>
> Best regards.
>
> Oscar Gomez Fuente
>
> On 6 May 2016 at 23:20, Nicholas Walton <nicholas.walton at gmail.com> wrote:
>
>> Plugin overlays are not part of mainline dtc. Try
>> https://git.kernel.org/cgit/utils/dtc/dtc.git and the instructions at
>> https://learn.adafruit.com/introduction-to-the-beaglebone-black-device-tree/compiling-an-overlay
>> .
>>
>> On Fri, May 6, 2016 at 5:17 AM, Oscar Gomez Fuente <oscargomezf at gmail.com
>> > wrote:
>>
>>> Hi,
>>>
>>> I'm working with the latest stable release: 2016.02 and with the
>>> raspberry pi 3B.
>>>
>>> I'm trying to compile my own .dtb overlay, because I need to add the IO
>>> Expander i2c TCA6424A to my HW. And I would like to know how to do this
>>> using overlays and device tree.
>>>
>>> But I've got this error when I tried to compile de .dts file:
>>>
>>> # dtc -I dts -O dtb -o tca6424a-overlay.dtb tca6424a-overlay.dts
>>> Error: tca6424a-overlay.dts:3.2-8 syntax error
>>> FATAL ERROR: Unable to parse input tree
>>> # dtc -v
>>> Version: DTC 1.4.1-g8ead5b66
>>> #
>>>
>>> This is the .dts file:
>>> ----------
>>> // Definitions for TCA6424A IO Extender from Texas Instruments
>>> /dts-v1/;
>>> /plugin/;
>>> / {
>>> compatible = "brcm,bcm2835", "brcm,bcm2708", "brcm,bcm2709";
>>>
>>> fragment at 0 {
>>> target = <&i2c1>;
>>> __overlay__ {
>>> status = "okay";
>>> };
>>> };
>>>
>>> fragment at 1 {
>>> target = <&gpio>;
>>> __overlay__ {
>>> tca6424_pins: tca6424_pins {
>>> brcm,pins = <4>;
>>> brcm,function = <0>;
>>> };
>>> };
>>> };
>>>
>>> fragment at 2 {
>>> target = <&i2c1>;
>>> __overlay__ {
>>> #address-cells = <1>;
>>> #size-cells = <0>;
>>> tca6424 at 22 {
>>> compatible = "ti,tca6424";
>>> reg = <0x22>;
>>> pinctrl-names = "default";
>>> pinctrl-0 = <&tca6424_pins>;
>>> interrupt-parent = <&gpio4>;
>>> interrupts = <23 IRQ_TYPE_LEVEL_LOW>;
>>> };
>>>
>>> };
>>> };
>>> };
>>> -----------
>>>
>>> Anyone could help me how to do this?
>>>
>>> Best regards.
>>>
>>> Oscar Gomez Fuente.
>>>
>>> _______________________________________________
>>> buildroot mailing list
>>> buildroot at busybox.net
>>> http://lists.busybox.net/mailman/listinfo/buildroot
>>>
>>
>>
>
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