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NanoPI Neo Core. How to activate a second SPI

Serge

By Serge
in Allwinner sunxi

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Serge

Serge

Posted
Posted

board: http://nanopi.io/nanopi-neo-core.html

image: Armbian Bionic mainline based kernel 4.19.38 from https://www.armbian.com/nanopi-neo/

There are two SPI separated buses with separated pins on NanoPi Core: SPI0 and SPI1

 

 /boot/armbianEnv.txt:

...

overlay-prefix=sun8i-h3

overlays=analog-codec i2c0 spi-spidev uart1 usbhost3

param_spidev_spi_bus=0

...

/dev/spidev0.0 presents

 

How to activate a SPI1?

martinayotte

martinayotte

Posted
Posted
2 hours ago, Serge said:

How to activate a SPI1?

With the current overlays, you can't have both SPIs at the same time, but you can create a custom SPI overlay that won't need any params and having both enabled by default.

martinayotte

martinayotte

Posted
Posted
40 minutes ago, Serge said:

does it mean the way to ./build/patch/kernel/sunxi-dev/my-super-2spi.patch?

Not necessarily ...

Such overlay could be compiled locally on the nanopi if you install DT compiler there. You can download it from http://ftp.debian.org/debian/pool/main/d/device-tree-compiler/device-tree-compiler_1.4.7-3_armhf.deb

Then, you can have something like this (not tested) : 

/dts-v1/;
/plugin/;

/ {
    compatible = "allwinner,sun8i-h3";

    fragment@0 {
	target-path = "/aliases";
	__overlay__ {
            /* Path to the SPI controller nodes */
            spi0 = "/soc@01c00000/spi@01c68000";
            spi1 = "/soc@01c00000/spi@01c69000";
        };
    };
    fragment@1 {
        target = <&spi0>;
        __overlay__ {
            pinctrl-names = "default";
            pinctrl-0 = <&spi0_pins>;
            status = "okay";
            #address-cells = <1>;
            #size-cells = <0>;
            spidev@0 {
                compatible = "spidev";
                reg = <0x0>;
                spi-max-frequency = <500000>;
            };
        };
    };
    fragment@2 {
        target = <&spi1>;
        __overlay__ {
            pinctrl-names = "default";
            pinctrl-0 = <&spi1_pins>;
            status = "okay";
            #address-cells = <1>;
            #size-cells = <0>;
            spidev@0 {
                compatible = "spidev";
                reg = <0x0>;
                spi-max-frequency = <500000>;
            };
        };
    };
};

 

Serge

Serge

Posted
  • Author
Posted

martinayotte, I've decompile original ...nanopi-neo.dtb file and found there are both spi's are enabled in .dtb file

the question is about correct parameter in armbianEnv.txt:

param_spidev_spi_bus=0

param_spidev_spi_bus=1

or

param_spidev_spi_bus=0 1 or how?

 

I didn't find any examples for using both SPIs. The most examples about SPI0 only.

 

at present project SPI1 will be used as well (it's a hardware connections of the shield) and SPI0 pins wil be used as GPIO pins.

later, I'd like to have possibility to use SPI0 also.

 

upd.:

param_spidev_spi_bus=1 - doesn't work .....upd2: conflict with serial because pin PA15  already requested by 1c28cc00.serial.....

PA15 is used bu uart3_rts_cts also (according original .dts file) but no UART3 interfaces on pinout:

http://wiki.friendlyarm.com/wiki/index.php/NanoPi_NEO_Core

I'm not going to use uart3 with rts_cts.

 

 

udp3:

I've remove all uart3 sections from decompiled .dts

now "param_spidev_spi_bus=1" is working and I can see /dev/spidev1.0

 

last question: for both SPIs using how I must setup a "param_spidev_bus"?

 

martinayotte

martinayotte

Posted
Posted
2 hours ago, Serge said:

last question: for both SPIs using how I must setup a "param_spidev_bus"?

Unfortunately, as I said before the current overlays and fixup.scr don't support double SPI.

So, use my custom overlay I've provided, compile it and place it into /boot/overlay-user/ along with entry "user_overlays=mydualspi" in /boot/armbianEnv.txt, you don't "param_spidev_bus" anymore with that.

Serge

Serge

Posted
  • Author
Posted

martinayotte, I've tried to use a SPI1 only. 

/dev/spidev1.0 presents.

tried to use a standard IO C functions (open(), read()....) and with wiringPI lib - no result

tried to analyse a phisical levels with PulseView - looks like confusion between pins and signals and wrong timing of signal.

checked pins deffinition in .dts file - all according pin names from datasheeet

tried to assign pins in .dts according results of signals from PulseView... no result

because of urgent I wrote SPI "driver" manually - now all works

please advice how to check what's wrong with hardware SPI1?

 

Serge

Serge

Posted
  • Author
Posted

Hello martinayotte

done. Double SPI is working

1. decompile /boot/dtb/sun8i-h3-nanopi-neo.dtb by command 
dtc -b 0 -O dts -I dtb -o sun8i-h3-nanopi-neo.dts sun8i-h3-nanopi-neo.dtb

all warnings ignored
2. remove all rows with UART3 because pins conflict (https://docs.armbian.com/User-Guide_Allwinner_overlays/  Overlay pinmux conflicts)

3. backup a old .dtb and compile a new .dtb

dtc -b 0 -O dtb -I dts -o sun8i-h3-nanopi-neo.dtb sun8i-h3-nanopi-neo.dts

all warnings ignored

4. create a new double-spi.dts  as you wrote before (similar to https://github.com/armbian/sunxi-DT-overlays/blob/master/sun8i-h3/sun8i-h3-spi-spidev.dts)

5.  compile a double-spi.dts with

armbian-add-overlay double-spi.dts (refer to https://docs.armbian.com/User-Guide_Allwinner_overlays/)

after that checked /boot/overlay-user for double-spi.dtbo presenting

6. in /boot/armbianEnv.txt remove from "overlay=...." all parameters about spi and all rows with "param_spi_xxx"

7. reboot

8. both spidev0.0 and spidev1.0 in /dev presents

9. in armbian-config load all kermel sources and compile spidev_test in

/usr/src/linux-source-xxx/tools/spi

10. MISO_0 and MOSI_0 are connected, MISO_1 and MOSI_1 are connected (refer to https://github.com/rm-hull/spidev-test)

spidev_test --device /dev/spidev0.0 -v
spidev_test --device /dev/spidev1.0 -v
all responds are identical

 

PS. how to use a new sun8i-h3-nanopi-neo-core.dtb with all modufucations which I need instead sun8i-h3-nanopi-neo.dtb?

martinayotte

martinayotte

Posted
Posted
2 hours ago, Serge said:

PS. how to use a new sun8i-h3-nanopi-neo-core.dtb with all modufucations which I need instead sun8i-h3-nanopi-neo.dtb?

What do you mean exactly ?

Do you simply wish that U-Boot should use a different file name ?

That could be workarounded in /boot/armbianEnv.txt by declaring "fdtfile=/boot/sun8i-h3-nanopi-neo-core.dtb" if I remember the syntax ...

 

 

Serge

Serge

Posted
  • Author
Posted

I mean:

now in /boot/armbianEnv.txt no "fdtfile" field

only "overlay_prefix=sun8i-h3"

Original DTB file which loadaed by the system is /boot/dtb/sun8i-h3-nanopi-neo.dtb (board is NanoPI Neo Core)

I'd like to keep /boot/dtb/sun8i-h3-nanopi-neo.dtb as is and create /boot/dtb/sun8i-h3-nanopi-neo-core.dtb with all modifications described above.

But in this case I have to direct the system to use a new DTB file.

martinayotte

martinayotte

Posted
Posted
1 hour ago, Serge said:

now in /boot/armbianEnv.txt no "fdtfile" field

Of course : the default value of fdtfile is hard coded at u-boot compile time, but it can be overwritten by adding it to /boot/armbianEnv.txt .

 

EDIT: BTW, I've looked at /boot/boot.scr, it seems that "fdtfile" should be without path, only the DTB filename...

martinayotte

martinayotte

Posted
Posted
15 hours ago, Serge said:

where to read about it?

The "fdtfile" trick isn't explain anywhere, you need to learn about Armbian U-Boot internals...

As I'm a developer, I've simply remembered that /boot/boot.scr is responsible of loading the DTB with specific filename according to that "fdtfile" variable with default value assign at compile time.

But any U-Boot variables values could be overwritten by assigning them new value in /boot/armbianEnv.txt since this is loaded before actually loading DTB/Kernel/uInitrd.

 

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