SPI and I2C for Rockchip

[Seraphim]

Hi everyone here. I was wondering is there any way to enable the SPI and I2C interfaces for Tinker? They have posted the kernel source and it seems that drivers for those are present there. Is there any chance to use SPI and I2C as of now?

[mcerveny]

SPI (3x) and I2C (6x) are in use now. You can study DeviceTree or newer from kernel sources and/or rk3288 Technical resource manuals (i2c) and (spi), schematics, connector and hardware config:

Code:

# cat /boot/hw_intf.conf
intf:i2c1=on
intf:i2c4=on
intf:spi2=on
intf:pwm2=on
intf:pwm3=on
intf:uart1=on

i2c0 - "pmu" - used internally for power management - chip rk808
i2c1 - "sensor" - on connector pin3+5
i2c2 - "audio" - on connector MIPI-CSI (camera) + eeprom (at24c08)
i2c3 - "cam" - on connector MIPI-DSI (display)
i2c4 - "tp" - on connector pin27+28
i2c5 - "hdmi" - used as hdmi ddc

spi0 - disabled - multiplexed with GPIO on connector pins 11,13,15,29,31
spi1 - disabled
spi2 - on connector pins 19,21,23,24,26

devices:
/dev/i2c*
/dev/spi*
find /sys/devices/platform/*i2c
find /sys/devices/platform/*spi
find /sys/firmware/devicetree/base/i2c*
find /sys/firmware/devicetree/base/spi*

Is there any chance to use SPI and I2C as of now?

Yes, you can use it too to be happy tinker/hacker.

[Seraphim]

SPI (3x) and I2C (6x) are in use now. You can study DeviceTree or newer from kernel sources and/or rk3288 Technical resource manuals (i2c) and (spi), schematics, connector and hardware config:

Code:

# cat /boot/hw_intf.conf
intf:i2c1=on
intf:i2c4=on
intf:spi2=on
intf:pwm2=on
intf:pwm3=on
intf:uart1=on

i2c0 - "pmu" - used internally for power management - chip rk808
i2c1 - "sensor" - on connector pin3+5
i2c2 - "audio" - on connector MIPI-CAM (touch+camera module) + eeprom (at24c08)
i2c3 - "cam" - on connector MIPI-DSI
i2c4 - "tp" - on connector pin27+28
i2c5 - "hdmi" - used as hdmi ddc

spi0 - disabled - multiplexed with GPIO on connector pins 11,13,15,29,31
spi1 - disabled
spi2 - on connector pins 19,21,23,24,26

devices:
/dev/i2c*
/dev/spi*
find /sys/devices/platform/*i2c
find /sys/devices/platform/*spi
find /sys/firmware/devicetree/base/i2c*
find /sys/firmware/devicetree/base/spi*

Is there any chance to use SPI and I2C as of now?

Yes, you can use it too to be happy tinker/hacker.

I understand that. However I can not find out how to place new drivers in system and how interface with them (My tries with Python an C fails). As of now system sees the interfaces, but when I run i2cdetect -y 1 there is no recognition. Please, advice the algorithm. Thank you in advance.

[mcerveny]

I understand that. However I can not find out how to place new drivers in system and how interface with them (My tries with Python an C fails). As of now system sees the interfaces, but when I run i2cdetect -y 1 there is no recognition. Please, advice the algorithm. Thank you in advance.

If you need kernel-level drivers you need modify main DeviceTree or make DeviceTree overlay (see CONFIG_OF_CONFIGFS) and enable driver in kernel. Search the internet.
If you need userspace access python is sufficient.

I attached BMP180 gadget to pins 1+3+5+9 (eg. i2c1). It is i2c bus gadget and it has embedded bus pull-up resistors on PCB.
"i2cdetect" works for me okay (TinkerOS1.4 kernel). I also prepared simple testing code (attached) for BMP180 in python and run it without problems.

Code:

# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- 77                         
# apt-get install python-smbus
# python bmp180.py
calibration data: 7321 -1007 -14425 33081 25481 21174 6515 32 -32768 -11786 2313
22.4 °C     980.7 hPa (rel. pres=1008.5 hPa)
22.4 °C     980.7 hPa (rel. pres=1008.5 hPa)
22.4 °C     980.8 hPa (rel. pres=1008.6 hPa)
22.4 °C     980.8 hPa (rel. pres=1008.5 hPa)
^C

[mcerveny]

More examples: https://github.com/sabrigultekin/Asus-Tinker-Board

[mcerveny]

spi2 - on connector pins 19,21,23,24,26

Do not use TinkerOS (or rockchip-linux derivates) with SPI driver "CONFIG_SPI_ROCKCHIP" ! It works only up to 32 bytes length transfers and sends random length and random data to device if more data is requested (and results to SPI chip is unpredictable). Issue#19 was logged. UPDATE: resolved with TinkerOS >= 2.0.1

[DVE]

Hi all,

Stupid question: finally, can I use SPI0, or its permanently disabled?

I have this config now:
cat /boot/hw_intf.conf
intf: spi0=off
...
intf: spi2=on

[DVE]

Small addition to the old post: even if I enable

Code:

"intf:spi0=on" in /boot/hw_intf.conf, "ls /dev/spi*"

 does not show it.

[Tinker Board]

Small addition to the old post: even if I enable

Code:

"intf:spi0=on" in /boot/hw_intf.conf, "ls /dev/spi*"

 does not show it.

Hi DVE,

That is our know issue...but have been fixed.
You can take a try by compiling and replace with new kernel, base-on https://github.com/TinkerBoard/debian_kernel/ (develop branch).

Or wait our next release image version.
Thanks.

[DVE]

Thanks. Will it be in 2.0.7, or later?

I am using SPI0 in my project but I don't want to replace kernel myself, so it would be nice to know, do I need to add software SPI in the project or not.