Re: Accessing I2C-Bus via ELV USB-I2C

From time to time the I2C layer on top of the uart locks up
and can’t be recovered via its built in reset command.
Initialialization at [1]:2564 is missing the greeting message.

looking at the traffic with
	usbdump -d ugen1.3 -v -v -v -s 1024 > usb.txt
I’m missing some response data from the I2C controller.

Questions:
1. On usbdump, why is the hexdump mssing on some lines like
	frame[0] WRITE <n> bytes  ?

2. Do we have a tool to dump traffic directly on the uart layer?


Any help appreciated, Axel

[1]: https://github.com/mc3/home2l/blob/master/brownies/brownies.C
	

> Am 27.04.2022 um 23:08 schrieb Axel Rau <Axel.Rau@chaos1.de>:
> 
> Next journey starts:
> 
> For the home2l project, I need a supported I2C interface via USB.
> I got this one:
> https://de.elv.com/elv-usb-ic-interface-usb-i2c-092255?fs=1805459039
> Unfortunately it shows up as a serial device on FreeBSD:
> 
> ugen0.2: <Silicon Labs ELV USB-I2C-Interface> at usbus0, cfg=0 md=HOST spd=FULL (12Mbps) pwr=ON (500mA)
> 
>  bLength = 0x0012
>  bDescriptorType = 0x0001
>  bcdUSB = 0x0110
>  bDeviceClass = 0x0000  <Probed by interface class>
>  bDeviceSubClass = 0x0000
>  bDeviceProtocol = 0x0000
>  bMaxPacketSize0 = 0x0040
>  idVendor = 0x10c4
>  idProduct = 0xea60
>  bcdDevice = 0x0100
>  iManufacturer = 0x0001  <Silicon Labs>
>  iProduct = 0x0002  <ELV USB-I2C-Interface>
>  iSerialNumber = 0x0003  <B5AAP0EEUK6A3CIZ>
>  bNumConfigurations = 0x0001
> 
> In loader.conf, I have:
> uslcom_load="YES"
> iic_load="YES"
> iicbus_loa
> 
> But the i2c utility does not show a new bus.
> 
> From dmesg:
> root@axels-bsdbox:~ # dmesg | grep iic
> ig4iic0: <Intel Sunrise Point-H I2C Controller-0> mem 0xdf230000-0xdf230fff irq 16 at device 21.0 on pci0
> ig4iic0: Using MSI
> iicbus0: <Philips I2C bus (ACPI-hinted)> on ig4iic0
> iic0: <I2C generic I/O> on iicbus0
> ig4iic1: <Intel Sunrise Point-H I2C Controller-1> mem 0xdf22f000-0xdf22ffff irq 17 at device 21.1 on pci0
> ig4iic1: Using MSI
> iicbus1: <Philips I2C bus (ACPI-hinted)> on ig4iic1
> iic1: <I2C generic I/O> on iicbus1
> root@axels-bsdbox:~ # dmesg | grep I2C
> ig4iic0: <Intel Sunrise Point-H I2C Controller-0> mem 0xdf230000-0xdf230fff irq 16 at device 21.0 on pci0
> iicbus0: <Philips I2C bus (ACPI-hinted)> on ig4iic0
> iic0: <I2C generic I/O> on iicbus0
> ig4iic1: <Intel Sunrise Point-H I2C Controller-1> mem 0xdf22f000-0xdf22ffff irq 17 at device 21.1 on pci0
> iicbus1: <Philips I2C bus (ACPI-hinted)> on ig4iic1
> iic1: <I2C generic I/O> on iicbus1
> ugen0.2: <Silicon Labs ELV USB-I2C-Interface> at usbus0
> uslcom0: <ELV USB-I2C-Interface> on usbus0
> 
> They provide a (linux) driver ("Treiber") which seems to implement the I2C protocoll on top of the serial interface.
> Do we have such a driver on FreeBSD, or exist other supported I2C devices to be plugged into USB?
> 
> Any help appreciated,
> Axel


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