On 08.02.22 12:34, Greg KH wrote:
On Mon, Feb 07, 2022 at 02:08:23AM +0200, Dmytro Bagrii wrote:
This reverts commit 46ee4abb10a07bd8f8ce910ee6b4ae6a947d7f63.
You forgot to cc: the author of that commit, why?
Also forgot to cc: the maintainer of the driver/subsytem?
Sorry, forgot to add them. Also adding Johan Hovold, Frank A Kingswood
and Frank Zago in the loop.
CH341A has three different modes of operation selectable either by
hardware pin connections or by external EEPROM configuration. Each
mode is represented by corresponding product ID:
0x5523: Asyncronous Serial Interface
0x5584: Parallel Printer Interface
0x5512: EPP/MEM Interface
That does not corrispond with what Jan-Niklas said in the original
commit.
The page mentioned in the original commit is unavailable for me for some
reason.
I refer to the chip manufacturer documentation from here:
http://wch-ic.com/downloads/CH341DS1_PDF.html.
I have this kind of CH341A programmer:
http://www.chinalctech.com/cpzx/Programmer/Serial_Module/266.html
When mode selection jumper is set to UART:
[52206.834474] usb 1-4.1: new full-speed USB device number 10 using xhci_hcd
[52206.925482] usb 1-4.1: New USB device found, idVendor=1a86,
idProduct=5523, bcdDevice= 3.04
[52206.925494] usb 1-4.1: New USB device strings: Mfr=0, Product=0,
SerialNumber=0
[52206.973701] usbcore: registered new interface driver ch341
[52206.973710] usbserial: USB Serial support registered for ch341-uart
[52206.973720] ch341 1-4.1:1.0: ch341-uart converter detected
[52206.974424] usb 1-4.1: ch341-uart converter now attached to ttyUSB0
ch341 creates /dev/ttyUSB0 and it works as a serial port, as expected.
When mode selection jumper is set to I2C/SPI (it uses EPP/MEM Interface):
[52413.942116] usb 1-4.1: new full-speed USB device number 11 using xhci_hcd
[52414.033085] usb 1-4.1: New USB device found, idVendor=1a86,
idProduct=5512, bcdDevice= 3.04
[52414.033097] usb 1-4.1: New USB device strings: Mfr=0, Product=0,
SerialNumber=0
[52414.040928] ch341 1-4.1:1.0: ch341-uart converter detected
[52414.041930] usb 1-4.1: ch341-uart converter now attached to ttyUSB0
ch341 creates /dev/ttyUSB0 but it doesn't work.
To use CH341A programmer as I2C/SPI converter either external module is
required or userspace tools must be used. But they don't work until
ch341 handles 1a86:5512.
If unbind device from ch341 module:
# echo 1-4.1:1.0 > /sys/bus/usb/drivers/ch341/unbind
I2C/SPI tools start to work correctly.
(See "5.3.Function configuration" in datasheet at wch-ic.com/downloads/CH341DS1_PDF.html)
When CH341A is configured as EPP/MEM Interface it appears as 1a86:5512 and being mistakenly
handled by ch341 USB serial driver.
It is possible to use CH341A in EPP/MEM mode only if ch341 module is blacklisted, but it must be
unblacklisted every time to use CH341A as a serial converter. Also obviously it is impossible
to use two CH341A boards in different modes simoultaneously.
Please wrap your lines at 72 columns.
Sure. Should i submit new patch verіon then?
thanks,
greg k-h
-dmytro
