USB Host Dual and Quad FTDI support with possible bugs?

[fertinator]

Hi all,

I am working on a LPC55S69 with USB host on USB0 with the OHCI driver.
I need to connect a FT4232H to the USB and interface with all 4 ports.

I got it partially working now but I did need to add 2 lines of code to the library to make it work better.

First the important configuration settings that I used:

#define CFG_TUH_CDC              4 
#define CFG_TUH_CDC_FTDI         1
#define CFG_TUH_INTERFACE_MAX    4

When connecting the FT4232 the device is recognized and proper endpoints are opened. It went wrong with the configuration thereafter. With any value of CFG_TUH_CDC higher than 1, the configuration got stuck into an endless loop.

I fixed this by changing the ift_offset in cdc_host.c in function set_config_complete from:
const uint8_t itf_offset = (p_cdc->serial_drid == SERIAL_DRIVER_ACM) ? 1 : 0;
to
const uint8_t itf_offset = p_cdc->ftdi.channel - 1;
Also the ftdi.channel is not properly updated in the driver so that needed also fixing in cdc_host.c in function ftdi_proccess_set_config

if (p_cdc->bInterfaceNumber == 0) {
TU_ASSERT(ftdi_determine_type(p_cdc));
p_cdc->ftdi.channel = 1 + xfer->setup->wIndex;
}

This solution made it at least possible to send data from LPC to the TX ports. However I am still only able to receive from 1 port, still debugging that.

It's not yet fully clear to me what the proper configuration is. For example 1 FT4232 vs 4 FT232.
In case of the FT4232 should the bInterfaceNumber property be always 0 while the ftdi_private_t ftdi.channel should be 1-4?
And for the 4 FT232 there should be 4 different bInterfaceNumber values?
What I am missing is the distinction of 1 device with 4 uarts and 4 devices with each 1 uart. I feel that is also missing from the implementation?