I have been trying to find a way to get my Adafruit FT232H breakout board [1] to appear as a user space GPIO device so I can use it with libgpiod. As far as I can tell from reading table 3.5 from the datasheet [2] ACBUS5, ACBUS6, ACBUS8 and ACBUS9 should all be usable for this. I found a patch that was submitted by Karoly Pados in 2018 [3] that seemes to add support for that (though maybe only for a specific chip). Through a little bit of ftrace and printk I realized that the switch statement in ftdi_gpio_init was falling through to the default case for the FT232H [4]. I'd like to see if an expert on these mailing lists can help me to understand if what I'm trying to achieve is possible. If so, to learn how I might go about getting it working. My current guess is that I need to implement a new ftdi_gpio_init_ft232h method and possibly the modify the ftdi_read_eeprom method. But I'm not really sure. Regards, Ryan Lovelett [1] https://www.adafruit.com/product/2264 [2] https://www.ftdichip.com/Support/Documents/DataSheets/ICs/DS_FT232H.pdf [3] https://patchwork.kernel.org/patch/10614055/ [4] https://github.com/torvalds/linux/blob/v5.3/drivers/usb/serial/ftdi_sio.c#L2100-L2109
