I'm having trouble getting the RK3288 OTG controller (the one at ff580000) to work in peripheral mode. I'm using a Firefly Reload board, and I know the hardware is fine because I can successfully use the port in device mode with U-Boot's mass storage gadget driver. Under Linux, the OTG port works fine when used in host mode, but fails to work in device mode: nothing happens when the a USB host is plugged into the OTG port, not even a single interrupt is generated by the controller. I'm using the latest device tree definitions from git://git.kernel.org/pub/scm/linux/kernel/git/mmind/linux-rockchip.git. Tried with different gadget drivers (g_audio, g_ether, g_mass_storage), but it makes no difference. Tried also forcing peripheral mode in the device tree, with dr_mode = "peripheral", to no avail. Are there any known problems with the RK3288 OTG controller? Here is the relevant log when the dwc2 driver is loaded at boot: [ 1.376935] ff580000.usb supply vusb_d not found, using dummy regulator [ 1.383683] ff580000.usb supply vusb_a not found, using dummy regulator [ 1.390627] dwc2 ff580000.usb: dwc2_core_reset() HANG! Soft Reset GRSTCTL=80000001 [ 1.509048] dwc2 ff580000.usb: dwc2_wait_for_mode: Couldn't set device mode [ 1.750626] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g-tx-fifo-size, setting to default average [ 1.761828] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[1]=104 [ 1.771192] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[2]=104 [ 1.780529] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[3]=104 [ 1.789888] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[4]=104 [ 1.799245] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[5]=104 [ 1.808614] dwc2 ff580000.usb: dwc2_check_param_tx_fifo_sizes: Invalid parameter g_tx_fifo_size[6]=104 [ 1.817993] usb 1-1: new high-speed USB device number 2 using dwc2 [ 1.824390] dwc2 ff580000.usb: EPs: 10, dedicated fifos, 972 entries in SPRAM [ 1.832098] dwc2 ff580000.usb: DWC OTG Controller [ 1.836924] dwc2 ff580000.usb: new USB bus registered, assigned bus number 2 [ 1.844125] dwc2 ff580000.usb: irq 41, io mem 0xff580000 [ 1.849747] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002 [ 1.856598] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 1.863875] usb usb2: Product: DWC OTG Controller [ 1.868601] usb usb2: Manufacturer: Linux 4.8.1+ dwc2_hsotg [ 1.874215] usb usb2: SerialNumber: ff580000.usb and this is what I get when I load a gadget driver (in this case, g_audio): [ 19.848590] dwc2 ff580000.usb: bound driver g_audio [ 19.853816] dwc2 ff580000.usb: dwc2_hsotg_enqueue_setup: failed queue (-11) Thank you, Francesco Lavra
