Dear Peng Fan, In message <db6pr0402mb2760ecb86dd133520449792c88...@db6pr0402mb2760.eurprd04.prod.outlook.com> you wrote: > > > > > > > > +static const struct udevice_id ci_udc_otg_ids[] = { > > > > > + { .compatible = "fsl,imx27-usb-gadget" }, > > > > > + { } > > > > > +}; > > > > > > > > What is imx27-usb-gadget ? > > > > > > This U-Boot specific compatible string. I have no better idea what we > > > need use here to make DM driver work. > > > > But what is "imx27" ? This is a i.MX8M family platform, right? > > Not ancient i.MX27 ? > > This is just a compatible string means all controllers compatible with > i.MX27 USB could use this driver. > > Yes this is for i.MX8MM, but the usb gadget feature could reuse > the i.MX27 code.
Maybe I'm missing something, but I cannot find imx27-usb-gadget being used anywhere - not in U-Boot nor in Linux mainline ? And if we introduce this completely new - then why imx27 ? Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de If you think the problem is bad now, just wait until we've solved it. Epstein's Law