On 6 May 2016 at 00:42, Rob Herring <robh@xxxxxxxxxx> wrote: > On Thu, May 05, 2016 at 02:34:13PM +0200, Krzysztof Kozlowski wrote: >> Hi, >> >> This is a different, second try to fix usb3503+lan on Odroid U3 board >> if it was initialized by bootloader (e.g. for TFTP boot). >> >> First version: >> http://www.spinics.net/lists/linux-usb/msg140042.html >> >> >> Problem >> ======= >> When Odroid U3 (usb3503 + smsc95xx + max77686) boots from network (TFTP), >> the usb3503 and LAN smsc95xx do not show up in "lsusb". Hard-reset >> is required, e.g. by suspend to RAM. The actual TFTP boot does >> not have to happen. Just "usb start" from U-Boot is sufficient. >> >> From the schematics, the regulator is a supply only to LAN, however >> without toggling it off/on, the usb3503 hub won appear neither. >> >> >> Solution >> ======== >> This is very similar to the MMC pwrseq behavior so the idea is to: >> 1. Move MMC pwrseq drivers to generic place, > > You can do that, but I'm going to NAK any use of pwrseq bindings outside > of MMC. I think it is the wrong way to do things. The DT should describe Huh, I didn't know that was your view of the mmc pwrseq bindings. Why didn't you NAK them before? > the devices. If they happen to be "simple" then the core can walk the > tree and do any setup. For example, look for "reset-gpios" and toggle > that GPIO. There is no need for a special node. > >> 2. Extend the pwrseq-simple with regulator toggling, >> 3. Add support to USB hub and port core for pwrseq, > > We discussed this for USB already[1] and is why we defined how to add > USB child devices. The idea is not to add pwrseq to that. I am not familiar with the USB discussion. Still, let me give you some more background to the mmc pwrseq. The idea from the mmc pwrseq bindings comes from the power-domain DT bindings, as I thought these things were a bit related. In both cases they are not directly a property of the device, but more describing a HW dependency to allow the device to work. One could probably use a child node instead of a phandle, but that wasn't chosen back then. Of course you are the DT expert, but could you perhaps tell me why a child node is better for cases like this? > > Rob > > [1] http://www.spinics.net/lists/linux-usb/msg134082.html Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
