Am Montag, den 16.11.2015, 17:49 +0100 schrieb Hans de Goede: > Hi, > > On 16-11-15 17:04, Chen-Yu Tsai wrote: > > On Mon, Nov 16, 2015 at 11:42 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > >> On Sun, 15 Nov 2015, Hans de Goede wrote: > >> > >>> From: Reinder de Haan <patchesrdh@xxxxxxxxx> > >>> > >>> At least the EHCI found on the Allwinnner H3 SoC needs multiple reset > >>> lines, the controller will not initialize while the reset for its > >>> companion OHCI is still asserted, which means we need to de-assert > >>> 2 reset-controllers for this EHCI controller to work. > >> > >> I assume that reset_control_deassert() is smart enough to maintain a > >> count of de-assertions, and it doesn't actually turn on the reset line > >> until the count drops to 0. Right? > > > > No it doesn't. That might be a problem when 2 devices (such as EHCI / OHCI > > pairs) share a reset line, one probes successfully while the other doesn't. > > Hans? > > Ugh, good catch Alan, so I think the best way to solve this is to > actually make reset_control do a deassert / (re)assert count like > is done already for clocks, there is bound to be more hardware out there > which shares a reset line between 2 related blocks. > > I'll whip up a patch for this, submit it and then we'll see. If there are two devices sharing the same reset line that is initially held asserted, do the two drivers somehow have to synchronize before releasing the reset together? regards Philipp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
