Quoting Heiko Stübner (2015-01-08 14:30:01) > Hi Kever, > > Am Montag, 17. November 2014, 22:55:36 schrieb Kever Yang: > > To support all kinds of frequency requirement for HDMI on rk3288, > > we need a PLL that can change rate at run time. > > > > There are some discussion before at [0], I think we can just leave > > the npll for HDMI(DCLK_VOP0) used to make it simple. > > > > Comments are welcome. > > I think I said it in private somewhere already, but just so it's also > available publically: > > I don't think customizing/limiting the clock usage like this will fly, > especially as this would require each and every rk3288 board to use vop0 for > hdmi and vop1 for other stuff. > > With the new rk3288 Firefly devboard this concern already becomes reality. > There a vga converter is connected to VOP0, which leaves only vop1 for hdmi if > one wants to support the vga connection. > > > From our discussion about this problem I remember that the missing clock > frequencies only affected more esotheric screen resolutions, so personally I'm > not this much concerned an would like to wait till we find a better solution to > the problem. Ack. We shouldn't have to limit the possible hardware configurations in software just to keep things simple. This points to a deficiency in the clock framework. This is a common concern: how to change a clock frequency for one user without exploding all of the other users. Do you think Tomeu's constraints API[0] might be a step in the right direction for you? [0] http://lkml.kernel.org/r/<1421071809-17402-3-git-send-email-tomeu.vizoso@xxxxxxxxxxxxx> Regards, Mike > > > Heiko -- 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
