> -----Original Message----- > From: Grazvydas Ignotas [mailto:notasas@xxxxxxxxx] > Sent: Thursday, December 10, 2009 7:31 PM > To: Hiremath, Vaibhav > Cc: Tomi Valkeinen; linux-omap@xxxxxxxxxxxxxxx > Subject: Re: DSS2 and power supplies > > On Thu, Dec 10, 2009 at 3:23 PM, Hiremath, Vaibhav <hvaibhav@xxxxxx> > wrote: > <snip> > > >> > > >> > To me the fig 15-1 does not tell that the powers are needed. > The > >> > DSS_DATA[] pins do not come from SDI/DSI blocks, but from the > main > >> DSS > >> > block. And the pin muxing component is outside also. This of > >> course > >> > doesn't really prove anything. =) > >> > >> True, but apparently vdds_dsi and/or vdds_sdi are also used to > drive > >> some data lines then (not supplying them produces blue-ish > display > >> with some parts missing). I'm working with pandora board, and I'm > >> sure > >> VPLL2 is not connected to anything else. > >> > > [Hiremath, Vaibhav] No, I think the "vdds_dsi" doesn't drive any > data in parallel mode of operation. > > I have also observed similar issue with OMAP3EVM, when you switch > the output to DVI interface, you will get bluish image. > > > > The issue came out as VPLL2_DEV_GRP (Bits 7-5) register > configuration. When you are working with LCD panel (in my case > sharp-ls037v7dw01.c), this file calls regulator_get and > regulator_enable functions which configures VPLL2_DEV_GRP to 0x2 > [Owns to P1 device group]. > > But when you switch the output to DVI, it doesn't do any > regulator_get/enable call so the VPLL2_DEV_GRP register becomes 0 > [Owns to no device group] leading to color loss. > > > > I am not regulator framework expert, so could not comment on what > is the relation of VPLL2_DEV_GRP with this issue. > > > > So what is required here is, panel_generic.c also should enable > regulator for "vdvi" > > > > I have a patch (tested on OMAP3EVM) which I submit once DSS2 goes > in. > > I think this regulator is misnamed, does VPLL2 really power DVI on > OMAP3EVM? Can you check the schematics? At least on pandora it's > connected to vdds_dsi/vdds_sdi and has nothing to do with the panel. [Hiremath, Vaibhav] yes you are right, I am really not sure how and from where the "vdvi" name came into picture. When had a Private discussion with Tomi on this, and If I understand correctly he borrowed it from old Fbdev driver. As far as OMAP3EVM is concerned, we do have VPLL2 going to sdi and dsi power supply lines. I need to understand more on how these power lines affecting parallel data lines. Is it only because that they are multiplexed with sdi/dsi? Thanks, Vaibhav -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
