On 07/02/2019 17:45, Tony Lindgren wrote: > Currently dsi_display_init_dsi() calls dss_pll_enable() but it is not > paired with dss_pll_disable() in dsi_display_uninit_dsi(). This leaves > the DSS clocks enabled when the display is blanked wasting about extra > 5mW of power while idle. > > The clock that is left on by not calling dss_pll_disable() is > DSS_CLKCTRL bit 10 OPTFCLKEN_SYS_CLK that is the source clock for > DSI PLL. > > We can fix this issue by by making the current dsi_pll_uninit() into > dsi_pll_disable(). This way we can just call dss_pll_disable() from > dsi_display_uninit_dsi() and the code becomes a bit easier to follow. > > However, we need to also consider that DSI PLL can be muxed for DVI too > as pointed out by Tomi Valkeinen <tomi.valkeinen@xxxxxx>. In the DVI > case, we want to unconditionally disable the clocks. To get around this > issue, we separate out the DSI lane handling from dsi_pll_enable() and > dsi_pll_disable() as suggested by Tomi in an earlier experimental patch. > > So we must only toggle the DSI regulator based on the vdds_dsi_enabled > flag from dsi_display_init_dsi() and dsi_display_uninit_dsi(). > > We need to make these two changes together to avoid breaking things > for DVI when fixing the DSI clock handling. And this all causes a > slight renumbering of the error path for dsi_display_init_dsi(). > > Suggested-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> > Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> > --- > > Changes since v1: > - Updated with Tomi's suggested changes to not break DVI with > regulator_enable() made conditional for dsi_display_init_dsi() > > - Updated comments to better describe what all goes wrong > > --- > drivers/gpu/drm/omapdrm/dss/dsi.c | 60 ++++++++++++++++--------------- > 1 file changed, 31 insertions(+), 29 deletions(-) Looks fine to me and works on panda. I'll queue this to the next merge window (I presume no rush to get this into the current -rcs, it's a bit late). Tomi -- Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
