[PATCH 1_2/8] omap: dss: Fix minimum PCD value

This patch was partly included, but some parts were missing. This patch adds the missing stuff.

The current driver had a hardcoded minimum value of 2 for pixel clock
divisor (PCD). This doesn't seem to be right.

OMAP4 TRM says that PCD can be 1 when not downscaling, and inverted
pixel clock (IPC) is off.

OMAP3 TRM says the same, but also in the register descriptions that PCD
value 1 is invalid.

OMAP2 TRM says PCD 2 is the minimum.

OMAP2 is still untested, but for both OMAP3 and OMAP4 PCD of 1 seems to
work fine.

This patch adds a new DSS feature, FEAT_PARAM_DSS_PCD, which is used to
find the minimum and maximum PCD. The minimum is set to 2 for OMAP2, and
1 for OMAP3/4.
[PATCH 3_4/8] OMAP: DSS2: HDMI: change regn definition

regn divider is currently programmed to the registers without change,
but when calculating clock frequencies it is used as regn+1.

To make this similar to how DSI handles the dividers this patch changes
the regn value to be used as such for calculations, but the value
programmed to registers is regn-1.

This simplifies the clock frequency calculations, makes it similar to
DSI, and also allows us to use regn value 0 as undefined
[PATCH 5/8] OMAP: DSS2: DISPC: Add missing IRQ definitions

Add IRQ definitions for missing OMAP4 IRQs: FRAMEDONEWB, FRAMEDONETV,
WBBUFFEROVERFLOW.
[PATCH 6/8] OMAP: DSS2: add dss_get_hdmi_venc_clk_source()

Add dss_get_hdmi_venc_clk_source(), which can be used to get the value
programmed with dss_select_hdmi_venc_clk_source(). This can be used to
find out if the digit output is going to VENC or HDMI.

For OMAP2/3 dss_get_hdmi_venc_clk_source() always returns
DSS_VENC_TV_CLK.
[PATCH 7/8] OMAP: DSS2: DISPC: improve dispc_mgr_enable_digit_out()

dispc_mgr_enable_digit_out() didn't handle HDMI case very well.

Improve the function to use FRAMEDONETV interrupt to see when HDMI has
been disabled.
[PATCH 8/8] OMAP: DSS2: HDMI: fix hdmi output enable

Enabling HDMI output often causes sync lost errors. The problem seems to
go away if we first enable the HDMI output, and only then enable the
DISPC output.

This will also fix the dispc's dispc_mgr_enable_digit_out(), as the code
waits for two VSYNCs after enabling the output. If the HDMI output is
disabled (as it was previously), there are no VSYNCs and
dispc_mgr_enable_digit_out() will print timeout errors.