After the commit 736e60ddc215b85e73bbf7da26e1cde84cc9500f ("OMAPDSS:
componentize omapdss") the dss core device will wait until all the
subdevices have been successfully probed. However, we don't have a
working driver for RFBI, so if RFBI device exists, omapdss will never
get probed.

All the .dtsi files set RFBI as disabled, except am4372.dtsi. This
causes omapdss probe to not finish on AM4 devices.

This patch makes omapdss driver skip adding rfbi device as a
subcomponent, solving the issue.

This should be reverted when we have a working RFBI driver.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: Felipe Balbi <balbi@ti.com>

At the moment when HDMI video output is stopped, we just clear the
enable bit and return. While it's unclear if this can cause any issues,
I think it's still better to wait for FRAMEDONE interrupt after clearing
the enable bit so that we're sure the HDMI IP has finished.

As we don't have any ready-made irq handling for HDMI, and this only
needs to be done when disabling the HDMI output, this patch implements a
simple loop with sleep, polling the FRAMEDONE bit.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Error handling in hdmi_power_on_full() is not correct, and could leave
resources unfreed.

Fix this by arranging the error labels correctly.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

Improve the DISPC debug print for scaling.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

The current driver does both x and y decimation on OMAP3 DSS. Testing
shows that x decimation rarely works, leading to underflows.

The exact reason for this is unclear, as the underflows seem to happen
even with low pixel clock rates, and I would presume that if the DSS can
manage a display with 140MHz pixel clock, it could manage x decimation
with factor 2 with a low pixel clock (~30MHz).

So it is possible that there is a problem somewhere else, in memory
management, or DSS DMA, or similar. I have not found anything that would
help this.

So, to fix the downscaling scaling, this patch removes x decimation for
OMAP3. This will limit some of the more demanding downscaling scenarios,
but one could argue that using DSS to downscale such a large amount is
insane in the first place, as the produced image is rather bad quality.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

The DISPC's scaling code seems to presume that decimation always
succeeds, and so we always do find a suitable downscaling setup.
However, this is not the case, and the algorithm can fail.

When that happens, the code just proceeds with wrong results, causing
issues later.

Add the necessary checks to bail out if the scaling algorithm failed.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

The DISPC driver uses 64 bit arithmetic to calculate the required clock
rate for scaling. The code does not seem to work correctly, and instead
calculates with 32 bit numbers, giving wrong result.

Fix the code by typecasting values to u64 first, so that the
calculations do happen in 64 bits.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

pixel_inc and row_inc work differently on OMAP2/3 and OMAP4+ DSS. On
OMAP2/3 DSS, the pixel_inc is _not_ added by the HW at the end of the
line, after the last pixel, whereas on OMAP4+ it is.

The driver currently works for OMAP4+, but does not handle OMAP2/3
correctly, which leads to tilted image when row_inc is used.

This patch adds a flag to DISPC driver so that the pixel_inc is added
when required.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

On OMAP3/AM43xx some scaling factors cause underflows/synclosts. After
studying this, I found that sometimes the driver uses three-tap scaling
with downscaling factor smaller than x0.5. This causes issues, as x0.5
is the limit for three-tap scaling.

The driver has FEAT_PARAM_DOWNSCALE parameter, but that seems to be for
five-tap scaling, which allows scaling down to x0.25.

This patch adds checks for both horizontal and vertical scaling. For
horizontal the HW always uses 5 taps, so the limit is x0.25.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>