Pull fbdev updates from Tomi Valkeinen:
 "Small fixes and improvements to various fbdev drivers"

* tag 'fbdev-4.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tomba/linux: (24 commits)
  omapdss: extend pm notifier to handle hibernation
  OMAPDSS: Correct video ports description file path in DT binding doc
  OMAPDSS: disable VT switch
  fbdev: sh_mobile_lcdc: Fix destruction of uninitialized mutex
  video: fbdev: sh_mobile_lcdcfb: Fix ROP3 sysfs attribute parsing
  fbdev: pm3fb: cleanup some confusing indenting
  hyperv: hyperv_fb: match wait_for_completion_timeout return type
  video: fbdev: use msecs_to_jiffies for time conversions
  fbdev: via/via_clock: fix sparse warning
  video: fbdev: make of_device_id array const
  fbdev: sm501fb: use memset_io
  OMAPDSS: workaround for MFLAG + NV12 issue
  OMAPDSS: Add support for MFLAG
  OMAPDSS: setup default fifo thresholds
  OMAPDSS: DISPC: lock access to DISPC_CONTROL & DISPC_CONFIG
  OMAPDSS: DISPC: fix div by zero issue in overlay scaling
  OMAPDSS: DISPC: change sync_pclk_edge default value
  OMAPDSS: change signal_level & signal_edge enum values
  OMAPDSS: DISPC: explicit handling for sync and de levels
  OMAPDSS: DISPC: remove OMAPDSS_DRIVE_SIG_OPPOSITE_EDGES
  ...

Add handling of missed events in omap_dss_pm_notif which are
needed to support hibernation (suspend to disk).

Signed-off-by: Grygorii Strashko <Grygorii.Strashko@linaro.org>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

We don't need VT switch when suspending/resuming, so disable it. This
speeds up suspend/resume.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: NeilBrown <neil@brown.name>

Pull of-graph helpers from Philipp Zabel:
of: Add of-graph helpers to loop over endpoints and find ports by id

This series converts of_graph_get_next_endpoint to decrement the refcount of
the passed prev parameter. This allows to add a for_each_endpoint_of_node
helper macro to loop over all endpoints in a device tree node.
The of_graph_get_port_by_id function is added to retrieve a port by its known
port id (contained in the reg property) from the device tree.

It was found that having two displays enabled and having an NV12 overlay
on one of the displays will cause underflows/synclosts. Debugging this
pointed to some issue with MFLAG.

It is unclear why this issue is happening, but it looks like there is a
HW bug related to MFLAG and FIFO management. Disabling MFLAG makes this
issue go away, but then we lose the benefit of MFLAG. Also forcing MFLAG
always on makes the issue go away.

Also, using certain values for MFLAG_START, MFLAG thresholds and PRELOAD
makes the issue go away, but there was no obvious logic to which values
work and which don't.

As a workaround until more information about this is found, force MFLAG
always on to make NV12 usable.

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

OMAP5 has support for MFLAG feature, which allows DSS to dynamically
increase the priority of DISPC's DMA traffic. At the moment we don't
have support for it.

It was noticed that on DRA7 with high bandwidth use cases we see FIFO
underflows. Implementing MFLAG support removed those underflows.
Interestingly, on OMAP5 uEVM no such overflows were seen.

This patch adds a simple MFLAG implementation, where we use a fixed
MFLAG threshold value based on the FIFO size. The thresholds are set to
4/8 of fifo size for low threshold, and 5/8 of fifo size for high
threshold.

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

At the moment we don't setup FIFO thresholds by default in omapdss. It's
supposed to be done by the user of omapdss. And that is missing from
omapdrm, causing unoptimal thresholds to be used when using omapdrm.

While I believe it's in theory better to allow the user of omapdss to
setup the fifo thresholds, in practice we always use the same values,
and we could as well setup the thresholds in omapdss.

Furthermore, in omapdss init we always swap the FIFO used for GFX and WB
overlays, but we don't swap the FIFO thresholds for those overlays
(which is the reason for omapdrm using unoptimal HW reset values). So
it would make sense to setup the thresholds to account for the swapping
of the FIFOs.

So, this patch adds code to setup default FIFO tresholds at omapdss
init.

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

Dispc driver presumes that the callers handle locking for all normal
functions. However, omapdrm doesn't handle this, and presumes that all
overlay manager registers are private to that overlay manager, and thus
presumes that configurations for overlay managers can be written via
different threads freely.

For many registers the above is true. The exceptions are DISPC_CONTROL
and DISPC_CONFIG registers, which contain bits for both LCD and TV
overlay managers.

Fixing this properly in omapdrm means a big omapdrm rewrite. So, for
now, add locking to dispc for the problematic registers.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reported-by: Somnath Mukherjee <somnath@ti.com>

omapdrm doesn't always configure the overlays correctly, causing the
overlay setup functions to be called with zero timings. This leads to
division by zero error.

This happens, for example, when a HDMI cable is not connected, but a
user tries to setup a plane with scaling.

Fixing omapdrm is a big job, so for now let's check for the bad timings
in DISPC and return an error.

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

The common 'struct videomode' does not have a flag to select when the
sync signals should be driven.

The default behavior of DISPC HW is to drive the sync signal on the
opposite pixel clock edge from data signal, which is also what the
videomode_to_omap_video_timings() uses.

However, it looks like what panels usually expect is that the data and
sync signals are driven on the same edge, so let's change
videomode_to_omap_video_timings() to set the sync_pclk_edge accordingly.

Note that this only affect panels drivers that use
videomode_to_omap_video_timings(), probably when getting the video
timings directly from DT data. The drivers can still configure the
sync_pclk_edge independently if they so wish.

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