Both TCON clocks are very sensitive to clock changes, since any change
might lead to improper timings.

Make sure our rate is never changed.
Tested-by: NGiulio Benetti <giulio.benetti@micronovasrl.com>
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/d5224d2e81ecf73dc09f234e580ada52c00eaee3.1519204731.git-series.maxime.ripard@bootlin.com

I noticed that with 4.16-rc1 LVDS output on A83T based TBS A711 tablet doesn't
work (there's output but it's garbled). I compared some older patches for LVDS
support with the mainlined ones and this change is missing from mainline Linux.

I don't know what the register does exactly and the harcoded register value
doesn't inspire much confidence that it will work in a general case, so I'm
sending this RFC.

This patch fixes the issue on A83T.
Signed-off-by: NOndrej Jirman <megous@megous.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180222161217.23904-1-megous@megous.com

We accidentally passed the wrong variable to PTR_ERR().

Fixes: a0c1214e ("drm/sun4i: Add LVDS support")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180115081113.wlam5wkmdynisf4r@mwanda

Add support for the A83T display pipeline.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/614b430adf3a67320362a75c01b01bd53013da8a.1513854122.git-series.maxime.ripard@free-electrons.com

The TCON supports the LVDS interface to output to a panel or a bridge.
Let's add support for it.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7fbb85f33ee1d5009fde4f0d7d236e11ca58b114.1513854122.git-series.maxime.ripard@free-electrons.com

The various outputs the TCON can provide have different constraints on the
dotclock divider. Let's make them configurable by the various mode_set
functions.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/92ff5881c8f8674056d34458b2f264cd48d4e136.1513854122.git-series.maxime.ripard@free-electrons.com

The commit 4c7f16d1 ("drm/sun4i: Fix TCON clock and regmap
initialization sequence") moved a bunch of logic around, but forgot to
update the gotos after the introduction of the err_free_dotclock label.

It means that if we fail later that the one introduced in that commit,
we'll just to the old label which isn't free the clock we created. This
will result in a breakage as soon as someone tries to do something with
that clock, since its resources will have been long reclaimed.

Cc: <stable@vger.kernel.org>
Fixes: 4c7f16d1 ("drm/sun4i: Fix TCON clock and regmap initialization sequence")
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f83c1cebc731f0b4251f5ddd7b38c718cd79bb0b.1512662253.git-series.maxime.ripard@free-electrons.com

The sun4i DRM driver maintains a list of compatible strings it uses to
check if a device node within the display component graph is a TCON.
The TCON driver also has this list, used to bind the TCON driver to
the device. These two lists are identical.

Instead of maintaining two identical lists, export the list from the
TCON driver for the DRM driver to use.
Suggested-by: NRob Herring <robh@kernel.org>
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171127084632.25511-1-wens@csie.org

The A20 display pipeline has 2 frontends, 2 backends, and 2 TCONs.
This patch adds support (or a compatible string in the frontend's
case) for these components.

The TCONs support directly outputting to CPU/RGB/LVDS LCD panels,
or it can output to HDMI via an on-chip HDMI controller, or
CVBS/YPbPr/VGA signals via on-chip TV encoders. These additional
encoders are not covered in this patch.
Signed-off-by: NJonathan Liu <net147@gmail.com>
[wens@csie.org: Expand commit message]
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171017121807.2994-6-wens@csie.org

The A10 has two TCONs that are similar to the ones found on other SoCs.
Like the A31, TCON0 has a register used to mux the TCON outputs to the
downstream encoders. The bit fields are slightly different.
Signed-off-by: NJonathan Liu <net147@gmail.com>
[wens@csie.org: Reworked for A10 and fixed up commit message]
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171017121807.2994-3-wens@csie.org

Some channel0 setup has to be done, no matter what the output interface is
(RGB, CPU, LVDS). Move that code into a common function in order to avoid
duplication.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/183100/

Just like we did for the TCON enable and disable, for historical reasons we
used to rely on the encoders calling the TCON mode_set function, while the
CRTC has a callback for that.

Let's implement it in order to reduce the boilerplate code.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/faa3a4d511039af1d116270dfef3a8b60ca3591e.1508231063.git-series.maxime.ripard@free-electrons.com

So far, we've required all the TCON-connected encoders to call the TCON
enable and disable functions.

This was made this way because in the RGB/LVDS case, the TCON is the CRTC
and the encoder. However, in all the other cases (HDMI, TV, DSI, etc.), we
have another encoder down the road that needs to be programmed.

We also needed to know which channel the encoder is connected to, which is
encoder-specific.

The CRTC's enable and disable callbacks can work just fine for our use
case, and we can get the channel to use just by looking at the type of
encoder, since that is fixed. Implement those callbacks, which will
remove some of the encoder boilerplate.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/90b4396e19b3eca61b2ebfdae0672074b88ad74d.1508231063.git-series.maxime.ripard@free-electrons.com

The drm_display_mode pointer can be mark const, so let's do it.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e6f92f126640aa6de639386f9b4677db3d8bb37b.1508231063.git-series.maxime.ripard@free-electrons.com

The drm_display_mode pointer can be mark const, so let's do it.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/b0cce5a43fc3b56953d21a54fc3c14672f755f42.1508231063.git-series.maxime.ripard@free-electrons.com

On systems with 2 TCONs such as the A31, it is possible to demux the
output of the TCONs to one encoder.

Add support for this for the A31.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010032008.682-3-wens@csie.org

Different SoCs have different muxing options and values for the TCON
outputs. Instead of stuffing every possibility in sun4i_tcon_set_mux(),
add a callback pointer to sun4i_tcon_quirks that each TCON variant
can use to provide muxing support.

The current muxing options in sun4i_tcon_set_mux() for sun5i-a13 are
moved to a new sun5i-specific callback function.

Since the new callback replaces what the .has_unknown_mux field in
tcon quirks did in the past, the field is removed.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171010032008.682-2-wens@csie.org

The TCON has a mux to select the source of the data to display.
This mux includes selecting the display backends. On the A31,
which has two display pipelines, this mux can let the TCON
select either backend as its data source. Although the muxing
can be changed on the fly, DRM needs to be able to group a
bunch of layers such that they get switched to another crtc
together. This is because the display backend does the layer
compositing, while the TCON generates the display timings.
This constraint is not supported by DRM.

Here we simply pair up backends and TCONs with the same ID.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170908075016.18657-7-wens@csie.org

Now that sun4i_tcon_find_engine_traverse() usage is restricted to the
single input case, we can remove the for_each_available_child_of_node
loop.

While at it, consolidate all the of_node_put calls into a common exit
path.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170908075016.18657-6-wens@csie.org

The device tree binding for sun4i-drm says:

    For all connections between components up to the TCONs in the display
    pipeline, when there are multiple components of the same type at the
    same depth, the local endpoint ID must be the same as the remote
    component's index. For example, if the remote endpoint is Frontend 1,
    then the local endpoint ID must be 1.

We should be able to get the TCON's ID directly from any of the remote
endpoints from its input port. With the ID, we can then go through the
list of registered engines and find a matching one by ID.

However the A31 device tree is incorrect. We assumed that there were no
cross pipeline connections between the backends and TCONs. As a result,
in all the endpoints between the backends and TCONs of the second
display pipeline, the endpoint IDs were incorrectly set to 0, when in
fact they should've been set to 1.

To maintain compatibility with this incorrect device tree, we first
check if the TCON's input port has 1 or many endpoints. If there are
more than 1, then it is likely a fixed version, and we can proceed
with the new method. If there is only 1 endpoint, then it is possibly
an incorrect version, or it could be the SoC only has one pipeline.
In either case we fall back to using the old method of traversing
the input connections to find a matching engine, and then get its
ID.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170908075016.18657-5-wens@csie.org

The patch b317fa3b ("drm/sun4i: tcon: Find matching display backend
by device node matching") assumed a one-to-one mapping between TCONs
and backends. This turned out wrong, as we found muxing controls in the
TCON of the A31, and undocumented usage of the backend output selector
of the A20.

Make sun4i_tcon_find_engine() bail out if the current node has multiple
input connections.

Fixes: b317fa3b ("drm/sun4i: tcon: Find matching display backend
		      by device node matching")
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170908075016.18657-4-wens@csie.org

When binding the TCON, we were checking the reset control status and
asserting reset if it wasn't in reset. The check failed to account for
the reset control API returning error codes if the status callback was
not implemented.

Since we want the TCON to be reset in all cases, use reset_control_reset
to force a reset instead.

Fixes: 9026e0d1 ("drm: Add Allwinner A10 Display Engine support")
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170908090016.32224-1-wens@csie.org

It appears that the total vertical resolution needs to be doubled when
we're not in interlaced. Make sure that is the case.
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Both TCON channels need to have the resolution doubled, since the size the
hardware is going to use is whatever we put in the register divided by two.

However, we handle it differently for the two channels: in the channel 0,
our register access macro does the multiplication of the value passed as
paremeter, while in the channel 1, the macro doesn't do this, and we need
to do it before calling it.

Make this consistent by aligning the channel 0 with the channel 1
behaviour.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

It seems like what's called a backporch in the datasheet is actually the
backporch plus the sync period. Fix that in our driver.
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Even though that mux is undocumented, it seems like it needs to be set to 1
when using composite, and 0 when using HDMI.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The muxing can actually happen on both channels on some SoCs, so it makes
more sense to just move it out of the sun4i_tcon1_mode_set function and
create a separate function that needs to be called by the encoders.

Let's do that and convert the existing drivers.
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

While all functions have debug logs, the channel enable and disable are not
logged. Make sure this is the case.
Acked-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Allwinner V3s SoC features a TCON without channel 1.

Add support for it.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.io>
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

As we are going to add support for the Allwinner DE2 engine in sun4i-drm
driver, we will finally have two types of display engines -- the DE1
backend and the DE2 mixer. They both do some display blending and feed
graphics data to TCON, and is part of the "Display Engine" called by
Allwinner, so I choose to call them both "engine" here.

Abstract the engine type to a new struct with an ops struct, which contains
functions that should be called outside the engine-specified code (in
TCON, CRTC or TV Encoder code).

In order to preserve bisectability, we also switch the backend and layer
code in its own module.
Signed-off-by: NIcenowy Zheng <icenowy@aosc.io>
Reviewed-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Currently we are configuring the TCON's dot clock or special clock
directly from the encoder mode_set functions. Since we already
provide mode_set helper functions for the TCON's 2 channels, we
can set the respective clock from those helpers, and reduce the
exposure of the TCON's internals.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The tcons and backends have a one-to-one relationship. Their IDs,
or indexes in the documentation, are also the same.

Copy the ID from the associated backend and save it in the tcon
structure. This will later be used when we add support for the
output data path muxes.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

With Allwinner's Display Engine 1.0, each TCON's input is tied to a
specific display backend, and the 2 comprise what is known as a crtc
in DRM KMS land: The layer, framebuffer, and compositing functions are
provided by the backend, while the TCON provides the display timing
signals and vblank interrupts. This 1 to 1 relationship is represented
in the device tree. On some systems there is an intermediate DRC
component.

Pointers to both matching components must be provided when initializing
the crtc. As the backend is always registered before the associated
tcon, we can recursively search upwards through the of_graph to find
the matching backend.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

To support multiple display pipelines, we need to keep track of the
multiple display backends and TCONs registered with the driver.

Switch to lists to track registered components. Components are only
appended to their respective lists if the bind process was successful.
The TCON bind function now defers if a backend was not registered.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

Similar to the previous commit, convert drivers open coding OF graph
parsing to use drm_of_find_panel_or_bridge instead.

This changes some error messages to debug messages (in the graph core).
Graph connections are often "no connects" depending on the particular
board, so we want to avoid spurious messages. Plus the kernel is not a
DT validator.
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-by: NArchit Taneja <architt@codeaurora.org>
Tested-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: NMaxime Ripard <maxime.ripard@free-electrons.com>
[seanpaul dropped rockchip changes since they're now obsolete]
Signed-off-by: NSean Paul <seanpaul@chromium.org>

sun4i_crtc controls the backend and tcon hardware blocks of the display
pipeline.

Pass pointers to the underlying devices into the crtc init function,
instead of trying to fetch them from the drm_device structure. This
avoids the headache of trying to figure out which devices the crtc
is actually associated with.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The backporch programmed into the tcon registers is actually the
backporch + hsync length from the display timings, as indicated in
the interface timing diagrams found in the user manual of the A31
and A33 SoCs.

The comments for channel 0 mistakenly describe the discrepancy as
TCON backporch = frontporch + hsync.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The TCON driver calls sun4i_tcon_init_regmap and sun4i_tcon_init_clocks
in its bind function. The former creates a regmap and writes to several
register to clear its configuration to a known default. The latter
initializes various clocks. This includes enabling the bus clock for
register access and creating the dotclock.

In order for the first step's writes to work, the bus clock must be
enabled which is done in the second step. but the dotclock's ops use
the regmap created in the first step.

Rearrange the function calls such that the clocks are initialized before
the regmap, and split out the dot clock creation to after the regmap is
initialized.

Fixes: 9026e0d1 ("drm: Add Allwinner A10 Display Engine support")
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The RGB encoder represents channel 0 of the TCON. Instead of fetching
the pointer to its TCON from the main sun4i_drv structure, pass it in
as part of the init call, save it, and use it directly in the encoder
and connector callbacks.

We can also drop the otherwise unused sun4i_drv pointer.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>

The tcon provides part of the functionality of the crtc, and also
provides the device node for the output port of the crtc. To be able
to use drm_of_find_possible_crtcs(), all crtc must be initialized before
any downstream encoders. The other part of the crtc is the display
backend.

The Rockchip DRM driver does this by first binding all vops, which is
their crtc, and this step also creates the crtc objects. Then all
remaining hardware components are bound. With the Allwinner display
pipeline, we have multiple components comprising the crtc, and varying
depths of the display pipeline. Since components are added with a depth
first search of the of_graph, we can initialize the crtc object within
the tcon bind function. Since the backend precedes the tcon, and the
backends cannot be muxed or switched around, we can be sure that the
associated backend is already initialized.

This patch also moves the crtc pointer from the main drm_device data to
the tcon device data. Besides the crtc callbacks, the crtc structure is
only used within the tcon driver to signal vblank events from its
interrupt handler.

As the crtc and layer bits are now called from the tcon bits, we must
move them from the sun4i-drm module to the sun4i-tcon module to avoid
circular dependencies between the two modules. This is because sun4i-drm
also calls into sun4i-tcon.
Signed-off-by: NChen-Yu Tsai <wens@csie.org>
Signed-off-by: NMaxime Ripard <maxime.ripard@free-electrons.com>