When I originally wrote these docs, I couldn't manage to insert a
cross-reference to a section. Here's how it can be done.

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Pekka Paalanen <pekka.paalanen@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230803095734.386761-1-contact@emersion.fr

fbcon_registered_fb and fbcon_num_registered_fb is not referred outside
drivers/video/fbdev/core/fbcon.c, so make them static.

Signed-off-by: GUO Zihua <guozihua@huawei.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20230803020939.491-1-guozihua@huawei.com

Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20230409131547.494128-1-15330273260@189.cn


Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This bridge has an interrupt line for event signaling. Add the
corresponding property.

Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230718084411.1189831-1-alexander.stein@ew.tq-group.com

CEC interrupt status/mask and logical address registers
will be reset when device enter suspend.
It will cause cec fail to work after device resume.
Add CEC suspend/resume functions, reinitialize logical address registers
and restore interrupt status/mask registers after resume.

Signed-off-by: Sandor Yu <Sandor.yu@nxp.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230721124415.1513223-1-Sandor.yu@nxp.com

Add support for Innolux G156HCE-L01 15.6" 1920x1080 24bpp
dual-link LVDS TFT panel. Documentation is available at [1].
The middle frequency is tuned slightly upward from 70.93 MHz
to 72 MHz, otherwise the panel shows slight flicker.

[1] https://www.distec.de/fileadmin/pdf/produkte/TFT-Displays/Innolux/G156HCE-L01_Rev.C3_Datasheet.pdf



Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230731210258.256152-2-marex@denx.de

Add entry for Innolux G156HCE-L01 15.6" 1920x1080 24bpp
dual-link LVDS TFT panel. Documentation is available at [1].

[1] https://www.distec.de/fileadmin/pdf/produkte/TFT-Displays/Innolux/G156HCE-L01_Rev.C3_Datasheet.pdf



Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230731210258.256152-1-marex@denx.de

In commit d2aacaf0 ("drm/panel: Check for already prepared/enabled
in drm_panel") the formatting for a code block was not quite
right. This caused an error when building htmldocs:

  Documentation/gpu/todo.rst:469: ERROR: Unexpected indentation.

Fix the error by using the proper syntax for a code block.

Fixes: d2aacaf0 ("drm/panel: Check for already prepared/enabled in drm_panel")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/r/20230802141724.0edce253@canb.auug.org.au


Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230802074727.2.Iaeb7b0f7951aee6b8c090364bbc87b1ae198a857@changeid

In the kernel doc for the `follower_lock` member of `struct drm_panel`
there was a typo where it was called `followers_lock`. This resulted
in a warning when making "htmldocs":

  ./include/drm/drm_panel.h:270: warning:
  Function parameter or member 'follower_lock' not described in 'drm_panel'

Fix the typo.

Fixes: de087416 ("drm/panel: Add a way for other devices to follow panel state")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/r/20230802142136.0f67b762@canb.auug.org.au


Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230802074727.1.I4036706ad5e7f45e80d41b777164258e52079cd8@changeid

Pointer pexec is being assigned a value however it is never read. The
assignment is redundant and can be removed. Replace sizeof(*pexec)
with sizeof the type and remove the declaration of pointer pexec.

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@quicinc.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230726140626.264952-1-colin.i.king@gmail.com

Displays that are connected to the same SPI bus may share the D/C GPIO.
Use GPIOD_FLAGS_BIT_NONEXCLUSIVE to allow access to the same GPIO for
multiple panel-mipi-dbi instances. Exclusive access to the GPIO during
transfers is ensured by the locking in drm_mipi_dbi.c.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230724065654.5269-3-otto.pflueger@abscue.de

Multiple displays may be connected to the same bus and share a D/C GPIO,
so the display driver needs exclusive access to the bus to ensure that
it can control the D/C GPIO safely.

Signed-off-by: Otto Pflüger <otto.pflueger@abscue.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: David Lechner <david@lechnology.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230724065654.5269-2-otto.pflueger@abscue.de

DRM bridges are not visible to the userspace and it may not be
immediately clear if the chain is somehow constructed incorrectly. I
have had two separate instances of a bridge driver failing to do a
drm_bridge_attach() call, resulting in the bridge connector not being
part of the chain. In some situations this doesn't seem to cause issues,
but it will if DRM_BRIDGE_ATTACH_NO_CONNECTOR flag is used.

Add a debugfs file to print the bridge chains. For me, on this TI AM62
based platform, I get the following output:

encoder[39]
	bridge[0] type: 0, ops: 0x0
	bridge[1] type: 0, ops: 0x0, OF: /bus@f0000/i2c@20000000/dsi@e:toshiba,tc358778
	bridge[2] type: 0, ops: 0x3, OF: /bus@f0000/i2c@20010000/hdmi@48:lontium,lt8912b
	bridge[3] type: 11, ops: 0x7, OF: /hdmi-connector:hdmi-connector

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230802-drm-bridge-chain-debugfs-v4-1-7e3ae3d137c0@ideasonboard.com

Turning on an i2c-hid device can be a slow process. This is why
i2c-hid devices use PROBE_PREFER_ASYNCHRONOUS. Unfortunately, when
we're a panel follower the i2c-hid power up sequence now blocks the
power on of the panel. Let's fix that by scheduling the work on the
system_wq.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.10.I962bb462ede779005341c49320740ed95810021d@changeid

As talked about in the patch ("drm/panel: Add a way for other devices
to follow panel state"), we really want to keep the power states of a
touchscreen and the panel it's attached to in sync with each other. In
that spirit, add support to i2c-hid to be a panel follower. This will
let the i2c-hid driver get informed when the panel is powered on and
off. From there we can match the i2c-hid device's power state to that
of the panel.

NOTE: this patch specifically _doesn't_ use pm_runtime to keep track
of / manage the power state of the i2c-hid device, even though my
first instinct said that would be the way to go. Specific problems
with using pm_runtime():
* The initial power up couldn't happen in a runtime resume function
  since it create sub-devices and, apparently, that's not good to do
  in your resume function.
* Managing our power state with pm_runtime meant fighting to make the
  right thing happen at system suspend to prevent the system from
  trying to resume us only to suspend us again. While this might be
  able to be solved, it added complexity.
Overall the code without pm_runtime() ended up being smaller and
easier to understand.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.9.Ib1a98309c455cd7e26b931c69993d4fba33bbe15@changeid

In the i2c-hid remove() function we currently try to power off,
depopulate our child device, and free our resources. That's OK, but...

* If the i2c-hid device is on a power rail that can't turn off (either
  an always-on or a shared power rail) we won't try to put the device
  in a low power state during remove(). This probably doesn't matter
  for very many devices but it could be nice in some instances.

* If the i2c-hid device somehow manages to generate an interrupt after
  we tried to power off it is conceivable that the interrupt could
  arrive during or after the call to hid_destroy_device() but before
  the call to free_irq(). That could cause a crash since our IRQ
  handler isn't expecting it. One could imagine this happening in
  the case where we couldn't turn off (see the previous bullet) or,
  possibly, if the interrupt line could glitch shortly after the
  device powered off.

Let's call the suspend code during remove to avoid these issues. That
will put the device into a low power state and also disable
interrupts.

Technically, one could consider this a "fix" of commit 4a200c3b
("HID: i2c-hid: introduce HID over i2c specification implementation").
However, since the above bullet points are more theoretical than
problems seen on real systems and since the remove() of an i2c-hid
touchscreen isn't terribly likely to be called in production, it's
probably not worth the bother of trying to backport it.

Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.8.Ic3ecad4a825905f4e4ce2a772b17f3c9cb2d60a2@changeid

In a future patch we'd like to be able to call the current i2c-hid
suspend and resume functions from times other than system
suspend. Move the functions higher up in the file and have them take a
"struct i2c_hid" to make this simpler. We'll then add tiny wrappers of
the functions for use with system suspend.

This change is expected to have no functional effect.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.7.I5c9894789b8b02f029bf266ae9b4f43c7907a173@changeid

In a future patch, we want to change i2c-hid not to necessarily power
up the touchscreen during probe. In preparation for that, rearrange
the probe function so that we put as much stuff _before_ powering up
the device as possible.

This change is expected to have no functional effect.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.6.Ifcc9b0a44895d164788966f9b9511fe094ca8cf9@changeid

The SYSTEM_SLEEP_PM_OPS() allows us to get rid of '#ifdef
CONFIG_PM_SLEEP', as talked about in commit 1a3c7bb0 ("PM: core:
Add new *_PM_OPS macros, deprecate old ones").

This change is expected to have no functional effect.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.5.Ib2a2865bd3c0b068432259dfc7d76cebcbb512be@changeid

Inform fw_devlink of the fact that a panel follower (like a
touchscreen) is effectively a consumer of the panel from the purposes
of fw_devlink.

NOTE: this patch isn't required for correctness but instead optimizes
probe order / helps avoid deferrals.

Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.4.Ibf8e1342b5b7906279db2365aca45e6253857bb3@changeid

These days, it's fairly common to see panels that have touchscreens
attached to them. The panel and the touchscreen can somewhat be
thought of as totally separate devices and, historically, this is how
Linux has treated them. However, treating them as separate isn't
necessarily the best way to model the two devices, it was just that
there was no better way. Specifically, there is little practical
reason to have the touchscreen powered on when the panel is turned
off, but if we model the devices separately we have no way to keep the
two devices' power states in sync with each other.

The issue described above makes it sound as if the problem here is
just about efficiency. We're wasting power keeping the touchscreen
powered up when the screen is off. While that's true, the problem can
go deeper. Specifically, hardware designers see that there's no reason
to have the touchscreen on while the screen is off and then build
hardware assuming that software would never turn the touchscreen on
while the screen is off.

In the very simplest case of hardware designs like this, the
touchscreen and the panel share some power rails. In most cases, this
turns out not to be terrible and is, again, just a little less
efficient. Specifically if we tell Linux that the touchscreen and the
panel are using the same rails then Linux will keep the rails on when
_either_ device is turned on. That ends to work OK-ish, but now if you
turn the panel off not only will the touchscreen remain powered, but
the power rails for the panel itself won't be switched off, burning
extra power.

The above two inefficiencies are _extra_ minor when you consider the
fact that laptops rarely spend much time with the screen off. The main
use case would be when an external screen (and presumably a power
supply) is attached.

Unfortunately, it gets worse from here. On sc7180-trogdor-homestar,
for instance, the display's TCON (timing controller) sometimes crashes
if you don't power cycle it whenever you stop and restart the video
stream (like during a modeset). The touchscreen keeping the power
rails on causes real problems. One proposal in the homestar timeframe
was to move the touchscreen to an always-on rail, dedicating the main
power rail to the panel. That caused _different_ problems as talked
about in commit 557e05fa ("HID: i2c-hid: goodix: Stop tying the
reset line to the regulator"). The end result of all of this was to
add an extra regulator to the board, increasing cost.

Recently, Cong Yang posted a patch [1] where things are even worse.
The panel and touch controller on that system seem even more
intimately tied together and really can't be thought of separately.

To address this issue, let's start allowing devices to register
themselves as "panel followers". These devices will get called after a
panel has been powered on and before a panel is powered off. This
makes the panel the primary device in charge of the power state, which
matches how userspace uses it.

The panel follower API should be fairly straightforward to use. The
current code assumes that panel followers are using device tree and
have a "panel" property pointing to the panel to follow. More
flexibility and non-DT implementations could be added as needed.

Right now, panel followers can follow the prepare/unprepare functions.
There could be arguments made that, instead, they should follow
enable/disable. I've chosen prepare/unprepare for now since those
functions are guaranteed to power up/power down the panel and it seems
better to start the process earlier.

A bit of explaining about why this is a roll-your-own API instead of
using something more standard:
1. In standard APIs in Linux, parent devices are automatically powered
   on when a child needs power. Applying that here, it would mean that
   we'd force the panel on any time someone was listening to the
   touchscreen. That, unfortunately, would have broken homestar's need
   (if we hadn't changed the hardware, as per above) where the panel
   absolutely needs to be able to power cycle itself. While one could
   argue that homestar is broken hardware and we shouldn't have the
   API do backflips for it, _officially_ the eDP timing guidelines
   agree with homestar's needs and the panel power sequencing diagrams
   show power going off. It's nice to be able to support this.
2. We could, conceibably, try to add a new flag to device_link causing
   the parent to be in charge of power. Then we could at least use
   normal pm_runtime APIs. This sounds great, except that we run into
   problems with initial probe. As talked about in the later patch
   ("HID: i2c-hid: Support being a panel follower") the initial power
   on of a panel follower might need to do things (like add
   sub-devices) that aren't allowed in a runtime_resume function.

The above complexities explain why this API isn't using common
functions. That being said, this patch is very small and
self-contained, so if someone was later able to adapt it to using more
common APIs while solving the above issues then that could happen in
the future.

[1] https://lore.kernel.org/r/20230519032316.3464732-1-yangcong5@huaqin.corp-partner.google.com



Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.3.Icd5f96342d2242051c754364f4bee13ef2b986d4@changeid

In a whole pile of panel drivers, we have code to make the
prepare/unprepare/enable/disable callbacks behave as no-ops if they've
already been called. It's silly to have this code duplicated
everywhere. Add it to the core instead so that we can eventually
delete it from all the drivers. Note: to get some idea of the
duplicated code, try:
  git grep 'if.*>prepared' -- drivers/gpu/drm/panel
  git grep 'if.*>enabled' -- drivers/gpu/drm/panel

NOTE: arguably, the right thing to do here is actually to skip this
patch and simply remove all the extra checks from the individual
drivers. Perhaps the checks were needed at some point in time in the
past but maybe they no longer are? Certainly as we continue
transitioning over to "panel_bridge" then we expect there to be much
less variety in how these calls are made. When we're called as part of
the bridge chain, things should be pretty simple. In fact, there was
some discussion in the past about these checks [1], including a
discussion about whether the checks were needed and whether the calls
ought to be refcounted. At the time, I decided not to mess with it
because it felt too risky.

Looking closer at it now, I'm fairly certain that nothing in the
existing codebase is expecting these calls to be refcounted. The only
real question is whether someone is already doing something to ensure
prepare()/unprepare() match and enabled()/disable() match. I would say
that, even if there is something else ensuring that things match,
there's enough complexity that adding an extra bool and an extra
double-check here is a good idea. Let's add a drm_warn() to let people
know that it's considered a minor error to take advantage of
drm_panel's double-checking but we'll still make things work fine.

We'll also add an entry to the official DRM todo list to remove the
now pointless check from the panels after this patch lands and,
eventually, fixup anyone who is triggering the new warning.

[1] https://lore.kernel.org/r/20210416153909.v4.27.I502f2a92ddd36c3d28d014dd75e170c2d405a0a5@changeid



Acked-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.2.I59b417d4c29151cc2eff053369ec4822b606f375@changeid

As talked about in the patch ("drm/panel: Add a way for other devices
to follow panel state"), touchscreens that are connected to panels are
generally expected to be power sequenced together with the panel
they're attached to. Today, nothing provides information allowing you
to find out that a touchscreen is connected to a panel. Let's add a
phandle for this.

The proerty is added to the generic touchscreen bindings and then
enabled in the bindings for the i2c-hid backed devices. This can and
should be added for other touchscreens in the future, but for now
let's start small.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Benjamin Tissoires <bentiss@kernel.org>
Acked-by: Benjamin Tissoires <bentiss@kernel.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.1.Id68e30343bb1e11470582a9078b086176cfec46b@changeid

Add timings for InnoLux N140HCA-EAC. This panel is found on some laptops
such as Acer Aspire 1.

Signed-off-by: Nikita Travkin <nikita@trvn.ru>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230801-aspire1-cmn-panel-v1-1-c3d88e389805@trvn.ru

A very basic debugging rule when a device is connected for the first
time is to access a read-only register which contains known data in
order to ensure the communication protocol is properly working. This
driver lacked any read helper which is often a critical piece for
speeding-up bring-ups.

Add a read helper and use it to verify the communication with the panel
is working as soon as possible in order to inform the user early if this
is not the case.

As this panel may work with no MISO line, the check is discarded in this
case. Upon error, we do not fail probing but just warn the user, in case
the DT description would be lacking the Rx bus width (which is likely on
old descriptions) in order to avoid breaking existing devices.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org> # no MISO line
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-20-sre@kernel.org

This panel from Emerging Display Technologies Corporation features an
ST7789V2 LCD controller panel inside which is almost identical to what
the Sitronix panel driver supports.

In practice, the module physical size is specific, and experiments show
that the display will malfunction if any of the following situation
occurs:
* Pixel clock is above 3MHz
* Pixel clock is not inverted
I could not properly identify the reasons behind these failures, scope
captures show valid input signals.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-19-sre@kernel.org

The Sitronix datasheet explains BIT(1) of the RGBCTRL register as the
DOTCLK/PCLK edge used to sample the data lines:

    “0” The data is input on the positive edge of DOTCLK
    “1” The data is input on the negative edge of DOTCLK

IOW, this bit implies a falling edge and not a high state. Correct the
definition to ease the comparison with the datasheet.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-18-sre@kernel.org

The Sitronix controller expects 9-bit words, provide this as default at
probe time rather than specifying this in each and every access.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-17-sre@kernel.org

The ST7789V LCD controller supports regular SPI wiring, as well as no Rx
data line at all. The operating system needs to know whether it can read
registers from the device or not. Let's detail this specific design
possibility by bounding the spi-rx-bus-width property.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Tested-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-16-sre@kernel.org

The ST7789V LCD controller is also embedded in the ET028013DMA
panel. Add a compatible string to describe this other panel.

Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Reviewed-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-15-sre@kernel.org

UNI-T UTi260b has a Inanbo T28CP45TN89 v17 panel. I could not find
proper documentation for the panel apart from a technical drawing, but
according to the vendor U-Boot it is based on a Sitronix st7789v chip.
I generated the init sequence by modifying the default one until proper
graphics output has been seen on the device.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-14-sre@kernel.org

Add polarity information via mode and bus flags, so that they are no
longer hardcoded and forward the information to the DRM stack. This is
required for adding panels with different settings.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-13-sre@kernel.org

While the default panel uses invert mode, some panels
require non-invert mode instead.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-12-sre@kernel.org

Add support for describing the media bus format in the
panel configuration and expose that to userspace. Since
both supported formats (RGB565 and RGB666) are using 6
bits per color also hardcode that information.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-11-sre@kernel.org

Move the panel size information to the mode struct, so
that different panel sizes can be specified depending
on the panel type.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-10-sre@kernel.org

Avoid hard-coding the default_mode and supply it from match data. One
additional layer of abstraction has been introduced, which will be
needed for specifying other panel information (e.g. bus flags) in the
next steps.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-9-sre@kernel.org

Improve error handling in the probe routine, so that probe
defer errors are captured in /sys/kernel/debug/devices_deferred

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-8-sre@kernel.org

st7789v_spi_write initializes a message with just
a single transfer, spi_sync_transfer can be used
for that.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-7-sre@kernel.org

The reset pin might not be software controllable from the SoC,
so make it optional.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-6-sre@kernel.org

ST7789V_COLMOD_RGB_FMT_18BITS and ST7789V_COLMOD_CTRL_FMT_18BITS
are unused in favour of MIPI_DCS_PIXEL_FMT_18BIT, remove them.

Reviewed-by: Michael Riesch <michael.riesch@wolfvision.net>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230714013756.1546769-5-sre@kernel.org