auxdisplay: ht16k33: Drop struct ht16k33_seg

The struct ht16k33_seg is repeating struct linedisp. Use the latter
directly.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: ht16k33: Switch to use line display character mapping

Since line display library supports necessary bits to map the characters
(if required), switch this driver to use that.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: ht16k33: Define a few helper macros

Define a few helper macros — wrappers on container_of() — for easier
maintenance in the future. While at it, include missing container_of.h.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: ht16k33: Move ht16k33_linedisp_ops down

We will need the update functions to be defined before
ht16k33_linedisp_ops. Move the latter down in the code.
No functional change intended.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: ht16k33: Add default to switch-cases

Currently the compiler (GCC) is able to figure out that there is no
other choices possible than those that are already listed in the
switch-cases. However, if we want to move some code to the callback,
compiler will start complaining that no default is defined. Make
sure we have all switch-cases equiped with default.

Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: linedisp: Allocate buffer for the string

Always allocate a buffer for the currently displayed characters.
It makes the line display API simpler.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: linedisp: Provide struct linedisp_ops for future extension

Currently the line display library doesn't scale in case we want to
provide more operations. Prepare the library to take a newly created
struct linedisp_ops that scales.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

auxdisplay: linedisp: Move exported symbols to a namespace

Avoid unnecessary pollution of the global symbol namespace by
moving library functions in to a specific namespace and import
that into the drivers that make use of the functions.

For more info: https://lwn.net/Articles/760045/

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

fbdev: Push pgprot_decrypted() into mmap implementations

If a driver sets struct fb_ops.fb_mmap, the fbdev core automatically
calls pgprot_decrypted(). But the default fb_mmap code doesn't handle
pgprot_decrypted().

Move the call to pgprot_decrypted() into each drivers' fb_mmap function.
This only concerns fb_mmap functions for system and DMA memory. For
I/O memory, which is the default case, nothing changes. The fb_mmap
for I/O-memory can later be moved into a helper as well.

DRM's fbdev emulation handles pgprot_decrypted() internally via the
Prime helpers. Fbdev doesn't have to do anything in this case. In
cases where DRM uses deferred I/O, this patch updates fb_mmap correctly.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-30-tzimmermann@suse.de

auxdisplay/ht16k33: Initialize fb_ops with fbdev macros

Initialize the instance of struct fb_ops with fbdev initializer
macros for framebuffers in virtual address space. Set the read/write,
draw and mmap callbacks to the correct implementation and avoid
implicit defaults. Also select the necessary helpers in Kconfig.

Fbdev drivers sometimes rely on the callbacks being NULL for a
default I/O-memory-based implementation to be invoked; hence
requiring the I/O helpers to be built in any case. Setting all
callbacks in all drivers explicitly will allow to make the I/O
helpers optional. This benefits systems that do not use these
functions.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-11-tzimmermann@suse.de

auxdisplay/ht16k33: Set FBINFO_VIRTFB flag

The ht16k33 driver operates on system memory. Mark the framebuffer
accordingly. Helpers operating on the framebuffer memory will test
for the presence of this flag.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-10-tzimmermann@suse.de

auxdisplay: Remove flag FBINFO_FLAG_DEFAULT from fbdev drivers

The flag FBINFO_FLAG_DEFAULT is 0 and has no effect, as struct
fbinfo.flags has been allocated to zero by framebuffer_alloc(). So do
not set it.

Flags should signal differences from the default values. After cleaning
up all occurrences of FBINFO_DEFAULT, the token will be removed.

v2:
* fix commit message (Miguel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Robin van der Gracht <robin@protonic.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20230715185343.7193-10-tzimmermann@suse.de

auxdisplay: Switch i2c drivers back to use .probe()

After commit b8a1a4cd5a98 ("i2c: Provide a temporary .probe_new()
call-back type"), all drivers being converted to .probe_new() and then
03c835f498b5 ("i2c: Switch .probe() to not take an id parameter")
convert back to (the new) .probe() to be able to eventually drop
.probe_new() from struct i2c_driver.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230525205840.734432-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay/ht16k33: Use struct fb_info.screen_buffer

Use info->screen_buffer when reading and writing framebuffers in
system memory. It's the correct pointer for this address space.

The struct fb_info has a union to store the framebuffer memory. This can
either be info->screen_base if the framebuffer is stored in I/O memory,
or info->screen_buffer if the framebuffer is stored in system memory.

As the driver operates on the latter address space, it is wrong to use
.screen_base and .screen_buffer must be used instead. This also gets
rid of casting needed due to not using the correct data type.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230428122452.4856-3-tzimmermann@suse.de

i2c: Make remove callback return void

The value returned by an i2c driver's remove function is mostly ignored.
(Only an error message is printed if the value is non-zero that the
error is ignored.)

So change the prototype of the remove function to return no value. This
way driver authors are not tempted to assume that passing an error to
the upper layer is a good idea. All drivers are adapted accordingly.
There is no intended change of behaviour, all callbacks were prepared to
return 0 before.

Reviewed-by: Peter Senna Tschudin <peter.senna@gmail.com>
Reviewed-by: Jeremy Kerr <jk@codeconstruct.com.au>
Reviewed-by: Benjamin Mugnier <benjamin.mugnier@foss.st.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Crt Mori <cmo@melexis.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Marek Behún <kabel@kernel.org> # for leds-turris-omnia
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Petr Machata <petrm@nvidia.com> # for mlxsw
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for surface3_power
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> # for bmc150-accel-i2c + kxcjk-1013
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> # for media/* + staging/media/*
Acked-by: Miguel Ojeda <ojeda@kernel.org> # for auxdisplay/ht16k33 + auxdisplay/lcd2s
Reviewed-by: Luca Ceresoli <luca.ceresoli@bootlin.com> # for versaclock5
Reviewed-by: Ajay Gupta <ajayg@nvidia.com> # for ucsi_ccg
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> # for iio
Acked-by: Peter Rosin <peda@axentia.se> # for i2c-mux-*, max9860
Acked-by: Adrien Grassein <adrien.grassein@gmail.com> # for lontium-lt8912b
Reviewed-by: Jean Delvare <jdelvare@suse.de> # for hwmon, i2c-core and i2c/muxes
Acked-by: Corey Minyard <cminyard@mvista.com> # for IPMI
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com> # for drivers/power
Acked-by: Krzysztof Hałasa <khalasa@piap.pl>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

auxdisplay: ht16k33: remove superfluous header files

ht16k33.c doesn't use any macro or function declared in
linux/slab.h. Thus, these files can be removed from ht16k33.c
safely without affecting the compilation.

Signed-off-by: Mianhan Liu <liumh1@shanghaitech.edu.cn>
Acked-by: Robin van der Gracht <robin@protonic.nl>
[reworded]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Make use of device properties

The device property API allows drivers to gather device resources from
different sources, such as ACPI, and lift the dependency on Device Tree.
Convert the driver to unleash the power of the device property API.

Suggested-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Add LED support

Instantiate a single LED based on the "led" subnode in DT.
This allows the user to control display brightness and blinking (backed
by hardware support) through the LED class API and triggers, and exposes
the display color. The LED will be named
"auxdisplay:<color>:<function>".

When running in dot-matrix mode and if no "led" subnode is found, the
driver falls back to the traditional backlight mode, to preserve
backwards compatibility.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Add support for segment displays

The Holtek HT16K33 LED controller is not only used for driving
dot-matrix displays, but also for driving segment displays.

Add support for 4-digit 7-segment and quad 14-segment alphanumeric
displays, like the Adafruit 7-segment and 14-segment display backpack
and FeatherWing expansion boards. Use the character line display core
support to display a message, which will be scrolled if it doesn't fit.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Extract frame buffer probing

Extract all frame buffer (including backlight) probing into
ht16k33_fbdev_probe().

Call ht16k33_fbdev_probe() after ht16k33_keypad_probe(), as the latter
does not need any manual cleanup in the probe error path.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Extract ht16k33_brightness_set()

Extract brightness handling into a helper function, so it can be called
from multiple places.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Move delayed work

Move delayed_work from ht16k33_fbdev to ht16k33_priv, as it is not
specific to dot-matrix displays, but common to all display types.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Add helper variable dev

This driver has many users of "client->dev". Add shorthands to simplify
the code.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Convert to simple i2c probe function

ht16k33_probe() does not use the passed i2c_device_id, so the driver can
be converted trivially to the new-style of i2c probing.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Remove unneeded error check in keypad probe()

There is no need to check the return code of input_register_device(),
just propagate it to the caller.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Use HT16K33_FB_SIZE in ht16k33_initialize()

Use the existing HT16K33_FB_SIZE definition instead of open-coding the
same calculation using an hardcoded value.
While at it, restore reverse Christmas tree variable declaration order.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Fix frame buffer device blanking

As the ht16k33 frame buffer sub-driver does not register an
fb_ops.fb_blank() handler, blanking does not work:

$ echo 1 > /sys/class/graphics/fb0/blank
sh: write error: Invalid argument

Fix this by providing a handler that always returns zero, to make sure
blank events will be sent to the actual device handling the backlight.

Reported-by: Robin van der Gracht <robin@protonic.nl>
Suggested-by: Robin van der Gracht <robin@protonic.nl>
Fixes: 8992da44c6805d53 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Connect backlight to fbdev

Currently /sys/class/graphics/fb0/bl_curve is not accessible (-ENODEV),
as the driver does not connect the backlight to the frame buffer device.
Fix this moving backlight initialization up, and filling in
fb_info.bl_dev.

Fixes: 8992da44c6805d53 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: ht16k33: Fix refresh rate handling

Drop the call to msecs_to_jiffies(), as "HZ / fbdev->refresh_rate" is
already the number of jiffies to wait.

Fixes: 8992da44c6805d53 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

dt-bindings: auxdisplay: ht16k33: Keyscan function should be optional

Keyscan should be optional to support simple LED matrix displays (output
only).

Reported-by: Michael Kaplan <M.KAPLAN@evva.com>
Signed-off-by: Robin van der Gracht <robin@protonic.nl>
[geert: Rebased]
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: constify fb ops

Now that the fbops member of struct fb_info is const, we can start
making the ops const as well.

Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Cc: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/31c18e3ce9d6962aabda4799b3051039ff591c92.1575390741.git.jani.nikula@intel.com

auxdisplay: ht16k33: Make ht16k33_fb_fix and ht16k33_fb_var constant

The static structures ht16k33_fb_fix and ht16k33_fb_var, of types
fb_fix_screeninfo and fb_var_screeninfo respectively, are not used
except to be copied into other variables. Hence make both of them
constant to prevent unintended modification.
Issue found with
Coccinelle.

Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay/ht16k33.c: Convert to use vm_map_pages_zero()

While using mmap, the incorrect values of length and vm_pgoff are
ignored and this driver goes ahead with mapping fbdev.buffer
to user vma.

Convert vm_insert_pages() to use vm_map_pages_zero(). We could later
"fix" these drivers to behave according to the normal vm_pgoff
offsetting simply by removing the _zero suffix on the function name
and if that causes regressions, it gives us an easy way to revert.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay: ht16k33: fix potential user-after-free on module unload

On module unload/remove, we need to ensure that work does not run
after we have freed resources. Concretely, cancel_delayed_work()
may return while the callback function is still running.

From kernel/workqueue.c:

The work callback function may still be running on return,
unless it returns true and the work doesn't re-arm itself.
Explicitly flush or use cancel_delayed_work_sync() to wait on it.

Link: https://lore.kernel.org/lkml/20190204220952.30761-1-TheSven73@googlemail.com/
Reported-by: Sven Van Asbroeck <thesven73@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay: Replace licenses with SPDX identifiers

Cc: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Willy Tarreau <w@1wt.eu>
Acked-by: Linus Walleij <triad@dflund.se>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay: ht16k33: use le16_to_cpup() to fetch LE16 data

The data read from the device is 3 little-endian words, so let's
annotate them as such and use le16_to_cpu() to convert them to host
endianness - it might turn out to be a bit more performant, and it
expresses the conversion more clearly.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: ht16k33: don't access uninitialized data

gcc-7.0.1 points out that we copy uninitialized data from the stack
into a per-device structure:

drivers/auxdisplay/ht16k33.c: In function 'ht16k33_keypad_irq_thread':
arch/x86/include/asm/string_32.h:78:16: error: 'new_state' may be used uninitialized in this function [-Werror=maybe-uninitialized]
arch/x86/include/asm/string_32.h:79:22: error: '*((void *)&new_state+4)' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The access is harmless because we never read the data, but we are better
off not doing this, so this changes the code to only copy the data
that was actually initialized. To make sure we don't overflow the
stack with an incorrect DT, we also need to add a sanity checkin the
probe function.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Robin van der Gracht <robin@protonic.nl>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: ht16k33: remove private workqueue

There is no need for the driver to use private workqueue, standard system
workqueue should suffice as they are going to use the same worker pool
anyway.

Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: ht16k33: rework input device initialization

This patch fixes following issues in input device (keypad) handling:

- requesting IRQ before allocating and initializing parts of the device
that can be referenced from IRQ handler is racy, even if we try to
disable interrupt after requesting it. Let's move allocations around
so that everything is ready by the time we request IRQ.

- using threaded interrupt handler to schedule a work item it sub-optimal.
Disabling and then re-enabling interrupts in work item and in open/close
methods is prone to races and exactly the reason theraded interrupts were
introduced. Let's use the infrastructure properly and keep scanning the
matrix array in IRQ thread, stopping when there are no keys, or when told
to do so.

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: ht16k33: do not try to free fbdev

'fbdev' is allocated as part of larger ht16k33_priv structure; trying to
free it will cause troubles.

Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: ht16k33: Driver for LED controller

Added a driver for the Holtek HT16K33 LED controller with keyscan.

Signed-off-by: Robin van der Gracht <robin@protonic.nl>
CC: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Acked-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>