auxdisplay: img-ascii-lcd: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-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>

auxdisplay: img-ascii-lcd: Make container_of() no-op for struct linedisp

Move embedded struct linedisp member to make container_of() no-op.

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: img-ascii-lcd: Use device_get_match_data()

Use preferred device_get_match_data() instead of of_match_device() to
get the driver match data. With this, adjust the includes to explicitly
include the correct headers.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Paul Burton <paulburton@kernel.org>
Link: https://lore.kernel.org/r/20231115210245.3744589-1-robh@kernel.org
[ As discussed, used `dev` and moved call to `cfg`'s initialization. ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: Extract character line display core support

Extract the character line display core support from the simple ASCII
LCD driver for the MIPS Boston, Malta & SEAD3 development boards into
its own subdriver, so it can be reused for other displays.

As this moves the "message" device attribute in sysfs in a "linedisp.N"
subdirectory, a symlink is added to preserve backwards compatibility.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: img-ascii-lcd: Convert device attribute to sysfs_emit()

Convert the "message" device attribute from sprintf() to sysfs_emit(),
as the latter is aware of the PAGE_SIZE buffer.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: img-ascii-lcd: Add helper variable dev

img_ascii_lcd_probe() has many users of "pdev->dev". Add a shorthand to
simplify the code.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: img-ascii-lcd: Fix lock-up when displaying empty string

While writing an empty string to a device attribute is a no-op, and thus
does not need explicit safeguards, the user can still write a single
newline to an attribute file:

echo > .../message

If that happens, img_ascii_lcd_display() trims the newline, yielding an
empty string, and causing an infinite loop in img_ascii_lcd_scroll().

Fix this by adding a check for empty strings. Clear the display in case
one is encountered.

Fixes: 0cad855fbd083ee5 ("auxdisplay: img-ascii-lcd: driver for simple ASCII LCD displays")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

auxdisplay: img-ascii-lcd: convert to devm_platform_ioremap_resource

Use devm_platform_ioremap_resource() to simplify code.

Signed-off-by: Yangtao Li <tiny.windzz@gmail.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: img-ascii-lcd: Silence 2 uninitialized warnings

The warnings are:

drivers/auxdisplay/img-ascii-lcd.c: warning: 'err' may be used
uninitialized in this function [-Wuninitialized]

At lines 109 and 207. Reported by Geert using the build service
several times, e.g.:

https://lkml.org/lkml/2018/2/19/303

They are two false positives, since num_chars > 0 in the three present
configurations (boston, malta, sead3). Initialize to 0 in order to
silence the warning.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay: img-ascii-lcd: Fix doc comment to silence warnings

Compiling with W=1 with gcc 7.2.0 gives 2 warnings:

drivers/auxdisplay/img-ascii-lcd.c:233: warning: Function parameter or
member 't' not described in 'img_ascii_lcd_scroll'
drivers/auxdisplay/img-ascii-lcd.c:233: warning: Excess function
parameter 'arg' description in 'img_ascii_lcd_scroll'

Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

auxdisplay: img-ascii-lcd: add missing MODULE_DESCRIPTION/AUTHOR/LICENSE

This change resolves a new compile-time warning
when built as a loadable module:

WARNING: modpost: missing MODULE_LICENSE() in drivers/auxdisplay/img-ascii-lcd.o
see include/linux/module.h for more information

This adds the license as "GPL", which matches the header of the file.

MODULE_DESCRIPTION and MODULE_AUTHOR are also added.

Signed-off-by: Jesse Chan <jc@linux.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Tested-by: Paul Burton <paul.burton@mips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Update MIPS email addresses

MIPS will soon not be a part of Imagination Technologies, and as such
many @imgtec.com email addresses will no longer be valid. This patch
updates the addresses for those who:

- Have 10 or more patches in mainline authored using an @imgtec.com
email address, or any patches dated within the past year.

- Are still with Imagination but leaving as part of the MIPS business
unit, as determined from an internal email address list.

- Haven't already updated their email address (ie. JamesH) or expressed
a desire to be excluded (ie. Maciej).

- Acked v2 or earlier of this patch, which leaves Deng-Cheng, Matt &
myself.

New addresses are of the form firstname.lastname@mips.com, and all
verified against an internal email address list. An entry is added to
.mailmap for each person such that get_maintainer.pl will report the new
addresses rather than @imgtec.com addresses which will soon be dead.

Instances of the affected addresses throughout the tree are then
mechanically replaced with the new @mips.com address.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@mips.com>
Acked-by: Dengcheng Zhu <dengcheng.zhu@mips.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@mips.com>
Acked-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

auxdisplay: Convert timers to use timer_setup()

In preparation for unconditionally passing the struct timer_list pointer to
all timer callbacks, switch to using the new timer_setup() and from_timer()
to pass the timer pointer explicitly.

Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Paul Burton <paul.burton@mips.com>
Tested-by: Paul Burton <paul.burton@mips.com> # for img-ascii-lcd

Update MIPS email addresses

MIPS will soon not be a part of Imagination Technologies, and as such
many @imgtec.com email addresses will no longer be valid. This patch
updates the addresses for those who:

- Have 10 or more patches in mainline authored using an @imgtec.com
email address, or any patches dated within the past year.

- Are still with Imagination but leaving as part of the MIPS business
unit, as determined from an internal email address list.

- Haven't already updated their email address (ie. JamesH) or expressed
a desire to be excluded (ie. Maciej).

- Acked v2 or earlier of this patch, which leaves Deng-Cheng, Matt &
myself.

New addresses are of the form firstname.lastname@mips.com, and all
verified against an internal email address list. An entry is added to
.mailmap for each person such that get_maintainer.pl will report the new
addresses rather than @imgtec.com addresses which will soon be dead.

Instances of the affected addresses throughout the tree are then
mechanically replaced with the new @mips.com address.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Cc: Deng-Cheng Zhu <dengcheng.zhu@mips.com>
Acked-by: Dengcheng Zhu <dengcheng.zhu@mips.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Matt Redfearn <matt.redfearn@mips.com>
Acked-by: Matt Redfearn <matt.redfearn@mips.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: trivial@kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/17540/
Signed-off-by: James Hogan <jhogan@kernel.org>

auxdisplay: img-ascii-lcd: Fix module autoload

If the driver is built as a module, autoload won't work because the module
alias information is not filled. So user-space can't match the registered
device with the corresponding module.

Export the module alias information using the MODULE_DEVICE_TABLE() macro.

Before this patch:

$ modinfo drivers/auxdisplay/img-ascii-lcd.ko | grep alias
$

After this patch:

$ modinfo drivers/auxdisplay/img-ascii-lcd.ko | grep alias
alias: of:N*T*Cmti,sead3-lcdC*
alias: of:N*T*Cmti,sead3-lcd
alias: of:N*T*Cmti,malta-lcdC*
alias: of:N*T*Cmti,malta-lcd
alias: of:N*T*Cimg,boston-lcdC*
alias: of:N*T*Cimg,boston-lcd

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: img-ascii-lcd: add missing sentinel entry in img_ascii_lcd_matches

The OF device table must be terminated, otherwise we'll be walking past it
and into areas unknown.

Fixes: 0cad855fbd08 ("auxdisplay: img-ascii-lcd: driver for simple ASCII...")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

auxdisplay: img-ascii-lcd: driver for simple ASCII LCD displays

Add a driver for simple ASCII LCD displays found on the MIPS Boston,
Malta & SEAD3 development boards. The Boston display is an independent
memory mapped device with a simple memory mapped 8 byte register space
containing the 8 ASCII characters to display. The Malta display is
exposed as part of the Malta board registers, and provides 8 registers
each of which corresponds to one of the ASCII characters to display. The
SEAD3 display is slightly more complex, exposing an interface to an
S6A0069 LCD controller via registers provided by the boards CPLD.
However although the displays differ in their register interface, we
require similar functionality on each board so abstracting away the
differences within a single driver allows us to share a significant
amount of code & ensure consistent behaviour.

The driver displays the Linux kernel version as the default message, but
allows the message to be changed via a character device. Messages longer
then the number of characters that the display can show will scroll.

This provides different behaviour to the existing LCD display code for
the MIPS Malta or MIPS SEAD3 platforms in the following ways:

- The default string to display is not "LINUX ON MALTA" or "LINUX ON
SEAD3" but "Linux" followed by the version number of the kernel
(UTS_RELEASE).

- Since that string tends to be significantly longer it scrolls twice
as fast, moving every 500ms rather than every 1s.

- The LCD won't be updated until the driver is probed, so it doesn't
provide the early "LINUX" string.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Miguel Ojeda Sandonis <miguel.ojeda.sandonis@gmail.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/14062/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>