linux-stable.git/drivers/auxdisplay, branch linux-4.9.y

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

2021-11-26T10:48:38+00:00

[ Upstream commit afcb5a811ff3ab3969f09666535eb6018a160358 ]

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 
Signed-off-by: Miguel Ojeda 
Signed-off-by: Sasha Levin

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

2018-02-13T11:35:55+00:00

commit 09c479f7f1fbfaf848e5813996793966cd50be81 upstream.

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 
Signed-off-by: Arnd Bergmann 
Signed-off-by: Greg Kroah-Hartman

auxdisplay: img-ascii-lcd: Only build on archs that have IOMEM

2018-02-03T16:05:38+00:00

[ Upstream commit 141cbfba1d0502006463aa80f57c64086226af1a ]

This avoids the MODPOST error:

  ERROR: "devm_ioremap_resource" [drivers/auxdisplay/img-ascii-lcd.ko] undefined!

Signed-off-by: Thomas Meyer 
Acked-by: Randy Dunlap 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

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

2017-03-30T07:41:27+00:00

commit abda288bb207e5c681306299126af8c022709c18 upstream.

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...")
Signed-off-by: Dmitry Torokhov 
Tested-by: Fengguang Wu 
Signed-off-by: Greg Kroah-Hartman

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

2016-10-06T15:03:41+00:00

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 
Cc: Mauro Carvalho Chehab 
Cc: Miguel Ojeda Sandonis 
Cc: Guenter Roeck 
Cc: David S. Miller 
Cc: Greg Kroah-Hartman 
Cc: Geert Uytterhoeven 
Cc: Andrew Morton 
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

auxdisplay: ks0108: initialize local parport variable

2015-08-15T00:27:17+00:00

The local variable ks0108_parport is used by other functions to write to
the parallel port. We missed initializing it when we converted the
driver to use new Parallel Port codes.

Fixes: 4edd70c133f3 ("auxdisplay: ks0108: use new parport device model")
Reported-by: Fengguang Wu 
Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

auxdisplay: ks0108: use new parport device model

2015-08-05T20:36:49+00:00

Modify auxdisplay driver to use the new parallel port device model.

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

auxdisplay: ks0108: use min_t

2015-08-05T20:36:49+00:00

Using min_t() is preffered than using min().

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

auxdisplay: ks0108: start using pr_*

2015-08-05T20:36:48+00:00

Start using pr_* macros instead of using printk and in the process
define pr_fmt.

Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman

auxdisplay: ks0108: fix refcount

2015-08-05T20:36:48+00:00

parport_find_base() will implicitly do parport_get_port() which
increases the refcount. Then parport_register_device() will again
increment the refcount. But while unloading the module we are only
doing parport_unregister_device() decrementing the refcount only once.
We add an parport_put_port() to neutralize the effect of
parport_get_port().

Cc:  # 2.6.32+
Signed-off-by: Sudip Mukherjee 
Signed-off-by: Greg Kroah-Hartman