staging: fbtft: Do not hardcode SPI CS polarity inversion

The current use of the mode flag SPI_CS_HIGH is fragile: it
overwrites anything already assigned by the SPI core.

Assign ^= SPI_CS_HIGH since we might be active high
already, and that is usually the case with GPIOs used
for chip select, even if they are in practice active low.

Add a comment clarifying why ^= SPI_CS_HIGH is the right
choice here.

Reported-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20191204233230.22309-1-linus.walleij@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: Fix duplicate arguments to bitwise AND

Fix duplicated arguments to bitwise & operator.
Issue detected by coccinelle.

Signed-off-by: Jamal Shareef <jamal.k.shareef@gmail.com>
Link: https://lore.kernel.org/r/20191023215105.18049-1-jamal.k.shareef@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Switch to the gpio descriptor interface

This switches the fbtft driver to use GPIO descriptors
rather than numerical gpios:

Utilize the GPIO library's intrinsic handling of OF GPIOs
and polarity. If the line is flagged active low, gpiolib
will deal with this.

Remove gpios from platform device structure. Neither assign
statically numbers to gpios in platform device nor allow
gpios to be parsed as module parameters.

Signed-off-by: Nishad Kamdar <nishadkamdar@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: Erases some repetitive usage of function name - Style

Changes this functions to avoid using "blank" on debug twice. Improves log readability.

Signed-off-by: Leonardo Brás <leobras.c@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: remove redundant license text

Now that the SPDX tag is in all fbtft files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.

This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.

No copyright headers or other non-license-description text was removed.

Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: add SPDX identifiers

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Fix up the all of the staging fbtft drivers to have a proper SPDX
identifier, based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: remove unnecessary parantheses around assignment

Parentheses are not needed around the right hand side of an assignment.
This patch is done using Coccinelle:

@@
expression a, b;
@@

b =
-(
a
-)

Signed-off-by: Aastha Gupta <aastha.gupta4104@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: fix checkpatch decimal permissions error

Fix the following errors:
Use 4 digit octal (0777) not decimal permissions

Signed-off-by: Abdul Rauf <abdulraufmujahid@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: fixed unsigned type warnings

Replace unsigned by unsigned int in fbtft driver. Issue found by
checkpatch.

Signed-off-by: Ming Yang <minos.future@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: fb_uc1611.c: Drop void pointer cast

Void pointers need not be cast to other pointer types.
Semantic patch used:

@r@
expression x;
void* e;
type T;
identifier f;
@@

(
*((T *)e)
|
((T *)x) [...]
|
((T *)x)->f
|
- (T *)
e
)

Signed-off-by: Janani Ravichandran <janani.rvchndrn@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: use alternate screen pointer

Member screen_base in struct fb_info is declared with __iomem
qualifier causing sparse warnings when used as a regular ponter.
To avoid the warnings, instead use alternate non-__iomem pointer,
screen_buffer, troughout the driver.

Signed-off-by: Lars Svensson <lars1.svensson@sonymobile.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Remove debug messages related to DEBUG_WRITE_VMEM

Remove debug messages related to fbtft_par_dbg(DEBUG_WRITE_VMEM.. )
as this info can be obtained using kernel function tracer

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Remove debug messages

Remove debug messages related to fbtft_par_dbg(DEBUG_INIT_DISPLAY.. )
as this info can be obtained using kernel function tracer

Signed-off-by: Shraddha Barke <shraddha.6596@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: replace master->setup() with spi_setup()

Calling the setup of the SPI master directly causes a NULL pointer
dereference with master drivers without a separate setup function.
This problem is reproduceable on ARM MXS platform.

So fix this issue by using spi_setup() instead.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging/fbtft : Remove repeated set_addr_win debug messages

fbtft_par_dbg(DEBUG_SET_ADDR_WIN.. ) is repeated in every
set_addr_win() handler, this could be replicated by using the kernel
function tracer instead.

Signed-off-by: Anish Bhatt <anish@chelsio.com>
Suggested-by: Greg KH <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Add support for the Ultrachip UC1611 LCD controller

This is a driver chip for 240x160 4-bit greyscale LCDs.
It is capable of 4-wire (8 bit) or 3-wire (9 bit) SPI that have both been
tested. (It also has a 6800 or 8080-style parallel interface, but I have
not included support for it.)

Signed-off-by: Henri Chain <henri.chain@eleves.ec-nantes.fr>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>