staging: fbtft: Rectify GPIO handling

The infamous commit c440eee1a7a1 ("Staging: staging: fbtft: Switch to
the GPIO descriptor interface") broke GPIO handling completely.
It has already four commits to rectify and it seems not enough.
In order to fix the mess here we:

1) Set default to "inactive" for all requested pins

2) Fix CS#, RD#, and WR# pins polarity since it's active low
and GPIO descriptor interface takes it into consideration
from the Device Tree or ACPI

3) Consolidate chip activation (CS# assertion) under default
->reset() callback

To summarize the expectations about polarity for GPIOs:

RD# Low
WR# Low
CS# Low
RESET# Low
DC or RS High
RW High
Data 0 .. 15 High

See also Adafruit learning course [1] for the example of the schematics.

While at it, drop unneeded NULL checks, since GPIO API is tolerant to that.

[1]: https://learn.adafruit.com/adafruit-2-8-and-3-2-color-tft-touchscreen-breakout-v2/downloads

Fixes: 92e3e884887c ("Staging: fbtft: Fix GPIO handling")
Fixes: b918d1c27066 ("Staging: fbtft: Fix reset assertion when using gpio descriptor")
Fixes: dbc4f989c878 ("Staging: fbtft: Fix probing of gpio descriptor")
Fixes: c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor interface")
Cc: Jan Sebastian Götte <linux@jaseg.net>
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Reviewed-by: Phil Reid <preid@electromag.com.au>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210503172114.27891-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Fix GPIO handling

Commit c440eee1a7a1 ("Staging: fbtft: Switch to the gpio descriptor
interface") breaks GPIO handling. In several places, checks to only set
a GPIO if it was configured ended up backwards.
I have tested this fix. The fixed driver works with a ili9486
display connected to a raspberry pi via SPI.

Fixes: c440eee1a7a1d ("Staging: fbtft: Switch to the gpio descriptor interface")
Tested-by: Jan Sebastian Götte <linux@jaseg.net>
Reviewed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Jan Sebastian Götte <linux@jaseg.net>
Link: https://lore.kernel.org/r/75ada52f-afa1-08bc-d0ce-966fc1110e70@jaseg.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: line over 80 characters

Fix the checkpatch.pl warning
WARNING: line over 80 characters

Signed-off-by: Bhagyashri Dighole <digholebhagyashri@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: 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: fb_ssd1331: fix mirrored display

When the row scan order is reversed (the default) we also need to
reverse the column scan order. This was not done previously, resulting
in a mirrored display.

Also add support for 180 degree display rotation, in which case simply
disable reversed row and column scan order.

Tested on an Adafruit 0.96" mini Color OLED display.

Signed-off-by: Johannes H. Jensen <joh@pseudoberries.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging/fbtft: Hush checkpatch.pl warning about unnecessary line continuations

Use a single string literal as the fmt argument passed to dev_err()
instead of multiple string literals split with an embedded backslash
character.

Signed-off-by: Alexander Kapshuk <alexander.kapshuk@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: fix unaligned parentheses

Fix the following formatting issues:
CHECK: Alignment should match open parenthesis

Signed-off-by: Umang Raghuvanshi <u@umangis.me>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: change 'gamma' array to u32

Having a local variable of 1024 bytes on 64-bit architectures is a bit
too much, and I ran into this warning while trying to see what functions
use the largest stack:

drivers/staging/fbtft/fbtft-sysfs.c: In function 'store_gamma_curve':
drivers/staging/fbtft/fbtft-sysfs.c:132:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]

As there is no need for 64-bit gamma values (on 32-bit architectures,
we don't use those either), I'm changing the type from 'unsigned long'
to 'u32' here, which cuts the required space in half everywhere.

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

staging: fbtft: fb_ssd1331: Fix checkpatch warning

Fix checkpatch.pl warning:
Block comments use * on subsequent lines

Signed-off-by: Anson Jacob <ansonjacob.aj@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: fb_ssd1331: Remove unnecessary cast

Compiler can typecast variables implicitly so, explicit type cast is not
required and should be removed.
Semantic patch used:

@@
type T;
T e;
identifier x;
@@

* T x = (T)e;

Signed-off-by: Shivani Bhardwaj <shivanib134@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 : Fix multiple/missing blank line issues

Remove or add blank lines as recommended by checkpatch.pl

Signed-off-by: Anish Bhatt <anish@chelsio.com>
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: clean dev_err() logging

This patch removes __func__ from dev_err. dev_err includes information about:
(devcice, driver, specific instance of device, etc) in the log printout.
This was done using Coccinelle, with the following semantic patch:

@a@
expression E, R;
expression msg;
@@

dev_err(E, msg, __func__, R);

@script:python b@
e << a.msg;
y;
@@

if(e.find("%s: ") == True):
m = e.replace("%s: ", "", 1);
coccinelle.y = m;
elif(e.find("%s ") == True):
m = e.replace("%s ", "", 1);
coccinelle.y = m;
elif(e.find("%s:") == True):
m = e.replace("%s:", "", 1);
coccinelle.y = m;
else:
m = e.replace("%s", "",1);
coccinelle.y = m;

@c@
expression a.E, a.msg, a.R;
identifier b.y;
@@

- dev_err(E, msg, __func__, R);
+ dev_err(E, y, R);

Signed-off-by: Haneen Mohammed <hamohammed.sa@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Staging: fbtft: Convert comment from C99 style to C89 style

This patch fixes checkpatch.pl error
ERROR: do not use C99 // comments

Signed-off-by: Melike Yurtoglu <aysemelikeyurtoglu@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: fix braces {} are not necessary for single statement blocks

This patch fixes the following checkpatch.pl warning:
braces {} are not necessary for single statement blocks

Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: fbtft: add fb_ssd1331 driver

This commit adds the fb_ssd1331 driver from the fbtft project at
https://github.com/notro/fbtft.

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