drm/ssd130x: Add support for the SSD133x OLED controller family

The Solomon SSD133x controllers (such as the SSD1331) are used by RGB dot
matrix OLED panels, add a modesetting pipeline to support the chip family.

The SSD133x controllers support 256 (8-bit) and 65k (16-bit) color depths
but only the 256-color mode (DRM_FORMAT_RGB332) is implemented for now.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231229112026.2797483-5-javierm@redhat.com

drm/solomon: Do not include <drm/drm_plane_helper.h>

Remove unnecessary include statements for <drm/drm_plane_helper.h>.
The file contains helpers for non-atomic code and should not be
required by most drivers. No functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231204090852.1650-6-tzimmermann@suse.de

drm/ssd130x: Add support for the SSD132x OLED controller family

The Solomon SSD132x controllers (such as the SSD1322, SSD1325 and SSD1327)
are used by 16 grayscale dot matrix OLED panels, extend the driver to also
support this chip family.

Instead adding an indirection level to allow the same modesetting pipeline
to be used by both controller families, add another pipeline for SSD132x.

This leads to some code duplication but it makes the driver easier to read
and reason about. Once other controller families are added (e.g: SSD133x),
some common code can be factored out in driver helpers to be shared by the
different families. But that can be done later once these patterns emerge.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231014071520.1342189-5-javierm@redhat.com

drm/ssd130x: Rename commands that are shared across chip families

There are some commands that are shared between the SSD130x and SSD132x
controller families, define these as a common SSD13XX set of commands.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231014071520.1342189-4-javierm@redhat.com

drm/ssd130x: Add a controller family id to the device info data

To allow the driver to have a per Solomon display controller modesetting
pipeline and support aother controller families besides SSD130x.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231014071520.1342189-3-javierm@redhat.com

drm/ssd130x: Replace .page_height field in device info with a constant

This deemed useful to avoid hardcoding a page height and allow to support
other Solomon controller families, but dividing the screen in pages seems
to be something that is specific to the SSD130x chip family.

For example, SSD132x chip family divides the screen in segments (columns)
and common outputs (rows), so the concept of screen pages does not exist
for the SSD132x family.

Let's drop this field from the device info struct and just use a constant
SSD130X_PAGE_HEIGHT macro to define the page height. While being there,
replace hardcoded 8 values in places where it is used as the page height.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20231014071520.1342189-2-javierm@redhat.com

drm/ssd130x: Use bool for ssd130x_deviceinfo flags

The .need_pwm and .need_chargepump fields in struct ssd130x_deviceinfo
are flags that can have only two possible values: 0 and 1.
Reduce kernel size by changing their types from int to bool.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/285005ff361969eff001386c5f97990f0e703838.1692888745.git.geert@linux-m68k.org

drm/ssd130x: Allocate buffer in the plane's .atomic_check() callback

Drivers are not allowed to fail after drm_atomic_helper_swap_state() has
been called and the new atomic state is stored into the current sw state.

Since the struct ssd130x_device .data_array is allocated in the encoder's
.atomic_enable callback, the operation can fail and this is after the new
state has been stored. So it can break an atomic mode settings assumption.

Fix this by having custom helpers to allocate, duplicate and destroy the
plane state, that will take care of allocating and freeing these buffers.

Suggested-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Maxime Ripard <mripard@kernel.org>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230726105433.389740-2-javierm@redhat.com

drm/ssd130x: Don't allocate buffers on each plane update

The resolutions for these panels are fixed and defined in the Device Tree,
so there's no point to allocate the buffers on each plane update and that
can just be done once.

Let's do the allocation and free on the encoder enable and disable helpers
since that's where others initialization and teardown operations are done.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609170941.1150941-5-javierm@redhat.com

drm/ssd130x: Set the page height value in the device info data

The driver only supports OLED controllers that have a page height of 8 but
there are devices that have different page heights. So it is better to not
hardcode this value and instead have it as a per controller data value.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609170941.1150941-4-javierm@redhat.com

drm/ssd130x: Make default width and height to be controller dependent

Currently the driver hardcodes the default values to 96x16 pixels but this
default resolution depends on the controller. The datasheets for the chips
describes the following display controller resolutions:

- SH1106: 132 x 64 Dot Matrix OLED/PLED
- SSD1305: 132 x 64 Dot Matrix OLED/PLED
- SSD1306: 128 x 64 Dot Matrix OLED/PLED
- SSD1307: 128 x 39 Dot Matrix OLED/PLED
- SSD1309: 128 x 64 Dot Matrix OLED/PLED

Add this information to the devices' info structures, and use it set as a
default if not defined in DT rather than hardcoding to an arbitrary value.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609170941.1150941-2-javierm@redhat.com

drm/ssd130x: Fix include guard name

This is a leftover from an early iteration of the driver when it was still
named ssd1307 instead of ssd130x. Change it for consistency with the rest.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Sui Jingfeng <suijingfeng@loongson.cn>
Link: https://patchwork.freedesktop.org/patch/msgid/20230512120232.304603-1-javierm@redhat.com

drm/ssd130x: Replace simple display helpers with the atomic helpers

The simple display pipeline is a set of helpers that can be used by DRM
drivers to avoid dealing with all the needed components and just define
a few functions to operate a simple display device with one full-screen
scanout buffer feeding a single output.

But it is arguable that this provides the correct level of abstraction
for simple drivers, and recently some have been ported from using these
simple display helpers to use the regular atomic helpers instead.

The rationale for this is that the simple display pipeline helpers don't
hide that much of the DRM complexity, while adding an indirection layer
that conflates the concepts of CRTCs and planes. This makes the helpers
less flexible and harder to be reused among different graphics drivers.

Also, for simple drivers, using the full atomic helpers doesn't require
a lot of additional code. So adding a simple display pipeline layer may
not be worth it.

For these reasons, let's follow that trend and make ssd130x a plain DRM
driver that creates its own primary plane, CRTC, enconder and connector.

Suggested-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905222759.2597186-1-javierm@redhat.com

drm/ssd130x: Make ssd130x_remove() return void

This function returns zero unconditionally, so there isn't any benefit
of returning a value. Make it return void to be able to see at a glance
that the return value of ssd130x_i2c_remove() is always zero.

This patch is a preparation for making i2c remove callbacks return void.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220425192306.59800-1-u.kleine-koenig@pengutronix.de

drm/solomon: Move device info from ssd130x-i2c to the core driver

These are declared in the ssd130x-i2c transport driver but the information
is not I2C specific, and could be used by other SSD130x transport drivers.

Move them to the ssd130x core driver and just set the OF device entries to
an ID that could be used to lookup the correct device info from an array.

While being there, also move the SSD130X_DATA and SSD130X_COMMAND control
bytes. Since even though they are used by the I2C interface, they could
also be useful for other transport protocols such as SPI.

Suggested-by: Chen-Yu Tsai <wens@kernel.org>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patchwork.freedesktop.org/patch/msgid/20220419214824.335075-5-javierm@redhat.com

drm/ssd130x: Support page addressing mode

On the SINO WEALTH SH1106, which is mostly compatible with the SSD1306,
only the basic page addressing mode is supported. This addressing mode
is not as easy to use compared to the currently supported horizontal
addressing mode, as the page address has to be set prior to writing
out each page, and each page must be written out separately as a result.
Also, there is no way to force the column address to wrap around early,
thus the column address must also be reset for each page to be accurate.

Add support for this addressing mode, with a flag to choose it. This
flag is designed to be set from the device info data structure, but
can be extended to be explicitly forced on through a device tree
property if such a need arises.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220406172956.3953-4-wens@kernel.org

drm: Add driver for Solomon SSD130x OLED displays

This adds a DRM driver for SSD1305, SSD1306, SSD1307 and SSD1309 Solomon
OLED display controllers.

It's only the core part of the driver and a bus specific driver is needed
for each transport interface supported by the display controllers.

Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220214133710.3278506-4-javierm@redhat.com