[PATCH v2 0/24] backlight: add init macros and accessors

[Sam Ravnborg <sam@ravnborg.org>]

The first patch trims backlight_update_status() so it can be called with a NULL
backlight_device. Then the caller do not need to add this check just to avoid
a NULL reference.

The backlight drivers uses several different patterns when registering
a backlight:

- Register backlight and assign properties later
- Define a local backlight_properties variable and use memset
- Define a const backlight_properties and assign relevant properties

On top of this there was differences in what members was assigned.

To align how backlight drivers are initialized introduce following helper macros:
- DECLARE_BACKLIGHT_INIT_FIRMWARE()
- DECLARE_BACKLIGHT_INIT_PLATFORM()
- DECLARE_BACKLIGHT_INIT_RAW()

The macros are introduced in patch 2.

The backlight drivers used direct access to backlight_properties.
Encapsulate these in get/set access operations resulting in following benefits:
- The access methods can be called with a NULL pointer so logic around the
  access can be made simpler.
- The update_brightness and enable_brightness simplifies the users
- The code is in most cases more readable with the access operations.
- When everyone uses the access methods refactoring in the backlight core is simpler.

The get/set operations are introduced in patch 3.

The gpio backlight driver received a small overhaul in a set of three patches.
The result is a smaller and more readable driver.

The remaining patches updates all backlight users in drivers/gpu/drm/*
With this patch set all of drivers/gpu/drm/:
- All backlight references to FB_BLANK* are gone from drm/*
- All direct references to backlight properties are gone
- All panel drivers uses the devm_ variant for registering backlight
  Daniel Vetter had some concerns with this for future updates,
  but we are aligned now and can update if refoctoring demands it
- All panel drivers uses the backlight support in drm_panel

Individual patches are only sent to the people listed in the patch + a few more.
Please check https://lore.kernel.org/dri-devel/ for the full series.

v2:
  - Documented BACKLIGHT_PROPS as it may be used by drivers
  - Dropped backlight_set_power_{on,off}, they were a mistake (Daniel)
  - Added backlight_update_brightness() and use it (Daniel)
  - Added backlight_enable_brightness() and use it
  - Moved remaining drm_panel driver to use backlight support in drm_panel
  - gpio backlight driver overhaul

The patches are made on top of the for-backlight-next branch at
https://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight.git
The branch needs v5.8-rc1 backported to build as dev_err_probe()
is used.

The first 6 patches are candidates for the backlight tree.
If they are applied then this should preferably be to an immutable
branch we can merge to drm-misc-next where the drm patches shall go.

The drm patches has known conflics and shall *not* be applied to the
backlight tree, they are included in this patchset to show how the
new functions are used.

Diffstat for the drm bits alone looks nice:
 25 files changed, 243 insertions(+), 460 deletions(-)

Feedback welcome!

	Sam

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: Andrzej Hajda <a.hajda@samsung.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Hoegeun Kwon <hoegeun.kwon@samsung.com>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jernej Skrabec <jernej.skrabec@siol.net>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Jonas Karlman <jonas@kwiboo.se>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Jyri Sarha <jsarha@ti.com>
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Cc: Konrad Dybcio <konradybcio@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: linux-renesas-soc@vger.kernel.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Neil Armstrong <narmstrong@baylibre.com>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Paweł Chmiel <pawel.mikolaj.chmiel@gmail.com>
Cc: Philippe CORNU <philippe.cornu@st.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Robert Chiras <robert.chiras@nxp.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Vinay Simha BN <simhavcs@gmail.com>
Cc: Wambui Karuga <wambui.karugax@gmail.com>
Cc: Zheng Bin <zhengbin13@huawei.com>

Sam Ravnborg (24):
      backlight: Silently fail backlight_update_status() if no device
      backlight: Add DECLARE_* macro for device registration
      backlight: Add get/set operations for brightness properties
      backlight: gpio: Introduce backlight_{enable,disable}
      backlight: gpio: Use dev_err_probe()
      backlight: gpio: Use DECLARE_BACKLIGHT_INIT_RAW
      drm/gma500: Backlight update
      drm/panel: asus-z00t-tm5p5-n35596: Backlight update
      drm/panel: jdi-lt070me05000: Backlight update
      drm/panel: novatek-nt35510: Backlight update
      drm/panel: orisetech-otm8009a: Backlight update
      drm/panel: raydium-rm67191: Backlight update
      drm/panel: samsung-s6e63m0: Backlight update
      drm/panel: samsung-s6e63j0x03: Backlight update
      drm/panel: samsung-s6e3ha2: Backlight update
      drm/panel: sony-acx424akp: Backlight update
      drm/panel: sony-acx565akm: Backlight update
      drm/bridge: parade-ps8622: Backlight update
      drm/tilcdc: Backlight update
      drm/radeon: Backlight update
      drm/amdgpu/atom: Backlight update
      drm/i915: Backlight update
      drm/omap: display: Backlight update
      drm/shmobile: Backlight update

 drivers/gpu/drm/amd/amdgpu/atombios_encoders.c     |  19 +--
 drivers/gpu/drm/bridge/parade-ps8622.c             |  43 ++++---
 drivers/gpu/drm/gma500/backlight.c                 |  34 +----
 drivers/gpu/drm/gma500/cdv_device.c                |  24 ++--
 drivers/gpu/drm/gma500/mdfld_device.c              |   9 +-
 drivers/gpu/drm/gma500/oaktrail_device.c           |  10 +-
 drivers/gpu/drm/gma500/opregion.c                  |   2 +-
 drivers/gpu/drm/gma500/psb_device.c                |  10 +-
 drivers/gpu/drm/gma500/psb_drv.c                   |   7 +-
 drivers/gpu/drm/i915/display/intel_panel.c         |  88 ++++++-------
 drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c    |  37 +-----
 .../gpu/drm/panel/panel-asus-z00t-tm5p5-n35596.c   |  15 +--
 drivers/gpu/drm/panel/panel-jdi-lt070me05000.c     |  54 ++------
 drivers/gpu/drm/panel/panel-novatek-nt35510.c      |   9 +-
 drivers/gpu/drm/panel/panel-orisetech-otm8009a.c   |  14 +--
 drivers/gpu/drm/panel/panel-raydium-rm67191.c      |  11 +-
 drivers/gpu/drm/panel/panel-samsung-s6e3ha2.c      |  70 +++++------
 drivers/gpu/drm/panel/panel-samsung-s6e63j0x03.c   |  53 ++++----
 drivers/gpu/drm/panel/panel-samsung-s6e63m0.c      |  25 ++--
 drivers/gpu/drm/panel/panel-sony-acx424akp.c       |  49 ++------
 drivers/gpu/drm/panel/panel-sony-acx565akm.c       |  47 +++----
 drivers/gpu/drm/radeon/atombios_encoders.c         |  24 ++--
 drivers/gpu/drm/radeon/radeon_legacy_encoders.c    |  16 +--
 drivers/gpu/drm/shmobile/shmob_drm_backlight.c     |  20 ++-
 drivers/gpu/drm/tilcdc/tilcdc_panel.c              |   9 +-
 drivers/video/backlight/gpio_backlight.c           |  41 +++---
 include/linux/backlight.h                          | 140 +++++++++++++++++++++
 27 files changed, 400 insertions(+), 480 deletions(-)