forked from Minki/linux
45527d435c
Panels often require an initialization sequence that consists of three steps: a) powering up the panel, b) starting transmission of video data and c) enabling the panel (e.g. turn on backlight). This is usually necessary to avoid visual glitches at the beginning of video data transmission. Similarly, the shutdown sequence is typically done in three steps as well: a) disable the panel (e.g. turn off backlight), b) cease video data transmission and c) power down the panel. Currently drivers can only implement .enable() and .disable() functions, which is not enough to implement the above sequences. This commit adds a second pair of functions, .prepare() and .unprepare() to allow more fine-grained control over when the above steps are performed. Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com> [treding: rewrite changelog, add kerneldoc] Signed-off-by: Thierry Reding <treding@nvidia.com>
133 lines
4.5 KiB
C
133 lines
4.5 KiB
C
/*
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* Copyright (C) 2013, NVIDIA Corporation. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sub license,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*/
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#ifndef __DRM_PANEL_H__
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#define __DRM_PANEL_H__
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#include <linux/list.h>
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struct drm_connector;
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struct drm_device;
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struct drm_panel;
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/**
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* struct drm_panel_funcs - perform operations on a given panel
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* @disable: disable panel (turn off back light, etc.)
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* @unprepare: turn off panel
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* @prepare: turn on panel and perform set up
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* @enable: enable panel (turn on back light, etc.)
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* @get_modes: add modes to the connector that the panel is attached to and
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* return the number of modes added
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*
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* The .prepare() function is typically called before the display controller
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* starts to transmit video data. Panel drivers can use this to turn the panel
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* on and wait for it to become ready. If additional configuration is required
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* (via a control bus such as I2C, SPI or DSI for example) this is a good time
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* to do that.
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*
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* After the display controller has started transmitting video data, it's safe
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* to call the .enable() function. This will typically enable the backlight to
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* make the image on screen visible. Some panels require a certain amount of
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* time or frames before the image is displayed. This function is responsible
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* for taking this into account before enabling the backlight to avoid visual
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* glitches.
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*
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* Before stopping video transmission from the display controller it can be
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* necessary to turn off the panel to avoid visual glitches. This is done in
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* the .disable() function. Analogously to .enable() this typically involves
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* turning off the backlight and waiting for some time to make sure no image
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* is visible on the panel. It is then safe for the display controller to
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* cease transmission of video data.
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*
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* To save power when no video data is transmitted, a driver can power down
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* the panel. This is the job of the .unprepare() function.
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*/
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struct drm_panel_funcs {
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int (*disable)(struct drm_panel *panel);
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int (*unprepare)(struct drm_panel *panel);
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int (*prepare)(struct drm_panel *panel);
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int (*enable)(struct drm_panel *panel);
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int (*get_modes)(struct drm_panel *panel);
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};
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struct drm_panel {
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struct drm_device *drm;
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struct drm_connector *connector;
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struct device *dev;
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const struct drm_panel_funcs *funcs;
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struct list_head list;
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};
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static inline int drm_panel_unprepare(struct drm_panel *panel)
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{
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if (panel && panel->funcs && panel->funcs->unprepare)
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return panel->funcs->unprepare(panel);
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return panel ? -ENOSYS : -EINVAL;
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}
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static inline int drm_panel_disable(struct drm_panel *panel)
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{
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if (panel && panel->funcs && panel->funcs->disable)
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return panel->funcs->disable(panel);
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return panel ? -ENOSYS : -EINVAL;
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}
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static inline int drm_panel_prepare(struct drm_panel *panel)
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{
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if (panel && panel->funcs && panel->funcs->prepare)
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return panel->funcs->prepare(panel);
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return panel ? -ENOSYS : -EINVAL;
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}
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static inline int drm_panel_enable(struct drm_panel *panel)
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{
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if (panel && panel->funcs && panel->funcs->enable)
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return panel->funcs->enable(panel);
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return panel ? -ENOSYS : -EINVAL;
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}
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void drm_panel_init(struct drm_panel *panel);
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int drm_panel_add(struct drm_panel *panel);
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void drm_panel_remove(struct drm_panel *panel);
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int drm_panel_attach(struct drm_panel *panel, struct drm_connector *connector);
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int drm_panel_detach(struct drm_panel *panel);
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#ifdef CONFIG_OF
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struct drm_panel *of_drm_find_panel(struct device_node *np);
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#else
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static inline struct drm_panel *of_drm_find_panel(struct device_node *np)
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{
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return NULL;
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}
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#endif
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#endif
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