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* drm/panel: Add a way for other devices to follow panel stateDouglas Anderson2023-08-011-4/+169
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | These days, it's fairly common to see panels that have touchscreens attached to them. The panel and the touchscreen can somewhat be thought of as totally separate devices and, historically, this is how Linux has treated them. However, treating them as separate isn't necessarily the best way to model the two devices, it was just that there was no better way. Specifically, there is little practical reason to have the touchscreen powered on when the panel is turned off, but if we model the devices separately we have no way to keep the two devices' power states in sync with each other. The issue described above makes it sound as if the problem here is just about efficiency. We're wasting power keeping the touchscreen powered up when the screen is off. While that's true, the problem can go deeper. Specifically, hardware designers see that there's no reason to have the touchscreen on while the screen is off and then build hardware assuming that software would never turn the touchscreen on while the screen is off. In the very simplest case of hardware designs like this, the touchscreen and the panel share some power rails. In most cases, this turns out not to be terrible and is, again, just a little less efficient. Specifically if we tell Linux that the touchscreen and the panel are using the same rails then Linux will keep the rails on when _either_ device is turned on. That ends to work OK-ish, but now if you turn the panel off not only will the touchscreen remain powered, but the power rails for the panel itself won't be switched off, burning extra power. The above two inefficiencies are _extra_ minor when you consider the fact that laptops rarely spend much time with the screen off. The main use case would be when an external screen (and presumably a power supply) is attached. Unfortunately, it gets worse from here. On sc7180-trogdor-homestar, for instance, the display's TCON (timing controller) sometimes crashes if you don't power cycle it whenever you stop and restart the video stream (like during a modeset). The touchscreen keeping the power rails on causes real problems. One proposal in the homestar timeframe was to move the touchscreen to an always-on rail, dedicating the main power rail to the panel. That caused _different_ problems as talked about in commit 557e05fa9fdd ("HID: i2c-hid: goodix: Stop tying the reset line to the regulator"). The end result of all of this was to add an extra regulator to the board, increasing cost. Recently, Cong Yang posted a patch [1] where things are even worse. The panel and touch controller on that system seem even more intimately tied together and really can't be thought of separately. To address this issue, let's start allowing devices to register themselves as "panel followers". These devices will get called after a panel has been powered on and before a panel is powered off. This makes the panel the primary device in charge of the power state, which matches how userspace uses it. The panel follower API should be fairly straightforward to use. The current code assumes that panel followers are using device tree and have a "panel" property pointing to the panel to follow. More flexibility and non-DT implementations could be added as needed. Right now, panel followers can follow the prepare/unprepare functions. There could be arguments made that, instead, they should follow enable/disable. I've chosen prepare/unprepare for now since those functions are guaranteed to power up/power down the panel and it seems better to start the process earlier. A bit of explaining about why this is a roll-your-own API instead of using something more standard: 1. In standard APIs in Linux, parent devices are automatically powered on when a child needs power. Applying that here, it would mean that we'd force the panel on any time someone was listening to the touchscreen. That, unfortunately, would have broken homestar's need (if we hadn't changed the hardware, as per above) where the panel absolutely needs to be able to power cycle itself. While one could argue that homestar is broken hardware and we shouldn't have the API do backflips for it, _officially_ the eDP timing guidelines agree with homestar's needs and the panel power sequencing diagrams show power going off. It's nice to be able to support this. 2. We could, conceibably, try to add a new flag to device_link causing the parent to be in charge of power. Then we could at least use normal pm_runtime APIs. This sounds great, except that we run into problems with initial probe. As talked about in the later patch ("HID: i2c-hid: Support being a panel follower") the initial power on of a panel follower might need to do things (like add sub-devices) that aren't allowed in a runtime_resume function. The above complexities explain why this API isn't using common functions. That being said, this patch is very small and self-contained, so if someone was later able to adapt it to using more common APIs while solving the above issues then that could happen in the future. [1] https://lore.kernel.org/r/20230519032316.3464732-1-yangcong5@huaqin.corp-partner.google.com Reviewed-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.3.Icd5f96342d2242051c754364f4bee13ef2b986d4@changeid
* drm/panel: Check for already prepared/enabled in drm_panelDouglas Anderson2023-08-011-6/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In a whole pile of panel drivers, we have code to make the prepare/unprepare/enable/disable callbacks behave as no-ops if they've already been called. It's silly to have this code duplicated everywhere. Add it to the core instead so that we can eventually delete it from all the drivers. Note: to get some idea of the duplicated code, try: git grep 'if.*>prepared' -- drivers/gpu/drm/panel git grep 'if.*>enabled' -- drivers/gpu/drm/panel NOTE: arguably, the right thing to do here is actually to skip this patch and simply remove all the extra checks from the individual drivers. Perhaps the checks were needed at some point in time in the past but maybe they no longer are? Certainly as we continue transitioning over to "panel_bridge" then we expect there to be much less variety in how these calls are made. When we're called as part of the bridge chain, things should be pretty simple. In fact, there was some discussion in the past about these checks [1], including a discussion about whether the checks were needed and whether the calls ought to be refcounted. At the time, I decided not to mess with it because it felt too risky. Looking closer at it now, I'm fairly certain that nothing in the existing codebase is expecting these calls to be refcounted. The only real question is whether someone is already doing something to ensure prepare()/unprepare() match and enabled()/disable() match. I would say that, even if there is something else ensuring that things match, there's enough complexity that adding an extra bool and an extra double-check here is a good idea. Let's add a drm_warn() to let people know that it's considered a minor error to take advantage of drm_panel's double-checking but we'll still make things work fine. We'll also add an entry to the official DRM todo list to remove the now pointless check from the panels after this patch lands and, eventually, fixup anyone who is triggering the new warning. [1] https://lore.kernel.org/r/20210416153909.v4.27.I502f2a92ddd36c3d28d014dd75e170c2d405a0a5@changeid Acked-by: Neil Armstrong <neil.armstrong@linaro.org> Reviewed-by: Maxime Ripard <mripard@kernel.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230727101636.v4.2.I59b417d4c29151cc2eff053369ec4822b606f375@changeid
* drm/panel: Add helper for reading DT rotationDerek Basehore2020-08-161-0/+43
| | | | | | | | | | | | This adds a helper function for reading the rotation (panel orientation) from the device tree. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Tested-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Derek Basehore <dbasehore@chromium.org> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200813215609.28643-2-digetx@gmail.com
* drm: Remove unnecessary drm_panel_attach and drm_panel_detachJoe Perches2020-08-081-36/+0
| | | | | | | | | | | | | | | | | | | | | | | | These functions are now empty and no longer useful so remove the functions and their uses. Signed-off-by: Joe Perches <joe@perches.com> Cc: Bernard Zhao <bernard@vivo.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org>, Cc: Thomas Zimmermann <tzimmermann@suse.de> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Icenowy Zheng <icenowy@aosc.io>, Cc: Jagan Teki <jagan@amarulasolutions.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Robert Chiras <robert.chiras@nxp.com> Cc: dri-devel@lists.freedesktop.org, Cc: linux-kernel@vger.kernel.org Cc: opensource.kernel@vivo.com Signed-off-by: Sam Ravnborg <sam@ravnborg.org> # Fixed build and a few warnings Link: https://patchwork.freedesktop.org/patch/msgid/9e13761020750b1ce2f1fabee23ef6e2a2942882.camel@perches.com
* drm/panel: remove return value of function drm_panel_addBernard Zhao2020-08-021-5/+1
| | | | | | | | | | | | The function "int drm_panel_add(struct drm_panel *panel)" always returns 0, this return value is meaningless. Also, there is no need to check return value which calls "drm_panel_add and", error branch code will never run. Signed-off-by: Bernard Zhao <bernard@vivo.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20200801120216.8488-1-bernard@vivo.com
* drm/drm_panel: Fix EXPORT of drm_panel_of_backlight() one more timeAndy Shevchenko2019-12-171-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The initial commit followed by the fix didn't take into consideration the case: CONFIG_DRM_PANEL=y CONFIG_BACKLIGHT_CLASS_DEVICE=m CONFIG_DRM_I915=y where symbol devm_of_find_backlight() is not reachable from DRM subsystem. Quick fix is to avoid drm_panel_of_backlight() from exporting in such case. Fixes: 907aa265fde6 ("drm/drm_panel: fix EXPORT of drm_panel_of_backlight") Reported-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Maxime Ripard <mripard@kernel.org> Cc: dri-devel@lists.freedesktop.org Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20191217140721.42432-1-andriy.shevchenko@linux.intel.com
* drm/drm_panel: fix EXPORT of drm_panel_of_backlightSam Ravnborg2019-12-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | Fix link failure for module builds of panels. The conditional compilation around drm_panel_of_backlight() was wrong for a module build. Fix it using IS_ENABLED(). Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Fixes: 152dbdeab1b2 ("drm/panel: add backlight support") Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Maxime Ripard <mripard@kernel.org> Cc: dri-devel@lists.freedesktop.org Link: https://patchwork.freedesktop.org/patch/msgid/20191210194758.24087-1-sam@ravnborg.org
* drm/panel: drop drm_device from drm_panelSam Ravnborg2019-12-091-6/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The panel drivers used drm_panel.drm for two purposes: 1) Argument to drm_mode_duplicate() 2) drm->dev was used in error messages The first usage is replaced with drm_connector.dev - drm_connector is already connected to a drm_device and we have a valid connector The second usage is replaced with drm_panel.dev - this makes drivers more consistent in their dev argument used for dev_err() and friends With these replacements there are no more uses of drm_panel.drm, so it is removed from struct drm_panel. With this change drm_panel_attach() and drm_panel_detach() no longer have any use as they are empty functions. v2: - editorial correction in changelog (Laurent) Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Jagan Teki <jagan@amarulasolutions.com> Cc: Stefan Mavrodiev <stefan@olimex.com> Cc: Robert Chiras <robert.chiras@nxp.com> Cc: "Guido Günther" <agx@sigxcpu.org> Cc: Purism Kernel Team <kernel@puri.sm> Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-8-sam@ravnborg.org
* drm/panel: decouple connector from drm_panelSam Ravnborg2019-12-091-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To facilitate moving connector creation to display drivers, decouple the drm_connector from drm_panel. This patch adds a connector argument to drm_panel_get_modes(). All users of drm_panel_get_modes() already had the connector available, so updating users was trivial. With this patch drm_panel no longer keeps a reference to the drm_connector. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Jeffrey Hugo <jeffrey.l.hugo@gmail.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Laurent Pinchart <Laurent.pinchart@ideasonboard.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Neil Armstrong <narmstrong@baylibre.com> Cc: Jonas Karlman <jonas@kwiboo.se> Cc: Jernej Skrabec <jernej.skrabec@siol.net> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Inki Dae <inki.dae@samsung.com> Cc: Joonyoung Shim <jy0922.shim@samsung.com> Cc: Seung-Woo Kim <sw0312.kim@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Krzysztof Kozlowski <krzk@kernel.org> Cc: Stefan Agner <stefan@agner.ch> Cc: Alison Wang <alison.wang@nxp.com> Cc: Philipp Zabel <p.zabel@pengutronix.de> Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Fabio Estevam <festevam@gmail.com> Cc: NXP Linux Team <linux-imx@nxp.com> Cc: CK Hu <ck.hu@mediatek.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Marek Vasut <marex@denx.de> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com> Cc: Sandy Huang <hjc@rock-chips.com> Cc: "Heiko Stübner" <heiko@sntech.de> Cc: Benjamin Gaignard <benjamin.gaignard@linaro.org> Cc: Vincent Abriou <vincent.abriou@st.com> Cc: Chen-Yu Tsai <wens@csie.org> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Torsten Duwe <duwe@lst.de> Cc: Vasily Khoruzhick <anarsoul@gmail.com> Cc: Icenowy Zheng <icenowy@aosc.io> Cc: Sean Paul <seanpaul@chromium.org> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Boris Brezillon <boris.brezillon@collabora.com> Cc: Hariprasad Kelam <hariprasad.kelam@gmail.com> Cc: Alexios Zavras <alexios.zavras@intel.com> Cc: Brian Masney <masneyb@onstation.org> Cc: Rob Clark <robdclark@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Allison Randal <allison@lohutok.net> Cc: Shayenne Moura <shayenneluzmoura@gmail.com> Cc: Abhinav Kumar <abhinavk@codeaurora.org> Cc: linux-arm-kernel@lists.infradead.org Cc: linux-samsung-soc@vger.kernel.org Cc: linux-mediatek@lists.infradead.org Cc: linux-renesas-soc@vger.kernel.org Cc: linux-rockchip@lists.infradead.org Cc: linux-tegra@vger.kernel.org Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-7-sam@ravnborg.org
* drm/panel: add drm_connector argument to get_modes()Sam Ravnborg2019-12-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Today the bridge creates the drm_connector, but that is planned to be moved to the display drivers. To facilitate this, update drm_panel_funcs.get_modes() to take drm_connector as an argument. All panel drivers implementing get_modes() are updated. v2: - drop accidental change (Laurent) - update docs for get_modes (Laurent) Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Jagan Teki <jagan@amarulasolutions.com> Cc: Stefan Mavrodiev <stefan@olimex.com> Cc: Robert Chiras <robert.chiras@nxp.com> Cc: "Guido Günther" <agx@sigxcpu.org> Cc: Purism Kernel Team <kernel@puri.sm> Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-6-sam@ravnborg.org
* drm/panel: add backlight supportSam Ravnborg2019-12-091-2/+60
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Panels often support backlight as specified in a device tree. Update the drm_panel infrastructure to support this to simplify the drivers. With this the panel driver just needs to add the following to the probe() function: err = drm_panel_of_backlight(panel); if (err) return err; Then drm_panel will handle all the rest. There is one caveat with the backlight support. If drm_panel_(enable|disable) are called multiple times in a row then backlight_(enable|disable) will be called multiple times. The above will happen when a panel drivers unconditionally calls drm_panel_disable() in their shutdown() function, whan the panel is already disabled and then shutdown() is called. Reading the backlight code it seems safe to call the backlight_(enable|disable) several times. v3: - Improve comments, fix grammar (Laurent) - Do not fail in drm_panel_of_backlight() if no DT support (Laurent) - Log if backlight_(enable|disable) fails (Laurent) - Improve drm_panel_of_backlight() docs - Updated changelog with backlight analysis (triggered by Laurent) v2: - Drop test of CONFIG_DRM_PANEL in header-file (Laurent) - do not enable backlight if ->enable() returns an error Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-3-sam@ravnborg.org
* drm/drm_panel: no error when no callbackSam Ravnborg2019-12-091-10/+25
| | | | | | | | | | | | | | | | | | | | The callbacks in drm_panel_funcs are optional, so do not return an error just because no callback is assigned. v2: - Document what functions in drm_panel_funcs are optional (Laurent) - Return -EOPNOTSUPP if get_modes() is not assigned (Laurent) (Sam: -EOPNOTSUPP seems to best error code in this situation) Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <mripard@kernel.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20191207140353.23967-2-sam@ravnborg.org
* drm/panel: Add and fill drm_panel type fieldLaurent Pinchart2019-09-081-1/+4
| | | | | | | | | | | | | | | | | | Add a type field to the drm_panel structure to report the panel type, using DRM_MODE_CONNECTOR_* macros (the values that make sense are LVDS, eDP, DSI and DPI). This will be used to initialise the corresponding connector type. Update all panel drivers accordingly. The panel-simple driver only specifies the type for the known to be LVDS panels, while all other panels are left as unknown and will be converted on a case-by-case basis as they all need to be carefully reviewed. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190904132804.29680-2-laurent.pinchart@ideasonboard.com
* drm/panel: Initialise panel dev and funcs through drm_panel_init()Laurent Pinchart2019-08-241-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of requiring all drivers to set the dev and funcs fields of drm_panel manually after calling drm_panel_init(), pass the data as arguments to the function. This simplifies the panel drivers, and will help future refactoring when adding new arguments to drm_panel_init(). The panel drivers have been updated with the following Coccinelle semantic patch, with manual inspection to verify that no call to drm_panel_init() with a single argument still exists. @@ expression panel; expression device; identifier ops; @@ drm_panel_init(&panel + , device, &ops ); ... ( -panel.dev = device; -panel.funcs = &ops; | -panel.funcs = &ops; -panel.dev = device; ) Suggested-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190823193245.23876-3-laurent.pinchart@ideasonboard.com
* drm/panel: drop return code from drm_panel_detach()Sam Ravnborg2019-08-101-5/+1
| | | | | | | | | | | | | | | | | | | | | | | There are no errors that can be reported by this function, so drop the return code. Fix the only bridge driver that checked the return result. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Emil Velikov <emil.velikov@collabora.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Cc: Andrzej Hajda <a.hajda@samsung.com> Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Walleij <linus.walleij@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20190804201637.1240-14-sam@ravnborg.org
* drm/panel: move drm_panel functions to .c fileSam Ravnborg2019-08-101-0/+96
| | | | | | | | | | | | | | | | | | | | | | Move inline functions from include/drm/drm_panel.h to drm_panel.c. This is in preparation for follow-up patches that will add extra logic to the functions. As they are no longer static inline, EXPORT them. v2: - align order of functions in drm_panel.h and drm_panel.c (Laurent) Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Emil Velikov <emil.velikov@collabora.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: Maxime Ripard <maxime.ripard@bootlin.com> Cc: Sean Paul <sean@poorly.run> Cc: David Airlie <airlied@linux.ie> Cc: Daniel Vetter <daniel@ffwll.ch> Link: https://patchwork.freedesktop.org/patch/msgid/20190804201637.1240-12-sam@ravnborg.org
* drm/panel: Small documentation polishDaniel Vetter2019-01-121-0/+3
| | | | | | | | | Need to make sure people can find the panel-bridge to avoid typing too much. Reviewed-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190111164048.29067-3-daniel.vetter@ffwll.ch
* BackMerge v4.19-rc6 into drm-nextDave Airlie2018-10-041-10/+0
|\ | | | | | | | | | | I have some pulls based on rc6, and I prefer to have an explicit backmerge. Signed-off-by: Dave Airlie <airlied@redhat.com>
| * Revert "drm/panel: Add device_link from panel device to DRM device"Linus Walleij2018-09-271-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit 0c08754b59da5557532d946599854e6df28edc22. commit 0c08754b59da ("drm/panel: Add device_link from panel device to DRM device") creates a circular dependency under these circumstances: 1. The panel depends on dsi-host because it is MIPI-DSI child device. 2. dsi-host depends on the drm parent device (connector->dev->dev) this should be allowed. 3. drm parent dev (connector->dev->dev) depends on the panel after this patch. This makes the dependency circular and while it appears it does not affect any in-tree drivers (they do not seem to have dsi hosts depending on the same parent device) this does not seem right. As noted in a response from Andrzej Hajda, the intent is likely to make the panel dependent on the DRM device (connector->dev) not its parent. But we have no way of doing that since the DRM device doesn't contain any struct device on its own (arguably it should). Revert this until a proper approach is figured out. Cc: Jyri Sarha <jsarha@ti.com> Cc: Eric Anholt <eric@anholt.net> Cc: Andrzej Hajda <a.hajda@samsung.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20180927124130.9102-1-linus.walleij@linaro.org
* | drm/panel: Fix sphinx warningSean Paul2018-08-161-0/+2
|/ | | | | | | | | | | | | | | | Resolves the following warnings. ../drivers/gpu/drm/drm_panel.c:158: WARNING: Unexpected indentation. ../drivers/gpu/drm/drm_panel.c:159: WARNING: Block quote ends without a blank line; unexpected unindent. Fixes: c59eb3cfde1f ("drm/panel: Let of_drm_find_panel() return -ENODEV when the panel is disabled") Cc: Boris Brezillon <boris.brezillon@bootlin.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jyri Sarha <jsarha@ti.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Sean Paul <seanpaul@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20180815203833.210143-1-sean@poorly.run
* drm/panel: Let of_drm_find_panel() return -ENODEV when the panel is disabledBoris Brezillon2018-07-101-2/+7
| | | | | | | | | | | | DT nodes might be present in the DT but with a status property set to "disabled" or "fail". In this case, we should not return -EPROBE_DEFER when the caller asks for a drm_panel instance. Return -ENODEV instead. Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com> Reviewed-by: Thierry Reding <treding@nvidia.com> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180509130042.9435-3-boris.brezillon@bootlin.com
* drm/panel: Make of_drm_find_panel() return an ERR_PTR() instead of NULLBoris Brezillon2018-07-101-2/+4
| | | | | | | | | | | | | | | | | | Right now, the DRM panel logic returns NULL when a panel pointing to the passed OF node is not present in the list of registered panels. Most drivers interpret this NULL value as -EPROBE_DEFER, but we are about to modify the semantic of of_drm_find_panel() and let the framework return -ENODEV when the device node we're pointing to has a status property that is not equal to "okay" or "ok". Let's first patch the of_drm_find_panel() implementation to return ERR_PTR(-EPROBE_DEFER) instead of NULL and patch all callers to replace the '!panel' check by an 'IS_ERR(panel)' one. Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180509130042.9435-2-boris.brezillon@bootlin.com
* drm/panel: Add device_link from panel device to DRM deviceJyri Sarha2018-05-181-0/+10
| | | | | | | | | | | | | | | | | Add device_link from panel device (supplier) to DRM device (consumer) when drm_panel_attach() is called. This patch should protect the master DRM driver if an attached panel driver unbinds while it is in use. The device_link should make sure the DRM device is unbound before the panel driver becomes unavailable. The device_link is removed when drm_panel_detach() is called. The drm_panel_detach() should be called by the consumer DRM driver, not the panel driver, otherwise both drivers are racing to delete the same link. Signed-off-by: Jyri Sarha <jsarha@ti.com> Reviewed-by: Eric Anholt <eric@anholt.net> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/b53584fd988d045c13de22d81825395b0ae0aad7.1524727888.git.jsarha@ti.com
* drm/panel: Remove drm_panel_detach() calls from all panel driversJyri Sarha2018-05-181-0/+6
| | | | | | | | | | | | | | | | | | Remove all drm_panel_detach() calls from all panel drivers and update the kerneldoc for drm_panel_detach(). Setting the connector and drm to NULL when the DRM panel device is going away hardly serves any purpose. Usually the whole memory structure is freed right after the remove call. However, calling the detach function from the master DRM device, and setting the connector pointer to NULL, has the logic of marking the panel again as available for another DRM master to attach. The usual situation would be the same DRM master device binding again. Signed-off-by: Jyri Sarha <jsarha@ti.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Thierry Reding <treding@nvidia.com> Link: https://patchwork.freedesktop.org/patch/msgid/464b8d330d6b4c94cfb5aad2ca9ea7eb2c52d934.1524727888.git.jsarha@ti.com
* drm/panel: Constify device node argument to of_drm_find_panel()Laurent Pinchart2017-01-041-1/+1
| | | | | | | The argument is never modified by the function, make it const. Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com> Signed-off-by: Thierry Reding <treding@nvidia.com>
* drm/panel: Flesh out kerneldocThierry Reding2016-05-061-0/+61
| | | | | | | | | Write more complete kerneldoc comments for the DRM panel API and integrate the helpers in the DRM DocBook reference. Signed-off-by: Thierry Reding <treding@nvidia.com>drm/panel: Add helper for simple panel connector Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/20160506140137.GA4641@ulmo.ba.sec
* drm: Add panel supportThierry Reding2013-12-171-0/+100
Add a very simple framework to register and lookup panels. Panel drivers can initialize a DRM panel and register it with the framework, allowing them to be retrieved and used by display drivers. Currently only support for DPMS and obtaining panel modes is provided. However it should be sufficient to enable a large number of panels. The framework should also be easily extensible to support more sophisticated kinds of panels such as DSI. The framework hasn't been tied into the DRM core, even though it should be easily possible to do so if that's what we want. In the current implementation, display drivers can simple make use of it to retrieve a panel, obtain its modes and control its DPMS mode. Note that this is currently only tested on systems that boot from a device tree. No glue code has been written yet for systems that use platform data, but it should be easy to add. Signed-off-by: Thierry Reding <treding@nvidia.com>