From 2eb22214c132374e11e681c44d7879c91f67f614 Mon Sep 17 00:00:00 2001 From: Pin-yen Lin Date: Mon, 18 Aug 2025 19:49:33 +0800 Subject: [PATCH 4845/5403] drm/panel: Allow powering on panel follower after panel is enabled Some touch controllers have to be powered on after the panel's backlight is enabled. To support these controllers, introduce .panel_enabled() and .panel_disabling() to panel_follower_funcs and use them to power on the device after the panel and its backlight are enabled. Signed-off-by: Pin-yen Lin Reviewed-by: Douglas Anderson Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20250818115015.2909525-1-treapking@chromium.org --- drivers/gpu/drm/drm_panel.c | 73 +++++++++++++++++++++++++++++++------ include/drm/drm_panel.h | 14 +++++++ 2 files changed, 76 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c index c8bb28dccdc1..d1e6598ea3bc 100644 --- a/drivers/gpu/drm/drm_panel.c +++ b/drivers/gpu/drm/drm_panel.c @@ -134,6 +134,9 @@ void drm_panel_prepare(struct drm_panel *panel) panel->prepared = true; list_for_each_entry(follower, &panel->followers, list) { + if (!follower->funcs->panel_prepared) + continue; + ret = follower->funcs->panel_prepared(follower); if (ret < 0) dev_info(panel->dev, "%ps failed: %d\n", @@ -179,6 +182,9 @@ void drm_panel_unprepare(struct drm_panel *panel) mutex_lock(&panel->follower_lock); list_for_each_entry(follower, &panel->followers, list) { + if (!follower->funcs->panel_unpreparing) + continue; + ret = follower->funcs->panel_unpreparing(follower); if (ret < 0) dev_info(panel->dev, "%ps failed: %d\n", @@ -209,6 +215,7 @@ EXPORT_SYMBOL(drm_panel_unprepare); */ void drm_panel_enable(struct drm_panel *panel) { + struct drm_panel_follower *follower; int ret; if (!panel) @@ -219,10 +226,12 @@ void drm_panel_enable(struct drm_panel *panel) return; } + mutex_lock(&panel->follower_lock); + if (panel->funcs && panel->funcs->enable) { ret = panel->funcs->enable(panel); if (ret < 0) - return; + goto exit; } panel->enabled = true; @@ -230,6 +239,19 @@ void drm_panel_enable(struct drm_panel *panel) if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to enable backlight: %d\n", ret); + + list_for_each_entry(follower, &panel->followers, list) { + if (!follower->funcs->panel_enabled) + continue; + + ret = follower->funcs->panel_enabled(follower); + if (ret < 0) + dev_info(panel->dev, "%ps failed: %d\n", + follower->funcs->panel_enabled, ret); + } + +exit: + mutex_unlock(&panel->follower_lock); } EXPORT_SYMBOL(drm_panel_enable); @@ -243,6 +265,7 @@ EXPORT_SYMBOL(drm_panel_enable); */ void drm_panel_disable(struct drm_panel *panel) { + struct drm_panel_follower *follower; int ret; if (!panel) @@ -262,6 +285,18 @@ void drm_panel_disable(struct drm_panel *panel) return; } + mutex_lock(&panel->follower_lock); + + list_for_each_entry(follower, &panel->followers, list) { + if (!follower->funcs->panel_disabling) + continue; + + ret = follower->funcs->panel_disabling(follower); + if (ret < 0) + dev_info(panel->dev, "%ps failed: %d\n", + follower->funcs->panel_disabling, ret); + } + ret = backlight_disable(panel->backlight); if (ret < 0) DRM_DEV_INFO(panel->dev, "failed to disable backlight: %d\n", @@ -270,9 +305,12 @@ void drm_panel_disable(struct drm_panel *panel) if (panel->funcs && panel->funcs->disable) { ret = panel->funcs->disable(panel); if (ret < 0) - return; + goto exit; } panel->enabled = false; + +exit: + mutex_unlock(&panel->follower_lock); } EXPORT_SYMBOL(drm_panel_disable); @@ -539,13 +577,13 @@ EXPORT_SYMBOL(drm_is_panel_follower); * @follower_dev: The 'struct device' for the follower. * @follower: The panel follower descriptor for the follower. * - * A panel follower is called right after preparing the panel and right before - * unpreparing the panel. It's primary intention is to power on an associated - * touchscreen, though it could be used for any similar devices. Multiple - * devices are allowed the follow the same panel. + * A panel follower is called right after preparing/enabling the panel and right + * before unpreparing/disabling the panel. It's primary intention is to power on + * an associated touchscreen, though it could be used for any similar devices. + * Multiple devices are allowed the follow the same panel. * - * If a follower is added to a panel that's already been turned on, the - * follower's prepare callback is called right away. + * If a follower is added to a panel that's already been prepared/enabled, the + * follower's prepared/enabled callback is called right away. * * The "panel" property of the follower points to the panel to be followed. * @@ -569,12 +607,18 @@ int drm_panel_add_follower(struct device *follower_dev, mutex_lock(&panel->follower_lock); list_add_tail(&follower->list, &panel->followers); - if (panel->prepared) { + if (panel->prepared && follower->funcs->panel_prepared) { ret = follower->funcs->panel_prepared(follower); if (ret < 0) dev_info(panel->dev, "%ps failed: %d\n", follower->funcs->panel_prepared, ret); } + if (panel->enabled && follower->funcs->panel_enabled) { + ret = follower->funcs->panel_enabled(follower); + if (ret < 0) + dev_info(panel->dev, "%ps failed: %d\n", + follower->funcs->panel_enabled, ret); + } mutex_unlock(&panel->follower_lock); @@ -587,7 +631,8 @@ EXPORT_SYMBOL(drm_panel_add_follower); * @follower: The panel follower descriptor for the follower. * * Undo drm_panel_add_follower(). This includes calling the follower's - * unprepare function if we're removed from a panel that's currently prepared. + * unpreparing/disabling function if we're removed from a panel that's currently + * prepared/enabled. * * Return: 0 or an error code. */ @@ -598,7 +643,13 @@ void drm_panel_remove_follower(struct drm_panel_follower *follower) mutex_lock(&panel->follower_lock); - if (panel->prepared) { + if (panel->enabled && follower->funcs->panel_disabling) { + ret = follower->funcs->panel_disabling(follower); + if (ret < 0) + dev_info(panel->dev, "%ps failed: %d\n", + follower->funcs->panel_disabling, ret); + } + if (panel->prepared && follower->funcs->panel_unpreparing) { ret = follower->funcs->panel_unpreparing(follower); if (ret < 0) dev_info(panel->dev, "%ps failed: %d\n", diff --git a/include/drm/drm_panel.h b/include/drm/drm_panel.h index 843fb756a295..2407bfa60236 100644 --- a/include/drm/drm_panel.h +++ b/include/drm/drm_panel.h @@ -160,6 +160,20 @@ struct drm_panel_follower_funcs { * Called before the panel is powered off. */ int (*panel_unpreparing)(struct drm_panel_follower *follower); + + /** + * @panel_enabled: + * + * Called after the panel and the backlight have been enabled. + */ + int (*panel_enabled)(struct drm_panel_follower *follower); + + /** + * @panel_disabling: + * + * Called before the panel and the backlight are disabled. + */ + int (*panel_disabling)(struct drm_panel_follower *follower); }; struct drm_panel_follower { -- 2.54.0