linux-kernel - [PATCH v2 03/11] drm: bridge: samsung-dsim: enter display mode in the enable() callback

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Date:   Sun, 26 Nov 2023 16:44:55 +0100
From:   Dario Binacchi <dario.binacchi@...rulasolutions.com>
To:     linux-kernel@...r.kernel.org
Cc:     Amarula patchwork <linux-amarula@...rulasolutions.com>,
        michael@...rulasolutions.com,
        Dario Binacchi <dario.binacchi@...rulasolutions.com>,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...il.com>,
        Inki Dae <inki.dae@...sung.com>,
        Jagan Teki <jagan@...rulasolutions.com>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Jonas Karlman <jonas@...boo.se>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Maxime Ripard <mripard@...nel.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH v2 03/11] drm: bridge: samsung-dsim: enter display mode in the enable() callback

The synaptics-r63353 (panel-bridge) can only be configured in command mode.
So, samsung-dsim (bridge) must not be in display mode during the
prepare()/unprepare() of the panel-bridge. Setting the
"pre_enable_prev_first" flag to true allows the prepare() of the
panel-bridge to be called between the pre_enabled() and enabled() of the
bridge. So, the bridge can enter display mode only in the enabled().
The unprepare() of the panel-bridge is instead called between the disable()
and post_disable() of the bridge. So, the disable() must exit the display
mode (i .e. enter command mode) to allow the panel-bridge to receive DSI
commands.

samsung_dsim_atomic_pre_enable   -> command mode
r63353_panel_prepare             -> send DSI commands
samsung_dsim_atomic_enable       -> enter display mode

samsung_dsim_atomic_disable      -> exit display mode (command mode)
r63353_panel_unprepare           -> send DSI commands
samsung_dsim_atomic_post_disable

Co-developed-by: Michael Trimarchi <michael@...rulasolutions.com>
Signed-off-by: Michael Trimarchi <michael@...rulasolutions.com>
Signed-off-by: Dario Binacchi <dario.binacchi@...rulasolutions.com>
---

(no changes since v1)

 drivers/gpu/drm/bridge/samsung-dsim.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index be5914caa17d..15bf05b2bbe4 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1494,7 +1494,6 @@ static void samsung_dsim_atomic_pre_enable(struct drm_bridge *bridge,
 			return;
 
 		samsung_dsim_set_display_mode(dsi);
-		samsung_dsim_set_display_enable(dsi, true);
 	}
 }
 
@@ -1507,6 +1506,7 @@ static void samsung_dsim_atomic_enable(struct drm_bridge *bridge,
 		samsung_dsim_set_display_mode(dsi);
 		samsung_dsim_set_display_enable(dsi, true);
 	} else {
+		samsung_dsim_set_display_enable(dsi, true);
 		samsung_dsim_set_stop_state(dsi, false);
 	}
 
@@ -1524,6 +1524,8 @@ static void samsung_dsim_atomic_disable(struct drm_bridge *bridge,
 	if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
 		samsung_dsim_set_stop_state(dsi, true);
 
+	samsung_dsim_set_display_enable(dsi, false);
+
 	dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
 }
 
@@ -1532,7 +1534,8 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
 {
 	struct samsung_dsim *dsi = bridge_to_dsi(bridge);
 
-	samsung_dsim_set_display_enable(dsi, false);
+	if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type))
+		samsung_dsim_set_stop_state(dsi, true);
 
 	dsi->state &= ~DSIM_STATE_ENABLED;
 	pm_runtime_put_sync(dsi->dev);
-- 
2.42.0