linux-kernel - [RFC PATCH 08/10] drm: bridge: samsung-dsim: don't re-activate the bridge if already setup

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Message-ID: <20241028102559.1451383-9-dario.binacchi@amarulasolutions.com>
Date: Mon, 28 Oct 2024 11:25:31 +0100
From: Dario Binacchi <dario.binacchi@...rulasolutions.com>
To: linux-kernel@...r.kernel.org
Cc: linux-amarula@...rulasolutions.com,
	Dario Binacchi <dario.binacchi@...rulasolutions.com>,
	Michael Trimarchi <michael@...rulasolutions.com>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	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>,
	Simona Vetter <simona@...ll.ch>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	dri-devel@...ts.freedesktop.org
Subject: [RFC PATCH 08/10] drm: bridge: samsung-dsim: don't re-activate the bridge if already setup

The patch does not re-execute the hardware initialization/activation
procedure for the bridge if it is already operational.
This feature is crucial when supporting the simple framebuffer, as the
controller has already been initialized by the bootloader.

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>
---

 drivers/gpu/drm/bridge/samsung-dsim.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index 430f8adebf9c..7c03215bb004 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1933,6 +1933,7 @@ int samsung_dsim_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct samsung_dsim *dsi;
+	bool initialized;
 	int ret, i;
 
 	dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
@@ -2010,6 +2011,13 @@ int samsung_dsim_probe(struct platform_device *pdev)
 	dsi->bridge.funcs = &samsung_dsim_bridge_funcs;
 	dsi->bridge.of_node = dev->of_node;
 	dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
+	initialized = of_property_read_bool(dev->of_node, "samsung,boot-on");
+	if (initialized) {
+		dsi->state = DSIM_STATE_INITIALIZED | DSIM_STATE_ENABLED;
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret)
+			goto err_disable_runtime;
+	}
 
 	/* DE_LOW: i.MX8M Mini/Nano LCDIF-DSIM glue logic inverts HS/VS/DE */
 	if (dsi->plat_data->hw_type == DSIM_TYPE_IMX8MM)
@@ -2020,11 +2028,14 @@ int samsung_dsim_probe(struct platform_device *pdev)
 	if (dsi->plat_data->host_ops && dsi->plat_data->host_ops->register_host) {
 		ret = dsi->plat_data->host_ops->register_host(dsi);
 		if (ret)
-			goto err_disable_runtime;
+			goto err_put_runtime;
 	}
 
 	return 0;
 
+err_put_runtime:
+	if (initialized)
+		pm_runtime_put_sync(dev);
 err_disable_runtime:
 	pm_runtime_disable(dev);
 
-- 
2.43.0