From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
Sam Ravnborg <sam@ravnborg.org>,
Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Rob Herring <robh+dt@kernel.org>,
Frank Rowand <frowand.list@gmail.com>
Cc: dri-devel@lists.freedesktop.org, linux-tegra@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v7 5/6] drm/tegra: output: rgb: Support LVDS encoder bridge
Date: Sun, 14 Jun 2020 20:22:33 +0300 [thread overview]
Message-ID: <20200614172234.8856-6-digetx@gmail.com> (raw)
In-Reply-To: <20200614172234.8856-1-digetx@gmail.com>
Newer Tegra device-trees will specify a video output graph, which involves
LVDS encoder bridge. This patch adds support for the LVDS encoder bridge
to the RGB output, allowing us to model the display hardware properly.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/gpu/drm/tegra/rgb.c | 58 +++++++++++++++++++++++++++++++------
1 file changed, 49 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c
index 0562a7eb793f..9a7024ec96bc 100644
--- a/drivers/gpu/drm/tegra/rgb.c
+++ b/drivers/gpu/drm/tegra/rgb.c
@@ -7,6 +7,7 @@
#include <linux/clk.h>
#include <drm/drm_atomic_helper.h>
+#include <drm/drm_bridge_connector.h>
#include <drm/drm_panel.h>
#include <drm/drm_simple_kms_helper.h>
@@ -267,24 +268,63 @@ int tegra_dc_rgb_remove(struct tegra_dc *dc)
int tegra_dc_rgb_init(struct drm_device *drm, struct tegra_dc *dc)
{
struct tegra_output *output = dc->rgb;
+ struct drm_connector *connector;
int err;
if (!dc->rgb)
return -ENODEV;
- drm_connector_init(drm, &output->connector, &tegra_rgb_connector_funcs,
- DRM_MODE_CONNECTOR_LVDS);
- drm_connector_helper_add(&output->connector,
- &tegra_rgb_connector_helper_funcs);
- output->connector.dpms = DRM_MODE_DPMS_OFF;
-
drm_simple_encoder_init(drm, &output->encoder, DRM_MODE_ENCODER_LVDS);
drm_encoder_helper_add(&output->encoder,
&tegra_rgb_encoder_helper_funcs);
- drm_connector_attach_encoder(&output->connector,
- &output->encoder);
- drm_connector_register(&output->connector);
+ /*
+ * Tegra devices that have LVDS panel utilize LVDS encoder bridge
+ * for converting up to 28 LCD LVTTL lanes into 5/4 LVDS lanes that
+ * go to display panel's receiver.
+ *
+ * Encoder usually have a power-down control which needs to be enabled
+ * in order to transmit data to the panel. Historically devices that
+ * use an older device-tree version didn't model the bridge, assuming
+ * that encoder is turned ON by default, while today's DRM allows us
+ * to model LVDS encoder properly.
+ *
+ * Newer device-trees utilize LVDS encoder bridge, which provides
+ * us with a connector and handles the display panel.
+ *
+ * For older device-trees we fall back to our own connector and use
+ * nvidia,panel phandle.
+ */
+ if (output->bridge) {
+ err = drm_bridge_attach(&output->encoder, output->bridge,
+ NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
+ if (err) {
+ dev_err(output->dev, "failed to attach bridge: %d\n",
+ err);
+ return err;
+ }
+
+ connector = drm_bridge_connector_init(drm, &output->encoder);
+ if (IS_ERR(connector)) {
+ dev_err(output->dev,
+ "failed to initialize bridge connector: %pe\n",
+ connector);
+ return PTR_ERR(connector);
+ }
+
+ drm_connector_attach_encoder(connector, &output->encoder);
+ } else {
+ drm_connector_init(drm, &output->connector,
+ &tegra_rgb_connector_funcs,
+ DRM_MODE_CONNECTOR_LVDS);
+ drm_connector_helper_add(&output->connector,
+ &tegra_rgb_connector_helper_funcs);
+ output->connector.dpms = DRM_MODE_DPMS_OFF;
+
+ drm_connector_attach_encoder(&output->connector,
+ &output->encoder);
+ drm_connector_register(&output->connector);
+ }
err = tegra_output_init(drm, output);
if (err < 0) {
--
2.26.0
next prev parent reply other threads:[~2020-06-14 17:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-14 17:22 [PATCH v7 0/6] Support DRM bridges on NVIDIA Tegra Dmitry Osipenko
2020-06-14 17:22 ` [PATCH v7 1/6] of_graph: add of_graph_get_local_port() Dmitry Osipenko
2020-06-16 1:21 ` Laurent Pinchart
2020-06-16 1:25 ` Laurent Pinchart
2020-06-16 13:56 ` Dmitry Osipenko
2020-06-16 14:14 ` Dmitry Osipenko
2020-06-14 17:22 ` [PATCH v7 2/6] drm/of: Make drm_of_find_panel_or_bridge() to check graph's presence Dmitry Osipenko
2020-06-16 1:26 ` Laurent Pinchart
2020-06-16 14:42 ` Dmitry Osipenko
2020-06-14 17:22 ` [PATCH v7 3/6] drm/tegra: output: Don't leak OF node on error Dmitry Osipenko
2020-06-14 17:22 ` [PATCH v7 4/6] drm/tegra: output: Support DRM bridges Dmitry Osipenko
2020-06-14 17:22 ` Dmitry Osipenko [this message]
2020-06-14 17:22 ` [PATCH v7 6/6] drm/tegra: output: rgb: Wrap directly-connected panel into DRM bridge Dmitry Osipenko
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