[PATCH 09/12] drm/imx: add internal bridge handling display-timings DT node

[Dmitry Baryshkov]

i.MX DRM DT bindings allow using either a proper panel / bridge graph to
provide information about connected panels, or just a display-timings DT
node, describing just the timings and the flags. Add helper bridge
driver supporting the latter usecase. It will be used by both LDB and
parallel-display drivers.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
---
 drivers/gpu/drm/imx/ipuv3/Kconfig             | 10 ++++
 drivers/gpu/drm/imx/ipuv3/Makefile            |  2 +
 drivers/gpu/drm/imx/ipuv3/imx-drm.h           |  5 ++
 drivers/gpu/drm/imx/ipuv3/imx-legacy-bridge.c | 85 +++++++++++++++++++++++++++
 4 files changed, 102 insertions(+)

diff --git a/drivers/gpu/drm/imx/ipuv3/Kconfig b/drivers/gpu/drm/imx/ipuv3/Kconfig
index 8aaf2441bcef..119e1431177f 100644
--- a/drivers/gpu/drm/imx/ipuv3/Kconfig
+++ b/drivers/gpu/drm/imx/ipuv3/Kconfig
@@ -37,6 +37,16 @@ config DRM_IMX_LDB
 	  Choose this to enable the internal LVDS Display Bridge (LDB)
 	  found on i.MX53 and i.MX6 processors.
 
+config DRM_IMX_LEGACY_BRIDGE
+	tristate
+	depends on DRM_IMX
+	help
+	  This is a DRM bridge implementation for the DRM i.MX driver, which
+	  uses of_get_drm_display_mode to acquire display mode.
+
+	  Newer designs should not use this bridge and should use proper panel
+	  driver instead.
+
 config DRM_IMX_HDMI
 	tristate "Freescale i.MX DRM HDMI"
 	select DRM_DW_HDMI
diff --git a/drivers/gpu/drm/imx/ipuv3/Makefile b/drivers/gpu/drm/imx/ipuv3/Makefile
index 21cdcc2faabc..dfc495e495ec 100644
--- a/drivers/gpu/drm/imx/ipuv3/Makefile
+++ b/drivers/gpu/drm/imx/ipuv3/Makefile
@@ -8,4 +8,6 @@ obj-$(CONFIG_DRM_IMX_PARALLEL_DISPLAY) += parallel-display.o
 obj-$(CONFIG_DRM_IMX_TVE) += imx-tve.o
 obj-$(CONFIG_DRM_IMX_LDB) += imx-ldb.o
 
+obj-$(CONFIG_DRM_IMX_LEGACY_BRIDGE) += imx-legacy-bridge.o
+
 obj-$(CONFIG_DRM_IMX_HDMI) += dw_hdmi-imx.o
diff --git a/drivers/gpu/drm/imx/ipuv3/imx-drm.h b/drivers/gpu/drm/imx/ipuv3/imx-drm.h
index e01f026047de..57a95926c492 100644
--- a/drivers/gpu/drm/imx/ipuv3/imx-drm.h
+++ b/drivers/gpu/drm/imx/ipuv3/imx-drm.h
@@ -3,6 +3,7 @@
 #define _IMX_DRM_H_
 
 struct device_node;
+struct drm_bridge;
 struct drm_connector;
 struct drm_device;
 struct drm_encoder;
@@ -30,4 +31,8 @@ void imx_drm_connector_destroy(struct drm_connector *connector);
 int ipu_planes_assign_pre(struct drm_device *dev,
 			  struct drm_atomic_state *state);
 
+struct drm_bridge *devm_imx_drm_legacy_bridge(struct device *dev,
+					      struct device_node *np,
+					      int type);
+
 #endif /* _IMX_DRM_H_ */
diff --git a/drivers/gpu/drm/imx/ipuv3/imx-legacy-bridge.c b/drivers/gpu/drm/imx/ipuv3/imx-legacy-bridge.c
new file mode 100644
index 000000000000..4853e0c41ab2
--- /dev/null
+++ b/drivers/gpu/drm/imx/ipuv3/imx-legacy-bridge.c
@@ -0,0 +1,85 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Freescale i.MX drm driver
+ * 
+ * bridge driver for legacy DT bindings, utilizing display-timings node
+ */
+
+#include <drm/drm_bridge.h>
+#include <drm/drm_modes.h>
+#include <drm/drm_probe_helper.h>
+
+#include <video/of_display_timing.h>
+#include <video/of_videomode.h>
+
+#include "imx-drm.h"
+
+struct imx_legacy_bridge {
+	struct drm_bridge base;
+
+	struct drm_display_mode mode;
+	u32 bus_flags;
+};
+
+#define to_imx_legacy_bridge(bridge)	container_of(bridge, struct imx_legacy_bridge, base)
+
+static int imx_legacy_bridge_attach(struct drm_bridge *bridge,
+				   enum drm_bridge_attach_flags flags)
+{
+	if (!(flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int imx_legacy_bridge_get_modes(struct drm_bridge *bridge,
+				       struct drm_connector *connector)
+{
+	struct imx_legacy_bridge *imx_bridge = to_imx_legacy_bridge(bridge);
+	int ret;
+
+	ret = drm_connector_helper_get_modes_fixed(connector, &imx_bridge->mode);
+	if (ret)
+		return ret;
+
+	connector->display_info.bus_flags = imx_bridge->bus_flags;
+
+	return 0;
+}
+
+struct drm_bridge_funcs imx_legacy_bridge_funcs = {
+	.attach = imx_legacy_bridge_attach,
+	.get_modes = imx_legacy_bridge_get_modes,
+};
+
+struct drm_bridge *devm_imx_drm_legacy_bridge(struct device *dev,
+					      struct device_node *np,
+					      int type)
+{
+	struct imx_legacy_bridge *imx_bridge;
+	int ret;
+
+	imx_bridge = devm_kzalloc(dev, sizeof(*imx_bridge), GFP_KERNEL);
+	if (!imx_bridge)
+		return ERR_PTR(-ENOMEM);
+
+	ret = of_get_drm_display_mode(np,
+				      &imx_bridge->mode,
+				      &imx_bridge->bus_flags,
+				      OF_USE_NATIVE_MODE);
+	if (ret)
+		return ERR_PTR(ret);
+
+	imx_bridge->mode.type |= DRM_MODE_TYPE_DRIVER;
+
+	imx_bridge->base.funcs = &imx_legacy_bridge_funcs;
+	imx_bridge->base.of_node = np;
+	imx_bridge->base.ops = DRM_BRIDGE_OP_MODES;
+	imx_bridge->base.type = type;
+
+	ret = devm_drm_bridge_add(dev, &imx_bridge->base);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return &imx_bridge->base;
+}

-- 
2.39.2