[PATCH 8/8] drm: mxsfb: Add support for the bus-width DT property

[Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>]

A new bus-width DT property has been introduced in the bindings to allow
overriding the bus width. Support it.

Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/mxsfb/mxsfb_drv.c | 26 ++++++++++++++++++++++++++
 drivers/gpu/drm/mxsfb/mxsfb_drv.h |  2 ++
 drivers/gpu/drm/mxsfb/mxsfb_kms.c |  8 ++++++--
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 8c549c3931af..fab3aae8cf73 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
@@ -95,10 +95,36 @@ static int mxsfb_attach_bridge(struct mxsfb_drm_private *mxsfb)
 {
 	struct drm_device *drm = mxsfb->drm;
 	struct drm_connector_list_iter iter;
+	struct device_node *ep;
 	struct drm_panel *panel;
 	struct drm_bridge *bridge;
+	u32 bus_width = 0;
 	int ret;
 
+	ep = of_graph_get_endpoint_by_regs(drm->dev->of_node, 0, 0);
+	if (!ep)
+		return -ENODEV;
+
+	of_property_read_u32(ep, "bus-width", &bus_width);
+	of_node_put(ep);
+
+	switch (bus_width) {
+	case 16:
+		mxsfb->bus_format = MEDIA_BUS_FMT_RGB565_1X16;
+		break;
+	case 18:
+		mxsfb->bus_format = MEDIA_BUS_FMT_RGB666_1X18;
+		break;
+	case 24:
+		mxsfb->bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+	case 0:
+		break;
+	default:
+		DRM_DEV_ERROR(drm->dev, "Invalid bus-width %u", bus_width);
+		return -ENODEV;
+	}
+
 	ret = drm_of_find_panel_or_bridge(drm->dev->of_node, 0, 0, &panel,
 					  &bridge);
 	if (ret)
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
index 399d23e91ed1..c4f7a8a0c891 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
@@ -32,6 +32,8 @@ struct mxsfb_drm_private {
 	struct clk			*clk_axi;
 	struct clk			*clk_disp_axi;
 
+	u32				bus_format;
+
 	struct drm_device		*drm;
 	struct {
 		struct drm_plane	primary;
diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index b721b8b262ce..6d512f346918 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -50,11 +50,15 @@ static void mxsfb_set_formats(struct mxsfb_drm_private *mxsfb)
 {
 	struct drm_device *drm = mxsfb->drm;
 	const u32 format = mxsfb->crtc.primary->state->fb->format->format;
-	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+	u32 bus_format;
 	u32 ctrl, ctrl1;
 
-	if (mxsfb->connector->display_info.num_bus_formats)
+	if (mxsfb->bus_format)
+		bus_format = mxsfb->bus_format;
+	else if (mxsfb->connector->display_info.num_bus_formats)
 		bus_format = mxsfb->connector->display_info.bus_formats[0];
+	else
+		bus_format = MEDIA_BUS_FMT_RGB888_1X24;
 
 	DRM_DEV_DEBUG_DRIVER(drm->dev, "Using bus_format: 0x%08X\n",
 			     bus_format);
-- 
Regards,

Laurent Pinchart