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

[Laurent Pinchart]

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.pinch...@ideasonboard.com>
---
 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

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