[PATCH] drm: mxsfb: Use bus_format from the nearest bridge if present

[Marek Vasut]

In case there is a bridge connected to the LCDIF, use bus_format
from the bridge, otherwise behave as before and use bus_format
from the connector. This way, even if there are multiple bridges
in the display pipeline, the LCDIF will use the correct format.

Signed-off-by: Marek Vasut <ma...@denx.de>
Cc: Daniel Abrecht <pub...@danielabrecht.ch>
Cc: Emil Velikov <emil.l.veli...@gmail.com>
Cc: Laurent Pinchart <laurent.pinch...@ideasonboard.com>
Cc: Lucas Stach <l.st...@pengutronix.de>
Cc: Stefan Agner <ste...@agner.ch>
---
 drivers/gpu/drm/mxsfb/mxsfb_kms.c | 33 +++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c 
b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 5bcc06c1ac0b..98d8ba0bae84 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -47,16 +47,13 @@ static u32 set_hsync_pulse_width(struct mxsfb_drm_private 
*mxsfb, u32 val)
  * Setup the MXSFB registers for decoding the pixels out of the framebuffer and
  * outputting them on the bus.
  */
-static void mxsfb_set_formats(struct mxsfb_drm_private *mxsfb)
+static void mxsfb_set_formats(struct mxsfb_drm_private *mxsfb,
+                             const u32 bus_format)
 {
        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 ctrl, ctrl1;
 
-       if (mxsfb->connector->display_info.num_bus_formats)
-               bus_format = mxsfb->connector->display_info.bus_formats[0];
-
        DRM_DEV_DEBUG_DRIVER(drm->dev, "Using bus_format: 0x%08X\n",
                             bus_format);
 
@@ -222,7 +219,8 @@ static dma_addr_t mxsfb_get_fb_paddr(struct drm_plane 
*plane)
        return gem->paddr;
 }
 
-static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)
+static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb,
+                                    const u32 bus_format)
 {
        struct drm_device *drm = mxsfb->crtc.dev;
        struct drm_display_mode *m = &mxsfb->crtc.state->adjusted_mode;
@@ -247,7 +245,7 @@ static void mxsfb_crtc_mode_set_nofb(struct 
mxsfb_drm_private *mxsfb)
        if (mxsfb->devdata->has_overlay)
                writel(0, mxsfb->base + LCDC_AS_CTRL);
 
-       mxsfb_set_formats(mxsfb);
+       mxsfb_set_formats(mxsfb, bus_format);
 
        clk_set_rate(mxsfb->clk, m->crtc_clock * 1000);
 
@@ -345,7 +343,9 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
                                     struct drm_atomic_state *state)
 {
        struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(crtc->dev);
+       struct drm_bridge_state *bridge_state;
        struct drm_device *drm = mxsfb->drm;
+       u32 bus_format = 0;
        dma_addr_t paddr;
 
        pm_runtime_get_sync(drm->dev);
@@ -353,7 +353,24 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
 
        drm_crtc_vblank_on(crtc);
 
-       mxsfb_crtc_mode_set_nofb(mxsfb);
+       /* If there is a bridge attached to the LCDIF, use its bus format */
+       if (mxsfb->bridge && state) {
+               bridge_state =
+                       drm_atomic_get_new_bridge_state(state,
+                                                       mxsfb->bridge);
+               if (bridge_state)
+                       bus_format = bridge_state->input_bus_cfg.format;
+       }
+
+       /* If there is no bridge, use bus format from connector */
+       if (!bus_format && mxsfb->connector->display_info.num_bus_formats)
+               bus_format = mxsfb->connector->display_info.bus_formats[0];
+
+       /* If all else fails, default to RGB888_1X24 */
+       if (!bus_format)
+               bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+
+       mxsfb_crtc_mode_set_nofb(mxsfb, bus_format);
 
        /* Write cur_buf as well to avoid an initial corrupt frame */
        paddr = mxsfb_get_fb_paddr(crtc->primary);
-- 
2.30.2