drm/mcde: dsi: Delay start of video stream generator

The initialization order for DSI video mode is important - if we
enable the video stream generator (VSG) before the MCDE DSI formatter
starts sending pixel data, it will immediately run into an error and
disable itself again.

Avoid this problem by delaying the activation of the VSG
until the MCDE DSI formatter is properly set up and running
(i.e. when mcde_dsi_bridge_enable() is called).
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191106165835.2863-5-stephan@gerhold.net

drivers/gpu/drm/mcde/mcde_dsi.c

@@ -583,11 +583,6 @@ static void mcde_dsi_setup_video_mode(struct mcde_dsi *d,
 	val |= DSI_VID_MODE_STS_CTL_ERR_MISSING_VSYNC;
 	val |= DSI_VID_MODE_STS_CTL_ERR_MISSING_DATA;
 	writel(val, d->regs + DSI_VID_MODE_STS_CTL);
-
-	/* Enable video mode */
-	val = readl(d->regs + DSI_MCTL_MAIN_DATA_CTL);
-	val |= DSI_MCTL_MAIN_DATA_CTL_VID_EN;
-	writel(val, d->regs + DSI_MCTL_MAIN_DATA_CTL);
 }
 
 static void mcde_dsi_start(struct mcde_dsi *d)
@@ -699,6 +694,14 @@ static void mcde_dsi_start(struct mcde_dsi *d)
 static void mcde_dsi_bridge_enable(struct drm_bridge *bridge)
 {
 	struct mcde_dsi *d = bridge_to_mcde_dsi(bridge);
+	u32 val;
+
+	if (d->mdsi->mode_flags & MIPI_DSI_MODE_VIDEO) {
+		/* Enable video mode */
+		val = readl(d->regs + DSI_MCTL_MAIN_DATA_CTL);
+		val |= DSI_MCTL_MAIN_DATA_CTL_VID_EN;
+		writel(val, d->regs + DSI_MCTL_MAIN_DATA_CTL);
+	}
 
 	dev_info(d->dev, "enable DSI master\n");
 };