video: fbdev: imxfb: Provide a reset mechanism

[cascardo/linux.git] / drivers / video / fbdev / imxfb.c

diff --git a/drivers/video/fbdev/imxfb.c b/drivers/video/fbdev/imxfb.c
index cee8860..bb2f1e8 100644 (file)
--- a/drivers/video/fbdev/imxfb.c
+++ b/drivers/video/fbdev/imxfb.c
@@ -902,6 +902,21 @@ static int imxfb_probe(struct platform_device *pdev)
                goto failed_getclock;
        }
 
+       /*
+        * The LCDC controller does not have an enable bit. The
+        * controller starts directly when the clocks are enabled.
+        * If the clocks are enabled when the controller is not yet
+        * programmed with proper register values (enabled at the
+        * bootloader, for example) then it just goes into some undefined
+        * state.
+        * To avoid this issue, let's enable and disable LCDC IPG clock
+        * so that we force some kind of 'reset' to the LCDC block.
+        */
+       ret = clk_prepare_enable(fbi->clk_ipg);
+       if (ret)
+               goto failed_getclock;
+       clk_disable_unprepare(fbi->clk_ipg);
+
        fbi->clk_ahb = devm_clk_get(&pdev->dev, "ahb");
        if (IS_ERR(fbi->clk_ahb)) {
                ret = PTR_ERR(fbi->clk_ahb);