[U-Boot] [PATCH v3] video: mxsfb: Fix reset hang when videomode variable is not present

[Fabio Estevam]

Currently the system hangs when the 'videomode' variable is not present
and a reset command is issued:

=> setenv videomode
=> saveenv
=> reset

(Board hangs)

lcdif_power_down() assumes that the LCDIF controller has been properly
configured and enabled, which may not be true.

To fix this issue check whether panel.frameAdrs has been initialized and
in case it has not been initialized, do not continue with the LCDIF
powerdown sequence.

Tested on a imx7dsabresd board.

Signed-off-by: Fabio Estevam <fabio.estevam at nxp.com>
---
Changes since v2:
- Check panel.frameAdrs instead

 drivers/video/mxsfb.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c
index 3cc03ca..32ecbe2 100644
--- a/drivers/video/mxsfb.c
+++ b/drivers/video/mxsfb.c
@@ -136,6 +136,9 @@ void lcdif_power_down(void)
 	struct mxs_lcdif_regs *regs = (struct mxs_lcdif_regs *)MXS_LCDIF_BASE;
 	int timeout = 1000000;
 
+	if (!panel.frameAdrs)
+		return;
+
 	writel(panel.frameAdrs, &regs->hw_lcdif_cur_buf_reg);
 	writel(panel.frameAdrs, &regs->hw_lcdif_next_buf_reg);
 	writel(LCDIF_CTRL1_VSYNC_EDGE_IRQ, &regs->hw_lcdif_ctrl1_clr);
-- 
2.7.4