OMAP: DSS2: DSI: Wait for DSI PLL clocks to be active before selecting them

The TRM tells us to wait for the DSI PLL derived clocks to become
active before selecting them for use. I didn't actually have any issues
which this would fix but according to the TRM it seems to be the right
thing to do.

Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index 04d84d1..6035904 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -3195,6 +3195,18 @@
 	return 0;
 }
 
+void dsi_wait_dsi1_pll_active(void)
+{
+	if (wait_for_bit_change(DSI_PLL_STATUS, 7, 1) != 1)
+		DSSERR("DSI1 PLL clock not active\n");
+}
+
+void dsi_wait_dsi2_pll_active(void)
+{
+	if (wait_for_bit_change(DSI_PLL_STATUS, 8, 1) != 1)
+		DSSERR("DSI2 PLL clock not active\n");
+}
+
 int dsi_init(struct platform_device *pdev)
 {
 	u32 rev;