OMAPDSS: DSI: Add FEAT_DSI_PLL_REFSEL

Add FEAT_DSI_PLL_REFSEL. OMAP5's DSI PLL needs configuration to select
the reference clock to be used. We always use SYSCLK.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dsi.c b/drivers/video/omap2/dss/dsi.c
index 0c3afc2..a16c8b2 100644
--- a/drivers/video/omap2/dss/dsi.c
+++ b/drivers/video/omap2/dss/dsi.c
@@ -1690,6 +1690,8 @@
 	l = FLD_MOD(l, 1, 13, 13);		/* DSI_PLL_REFEN */
 	l = FLD_MOD(l, 0, 14, 14);		/* DSIPHY_CLKINEN */
 	l = FLD_MOD(l, 1, 20, 20);		/* DSI_HSDIVBYPASS */
+	if (dss_has_feature(FEAT_DSI_PLL_REFSEL))
+		l = FLD_MOD(l, 3, 22, 21);	/* REF_SYSCLK = sysclk */
 	dsi_write_reg(dsidev, DSI_PLL_CONFIGURATION2, l);
 
 	REG_FLD_MOD(dsidev, DSI_PLL_GO, 1, 0, 0);	/* DSI_PLL_GO */
diff --git a/drivers/video/omap2/dss/dss_features.c b/drivers/video/omap2/dss/dss_features.c
index 177f6e8..4685531 100644
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c
@@ -520,6 +520,7 @@
 	FEAT_FIFO_MERGE,
 	FEAT_BURST_2D,
 	FEAT_DSI_PLL_SELFREQDCO,
+	FEAT_DSI_PLL_REFSEL,
 };
 
 /* OMAP2 DSS Features */
diff --git a/drivers/video/omap2/dss/dss_features.h b/drivers/video/omap2/dss/dss_features.h
index f9b9d28..0020bf6 100644
--- a/drivers/video/omap2/dss/dss_features.h
+++ b/drivers/video/omap2/dss/dss_features.h
@@ -66,6 +66,7 @@
 	FEAT_OMAP3_DSI_FIFO_BUG,
 	FEAT_BURST_2D,
 	FEAT_DSI_PLL_SELFREQDCO,
+	FEAT_DSI_PLL_REFSEL,
 };
 
 /* DSS register field id */