[PATCH 1/2] drm: rcar-du: Add Standby Mode support

[Nguyen An Hoan <na-hoan@jinso.co.jp>]

From: Hoan Nguyen An <na-hoan@jinso.co.jp>

Add function support for Module Standby Mode

Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 26 ++++++++++++++++++++++++++
 drivers/gpu/drm/rcar-du/rcar_du_crtc.h |  1 +
 2 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index 90dacab..935cdd1 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -651,6 +651,32 @@ static void rcar_du_crtc_stop(struct rcar_du_crtc *rcrtc)
 	rcar_du_group_start_stop(rcrtc->group, false);
 }
 
+int rcar_du_crtc_standby(struct rcar_du_crtc *rcrtc)
+{
+	u32 val_reg;
+	unsigned int i = 0;
+
+	/* Enter Standby mode */
+	rcar_du_crtc_dsysr_clr_set(rcrtc, DSYSR_DRES | DSYSR_DEN, 0);
+
+	for(i = 100; i > 0; i--)
+	{
+		val_reg = rcar_du_crtc_read(rcrtc, DSSR);
+		if(!(val_reg & DSSR_VBK))
+			break;
+		udelay(10);
+	}
+
+	if(!(i > 0))
+		return -ETIMEDOUT;
+
+	/* Stop clock */
+	clk_set_rate(rcrtc->extclock, 0);
+	clk_set_rate(rcrtc->clock, 0);
+
+	return 0;
+}
+
 /* -----------------------------------------------------------------------------
  * CRTC Functions
  */
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
index 59ac6e7..6e0de42 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.h
@@ -99,6 +99,7 @@ enum rcar_du_output {
 
 int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int swindex,
 			unsigned int hwindex);
+int rcar_du_crtc_standby(struct rcar_du_crtc *rcrtc);
 void rcar_du_crtc_suspend(struct rcar_du_crtc *rcrtc);
 void rcar_du_crtc_resume(struct rcar_du_crtc *rcrtc);
 
-- 
2.7.4