linux-kernel - [PATCH v3 16/21] drm/sun4i: Move access control before setting the register as documented

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Message-Id: <20181204142218.16284-17-paul.kocialkowski@bootlin.com>
Date:   Tue,  4 Dec 2018 15:22:13 +0100
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc:     Maxime Ripard <maxime.ripard@...tlin.com>,
        David Airlie <airlied@...ux.ie>, Chen-Yu Tsai <wens@...e.org>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Sean Paul <sean@...rly.run>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        linux-sunxi@...glegroups.com, Daniel Vetter <daniel@...ll.ch>,
        Paul Kocialkowski <paul.kocialkowski@...tlin.com>
Subject: [PATCH v3 16/21] drm/sun4i: Move access control before setting the register as documented

From: Maxime Ripard <maxime.ripard@...tlin.com>

Unlike what is currently being done, the ACCESS_CTRL bit documentation asks
that this bit should be set before modifying any register. The code in the
BSP also does this, so make sure we do this as well.

Signed-off-by: Maxime Ripard <maxime.ripard@...tlin.com>
Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
---
 drivers/gpu/drm/sun4i/sun4i_frontend.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun4i_frontend.c b/drivers/gpu/drm/sun4i/sun4i_frontend.c
index d69d426c3014..c80338368992 100644
--- a/drivers/gpu/drm/sun4i/sun4i_frontend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_frontend.c
@@ -74,6 +74,10 @@ static void sun4i_frontend_scaler_init(struct sun4i_frontend *frontend)
 {
 	int i;
 
+	regmap_write_bits(frontend->regs, SUN4I_FRONTEND_FRM_CTRL_REG,
+			  SUN4I_FRONTEND_FRM_CTRL_COEF_ACCESS_CTRL,
+			  SUN4I_FRONTEND_FRM_CTRL_COEF_ACCESS_CTRL);
+
 	for (i = 0; i < 32; i++) {
 		regmap_write(frontend->regs, SUN4I_FRONTEND_CH0_HORZCOEF0_REG(i),
 			     sun4i_frontend_horz_coef[2 * i]);
@@ -89,9 +93,6 @@ static void sun4i_frontend_scaler_init(struct sun4i_frontend *frontend)
 			     sun4i_frontend_vert_coef[i]);
 	}
 
-	regmap_update_bits(frontend->regs, SUN4I_FRONTEND_FRM_CTRL_REG,
-			   SUN4I_FRONTEND_FRM_CTRL_COEF_ACCESS_CTRL,
-			   SUN4I_FRONTEND_FRM_CTRL_COEF_ACCESS_CTRL);
 }
 
 int sun4i_frontend_init(struct sun4i_frontend *frontend)
-- 
2.19.2