linux-kernel - [PATCH v2 38/43] drm/sun4i: Move access control before setting the register as documented

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Date:   Fri, 23 Nov 2018 10:25:10 +0100
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org
Cc:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Chen-Yu Tsai <wens@...e.org>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
        linux-sunxi@...glegroups.com, Daniel Vetter <daniel@...ll.ch>
Subject: [PATCH v2 38/43] 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>
---
 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 b9c18fa2fff3..2c9dcb4ffde0 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)
-- 
2.19.1