linux-kernel - [PATCH 36/40] drm/bridge: analogix_dp: Properly disable aux chan retries on rockchip

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Message-Id: <20180115171614.14474-37-thierry.escande@collabora.com>
Date:   Mon, 15 Jan 2018 18:16:10 +0100
From:   Thierry Escande <thierry.escande@...labora.com>
To:     Archit Taneja <architt@...eaurora.org>,
        Inki Dae <inki.dae@...sung.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Sandy Huang <hjc@...k-chips.com>,
        Sean Paul <seanpaul@...omium.org>,
        David Airlie <airlied@...ux.ie>
Cc:     Tomasz Figa <tfiga@...omium.org>, Haixia Shi <hshi@...omium.org>,
        Ørjan Eide <orjan.eide@....com>,
        zain wang <wzz@...k-chips.com>,
        Yakir Yang <ykk@...k-chips.com>, Lin Huang <hl@...k-chips.com>,
        Douglas Anderson <dianders@...omium.org>,
        Mark Yao <mark.yao@...k-chips.com>,
        linux-kernel@...r.kernel.org, linux-rockchip@...ts.infradead.org,
        dri-devel@...ts.freedesktop.org
Subject: [PATCH 36/40] drm/bridge: analogix_dp: Properly disable aux chan retries on rockchip

From: Douglas Anderson <dianders@...omium.org>

The comments in analogix_dp_init_aux() claim that we're disabling aux
channel retries, but then right below it for Rockchip it sets them to
3.  If we actually need 3 retries for Rockchip then we could adjust
the comment, but it seems more likely that we want the same retry
behavior across all platforms.

Cc: Stéphane Marchesin <marcheu@...omium.org>
Cc: 征增 王 <wzz@...k-chips.com>
Signed-off-by: Douglas Anderson <dianders@...omium.org>
Signed-off-by: Sean Paul <seanpaul@...omium.org>
Signed-off-by: Thierry Escande <thierry.escande@...labora.com>
---
 drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 58e8a28e99aa..a5f2763d72e4 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -481,15 +481,16 @@ void analogix_dp_init_aux(struct analogix_dp_device *dp)
 
 	analogix_dp_reset_aux(dp);
 
-	/* Disable AUX transaction H/W retry */
+	/* AUX_BIT_PERIOD_EXPECTED_DELAY doesn't apply to Rockchip IP */
 	if (dp->plat_data && is_rockchip(dp->plat_data->dev_type))
-		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(0) |
-		      AUX_HW_RETRY_COUNT_SEL(3) |
-		      AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
+		reg = 0;
 	else
-		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(3) |
-		      AUX_HW_RETRY_COUNT_SEL(0) |
-		      AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
+		reg = AUX_BIT_PERIOD_EXPECTED_DELAY(3);
+
+	/* Disable AUX transaction H/W retry */
+	reg |= AUX_HW_RETRY_COUNT_SEL(0) |
+	       AUX_HW_RETRY_INTERVAL_600_MICROSECONDS;
+
 	writel(reg, dp->reg_base + ANALOGIX_DP_AUX_HW_RETRY_CTL);
 
 	/* Receive AUX Channel DEFER commands equal to DEFFER_COUNT*64 */
-- 
2.14.1