linux-kernel - [PATCH v3 1/4] drm: bridge: dw_hdmi: default enable workaround to clear the overflow

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Message-Id: <561951005a85574dcdd108e5d6a3a87df930ea3d.1649989179.git.Sandor.yu@nxp.com>
Date:   Fri, 15 Apr 2022 10:42:47 +0800
From:   Sandor.yu@....com
To:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        andrzej.hajda@...el.com, narmstrong@...libre.com,
        robert.foss@...aro.org, Laurent.pinchart@...asonboard.com,
        jonas@...boo.se, jernej.skrabec@...il.com, hverkuil-cisco@...all.nl
Cc:     Sandor.yu@....com, shengjiu.wang@....com, cai.huoqing@...ux.dev,
        maxime@...no.tech, harry.wentland@....com
Subject: [PATCH v3 1/4] drm: bridge: dw_hdmi: default enable workaround to clear the overflow

From: Sandor Yu <Sandor.yu@....com>

i.MX8MPlus (v2.13a) has verified need the workaround to clear the
overflow with one iteration.
Only i.MX6Q(v1.30a) need the workaround with 4 iterations,
the others versions later than v1.3a have been identified as needing
the workaround with a single iteration.

Default enable the workaround with one iteration for all versions
later than v1.30a.

Signed-off-by: Sandor Yu <Sandor.yu@....com>
Acked-by: Neil Armstrong <narmstrong@...libre.com>
---
 drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 4befc104d220..02d8f7e08814 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -2086,30 +2086,21 @@ static void dw_hdmi_clear_overflow(struct dw_hdmi *hdmi)
 	 * then write one of the FC registers several times.
 	 *
 	 * The number of iterations matters and depends on the HDMI TX revision
-	 * (and possibly on the platform). So far i.MX6Q (v1.30a), i.MX6DL
-	 * (v1.31a) and multiple Allwinner SoCs (v1.32a) have been identified
-	 * as needing the workaround, with 4 iterations for v1.30a and 1
-	 * iteration for others.
-	 * The Amlogic Meson GX SoCs (v2.01a) have been identified as needing
-	 * the workaround with a single iteration.
-	 * The Rockchip RK3288 SoC (v2.00a) and RK3328/RK3399 SoCs (v2.11a) have
-	 * been identified as needing the workaround with a single iteration.
+	 * (and possibly on the platform).
+	 * 4 iterations for i.MX6Q(v1.30a) and 1 iteration for others.
+	 * i.MX6DL (v1.31a), Allwinner SoCs (v1.32a), Rockchip RK3288 SoC (v2.00a),
+	 * Amlogic Meson GX SoCs (v2.01a), RK3328/RK3399 SoCs (v2.11a)
+	 * and i.MX8MPlus (v2.13a) have been identified as needing the workaround
+	 * with a single iteration.
 	 */
 
 	switch (hdmi->version) {
 	case 0x130a:
 		count = 4;
 		break;
-	case 0x131a:
-	case 0x132a:
-	case 0x200a:
-	case 0x201a:
-	case 0x211a:
-	case 0x212a:
+	default:
 		count = 1;
 		break;
-	default:
-		return;
 	}
 
 	/* TMDS software reset */
-- 
2.25.1