linux-kernel - [PATCH v1 1/9] drm/bridge: tc358768: always enable HS video mode

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Message-Id: <20230427142934.55435-2-francesco@dolcini.it>
Date:   Thu, 27 Apr 2023 16:29:26 +0200
From:   Francesco Dolcini <francesco@...cini.it>
To:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        tomi.valkeinen@...asonboard.com, dri-devel@...ts.freedesktop.org
Cc:     Francesco Dolcini <francesco.dolcini@...adex.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>, linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/9] drm/bridge: tc358768: always enable HS video mode

From: Francesco Dolcini <francesco.dolcini@...adex.com>

Always enable HS video mode setting the TXMD bit, without this change no
video output is present with DSI sinks that are setting
MIPI_DSI_MODE_LPM flag (tested with LT8912B DSI-HDMI bridge).

Previously the driver was enabling HS mode only when the DSI sink was
not explicitly setting the MIPI_DSI_MODE_LPM, however this is not
correct.

The MIPI_DSI_MODE_LPM is supposed to indicate that the sink is willing
to receive data in low power mode, however clearing the
TC358768_DSI_CONTROL_TXMD bit will make the TC358768 send video in
LP mode that is not the intended behavior.

Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Francesco Dolcini <francesco.dolcini@...adex.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 7c0cbe84611b..8f349bf4fc32 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -866,8 +866,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	val = TC358768_DSI_CONFW_MODE_SET | TC358768_DSI_CONFW_ADDR_DSI_CONTROL;
 	val |= (dsi_dev->lanes - 1) << 1;
 
-	if (!(dsi_dev->mode_flags & MIPI_DSI_MODE_LPM))
-		val |= TC358768_DSI_CONTROL_TXMD;
+	val |= TC358768_DSI_CONTROL_TXMD;
 
 	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
 		val |= TC358768_DSI_CONTROL_HSCKMD;
-- 
2.25.1