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From:   Jagan Teki <jagan@amarulasolutions.com>
To:     Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <maxime.ripard@bootlin.com>,
        Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
        Rob Herring <robh+dt@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
        Icenowy Zheng <icenowy@aosc.io>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Vasily Khoruzhick <anarsoul@gmail.com>,
        Thierry Reding <thierry.reding@gmail.com>,
        Mark Rutland <mark.rutland@arm.com>,
        dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Michael Trimarchi <michael@amarulasolutions.com>,
        TL Lim <tllim@pine64.org>, linux-sunxi@googlegroups.com,
        linux-amarula@amarulasolutions.com
Cc:     Jagan Teki <jagan@amarulasolutions.com>
Subject: [PATCH v2 08/12] drm/sun4i: sun6i_mipi_dsi: Enable 2byte trail for 4-lane burst mode
Date:   Fri, 16 Nov 2018 22:09:12 +0530
Message-Id: <20181116163916.29621-9-jagan@amarulasolutions.com>
In-Reply-To: <20181116163916.29621-1-jagan@amarulasolutions.com>
References: <20181116163916.29621-1-jagan@amarulasolutions.com>
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Sender: linux-kernel-owner@vger.kernel.org
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For 4-lane, burst mode panels would need to enable 2byte trail_fill
along with filling trail_env in dsi base control register.

Similar reference code avialable in BSP (from linux-sunxi/
drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)

if (panel->lcd_dsi_lane == 4)
{
   dsi_dev[sel]->dsi_basic_ctl.bits.trail_inv = 0xc;
   dsi_dev[sel]->dsi_basic_ctl.bits.trail_fill     = 1;
}

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 0182408f8932..22d2987c3298 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -34,6 +34,8 @@
 #define SUN6I_DSI_CTL_EN			BIT(0)
 
 #define SUN6I_DSI_BASIC_CTL_REG		0x00c
+#define SUN6I_DSI_BASIC_CTL_TRAIL_INV(n)	(((n) & 0xf) << 4)
+#define SUN6I_DSI_BASIC_CTL_TRAIL_FILL		BIT(3)
 #define SUN6I_DSI_BASIC_CTL_HBP_DIS		BIT(2)
 #define SUN6I_DSI_BASIC_CTL_HSA_HSE_DIS		BIT(1)
 #define SUN6I_DSI_BASIC_CTL_VIDEO_BURST		BIT(0)
@@ -559,6 +561,10 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 	/* enable burst mode */
 	regmap_read(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, &val);
 	val |= SUN6I_DSI_BASIC_CTL_VIDEO_BURST;
+	if (device->lanes == 4) {
+		val |= SUN6I_DSI_BASIC_CTL_TRAIL_INV(0xc);
+		val |= SUN6I_DSI_BASIC_CTL_TRAIL_FILL;
+	}
 	regmap_write(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, val);
 }
 
-- 
2.18.0.321.gffc6fa0e3