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From:   Jagan Teki <jagan@amarulasolutions.com>
To:     Maxime Ripard <maxime.ripard@free-electrons.com>,
        Chen-Yu Tsai <wens@csie.org>, Icenowy Zheng <icenowy@aosc.io>,
        Jernej Skrabec <jernej.skrabec@siol.net>,
        Vasily Khoruzhick <anarsoul@gmail.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        David Airlie <airlied@linux.ie>,
        dri-devel@lists.freedesktop.org,
        Michael Turquette <mturquette@baylibre.com>,
        Stephen Boyd <sboyd@kernel.org>, linux-clk@vger.kernel.org,
        Michael Trimarchi <michael@amarulasolutions.com>,
        linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Cc:     Jagan Teki <jagan@amarulasolutions.com>
Subject: [PATCH v2 08/15] drm/sun4i: sun6i_mipi_dsi: Fix TCON DRQ set bits
Date:   Tue, 23 Oct 2018 21:20:28 +0530
Message-Id: <20181023155035.9101-9-jagan@amarulasolutions.com>
In-Reply-To: <20181023155035.9101-1-jagan@amarulasolutions.com>
References: <20181023155035.9101-1-jagan@amarulasolutions.com>
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TCON DRQ set bits for non-burst DSI mode can computed via
horizontal front porch instead of front porch + sync timings.

According to BSP code form BPI-M64-bsp in
linux-sunxi/drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c
TCON DRQ set bits are computed for non-burst mode as

=> panel->lcd_ht -    panel->lcd_x - panel->lcd_hbp
=> (timmings->hor_front_porch + panel->lcd_hbp + panel->lcd_x)
   - panel->lcd_x - panel->hbp
=> timmings->hor_front_porch
=> mode->hsync_start - mode->hdisplay

So, update the DRQ set bits accordingly.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
---
Changes for v2:
- Add detailed commit message

 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 3a1d48bc1996..8d154cf2e6d6 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -367,9 +367,9 @@ static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 	struct mipi_dsi_device *device = dsi->device;
 	u32 val = 0;
 
-	if ((mode->hsync_end - mode->hdisplay) > 20) {
+	if ((mode->hsync_start - mode->hdisplay) > 20) {
 		/* Maaaaaagic */
-		u16 drq = (mode->hsync_end - mode->hdisplay) - 20;
+		u16 drq = (mode->hsync_start - mode->hdisplay) - 20;
 
 		drq *= mipi_dsi_pixel_format_to_bpp(device->format);
 		drq /= 32;
-- 
2.18.0.321.gffc6fa0e3