[PATCH v7 07/23] drm/sun4i: sun6i_mipi_dsi: Setup burst mode

From: Jagan Teki <jagan@amarulasolutions.com>
To: Maxime Ripard <maxime.ripard@bootlin.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Chen-Yu Tsai <wens@csie.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Rob Herring <robh+dt@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	Michael Trimarchi <michael@amarulasolutions.com>,
	linux-amarula@amarulasolutions.com, linux-sunxi@googlegroups.com,
	Jagan Teki <jagan@amarulasolutions.com>
Subject: [PATCH v7 07/23] drm/sun4i: sun6i_mipi_dsi: Setup burst mode
Date: Fri,  1 Feb 2019 21:12:16 +0530	[thread overview]
Message-ID: <20190201154232.10505-8-jagan@amarulasolutions.com> (raw)
In-Reply-To: <20190201154232.10505-1-jagan@amarulasolutions.com>

Burst mode in DSI would require separate setup initialization
with respect to conventional video mode.

Allwinner DSI controller would need below sequence to setup the
burst mode.
1) configure the burst drq.
2) configure the burst line.
3) finally enable mode.

To configure burst drq, controller would require to compute the edge0,
edge1 and fill into burst mode register.

To configure burst line, controller would require to compute the line,
sync values and fill into burst line register.

Enable burst mode, would require to enable burst mode bit in DSI control
register.

Since there is no direct documentation for these computations
the edge and line formulas are taken from BSP code (from linux-sunxi/
drivers/video/sunxi/disp2/disp/de/lowlevel_sun50iw1/de_dsi.c)

line_num = panel->lcd_ht*dsi_pixel_bits[panel->lcd_dsi_format]/
	  (8*panel->lcd_dsi_lane);
edge1 = sync_point+(panel->lcd_x+panel->lcd_hbp+20)*
	dsi_pixel_bits[panel->lcd_dsi_format] /(8*panel->lcd_dsi_lane);
edge1 = (edge1>line_num)?line_num:edge1;
edge0 = edge1+(panel->lcd_x+40)*tcon_div/8;
edge0 = (edge0>line_num)?(edge0-line_num):1;

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Tested-by: Merlijn Wajer <merlijn@wizzup.org>
---
 drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 70 ++++++++++++++++++++++++--
 1 file changed, 67 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
index 2aeaa19a8d1e..46ad142e66e8 100644
--- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
+++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
@@ -355,6 +355,41 @@ static void sun6i_dsi_inst_init(struct sun6i_dsi *dsi,
 		     SUN6I_DSI_INST_JUMP_CFG_NUM(1));
 };
 
+static u32 sun6i_dsi_get_edge1(struct sun6i_dsi *dsi,
+			       struct drm_display_mode *mode, u32 sync_point)
+{
+	struct mipi_dsi_device *device = dsi->device;
+	unsigned int bpp = mipi_dsi_pixel_format_to_bpp(device->format);
+	u32 hact_sync_bp;
+
+	/* Horizontal timings duration excluding front porch */
+	hact_sync_bp = (mode->hdisplay + mode->htotal - mode->hsync_start);
+
+	return (sync_point + ((hact_sync_bp + 20) * bpp / (8 * device->lanes)));
+}
+
+static u32 sun6i_dsi_get_edge0(struct sun6i_dsi *dsi,
+			       struct drm_display_mode *mode, u32 edge1)
+{
+	struct sun4i_tcon *tcon = dsi->tcon;
+	unsigned long dclk_rate, dclk_parent_rate, tcon0_div;
+
+	dclk_rate = clk_get_rate(tcon->dclk);
+	dclk_parent_rate = clk_get_rate(clk_get_parent(tcon->dclk));
+	tcon0_div = dclk_parent_rate / dclk_rate;
+
+	return (edge1 + (mode->hdisplay + 40) * tcon0_div / 8);
+}
+
+static u32 sun6i_dsi_get_line_num(struct sun6i_dsi *dsi,
+				  struct drm_display_mode *mode)
+{
+	struct mipi_dsi_device *device = dsi->device;
+	unsigned int bpp = mipi_dsi_pixel_format_to_bpp(device->format);
+
+	return (mode->htotal * bpp / (8 * device->lanes));
+}
+
 static int sun6i_dsi_get_drq(struct sun6i_dsi *dsi,
 			      struct drm_display_mode *mode)
 {
@@ -404,8 +439,32 @@ static u16 sun6i_dsi_get_video_start_delay(struct sun6i_dsi *dsi,
 static void sun6i_dsi_setup_burst(struct sun6i_dsi *dsi,
 				  struct drm_display_mode *mode)
 {
-	regmap_write(dsi->regs, SUN6I_DSI_TCON_DRQ_REG,
-		     sun6i_dsi_get_drq(dsi, mode));
+	struct mipi_dsi_device *device = dsi->device;
+	u32 sync_point = 40;
+	u32 line_num = sun6i_dsi_get_line_num(dsi, mode);
+	u32 edge1 = sun6i_dsi_get_edge1(dsi, mode, sync_point);
+	u32 edge0 = sun6i_dsi_get_edge0(dsi, mode, edge1);
+	u32 val;
+
+	if (edge1 > line_num)
+		edge1 = line_num;
+
+	if (edge0 > line_num)
+		edge0 -= line_num;
+	else
+		edge0 = 1;
+
+	regmap_write(dsi->regs, SUN6I_DSI_BURST_DRQ_REG,
+		     SUN6I_DSI_BURST_DRQ_EDGE1(edge1) |
+		     SUN6I_DSI_BURST_DRQ_EDGE0(edge0));
+	regmap_write(dsi->regs, SUN6I_DSI_BURST_LINE_REG,
+		     SUN6I_DSI_BURST_LINE_NUM(line_num) |
+		     SUN6I_DSI_BURST_LINE_SYNC_POINT(sync_point));
+
+	/* enable burst mode */
+	regmap_read(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, &val);
+	val |= SUN6I_DSI_BASIC_CTL_VIDEO_BURST;
+	regmap_write(dsi->regs, SUN6I_DSI_BASIC_CTL_REG, val);
 }
 
 static void sun6i_dsi_setup_inst_loop(struct sun6i_dsi *dsi,
@@ -667,7 +726,12 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
 		     SUN6I_DSI_BASIC_CTL1_VIDEO_PRECISION |
 		     SUN6I_DSI_BASIC_CTL1_VIDEO_MODE);
 
-	sun6i_dsi_setup_burst(dsi, mode);
+	regmap_write(dsi->regs, SUN6I_DSI_TCON_DRQ_REG,
+		     sun6i_dsi_get_drq(dsi, mode));
+
+	if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+		sun6i_dsi_setup_burst(dsi, mode);
+
 	sun6i_dsi_setup_inst_loop(dsi, mode);
 	sun6i_dsi_setup_format(dsi, mode);
 	sun6i_dsi_setup_timings(dsi, mode);
-- 
2.18.0.321.gffc6fa0e3

