[PATCH v6 07/22] drm/sun4i: sun6i_mipi_dsi: Setup burst mode

[Jagan Teki <jagan@amarulasolutions.com>]

Setting up burst mode display would require to compute
- Horizontal timing edge values to fill burst drq register
- Line, sync values to fill burst line 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>
---
 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