[PATCH v3 02/12] video: rockchip: dw_mipi_dsi: Improve pixel clock calculations

[Dang Huynh <danct12@riseup.net>]

From: Ondrej Jirman <megi@xff.cz>

Calculate burst mode overhead in one place for both internal
and external PHY use case and exit if out of range, instead
of ignoring the wrong value.

Signed-off-by: Ondrej Jirman <megi@xff.cz>
Signed-off-by: Dang Huynh <danct12@riseup.net>
---
 drivers/video/rockchip/dw_mipi_dsi_rockchip.c | 24 ++++++++++--------------
 1 file changed, 10 insertions(+), 14 deletions(-)

diff --git a/drivers/video/rockchip/dw_mipi_dsi_rockchip.c b/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
index fa512173510b1ee6f51e6269eb249e24d0e980f8..c47992dfb133cda029eba82e842ac824ceead64b 100644
--- a/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
+++ b/drivers/video/rockchip/dw_mipi_dsi_rockchip.c
@@ -526,8 +526,6 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, struct display_timing *timings,
 	struct udevice *dev = device->dev;
 	struct dw_rockchip_dsi_priv *dsi = dev_get_priv(dev);
 	int bpp;
-	unsigned long mpclk, tmp;
-	unsigned int target_mbps = 1000;
 	unsigned int max_mbps = dppa_map[ARRAY_SIZE(dppa_map) - 1].max_mbps;
 	unsigned long best_freq = 0;
 	unsigned long fvco_min, fvco_max, fin, fout;
@@ -544,30 +542,28 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, struct display_timing *timings,
 		return bpp;
 	}
 
-	mpclk = DIV_ROUND_UP(timings->pixelclock.typ, 1000);
-	if (mpclk) {
-		/* take 1 / 0.8, since mbps must big than bandwidth of RGB */
-		tmp = (mpclk * (bpp / lanes) * 10 / 8) / 1000;
-		if (tmp < max_mbps)
-			target_mbps = tmp;
-		else
-			dev_err(dsi->dsi_host,
-				"DPHY clock frequency is out of range\n");
+	fout = timings->pixelclock.typ / MSEC_PER_SEC * bpp / lanes;
+	if (device->mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+		fout = fout * 12 / 10;
+	fout *= MSEC_PER_SEC;
+
+	if (fout > max_mbps * USEC_PER_SEC) {
+		dev_err(dsi->dsi_host, "DPHY clock frequency is out of range\n");
+		return -EINVAL;
 	}
 
 	/* for external phy only the mipi_dphy_config is necessary */
 	if (generic_phy_valid(&dsi->phy)) {
-		phy_mipi_dphy_get_default_config(timings->pixelclock.typ  * 10 / 8,
+		phy_mipi_dphy_get_default_config(fout / bpp * lanes,
 						 bpp, lanes,
 						 &dsi->phy_opts);
-		dsi->lane_mbps = target_mbps;
+		dsi->lane_mbps = DIV_ROUND_UP(fout, USEC_PER_SEC);
 		*lane_mbps = dsi->lane_mbps;
 
 		return 0;
 	}
 
 	fin = clk_get_rate(dsi->ref);
-	fout = target_mbps * USEC_PER_SEC;
 
 	/* constraint: 5Mhz <= Fref / N <= 40MHz */
 	min_prediv = DIV_ROUND_UP(fin, 40 * USEC_PER_SEC);

-- 
2.49.0