Subject: [PATCH 1/2] drm/rockchip: dsi: Add maximum per lane bit rate calculation

From: Chaoyi Chen <[email-masked]>
Date: Tue, 24 Mar 2026 16:58:37 +0800

From: Chaoyi Chen <[email-masked]>

Different chips have varying support for the maximum bit rate per lane.

Add calculation for the maximum per lane bit rate for various chip
platforms, and relax the bandwidth margin requirements.

Signed-off-by: Chaoyi Chen <[email-masked]>
---
 .../gpu/drm/rockchip/dw-mipi-dsi-rockchip.c   | 21 +++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
index 3547d91b25d3..d3bacfae174e 100644
--- a/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
+++ b/drivers/gpu/drm/rockchip/dw-mipi-dsi-rockchip.c
@@ -268,6 +268,7 @@ struct rockchip_dw_dsi_chip_data {
 
 	unsigned int flags;
 	unsigned int max_data_lanes;
+	unsigned long max_bit_rate_per_lane;
 };
 
 struct dw_mipi_dsi_rockchip {
@@ -565,7 +566,7 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
 	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 int max_mbps;
 	unsigned long best_freq = 0;
 	unsigned long fvco_min, fvco_max, fin, fout;
 	unsigned int min_prediv, max_prediv;
@@ -573,6 +574,7 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
 	unsigned long _fbdiv, best_fbdiv;
 	unsigned long min_delta = ULONG_MAX;
 
+	max_mbps = dsi->cdata->max_bit_rate_per_lane;
 	dsi->format = format;
 	bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);
 	if (bpp < 0) {
@@ -584,8 +586,8 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
 
 	mpclk = DIV_ROUND_UP(mode->clock, MSEC_PER_SEC);
 	if (mpclk) {
-		/* take 1 / 0.8, since mbps must big than bandwidth of RGB */
-		tmp = mpclk * (bpp / lanes) * 10 / 8;
+		/* take 1 / 0.9, since mbps must big than bandwidth of RGB */
+		tmp = mpclk * (bpp / lanes) * 10 / 9;
 		if (tmp < max_mbps)
 			target_mbps = tmp;
 		else
@@ -595,7 +597,7 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
 
 	/* for external phy only a the mipi_dphy_config is necessary */
 	if (dsi->phy) {
-		phy_mipi_dphy_get_default_config(mode->clock * 1000 * 10 / 8,
+		phy_mipi_dphy_get_default_config(mode->clock * 1000 * 10 / 9,
 						 bpp, lanes,
 						 &dsi->phy_opts.mipi_dphy);
 		dsi->lane_mbps = target_mbps;
@@ -1503,6 +1505,7 @@ static const struct rockchip_dw_dsi_chip_data px30_chip_data[] = {
 						PX30_DSI_FORCETXSTOPMODE), 0),
 
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1000000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1515,6 +1518,7 @@ static const struct rockchip_dw_dsi_chip_data rk3128_chip_data[] = {
 						RK3128_DSI_FORCERXMODE |
 						RK3128_DSI_FORCETXSTOPMODE), 0),
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1000000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1527,6 +1531,7 @@ static const struct rockchip_dw_dsi_chip_data rk3288_chip_data[] = {
 		.lcdsel_lit = FIELD_PREP_WM16_CONST(RK3288_DSI0_LCDC_SEL, 1),
 
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1500000000UL,
 	},
 	{
 		.reg = 0xff964000,
@@ -1535,6 +1540,7 @@ static const struct rockchip_dw_dsi_chip_data rk3288_chip_data[] = {
 		.lcdsel_lit = FIELD_PREP_WM16_CONST(RK3288_DSI1_LCDC_SEL, 1),
 
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1500000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1547,6 +1553,7 @@ static const struct rockchip_dw_dsi_chip_data rk3368_chip_data[] = {
 						RK3368_DSI_FORCETXSTOPMODE |
 						RK3368_DSI_FORCERXMODE), 0),
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1500000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1634,6 +1641,7 @@ static const struct rockchip_dw_dsi_chip_data rk3399_chip_data[] = {
 
 		.flags = DW_MIPI_NEEDS_PHY_CFG_CLK | DW_MIPI_NEEDS_GRF_CLK,
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1500000000UL,
 	},
 	{
 		.reg = 0xff968000,
@@ -1658,6 +1666,7 @@ static const struct rockchip_dw_dsi_chip_data rk3399_chip_data[] = {
 
 		.flags = DW_MIPI_NEEDS_PHY_CFG_CLK | DW_MIPI_NEEDS_GRF_CLK,
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1500000000UL,
 
 		.dphy_rx_init = rk3399_dphy_tx1rx1_init,
 		.dphy_rx_power_on = rk3399_dphy_tx1rx1_power_on,
@@ -1674,6 +1683,7 @@ static const struct rockchip_dw_dsi_chip_data rk3506_chip_data[] = {
 			     FIELD_PREP_WM16_CONST(RK3506_DSI_FORCERXMODE, 0) |
 			     FIELD_PREP_WM16_CONST(RK3506_DSI_FORCETXSTOPMODE, 0)),
 		.max_data_lanes = 2,
+		.max_bit_rate_per_lane = 1500000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1687,6 +1697,7 @@ static const struct rockchip_dw_dsi_chip_data rk3568_chip_data[] = {
 			     FIELD_PREP_WM16_CONST(RK3568_DSI0_TURNDISABLE, 0) |
 			     FIELD_PREP_WM16_CONST(RK3568_DSI0_FORCERXMODE, 0)),
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1200000000UL,
 	},
 	{
 		.reg = 0xfe070000,
@@ -1696,6 +1707,7 @@ static const struct rockchip_dw_dsi_chip_data rk3568_chip_data[] = {
 			     FIELD_PREP_WM16_CONST(RK3568_DSI1_TURNDISABLE, 0) |
 			     FIELD_PREP_WM16_CONST(RK3568_DSI1_FORCERXMODE, 0)),
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1200000000UL,
 	},
 	{ /* sentinel */ }
 };
@@ -1708,6 +1720,7 @@ static const struct rockchip_dw_dsi_chip_data rv1126_chip_data[] = {
 			     FIELD_PREP_WM16_CONST(RV1126_DSI_FORCERXMODE, 0) |
 			     FIELD_PREP_WM16_CONST(RV1126_DSI_FORCETXSTOPMODE, 0)),
 		.max_data_lanes = 4,
+		.max_bit_rate_per_lane = 1000000000UL,
 	},
 	{ /* sentinel */ }
 };
-- 
2.51.1