[PATCH v7 1/9] drm: renesas: rz-du: mipi_dsi: Add min check for VCLK range

From: Prabhakar
Date: Mon Jun 09 2025 - 18:57:45 EST


From: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>

The VCLK range for Renesas RZ/G2L SoC is 5.803 MHz to 148.5 MHz. Add a
minimum clock check in the mode_valid callback to ensure that the clock
value does not fall below the valid range.

Co-developed-by: Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx>
Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@xxxxxxxxxxx>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
---
v6->v7:
- No changes

v5->v6:
- Updated commit message
- Added reviewed tag from Laurent

v4->v5:
- No changes

v3->v4:
- No changes

v2->v3:
- No changes

v1->v2:
- Added reviewed tag from Biju
---
drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
index 50ec109aa6ed..70f36258db63 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -612,6 +612,9 @@ rzg2l_mipi_dsi_bridge_mode_valid(struct drm_bridge *bridge,
if (mode->clock > 148500)
return MODE_CLOCK_HIGH;

+ if (mode->clock < 5803)
+ return MODE_CLOCK_LOW;
+
return MODE_OK;
}

--
2.49.0