From fb797a70108f3fda83fde6dea30bee4be7d5df8b Mon Sep 17 00:00:00 2001 From: Chris Brandt Date: Thu, 26 Feb 2026 20:52:16 -0500 Subject: [PATCH] drm: renesas: rz-du: mipi_dsi: Set DSI divider Before the MIPI DSI clock source can be configured, the target divide ratio needs to be set. Signed-off-by: Chris Brandt Reviewed-by: Biju Das Tested-by: Biju Das Fixes: 5a4326f2e3b1 ("clk: renesas: rzg2l: Remove DSI clock rate restrictions") Link: https://patch.msgid.link/20260227015216.2721504-1-chris.brandt@renesas.com Signed-off-by: Biju Das --- drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) 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 f74a0aa85ba8..29f2b7d24fe5 100644 --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c @@ -1122,6 +1122,7 @@ static int rzg2l_mipi_dsi_host_attach(struct mipi_dsi_host *host, struct mipi_dsi_device *device) { struct rzg2l_mipi_dsi *dsi = host_to_rzg2l_mipi_dsi(host); + int bpp; int ret; if (device->lanes > dsi->num_data_lanes) { @@ -1131,7 +1132,8 @@ static int rzg2l_mipi_dsi_host_attach(struct mipi_dsi_host *host, return -EINVAL; } - switch (mipi_dsi_pixel_format_to_bpp(device->format)) { + bpp = mipi_dsi_pixel_format_to_bpp(device->format); + switch (bpp) { case 24: break; case 18: @@ -1162,6 +1164,18 @@ static int rzg2l_mipi_dsi_host_attach(struct mipi_dsi_host *host, drm_bridge_add(&dsi->bridge); + /* + * Report the required division ratio setting for the MIPI clock dividers. + * + * vclk * bpp = hsclk * 8 * num_lanes + * + * vclk * DSI_AB_divider = hsclk * 16 + * + * which simplifies to... + * DSI_AB_divider = bpp * 2 / num_lanes + */ + rzg2l_cpg_dsi_div_set_divider(bpp * 2 / dsi->lanes, PLL5_TARGET_DSI); + return 0; }