From: Luca Ceresoli Date: Thu, 26 Feb 2026 16:16:44 +0000 (+0100) Subject: drm/bridge: ti-sn65dsi83: fix CHA_DSI_CLK_RANGE rounding X-Git-Tag: v7.0-rc4~17^2~3^2~4 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f22702dc0fee06a240404e0f7ead5b789b253d8;p=thirdparty%2Flinux.git drm/bridge: ti-sn65dsi83: fix CHA_DSI_CLK_RANGE rounding The DSI frequency must be in the range: (CHA_DSI_CLK_RANGE * 5 MHz) <= DSI freq < ((CHA_DSI_CLK_RANGE + 1) * 5 MHz) So the register value should point to the lower range value, but DIV_ROUND_UP() rounds the division to the higher range value, resulting in an excess of 1 (unless the frequency is an exact multiple of 5 MHz). For example for a 437100000 MHz clock CHA_DSI_CLK_RANGE should be 87 (0x57): (87 * 5 = 435) <= 437.1 < (88 * 5 = 440) but current code returns 88 (0x58). Fix the computation by removing the DIV_ROUND_UP(). Fixes: ceb515ba29ba ("drm/bridge: ti-sn65dsi83: Add TI SN65DSI83 and SN65DSI84 driver") Cc: stable@vger.kernel.org Reviewed-by: Marek Vasut Link: https://patch.msgid.link/20260226-ti-sn65dsi83-dual-lvds-fixes-and-test-pattern-v1-1-2e15f5a9a6a0@bootlin.com Signed-off-by: Luca Ceresoli --- diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi83.c b/drivers/gpu/drm/bridge/ti-sn65dsi83.c index f6736b4457bb..d2a81175d279 100644 --- a/drivers/gpu/drm/bridge/ti-sn65dsi83.c +++ b/drivers/gpu/drm/bridge/ti-sn65dsi83.c @@ -351,9 +351,9 @@ static u8 sn65dsi83_get_dsi_range(struct sn65dsi83 *ctx, * DSI_CLK = mode clock * bpp / dsi_data_lanes / 2 * the 2 is there because the bus is DDR. */ - return DIV_ROUND_UP(clamp((unsigned int)mode->clock * - mipi_dsi_pixel_format_to_bpp(ctx->dsi->format) / - ctx->dsi->lanes / 2, 40000U, 500000U), 5000U); + return clamp((unsigned int)mode->clock * + mipi_dsi_pixel_format_to_bpp(ctx->dsi->format) / + ctx->dsi->lanes / 2, 40000U, 500000U) / 5000U; } static u8 sn65dsi83_get_dsi_div(struct sn65dsi83 *ctx)