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 29f2b7d24fe5..a87a301326c7 100644
--- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
+++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
@@ -808,8 +808,7 @@ static int rzg2l_mipi_dsi_startup(struct rzg2l_mipi_dsi *dsi,
 	 * commands payload not being saved to memory.
 	 */
 	dsisetr = rzg2l_mipi_dsi_link_read(dsi, DSISETR);
-	dsisetr &= ~DSISETR_MRPSZ;
-	dsisetr |= FIELD_PREP(DSISETR_MRPSZ, RZG2L_DCS_BUF_SIZE);
+	FIELD_MODIFY(DSISETR_MRPSZ, &dsisetr, RZG2L_DCS_BUF_SIZE);
 	rzg2l_mipi_dsi_link_write(dsi, DSISETR, dsisetr);
 
 	return 0;