From b6b5dc12bd7cb70792db0c02dd74392be4189183 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Mon, 21 Jun 2021 00:49:46 +0200 Subject: [PATCH] drm: mxsfb: Clear FIFO_CLEAR bit [ Upstream commit 5e23c98178eb1a2cdb7c4fee9a39baf8cabf282d ] Make sure the FIFO_CLEAR bit is latched in when configuring the controller, so that the FIFO is really cleared. And then clear the FIFO_CLEAR bit, since it is not self-clearing. Fixes: 45d59d704080 ("drm: Add new driver for MXSFB controller") Signed-off-by: Marek Vasut Cc: Daniel Abrecht Cc: Emil Velikov Cc: Laurent Pinchart Cc: Lucas Stach Cc: Stefan Agner Reviewed-by: Jagan Teki Tested-by: Jagan Teki # i.Core MX8MM Acked-by: Lucas Stach Signed-off-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20210620224946.189524-1-marex@denx.de Signed-off-by: Sasha Levin --- drivers/gpu/drm/mxsfb/mxsfb_kms.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c index 007ea29abfccd..b535621f4f78d 100644 --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c @@ -243,6 +243,9 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb) /* Clear the FIFOs */ writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET); + readl(mxsfb->base + LCDC_CTRL1); + writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_CLR); + readl(mxsfb->base + LCDC_CTRL1); if (mxsfb->devdata->has_overlay) writel(0, mxsfb->base + LCDC_AS_CTRL);