diff mbox series

[10/10] drm/mxsfb: Clear OUTSTANDING_REQS bits

Message ID 1547043209-8283-11-git-send-email-robert.chiras@nxp.com (mailing list archive)
State New, archived
Headers show
Series Add support for DRM bridge and additional pixel formats | expand

Commit Message

Robert Chiras Jan. 9, 2019, 2:13 p.m. UTC 
Bit 21 can alter the CTRL2_OUTSTANDING_REQS value right after the eLCDIF
is enabled, since it comes up with default value of 1 (this behaviour
has been seen on some imx8 platforms).
In order to fix this, clear CTRL2_OUTSTANDING_REQS bits before setting
its value.

Signed-off-by: Robert Chiras <robert.chiras@nxp.com>
---
 drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 7 +++++++
 1 file changed, 7 insertions(+)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
index b9437c7..c5689c2 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
@@ -231,6 +231,13 @@  static void mxsfb_enable_controller(struct mxsfb_drm_private *mxsfb)
 	clk_prepare_enable(mxsfb->clk);
 
 	if (mxsfb->devdata->ipversion >= 4) {
+		/*
+		 * On some platforms, bit 21 is defaulted to 1, which may alter
+		 * the below setting. So, to make sure we have the right setting
+		 * clear all the bits for CTRL2_OUTSTANDING_REQS.
+		 */
+		writel(CTRL2_OUTSTANDING_REQS(0x7),
+			mxsfb->base + LCDC_V4_CTRL2 + REG_CLR);
 		writel(CTRL2_OUTSTANDING_REQS(REQ_16),
 			mxsfb->base + LCDC_V4_CTRL2 + REG_SET);
 		/* Assert LCD Reset bit */