[PATCH v3 04/15] drm/mxsfb: Reset vital registers for a proper initialization

[Robert Chiras]

Some of the registers, like LCDC_CTRL, CTRL2_OUTSTANDING_REQS and
CTRL1_RECOVERY_ON_UNDERFLOW needs to be properly cleared/initialized
for a better start and stop routine.

Signed-off-by: Robert Chiras <robert.chi...@nxp.com>
---
 drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c 
b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
index b69ace8..5e44f57 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
@@ -127,6 +127,10 @@ static void mxsfb_enable_controller(struct 
mxsfb_drm_private *mxsfb)
                clk_prepare_enable(mxsfb->clk_disp_axi);
        clk_prepare_enable(mxsfb->clk);
 
+       if (mxsfb->devdata->ipversion >= 4)
+               writel(CTRL2_OUTSTANDING_REQS(REQ_16),
+                      mxsfb->base + LCDC_V4_CTRL2 + REG_SET);
+
        /* If it was disabled, re-enable the mode again */
        writel(CTRL_DOTCLK_MODE, mxsfb->base + LCDC_CTRL + REG_SET);
 
@@ -136,12 +140,19 @@ static void mxsfb_enable_controller(struct 
mxsfb_drm_private *mxsfb)
        writel(reg, mxsfb->base + LCDC_VDCTRL4);
 
        writel(CTRL_RUN, mxsfb->base + LCDC_CTRL + REG_SET);
+       writel(CTRL1_RECOVERY_ON_UNDERFLOW, mxsfb->base + LCDC_CTRL1 + REG_SET);
 }
 
 static void mxsfb_disable_controller(struct mxsfb_drm_private *mxsfb)
 {
        u32 reg;
 
+       if (mxsfb->devdata->ipversion >= 4)
+               writel(CTRL2_OUTSTANDING_REQS(0x7),
+                      mxsfb->base + LCDC_V4_CTRL2 + REG_CLR);
+
+       writel(CTRL_RUN, mxsfb->base + LCDC_CTRL + REG_CLR);
+
        /*
         * Even if we disable the controller here, it will still continue
         * until its FIFOs are running out of data
@@ -295,6 +306,7 @@ void mxsfb_crtc_enable(struct mxsfb_drm_private *mxsfb)
        dma_addr_t paddr;
 
        mxsfb_enable_axi_clk(mxsfb);
+       writel(0, mxsfb->base + LCDC_CTRL);
        mxsfb_crtc_mode_set_nofb(mxsfb);
 
        /* Write cur_buf as well to avoid an initial corrupt frame */
-- 
2.7.4