linux-kernel - [PATCH 1/4] drm/msm/dpu: Introduce knowledge of widebus feature

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Date:   Mon, 10 May 2021 23:18:49 -0500
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/4] drm/msm/dpu: Introduce knowledge of widebus feature

Some hardware supports clocking 2 pixels per pixel clock pulse, known as
"widebus". The configuration needs to match between the DPU and the
interface controller, and the timing parameters must be adjusted.

As a first step towards supporting this, start by adding a INTF mask
flag to signal the timing configuration code that the INTF_CONFIG2
register should be written - which will clear the bit, in the case that
the bootloader left it set.

Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h | 2 ++
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c    | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
index 4dfd8a20ad5c..c2f34a4f82d9 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_catalog.h
@@ -196,12 +196,14 @@ enum {
  * @DPU_INTF_TE                 INTF block has TE configuration support
  * @DPU_DATA_HCTL_EN            Allows data to be transferred at different rate
                                 than video timing
+ * @DPU_INTF_WIDEBUS            INTF block supports driving 2 pixels per clock
  * @DPU_INTF_MAX
  */
 enum {
 	DPU_INTF_INPUT_CTRL = 0x1,
 	DPU_INTF_TE,
 	DPU_DATA_HCTL_EN,
+	DPU_INTF_WIDEBUS,
 	DPU_INTF_MAX
 };
 
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
index 1599e3f49a4f..933485d8c03c 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
@@ -183,7 +183,6 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	if (ctx->cap->features & BIT(DPU_DATA_HCTL_EN)) {
 		intf_cfg2 |= BIT(4);
 		display_data_hctl = display_hctl;
-		DPU_REG_WRITE(c, INTF_CONFIG2, intf_cfg2);
 		DPU_REG_WRITE(c, INTF_DISPLAY_DATA_HCTL, display_data_hctl);
 	}
 
@@ -204,6 +203,8 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	DPU_REG_WRITE(c, INTF_FRAME_LINE_COUNT_EN, 0x3);
 	DPU_REG_WRITE(c, INTF_CONFIG, intf_cfg);
 	DPU_REG_WRITE(c, INTF_PANEL_FORMAT, panel_format);
+	if (ctx->cap->features & (BIT(DPU_DATA_HCTL_EN) | BIT(DPU_INTF_WIDEBUS)))
+		DPU_REG_WRITE(c, INTF_CONFIG2, intf_cfg2);
 }
 
 static void dpu_hw_intf_enable_timing_engine(
-- 
2.29.2