[PATCH v2 0/5] drm/fsl-dcu: initialization fixes

[PATCH v2 0/5] drm/fsl-dcu: initialization fixes

[Stefan Agner]

Hi All,

This is an assortment of fixes which solve issues seen using an
external RGB converter and makes sure that pixel clock is only
on when really required.

Meng, would be good if you can test it on a LS1021a.

--
Stefan

Changes since v1:
- add patch to no not transfer registers in mode_set_nofb
- add patch which only init fbdev if required
- remove disable unprepare pixel clock on module remove (already disabled
  in CRTC disable callback).
- remove unused label

Stefan Agner (5):
  drm/fsl-dcu: enable TCON bypass mode by default
  drm/fsl-dcu: do not transfer registers on plane init
  drm/fsl-dcu: do not transfer registers in mode_set_nofb
  drm/fsl-dcu: enable pixel clock when enabling CRTC
  drm/fsl-dcu: only init fbdev if required

 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c  |  4 +--
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c   | 25 +++----------------
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c |  5 ----
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c   | 38 +++--------------------------
 4 files changed, 10 insertions(+), 62 deletions(-)

-- 
2.10.0

[PATCH v2 1/5] drm/fsl-dcu: enable TCON bypass mode by default

[Stefan Agner]

Do not use encoder disable/enable callbacks to control bypass
mode as this seems to mess with the signals not liked by
displays. This also makes more sense since the encoder is
already defined to be parallel RGB/LVDS at creation time.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c |  1 +
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c | 38 ++++---------------------------
 2 files changed, 5 insertions(+), 34 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 0884c45..68db834 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -273,6 +273,7 @@ static int fsl_dcu_drm_pm_resume(struct device *dev)
 		goto disable_dcu_clk;
 	}
 
+	fsl_tcon_bypass_enable(fsl_dev->tcon);
 	fsl_dcu_drm_init_planes(fsl_dev->drm);
 	drm_atomic_helper_resume(fsl_dev->drm, fsl_dev->state);
 
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
index 26edcc8..ec88719 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_rgb.c
@@ -20,38 +20,6 @@
 #include "fsl_dcu_drm_drv.h"
 #include "fsl_tcon.h"
 
-static int
-fsl_dcu_drm_encoder_atomic_check(struct drm_encoder *encoder,
-				 struct drm_crtc_state *crtc_state,
-				 struct drm_connector_state *conn_state)
-{
-	return 0;
-}
-
-static void fsl_dcu_drm_encoder_disable(struct drm_encoder *encoder)
-{
-	struct drm_device *dev = encoder->dev;
-	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
-
-	if (fsl_dev->tcon)
-		fsl_tcon_bypass_disable(fsl_dev->tcon);
-}
-
-static void fsl_dcu_drm_encoder_enable(struct drm_encoder *encoder)
-{
-	struct drm_device *dev = encoder->dev;
-	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
-
-	if (fsl_dev->tcon)
-		fsl_tcon_bypass_enable(fsl_dev->tcon);
-}
-
-static const struct drm_encoder_helper_funcs encoder_helper_funcs = {
-	.atomic_check = fsl_dcu_drm_encoder_atomic_check,
-	.disable = fsl_dcu_drm_encoder_disable,
-	.enable = fsl_dcu_drm_encoder_enable,
-};
-
 static void fsl_dcu_drm_encoder_destroy(struct drm_encoder *encoder)
 {
 	drm_encoder_cleanup(encoder);
@@ -68,13 +36,15 @@ int fsl_dcu_drm_encoder_create(struct fsl_dcu_drm_device *fsl_dev,
 	int ret;
 
 	encoder->possible_crtcs = 1;
+
+	/* Use bypass mode for parallel RGB/LVDS encoder */
+	fsl_tcon_bypass_enable(fsl_dev->tcon);
+
 	ret = drm_encoder_init(fsl_dev->drm, encoder, &encoder_funcs,
 			       DRM_MODE_ENCODER_LVDS, NULL);
 	if (ret < 0)
 		return ret;
 
-	drm_encoder_helper_add(encoder, &encoder_helper_funcs);
-
 	return 0;
 }
 
-- 
2.10.0

[PATCH v2 2/5] drm/fsl-dcu: do not explicitly transfer registers on plane init

[Stefan Agner]

There is no need to explicitly initiate a register transfer and
turn off the DCU after initializing the plane registers. In fact,
this is harmful and leads to unnecessary flickers if the DCU has
been left on by the bootloader.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
index a7e5486..9e6f7d8 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
@@ -211,11 +211,6 @@ void fsl_dcu_drm_init_planes(struct drm_device *dev)
 		for (j = 1; j <= fsl_dev->soc->layer_regs; j++)
 			regmap_write(fsl_dev->regmap, DCU_CTRLDESCLN(i, j), 0);
 	}
-	regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
-			   DCU_MODE_DCU_MODE_MASK,
-			   DCU_MODE_DCU_MODE(DCU_MODE_OFF));
-	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-		     DCU_UPDATE_MODE_READREG);
 }
 
 struct drm_plane *fsl_dcu_drm_primary_create_plane(struct drm_device *dev)
-- 
2.10.0

[PATCH v2 2/5] drm/fsl-dcu: do not transfer registers on plane init

[Stefan Agner]

There is no need to explicitly initiate a register transfer and
turn off the DCU after initializing the plane registers. In fact,
this is harmful and leads to unnecessary flickers if the DCU has
been left on by the bootloader.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
index a7e5486..9e6f7d8 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c
@@ -211,11 +211,6 @@ void fsl_dcu_drm_init_planes(struct drm_device *dev)
 		for (j = 1; j <= fsl_dev->soc->layer_regs; j++)
 			regmap_write(fsl_dev->regmap, DCU_CTRLDESCLN(i, j), 0);
 	}
-	regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
-			   DCU_MODE_DCU_MODE_MASK,
-			   DCU_MODE_DCU_MODE(DCU_MODE_OFF));
-	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-		     DCU_UPDATE_MODE_READREG);
 }
 
 struct drm_plane *fsl_dcu_drm_primary_create_plane(struct drm_device *dev)
-- 
2.10.0

[PATCH v2 3/5] drm/fsl-dcu: do not transfer register in mode_set_nofb

[Stefan Agner]

Do not schedule a transfer of mode settings early. Modes should
get applied on on CRTC enable where we also enable the pixel clock.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 3371635..5ad1d68 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -116,8 +116,6 @@ static void fsl_dcu_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
 		     DCU_THRESHOLD_LS_BF_VS(BF_VS_VAL) |
 		     DCU_THRESHOLD_OUT_BUF_HIGH(BUF_MAX_VAL) |
 		     DCU_THRESHOLD_OUT_BUF_LOW(BUF_MIN_VAL));
-	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-		     DCU_UPDATE_MODE_READREG);
 	return;
 }
 
-- 
2.10.0

[PATCH v2 3/5] drm/fsl-dcu: do not transfer registers in mode_set_nofb

[Stefan Agner]

Do not schedule a transfer of mode settings early. Modes should
get applied on on CRTC enable where we also enable the pixel clock.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 3371635..5ad1d68 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -116,8 +116,6 @@ static void fsl_dcu_drm_crtc_mode_set_nofb(struct drm_crtc *crtc)
 		     DCU_THRESHOLD_LS_BF_VS(BF_VS_VAL) |
 		     DCU_THRESHOLD_OUT_BUF_HIGH(BUF_MAX_VAL) |
 		     DCU_THRESHOLD_OUT_BUF_LOW(BUF_MIN_VAL));
-	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-		     DCU_UPDATE_MODE_READREG);
 	return;
 }
 
-- 
2.10.0

[PATCH v2 4/5] drm/fsl-dcu: enable pixel clock when enabling CRTC

[Stefan Agner]

The pixel clock should not be on if the CRTC is not in use, hence
move clock enable/disable calls into CRTC callbacks.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c |  2 ++
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c  | 21 +--------------------
 2 files changed, 3 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
index 5ad1d68..b2d5e18 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c
@@ -51,6 +51,7 @@ static void fsl_dcu_drm_disable_crtc(struct drm_crtc *crtc)
 			   DCU_MODE_DCU_MODE(DCU_MODE_OFF));
 	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
 		     DCU_UPDATE_MODE_READREG);
+	clk_disable_unprepare(fsl_dev->pix_clk);
 }
 
 static void fsl_dcu_drm_crtc_enable(struct drm_crtc *crtc)
@@ -58,6 +59,7 @@ static void fsl_dcu_drm_crtc_enable(struct drm_crtc *crtc)
 	struct drm_device *dev = crtc->dev;
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 
+	clk_prepare_enable(fsl_dev->pix_clk);
 	regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
 			   DCU_MODE_DCU_MODE_MASK,
 			   DCU_MODE_DCU_MODE(DCU_MODE_NORMAL));
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 68db834..07969f5 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -267,12 +267,6 @@ static int fsl_dcu_drm_pm_resume(struct device *dev)
 		return ret;
 	}
 
-	ret = clk_prepare_enable(fsl_dev->pix_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable pix clk\n");
-		goto disable_dcu_clk;
-	}
-
 	fsl_tcon_bypass_enable(fsl_dev->tcon);
 	fsl_dcu_drm_init_planes(fsl_dev->drm);
 	drm_atomic_helper_resume(fsl_dev->drm, fsl_dev->state);
@@ -285,10 +279,6 @@ static int fsl_dcu_drm_pm_resume(struct device *dev)
 	enable_irq(fsl_dev->irq);
 
 	return 0;
-
-disable_dcu_clk:
-	clk_disable_unprepare(fsl_dev->clk);
-	return ret;
 }
 #endif
 
@@ -402,18 +392,12 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 		goto disable_clk;
 	}
 
-	ret = clk_prepare_enable(fsl_dev->pix_clk);
-	if (ret < 0) {
-		dev_err(dev, "failed to enable pix clk\n");
-		goto unregister_pix_clk;
-	}
-
 	fsl_dev->tcon = fsl_tcon_init(dev);
 
 	drm = drm_dev_alloc(driver, dev);
 	if (IS_ERR(drm)) {
 		ret = PTR_ERR(drm);
-		goto disable_pix_clk;
+		goto unregister_pix_clk;
 	}
 
 	fsl_dev->dev = dev;
@@ -434,8 +418,6 @@ static int fsl_dcu_drm_probe(struct platform_device *pdev)
 
 unref:
 	drm_dev_unref(drm);
-disable_pix_clk:
-	clk_disable_unprepare(fsl_dev->pix_clk);
 unregister_pix_clk:
 	clk_unregister(fsl_dev->pix_clk);
 disable_clk:
@@ -448,7 +430,6 @@ static int fsl_dcu_drm_remove(struct platform_device *pdev)
 	struct fsl_dcu_drm_device *fsl_dev = platform_get_drvdata(pdev);
 
 	clk_disable_unprepare(fsl_dev->clk);
-	clk_disable_unprepare(fsl_dev->pix_clk);
 	clk_unregister(fsl_dev->pix_clk);
 	drm_put_dev(fsl_dev->drm);
 
-- 
2.10.0

[PATCH v2 5/5] drm/fsl-dcu: only init fbdev if required

[Stefan Agner]

There is no need to request a CMA backed framebuffer if fbdev
emulation is not enabled.

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index 07969f5..86dd4e3 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -87,7 +87,8 @@ static int fsl_dcu_load(struct drm_device *dev, unsigned long flags)
 		goto done;
 	dev->irq_enabled = true;
 
-	fsl_dcu_fbdev_init(dev);
+	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION))
+		fsl_dcu_fbdev_init(dev);
 
 	return 0;
 done:
-- 
2.10.0