[v11, 0/3] force hsa hbp hfp packets multiple of lanenum to avoid screen shift

[v11, 0/3] force hsa hbp hfp packets multiple of lanenum to avoid screen shift

[Rex-BC Chen]

Changes since v10:
 - Rebase to 5.17-rc3.
 - Add more maintainers.

Changes since v9:
 - Change description of "MIPI_DSI_HS_PKT_END_ALIGNED".
 - Use mode_flags directly instead of another variable on patch [2/3].
 - Add explanation of implementation in mtk_dsi.c on commit message of [2/3].

Changes since v8:
 - Use mode_flags to control this limitation instead of "hs_packet_end_aligned".
 - Add new bit definition "MIPI_DSI_HS_PKT_END_ALIGNED" for mode_flags.

Changes since v7:
 - Rebase to kernel 5.16
 - Add tags of reviewed-by and acked-by.
 - Add detailed commit message for flag "hs_packet_end_aligned" in DSI common driver.

Changes since v6:
 - Add "bool hs_packet_end_aligned" in "struct mipi_dsi_device" to control the dsi aligned.
 - Config the "hs_packet_end_aligned" in ANX7725 .attach().

Changes since v5:
 - Search the anx7625 compatible as flag to control dsi output aligned.

Changes since v4:
 - Move "dt-bindings: drm/bridge: anx7625: add force_dsi_end_without_null" before
   "drm/mediatek: force hsa hbp hfp packets multiple of lanenum to avoid".
 - Retitle "dt-bindings: drm/bridge: anx7625: add force_dsi_end_without_null".

Rex-BC Chen (3):
  drm/dsi: transfer DSI HS packets ending at the same time
  drm/mediatek: implement the DSI HS packets aligned
  drm/bridge: anx7625: config hs packets end aligned to avoid screen shift

 drivers/gpu/drm/bridge/analogix/anx7625.c |  3 ++-
 drivers/gpu/drm/mediatek/mtk_dsi.c        | 12 ++++++++++++
 include/drm/drm_mipi_dsi.h                |  2 ++
 3 files changed, 16 insertions(+), 1 deletion(-)

-- 
2.31.0


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[v11,1/3] drm/dsi: transfer DSI HS packets ending at the same time

[Rex-BC Chen]

Since a HS transmission is composed of an arbitrary number
of bytes that may not be an integer multiple of lanes, some
lanes may run out of data before others.
(Defined in 6.1.3 of mipi_DSI_specification_v.01-02-00)

However, for some DSI RX devices (for example, anx7625),
there is a limitation that packet number should be the same
on all DSI lanes. In other words, they need to end a HS at
the same time.

Because this limitation is for some specific DSI RX devices,
it is more reasonable to put the enable control in these
DSI RX drivers. If DSI TX driver knows the information,
they can adjust the setting for this situation.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
---
 include/drm/drm_mipi_dsi.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
index 147e51b6d241..51e09a1a106a 100644
--- a/include/drm/drm_mipi_dsi.h
+++ b/include/drm/drm_mipi_dsi.h
@@ -137,6 +137,8 @@ struct mipi_dsi_host *of_find_mipi_dsi_host_by_node(struct device_node *node);
 #define MIPI_DSI_CLOCK_NON_CONTINUOUS	BIT(10)
 /* transmit data in low power */
 #define MIPI_DSI_MODE_LPM		BIT(11)
+/* transmit data ending at the same time for all lanes within one hsync */
+#define MIPI_DSI_HS_PKT_END_ALIGNED	BIT(12)
 
 enum mipi_dsi_pixel_format {
 	MIPI_DSI_FMT_RGB888,
-- 
2.31.0


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Re: [v11,1/3] drm/dsi: transfer DSI HS packets ending at the same time

[Rex-BC Chen]

Hello common DRM maintainers,

We have proposed a DSI mode_flag definition in
include/drm/drm_mipi_dsi.h.
The maintainer of bridge chip, Andrzej, also reviewed this patch.

Is there any chance that you can give us some suggestions?
We also need your approvement if this series is acceptable.

Also, if the patch is not proper for you, please let us know.

Thanks for your help.

BRs,
Rex

On Mon, 2022-02-07 at 12:56 +0800, Rex-BC Chen wrote:
> Since a HS transmission is composed of an arbitrary number
> of bytes that may not be an integer multiple of lanes, some
> lanes may run out of data before others.
> (Defined in 6.1.3 of mipi_DSI_specification_v.01-02-00)
> 
> However, for some DSI RX devices (for example, anx7625),
> there is a limitation that packet number should be the same
> on all DSI lanes. In other words, they need to end a HS at
> the same time.
> 
> Because this limitation is for some specific DSI RX devices,
> it is more reasonable to put the enable control in these
> DSI RX drivers. If DSI TX driver knows the information,
> they can adjust the setting for this situation.
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
> Acked-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@collabora.com>
> Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
> ---
>  include/drm/drm_mipi_dsi.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/drm/drm_mipi_dsi.h b/include/drm/drm_mipi_dsi.h
> index 147e51b6d241..51e09a1a106a 100644
> --- a/include/drm/drm_mipi_dsi.h
> +++ b/include/drm/drm_mipi_dsi.h
> @@ -137,6 +137,8 @@ struct mipi_dsi_host
> *of_find_mipi_dsi_host_by_node(struct device_node *node);
>  #define MIPI_DSI_CLOCK_NON_CONTINUOUS	BIT(10)
>  /* transmit data in low power */
>  #define MIPI_DSI_MODE_LPM		BIT(11)
> +/* transmit data ending at the same time for all lanes within one
> hsync */
> +#define MIPI_DSI_HS_PKT_END_ALIGNED	BIT(12)
>  
>  enum mipi_dsi_pixel_format {
>  	MIPI_DSI_FMT_RGB888,


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[v11,2/3] drm/mediatek: implement the DSI HS packets aligned

[Rex-BC Chen]

Some DSI RX devices (for example, anx7625) require last alignment of
packets on all lanes after each row of data is sent.
Otherwise, there will be some issues of shift or scroll for screen.

Take horizontal_sync_active_byte for a example,
we roundup the HSA packet data to lane number, and the subtraction of 2
is the packet data value added by the roundup operation, making the
long packets are integer multiples of lane number.
This value (2) varies with the lane number, and that is the reason we
do this operation when the lane number is 4.

In the previous operation of function "mtk_dsi_config_vdo_timing",
the length of HSA and HFP data packets has been adjusted to an
integration multiple of lane number.
Since the number of RGB data packets cannot be guaranteed to be an
integer multiple of lane number, we modify the data packet length of
HBP so that the number of HBP + RGB is equal to the lane number.
So after sending a line of data (HSA + HBP + RGB + HFP), the data
lanes are aligned.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Acked-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 5d90d2eb0019..e91b3fff4342 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -500,6 +500,18 @@ static void mtk_dsi_config_vdo_timing(struct mtk_dsi *dsi)
 		DRM_WARN("HFP + HBP less than d-phy, FPS will under 60Hz\n");
 	}
 
+	if ((dsi->mode_flags & MIPI_DSI_HS_PKT_END_ALIGNED) &&
+	    (dsi->lanes == 4)) {
+		horizontal_sync_active_byte =
+			roundup(horizontal_sync_active_byte, dsi->lanes) - 2;
+		horizontal_frontporch_byte =
+			roundup(horizontal_frontporch_byte, dsi->lanes) - 2;
+		horizontal_backporch_byte =
+			roundup(horizontal_backporch_byte, dsi->lanes) - 2;
+		horizontal_backporch_byte -=
+			(vm->hactive * dsi_tmp_buf_bpp + 2) % dsi->lanes;
+	}
+
 	writel(horizontal_sync_active_byte, dsi->regs + DSI_HSA_WC);
 	writel(horizontal_backporch_byte, dsi->regs + DSI_HBP_WC);
 	writel(horizontal_frontporch_byte, dsi->regs + DSI_HFP_WC);
-- 
2.31.0


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[v11, 3/3] drm/bridge: anx7625: config hs packets end aligned to avoid screen shift

[Rex-BC Chen]

This device requires the packets on lanes aligned at the end to fix
screen shift or scroll.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Acked-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Xin Ji <xji@analogixsemi.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com>
---
 drivers/gpu/drm/bridge/analogix/anx7625.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
index 2346dbcc505f..fe32ab0878ae 100644
--- a/drivers/gpu/drm/bridge/analogix/anx7625.c
+++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
@@ -1673,7 +1673,8 @@ static int anx7625_attach_dsi(struct anx7625_data *ctx)
 	dsi->format = MIPI_DSI_FMT_RGB888;
 	dsi->mode_flags = MIPI_DSI_MODE_VIDEO	|
 		MIPI_DSI_MODE_VIDEO_SYNC_PULSE	|
-		MIPI_DSI_MODE_VIDEO_HSE;
+		MIPI_DSI_MODE_VIDEO_HSE	|
+		MIPI_DSI_HS_PKT_END_ALIGNED;
 
 	ret = devm_mipi_dsi_attach(dev, dsi);
 	if (ret) {
-- 
2.31.0


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