[PATCH v4,0/4] Cooperate with DSI RX devices to modify dsi funcs and delay mipi high to cooperate with panel sequence

[PATCH v4,0/4] Cooperate with DSI RX devices to modify dsi funcs and delay mipi high to cooperate with panel sequence

[xinlei.lee]

From: Xinlei Lee <xinlei.lee@mediatek.com>

In upstream-v5.8, dsi_enable will operate panel_enable, but this
modification has been moved in v5.9. In order to ensure the timing of
dsi_power_on/off and the timing of pulling up/down the MIPI signal,
the modification of v5.9 is synchronized in this series of patches.

Changes since v3:
1. Rebase kernel-5.18-rc1.
2. Added dsi_enable protection.
3. Encapsulates the dsi_lane_ready function.

Changes since v2:
1. Rebase linux-next.

Changes since v1:
1. Dsi sequence marked with patch adjustment.
2. Fixes: mtk_dsi: Use the drm_panel_bridge.

Jitao Shi (3):
  drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11
  drm/mediatek: Separate poweron/poweroff from enable/disable and define
    new funcs
  drm/mediatek: keep dsi as LP00 before dcs cmds transfer

Xinlei Lee (1):
  drm/mediatek: Add pull-down MIPI operation in mtk_dsi_poweroff
    function

 drivers/gpu/drm/mediatek/mtk_dsi.c | 81 ++++++++++++++++++++----------
 1 file changed, 55 insertions(+), 26 deletions(-)

-- 
2.18.0

[PATCH v4,1/4] drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11

[xinlei.lee]

From: Jitao Shi <jitao.shi@mediatek.com>

Old sequence:
1. Pull the MIPI signal high
2. Delay & Dsi_reset
3. Set the dsi timing register
4. dsi clk & lanes leave ulp mode and enter hs mode

The sequence after patching is:
1. Set the dsi timing register
2. Pull the MIPI signal high
3. Delay & Dsi_reset
4. dsi clk & lanes leave ulp mode and enter hs mode

Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index ccb0511b9cd5..262c027d8c2f 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -649,14 +649,14 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
 	mtk_dsi_reset_engine(dsi);
 	mtk_dsi_phy_timconfig(dsi);
 
-	mtk_dsi_rxtx_control(dsi);
-	usleep_range(30, 100);
-	mtk_dsi_reset_dphy(dsi);
 	mtk_dsi_ps_control_vact(dsi);
 	mtk_dsi_set_vm_cmd(dsi);
 	mtk_dsi_config_vdo_timing(dsi);
 	mtk_dsi_set_interrupt_enable(dsi);
 
+	mtk_dsi_rxtx_control(dsi);
+	usleep_range(30, 100);
+	mtk_dsi_reset_dphy(dsi);
 	mtk_dsi_clk_ulp_mode_leave(dsi);
 	mtk_dsi_lane0_ulp_mode_leave(dsi);
 	mtk_dsi_clk_hs_mode(dsi, 0);
-- 
2.18.0

[PATCH v4,2/4] drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs

[xinlei.lee]

From: Jitao Shi <jitao.shi@mediatek.com>

In order to match the changes of "Use the drm_panel_bridge API",
the poweron/poweroff of dsi is extracted from enable/disable and
defined as new funcs (pre_enable/post_disable).

Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 51 +++++++++++++++++++-----------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 262c027d8c2f..cf76c53a1af6 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -679,16 +679,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 	if (--dsi->refcount != 0)
 		return;
 
-	/*
-	 * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
-	 * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
-	 * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
-	 * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
-	 * after dsi is fully set.
-	 */
-	mtk_dsi_stop(dsi);
-
-	mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
 	mtk_dsi_reset_engine(dsi);
 	mtk_dsi_lane0_ulp_mode_enter(dsi);
 	mtk_dsi_clk_ulp_mode_enter(dsi);
@@ -703,17 +693,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
 {
-	int ret;
-
 	if (dsi->enabled)
 		return;
 
-	ret = mtk_dsi_poweron(dsi);
-	if (ret < 0) {
-		DRM_ERROR("failed to power on dsi\n");
-		return;
-	}
-
 	mtk_dsi_set_mode(dsi);
 	mtk_dsi_clk_hs_mode(dsi, 1);
 
@@ -727,7 +709,16 @@ static void mtk_output_dsi_disable(struct mtk_dsi *dsi)
 	if (!dsi->enabled)
 		return;
 
-	mtk_dsi_poweroff(dsi);
+	/*
+	 * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
+	 * mtk_dsi_stop() should be called after mtk_drm_crtc_atomic_disable(),
+	 * which needs irq for vblank, and mtk_dsi_stop() will disable irq.
+	 * mtk_dsi_start() needs to be called in mtk_output_dsi_enable(),
+	 * after dsi is fully set.
+	 */
+	mtk_dsi_stop(dsi);
+
+	mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
 
 	dsi->enabled = false;
 }
@@ -762,13 +753,35 @@ static void mtk_dsi_bridge_enable(struct drm_bridge *bridge)
 {
 	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
 
+	if (dsi->refcount == 0)
+		return;
+
 	mtk_output_dsi_enable(dsi);
 }
 
+static void mtk_dsi_bridge_pre_enable(struct drm_bridge *bridge)
+{
+	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
+	int ret;
+
+	ret = mtk_dsi_poweron(dsi);
+	if (ret < 0)
+		DRM_ERROR("failed to power on dsi\n");
+}
+
+static void mtk_dsi_bridge_post_disable(struct drm_bridge *bridge)
+{
+	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
+
+	mtk_dsi_poweroff(dsi);
+}
+
 static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
 	.attach = mtk_dsi_bridge_attach,
 	.disable = mtk_dsi_bridge_disable,
 	.enable = mtk_dsi_bridge_enable,
+	.pre_enable = mtk_dsi_bridge_pre_enable,
+	.post_disable = mtk_dsi_bridge_post_disable,
 	.mode_set = mtk_dsi_bridge_mode_set,
 };
 
-- 
2.18.0

[PATCH v4,3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

[xinlei.lee]

From: Jitao Shi <jitao.shi@mediatek.com>

To comply with the panel sequence, hold the mipi signal to LP00 before the dcs cmds transmission,
and pull the mipi signal high from LP00 to LP11 until the start of the dcs cmds transmission.
The normal panel timing is :
(1) pp1800 DC pull up
(2) avdd & avee AC pull high
(3) lcm_reset pull high -> pull low -> pull high
(4) Pull MIPI signal high (LP11) -> initial code -> send video data(HS mode)
The power-off sequence is reversed.
If dsi is not in cmd mode, then dsi will pull the mipi signal high in the mtk_output_dsi_enable function.

Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index cf76c53a1af6..9ad6f08c8bfe 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -203,6 +203,7 @@ struct mtk_dsi {
 	struct mtk_phy_timing phy_timing;
 	int refcount;
 	bool enabled;
+	bool lanes_ready;
 	u32 irq_data;
 	wait_queue_head_t irq_wait_queue;
 	const struct mtk_dsi_driver_data *driver_data;
@@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
 	mtk_dsi_config_vdo_timing(dsi);
 	mtk_dsi_set_interrupt_enable(dsi);
 
-	mtk_dsi_rxtx_control(dsi);
-	usleep_range(30, 100);
-	mtk_dsi_reset_dphy(dsi);
-	mtk_dsi_clk_ulp_mode_leave(dsi);
-	mtk_dsi_lane0_ulp_mode_leave(dsi);
-	mtk_dsi_clk_hs_mode(dsi, 0);
-
 	return 0;
 err_disable_engine_clk:
 	clk_disable_unprepare(dsi->engine_clk);
@@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 	clk_disable_unprepare(dsi->digital_clk);
 
 	phy_power_off(dsi->phy);
+
+	dsi->lanes_ready = false;
+}
+
+static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
+{
+	if (!dsi->lanes_ready) {
+		dsi->lanes_ready = true;
+		mtk_dsi_rxtx_control(dsi);
+		usleep_range(30, 100);
+		mtk_dsi_reset_dphy(dsi);
+		mtk_dsi_clk_ulp_mode_leave(dsi);
+		mtk_dsi_lane0_ulp_mode_leave(dsi);
+		mtk_dsi_clk_hs_mode(dsi, 0);
+		msleep(20);
+	} else
+		DRM_DEBUG("The dsi_lane is ready\n");
 }
 
 static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
@@ -696,6 +707,7 @@ static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
 	if (dsi->enabled)
 		return;
 
+	mtk_dsi_lane_ready(dsi);
 	mtk_dsi_set_mode(dsi);
 	mtk_dsi_clk_hs_mode(dsi, 1);
 
@@ -1001,6 +1013,8 @@ static ssize_t mtk_dsi_host_transfer(struct mipi_dsi_host *host,
 	if (MTK_DSI_HOST_IS_READ(msg->type))
 		irq_flag |= LPRX_RD_RDY_INT_FLAG;
 
+	mtk_dsi_lane_ready(dsi);
+
 	ret = mtk_dsi_host_send_cmd(dsi, msg, irq_flag);
 	if (ret)
 		goto restore_dsi_mode;
-- 
2.18.0

[PATCH v4,4/4] drm/mediatek: Add pull-down MIPI operation in mtk_dsi_poweroff function

[xinlei.lee]

From: Xinlei Lee <xinlei.lee@mediatek.com>

In the dsi_enable function, mtk_dsi_rxtx_control is to
pull up the MIPI signal operation. Before dsi_disable,
MIPI should also be pulled down by writing a register 
instead of disabling dsi.

If disable dsi without pulling the mipi signal low, the value of
the register will still maintain the setting of the mipi signal being
pulled high.
After resume, even if the mipi signal is not pulled high, it will still
be in the high state.

Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 9ad6f08c8bfe..e35343357f90 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -676,6 +676,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
 	mtk_dsi_reset_engine(dsi);
 	mtk_dsi_lane0_ulp_mode_enter(dsi);
 	mtk_dsi_clk_ulp_mode_enter(dsi);
+	/* set the lane number as 0 to pull down mipi */
+	writel(0, dsi->regs + DSI_TXRX_CTRL);
 
 	mtk_dsi_disable(dsi);
 
-- 
2.18.0

Re: [PATCH v4, 1/4] drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11

[AngeloGioacchino Del Regno]

Il 11/04/22 04:31, xinlei.lee@mediatek.com ha scritto:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> Old sequence:
> 1. Pull the MIPI signal high
> 2. Delay & Dsi_reset
> 3. Set the dsi timing register
> 4. dsi clk & lanes leave ulp mode and enter hs mode
> 
> The sequence after patching is:
> 1. Set the dsi timing register
> 2. Pull the MIPI signal high
> 3. Delay & Dsi_reset
> 4. dsi clk & lanes leave ulp mode and enter hs mode
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Re: [PATCH v4, 2/4] drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs

[AngeloGioacchino Del Regno]

Il 11/04/22 04:31, xinlei.lee@mediatek.com ha scritto:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> In order to match the changes of "Use the drm_panel_bridge API",
> the poweron/poweroff of dsi is extracted from enable/disable and
> defined as new funcs (pre_enable/post_disable).
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Re: [PATCH v4, 3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

[AngeloGioacchino Del Regno]

Il 11/04/22 04:31, xinlei.lee@mediatek.com ha scritto:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> To comply with the panel sequence, hold the mipi signal to LP00 before the dcs cmds transmission,
> and pull the mipi signal high from LP00 to LP11 until the start of the dcs cmds transmission.
> The normal panel timing is :
> (1) pp1800 DC pull up
> (2) avdd & avee AC pull high
> (3) lcm_reset pull high -> pull low -> pull high
> (4) Pull MIPI signal high (LP11) -> initial code -> send video data(HS mode)
> The power-off sequence is reversed.
> If dsi is not in cmd mode, then dsi will pull the mipi signal high in the mtk_output_dsi_enable function.
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>   drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++-------
>   1 file changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index cf76c53a1af6..9ad6f08c8bfe 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -203,6 +203,7 @@ struct mtk_dsi {
>   	struct mtk_phy_timing phy_timing;
>   	int refcount;
>   	bool enabled;
> +	bool lanes_ready;
>   	u32 irq_data;
>   	wait_queue_head_t irq_wait_queue;
>   	const struct mtk_dsi_driver_data *driver_data;
> @@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>   	mtk_dsi_config_vdo_timing(dsi);
>   	mtk_dsi_set_interrupt_enable(dsi);
>   
> -	mtk_dsi_rxtx_control(dsi);
> -	usleep_range(30, 100);
> -	mtk_dsi_reset_dphy(dsi);
> -	mtk_dsi_clk_ulp_mode_leave(dsi);
> -	mtk_dsi_lane0_ulp_mode_leave(dsi);
> -	mtk_dsi_clk_hs_mode(dsi, 0);
> -
>   	return 0;
>   err_disable_engine_clk:
>   	clk_disable_unprepare(dsi->engine_clk);
> @@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>   	clk_disable_unprepare(dsi->digital_clk);
>   
>   	phy_power_off(dsi->phy);
> +
> +	dsi->lanes_ready = false;
> +}
> +
> +static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
> +{
> +	if (!dsi->lanes_ready) {
> +		dsi->lanes_ready = true;
> +		mtk_dsi_rxtx_control(dsi);
> +		usleep_range(30, 100);
> +		mtk_dsi_reset_dphy(dsi);
> +		mtk_dsi_clk_ulp_mode_leave(dsi);
> +		mtk_dsi_lane0_ulp_mode_leave(dsi);
> +		mtk_dsi_clk_hs_mode(dsi, 0);
> +		msleep(20);

This is a very long sleep, which wasn't present before this change.
Please document the reasons why we need this 20ms sleep with a comment
in the code.

Regards,
Angelo

Re: [PATCH v4,1/4] drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11

[Rex-BC Chen]

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> Old sequence:
> 1. Pull the MIPI signal high
> 2. Delay & Dsi_reset
> 3. Set the dsi timing register
> 4. dsi clk & lanes leave ulp mode and enter hs mode
> 
> The sequence after patching is:
> 1. Set the dsi timing register
> 2. Pull the MIPI signal high
> 3. Delay & Dsi_reset
> 4. dsi clk & lanes leave ulp mode and enter hs mode
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index ccb0511b9cd5..262c027d8c2f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -649,14 +649,14 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>  	mtk_dsi_reset_engine(dsi);
>  	mtk_dsi_phy_timconfig(dsi);
>  
> -	mtk_dsi_rxtx_control(dsi);
> -	usleep_range(30, 100);
> -	mtk_dsi_reset_dphy(dsi);
>  	mtk_dsi_ps_control_vact(dsi);
>  	mtk_dsi_set_vm_cmd(dsi);
>  	mtk_dsi_config_vdo_timing(dsi);
>  	mtk_dsi_set_interrupt_enable(dsi);
>  
> +	mtk_dsi_rxtx_control(dsi);
> +	usleep_range(30, 100);
> +	mtk_dsi_reset_dphy(dsi);
>  	mtk_dsi_clk_ulp_mode_leave(dsi);
>  	mtk_dsi_lane0_ulp_mode_leave(dsi);
>  	mtk_dsi_clk_hs_mode(dsi, 0);

Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>

Re: [PATCH v4,2/4] drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs

[Rex-BC Chen]

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> In order to match the changes of "Use the drm_panel_bridge API",
> the poweron/poweroff of dsi is extracted from enable/disable and
> defined as new funcs (pre_enable/post_disable).
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>

Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>

Re: [PATCH v4,4/4] drm/mediatek: Add pull-down MIPI operation in mtk_dsi_poweroff function

[Rex-BC Chen]

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Xinlei Lee <xinlei.lee@mediatek.com>
> 
> In the dsi_enable function, mtk_dsi_rxtx_control is to
> pull up the MIPI signal operation. Before dsi_disable,
> MIPI should also be pulled down by writing a register 
> instead of disabling dsi.
> 
> If disable dsi without pulling the mipi signal low, the value of
> the register will still maintain the setting of the mipi signal being
> pulled high.
> After resume, even if the mipi signal is not pulled high, it will
> still
> be in the high state.
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 9ad6f08c8bfe..e35343357f90 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -676,6 +676,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>  	mtk_dsi_reset_engine(dsi);
>  	mtk_dsi_lane0_ulp_mode_enter(dsi);
>  	mtk_dsi_clk_ulp_mode_enter(dsi);
> +	/* set the lane number as 0 to pull down mipi */
> +	writel(0, dsi->regs + DSI_TXRX_CTRL);
>  
>  	mtk_dsi_disable(dsi);
>  

Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>

Re: [PATCH v4, 3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

[Rex-BC Chen]

On Mon, 2022-04-11 at 11:07 +0200, AngeloGioacchino Del Regno wrote:
> Il 11/04/22 04:31, xinlei.lee@mediatek.com ha scritto:
> > From: Jitao Shi <jitao.shi@mediatek.com>
> > 
> > To comply with the panel sequence, hold the mipi signal to LP00
> > before the dcs cmds transmission,
> > and pull the mipi signal high from LP00 to LP11 until the start of
> > the dcs cmds transmission.
> > The normal panel timing is :
> > (1) pp1800 DC pull up
> > (2) avdd & avee AC pull high
> > (3) lcm_reset pull high -> pull low -> pull high
> > (4) Pull MIPI signal high (LP11) -> initial code -> send video
> > data(HS mode)
> > The power-off sequence is reversed.
> > If dsi is not in cmd mode, then dsi will pull the mipi signal high
> > in the mtk_output_dsi_enable function.
> > 
> > Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the
> > drm_panel_bridge API")
> > 
> > Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> > Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> > ---
> >   drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++--
> > -----
> >   1 file changed, 21 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > index cf76c53a1af6..9ad6f08c8bfe 100644
> > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> > @@ -203,6 +203,7 @@ struct mtk_dsi {
> >   	struct mtk_phy_timing phy_timing;
> >   	int refcount;
> >   	bool enabled;
> > +	bool lanes_ready;
> >   	u32 irq_data;
> >   	wait_queue_head_t irq_wait_queue;
> >   	const struct mtk_dsi_driver_data *driver_data;
> > @@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi
> > *dsi)
> >   	mtk_dsi_config_vdo_timing(dsi);
> >   	mtk_dsi_set_interrupt_enable(dsi);
> >   
> > -	mtk_dsi_rxtx_control(dsi);
> > -	usleep_range(30, 100);
> > -	mtk_dsi_reset_dphy(dsi);
> > -	mtk_dsi_clk_ulp_mode_leave(dsi);
> > -	mtk_dsi_lane0_ulp_mode_leave(dsi);
> > -	mtk_dsi_clk_hs_mode(dsi, 0);
> > -
> >   	return 0;
> >   err_disable_engine_clk:
> >   	clk_disable_unprepare(dsi->engine_clk);
> > @@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> > *dsi)
> >   	clk_disable_unprepare(dsi->digital_clk);
> >   
> >   	phy_power_off(dsi->phy);
> > +
> > +	dsi->lanes_ready = false;
> > +}
> > +
> > +static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
> > +{
> > +	if (!dsi->lanes_ready) {
> > +		dsi->lanes_ready = true;
> > +		mtk_dsi_rxtx_control(dsi);
> > +		usleep_range(30, 100);
> > +		mtk_dsi_reset_dphy(dsi);
> > +		mtk_dsi_clk_ulp_mode_leave(dsi);
> > +		mtk_dsi_lane0_ulp_mode_leave(dsi);
> > +		mtk_dsi_clk_hs_mode(dsi, 0);
> > +		msleep(20);
> 
> This is a very long sleep, which wasn't present before this change.
> Please document the reasons why we need this 20ms sleep with a
> comment
> in the code.
> 
> Regards,
> Angelo
> 
> 

Hello Xinlei,

As Angelo mentioned.
I think you should add this in commit message and driver comments.
(Your reply in v3.)
"The 20ms delay in mtk_dsi_lane_ready() is because dsi needs to give
dsi_rx(panel) a reaction time after pulling up the mipi signal."

BRs,
Rex

Re: [PATCH v4, 1/4] drm/mediatek: Adjust the timing of mipi signal from LP00 to LP11

[CK Hu]

Hi, Xinlei:

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> Old sequence:
> 1. Pull the MIPI signal high
> 2. Delay & Dsi_reset
> 3. Set the dsi timing register
> 4. dsi clk & lanes leave ulp mode and enter hs mode
> 
> The sequence after patching is:
> 1. Set the dsi timing register
> 2. Pull the MIPI signal high
> 3. Delay & Dsi_reset
> 4. dsi clk & lanes leave ulp mode and enter hs mode

You just describe WHAT this patch do, but WHY this patch do? Does this
patch reorder sequence to follow any spec?

> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index ccb0511b9cd5..262c027d8c2f 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -649,14 +649,14 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>  	mtk_dsi_reset_engine(dsi);
>  	mtk_dsi_phy_timconfig(dsi);
>  
> -	mtk_dsi_rxtx_control(dsi);
> -	usleep_range(30, 100);
> -	mtk_dsi_reset_dphy(dsi);
>  	mtk_dsi_ps_control_vact(dsi);
>  	mtk_dsi_set_vm_cmd(dsi);
>  	mtk_dsi_config_vdo_timing(dsi);
>  	mtk_dsi_set_interrupt_enable(dsi);
>  
> +	mtk_dsi_rxtx_control(dsi);
> +	usleep_range(30, 100);
> +	mtk_dsi_reset_dphy(dsi);

The original sequence is done by patch [1] not the patch in the Fixes
tag. So modify the Fixes tag.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek/mtk_dsi.c?h=v5.18-rc2&id=75374fc2c152ef42c45c6bf716743d5f5bb6d24d

Regards,
CK

>  	mtk_dsi_clk_ulp_mode_leave(dsi);
>  	mtk_dsi_lane0_ulp_mode_leave(dsi);
>  	mtk_dsi_clk_hs_mode(dsi, 0);

Re: [PATCH v4, 2/4] drm/mediatek: Separate poweron/poweroff from enable/disable and define new funcs

[CK Hu]

Hi, Xinlei:

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> In order to match the changes of "Use the drm_panel_bridge API",
> the poweron/poweroff of dsi is extracted from enable/disable and
> defined as new funcs (pre_enable/post_disable).
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 51 +++++++++++++++++++---------
> --
>  1 file changed, 32 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 262c027d8c2f..cf76c53a1af6 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -679,16 +679,6 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> *dsi)
>  	if (--dsi->refcount != 0)
>  		return;
>  
> -	/*
> -	 * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
> -	 * mtk_dsi_stop() should be called after
> mtk_drm_crtc_atomic_disable(),
> -	 * which needs irq for vblank, and mtk_dsi_stop() will disable
> irq.
> -	 * mtk_dsi_start() needs to be called in
> mtk_output_dsi_enable(),
> -	 * after dsi is fully set.
> -	 */
> -	mtk_dsi_stop(dsi);
> -
> -	mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
>  	mtk_dsi_reset_engine(dsi);
>  	mtk_dsi_lane0_ulp_mode_enter(dsi);
>  	mtk_dsi_clk_ulp_mode_enter(dsi);
> @@ -703,17 +693,9 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> *dsi)
>  
>  static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
>  {
> -	int ret;
> -
>  	if (dsi->enabled)
>  		return;
>  
> -	ret = mtk_dsi_poweron(dsi);
> -	if (ret < 0) {
> -		DRM_ERROR("failed to power on dsi\n");
> -		return;
> -	}
> -
>  	mtk_dsi_set_mode(dsi);
>  	mtk_dsi_clk_hs_mode(dsi, 1);
>  
> @@ -727,7 +709,16 @@ static void mtk_output_dsi_disable(struct
> mtk_dsi *dsi)
>  	if (!dsi->enabled)
>  		return;
>  
> -	mtk_dsi_poweroff(dsi);
> +	/*
> +	 * mtk_dsi_stop() and mtk_dsi_start() is asymmetric, since
> +	 * mtk_dsi_stop() should be called after
> mtk_drm_crtc_atomic_disable(),
> +	 * which needs irq for vblank, and mtk_dsi_stop() will disable
> irq.
> +	 * mtk_dsi_start() needs to be called in
> mtk_output_dsi_enable(),
> +	 * after dsi is fully set.
> +	 */
> +	mtk_dsi_stop(dsi);
> +
> +	mtk_dsi_switch_to_cmd_mode(dsi, VM_DONE_INT_FLAG, 500);
>  
>  	dsi->enabled = false;
>  }
> @@ -762,13 +753,35 @@ static void mtk_dsi_bridge_enable(struct
> drm_bridge *bridge)
>  {
>  	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
>  
> +	if (dsi->refcount == 0)
> +		return;
> +
>  	mtk_output_dsi_enable(dsi);
>  }
>  
> +static void mtk_dsi_bridge_pre_enable(struct drm_bridge *bridge)
> +{
> +	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> +	int ret;
> +
> +	ret = mtk_dsi_poweron(dsi);
> +	if (ret < 0)
> +		DRM_ERROR("failed to power on dsi\n");
> +}
> +
> +static void mtk_dsi_bridge_post_disable(struct drm_bridge *bridge)
> +{
> +	struct mtk_dsi *dsi = bridge_to_dsi(bridge);
> +
> +	mtk_dsi_poweroff(dsi);
> +}
> +
>  static const struct drm_bridge_funcs mtk_dsi_bridge_funcs = {
>  	.attach = mtk_dsi_bridge_attach,
>  	.disable = mtk_dsi_bridge_disable,
>  	.enable = mtk_dsi_bridge_enable,
> +	.pre_enable = mtk_dsi_bridge_pre_enable,

The flow looks good to me, but according to [1], pre_enable is
deprecated. Use atomic_pre_enable instead.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/drm/drm_bridge.h?h=v5.18-rc2#n235


> +	.post_disable = mtk_dsi_bridge_post_disable,

Ditto.

Regards,
CK

>  	.mode_set = mtk_dsi_bridge_mode_set,
>  };
>  

Re: [PATCH v4, 3/4] drm/mediatek: keep dsi as LP00 before dcs cmds transfer

[CK Hu]

Hi, Xinlei:

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Jitao Shi <jitao.shi@mediatek.com>
> 
> To comply with the panel sequence, hold the mipi signal to LP00
> before the dcs cmds transmission,
> and pull the mipi signal high from LP00 to LP11 until the start of
> the dcs cmds transmission.
> The normal panel timing is :
> (1) pp1800 DC pull up
> (2) avdd & avee AC pull high
> (3) lcm_reset pull high -> pull low -> pull high
> (4) Pull MIPI signal high (LP11) -> initial code -> send video
> data(HS mode)
> The power-off sequence is reversed.
> If dsi is not in cmd mode, then dsi will pull the mipi signal high in
> the mtk_output_dsi_enable function.
> 
> Fixes: 2dd8075d2185 ("drm/mediatek: mtk_dsi: Use the drm_panel_bridge
> API")
> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index cf76c53a1af6..9ad6f08c8bfe 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -203,6 +203,7 @@ struct mtk_dsi {
>  	struct mtk_phy_timing phy_timing;
>  	int refcount;
>  	bool enabled;
> +	bool lanes_ready;
>  	u32 irq_data;
>  	wait_queue_head_t irq_wait_queue;
>  	const struct mtk_dsi_driver_data *driver_data;
> @@ -654,13 +655,6 @@ static int mtk_dsi_poweron(struct mtk_dsi *dsi)
>  	mtk_dsi_config_vdo_timing(dsi);
>  	mtk_dsi_set_interrupt_enable(dsi);
>  
> -	mtk_dsi_rxtx_control(dsi);
> -	usleep_range(30, 100);
> -	mtk_dsi_reset_dphy(dsi);
> -	mtk_dsi_clk_ulp_mode_leave(dsi);
> -	mtk_dsi_lane0_ulp_mode_leave(dsi);
> -	mtk_dsi_clk_hs_mode(dsi, 0);
> -
>  	return 0;
>  err_disable_engine_clk:
>  	clk_disable_unprepare(dsi->engine_clk);
> @@ -689,6 +683,23 @@ static void mtk_dsi_poweroff(struct mtk_dsi
> *dsi)
>  	clk_disable_unprepare(dsi->digital_clk);
>  
>  	phy_power_off(dsi->phy);
> +
> +	dsi->lanes_ready = false;
> +}
> +
> +static void mtk_dsi_lane_ready(struct mtk_dsi *dsi)
> +{
> +	if (!dsi->lanes_ready) {
> +		dsi->lanes_ready = true;
> +		mtk_dsi_rxtx_control(dsi);
> +		usleep_range(30, 100);
> +		mtk_dsi_reset_dphy(dsi);
> +		mtk_dsi_clk_ulp_mode_leave(dsi);
> +		mtk_dsi_lane0_ulp_mode_leave(dsi);
> +		mtk_dsi_clk_hs_mode(dsi, 0);
> +		msleep(20);
> +	} else
> +		DRM_DEBUG("The dsi_lane is ready\n");
>  }
>  
>  static void mtk_output_dsi_enable(struct mtk_dsi *dsi)
> @@ -696,6 +707,7 @@ static void mtk_output_dsi_enable(struct mtk_dsi
> *dsi)
>  	if (dsi->enabled)
>  		return;
>  
> +	mtk_dsi_lane_ready(dsi);
>  	mtk_dsi_set_mode(dsi);
>  	mtk_dsi_clk_hs_mode(dsi, 1);
>  
> @@ -1001,6 +1013,8 @@ static ssize_t mtk_dsi_host_transfer(struct
> mipi_dsi_host *host,
>  	if (MTK_DSI_HOST_IS_READ(msg->type))
>  		irq_flag |= LPRX_RD_RDY_INT_FLAG;
>  
> +	mtk_dsi_lane_ready(dsi);

In [1], YT has move mtk_dsi_lane_ready() before panel prepare for dsi-
>panel case. Now you move mtk_dsi_lane_ready() after panel prepare,
this may break dsi->panel case. Please provide a solution for both
case.

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek/mtk_dsi.c?h=v5.18-rc2&id=0707632b5bacc490f58dfbad741d586c06595ff3

Regards,
CK

> +
>  	ret = mtk_dsi_host_send_cmd(dsi, msg, irq_flag);
>  	if (ret)
>  		goto restore_dsi_mode;

Re: [PATCH v4, 4/4] drm/mediatek: Add pull-down MIPI operation in mtk_dsi_poweroff function

[CK Hu]

Hi, Xinlei:

On Mon, 2022-04-11 at 10:31 +0800, xinlei.lee@mediatek.com wrote:
> From: Xinlei Lee <xinlei.lee@mediatek.com>
> 
> In the dsi_enable function, mtk_dsi_rxtx_control is to
> pull up the MIPI signal operation. Before dsi_disable,
> MIPI should also be pulled down by writing a register 
> instead of disabling dsi.
> 
> If disable dsi without pulling the mipi signal low, the value of
> the register will still maintain the setting of the mipi signal being
> pulled high.
> After resume, even if the mipi signal is not pulled high, it will
> still
> be in the high state.

After add Fixes tag for [1], then

Reviewed-by: CK Hu <ck.hu@mediatek.com>

[1] 
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek/mtk_dsi.c?h=v5.18-rc2&id=2e54c14e310f655bb0915413e8e4a3da67c78a66

> 
> Signed-off-by: Jitao Shi <jitao.shi@mediatek.com>
> Signed-off-by: Xinlei Lee <xinlei.lee@mediatek.com>
> ---
>  drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c
> b/drivers/gpu/drm/mediatek/mtk_dsi.c
> index 9ad6f08c8bfe..e35343357f90 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> @@ -676,6 +676,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi)
>  	mtk_dsi_reset_engine(dsi);
>  	mtk_dsi_lane0_ulp_mode_enter(dsi);
>  	mtk_dsi_clk_ulp_mode_enter(dsi);
> +	/* set the lane number as 0 to pull down mipi */
> +	writel(0, dsi->regs + DSI_TXRX_CTRL);
>  
>  	mtk_dsi_disable(dsi);
>