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* [PATCH v2] drm/mxsfb: fix pixel clock polarity
@ 2016-12-14 20:48 Stefan Agner
  2016-12-14 21:25 ` Marek Vasut
  0 siblings, 1 reply; 5+ messages in thread
From: Stefan Agner @ 2016-12-14 20:48 UTC (permalink / raw)
  To: marex; +Cc: airlied, dri-devel, linux-kernel, Stefan Agner

The DRM subsystem specifies the pixel clock polarity from a
controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
the controller drives the data on pixel clocks falling edge.
That is the controllers DOTCLK_POL=0 (Default is data launched
at negative edge).

Also change the data enable logic to be high active by default
and only change if explicitly requested via bus_flags. With
that defaults are:
- Data enable: high active
- Pixel clock polarity: controller drives data on negative edge

Signed-off-by: Stefan Agner <stefan@agner.ch>
---
Changes since v1:
- Improved comments/fixed typo

 drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
index 3770dd2..5556e53 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
@@ -195,9 +195,16 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)
 		vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH;
 	if (m->flags & DRM_MODE_FLAG_PVSYNC)
 		vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH;
-	if (bus_flags & DRM_BUS_FLAG_DE_HIGH)
+	/* Make sure Data Enable is high active by default */
+	if (!(bus_flags & DRM_BUS_FLAG_DE_LOW))
 		vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
-	if (bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE)
+	/*
+	 * DRM_BUS_FLAG_PIXDATA_ defines are controller centric,
+	 * controllers VDCTRL0_DOTCLK is display centric.
+	 * Drive on positive edge       -> display samples on falling edge
+	 * DRM_BUS_FLAG_PIXDATA_POSEDGE -> VDCTRL0_DOTCLK_ACT_FALLING
+	 */
+	if (bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE)
 		vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING;
 
 	writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0);
-- 
2.10.2

^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH v2] drm/mxsfb: fix pixel clock polarity
  2016-12-14 20:48 [PATCH v2] drm/mxsfb: fix pixel clock polarity Stefan Agner
@ 2016-12-14 21:25 ` Marek Vasut
  2017-02-08  5:19   ` Stefan Agner
  0 siblings, 1 reply; 5+ messages in thread
From: Marek Vasut @ 2016-12-14 21:25 UTC (permalink / raw)
  To: Stefan Agner; +Cc: airlied, dri-devel, linux-kernel

On 12/14/2016 09:48 PM, Stefan Agner wrote:
> The DRM subsystem specifies the pixel clock polarity from a
> controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
> the controller drives the data on pixel clocks falling edge.
> That is the controllers DOTCLK_POL=0 (Default is data launched
> at negative edge).
> 
> Also change the data enable logic to be high active by default
> and only change if explicitly requested via bus_flags. With
> that defaults are:
> - Data enable: high active
> - Pixel clock polarity: controller drives data on negative edge
> 
> Signed-off-by: Stefan Agner <stefan@agner.ch>

Acked-by: Marek Vasut <marex@denx.de>

> ---
> Changes since v1:
> - Improved comments/fixed typo
> 
>  drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> index 3770dd2..5556e53 100644
> --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
> @@ -195,9 +195,16 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)
>  		vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH;
>  	if (m->flags & DRM_MODE_FLAG_PVSYNC)
>  		vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH;
> -	if (bus_flags & DRM_BUS_FLAG_DE_HIGH)
> +	/* Make sure Data Enable is high active by default */
> +	if (!(bus_flags & DRM_BUS_FLAG_DE_LOW))
>  		vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
> -	if (bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE)
> +	/*
> +	 * DRM_BUS_FLAG_PIXDATA_ defines are controller centric,
> +	 * controllers VDCTRL0_DOTCLK is display centric.
> +	 * Drive on positive edge       -> display samples on falling edge
> +	 * DRM_BUS_FLAG_PIXDATA_POSEDGE -> VDCTRL0_DOTCLK_ACT_FALLING
> +	 */
> +	if (bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE)
>  		vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING;
>  
>  	writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0);
> 


-- 
Best regards,
Marek Vasut

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH v2] drm/mxsfb: fix pixel clock polarity
  2016-12-14 21:25 ` Marek Vasut
@ 2017-02-08  5:19   ` Stefan Agner
  2017-02-08  7:19     ` Daniel Vetter
  0 siblings, 1 reply; 5+ messages in thread
From: Stefan Agner @ 2017-02-08  5:19 UTC (permalink / raw)
  To: Marek Vasut, airlied; +Cc: airlied, dri-devel, linux-kernel

Dave, Marek,

On 2016-12-14 13:25, Marek Vasut wrote:
> On 12/14/2016 09:48 PM, Stefan Agner wrote:
>> The DRM subsystem specifies the pixel clock polarity from a
>> controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
>> the controller drives the data on pixel clocks falling edge.
>> That is the controllers DOTCLK_POL=0 (Default is data launched
>> at negative edge).
>>
>> Also change the data enable logic to be high active by default
>> and only change if explicitly requested via bus_flags. With
>> that defaults are:
>> - Data enable: high active
>> - Pixel clock polarity: controller drives data on negative edge
>>
>> Signed-off-by: Stefan Agner <stefan@agner.ch>
> 
> Acked-by: Marek Vasut <marex@denx.de>
> 

This seems not have made into drm-next yet. Not sure what the plan is
here, who will pick this up? There is also another fix on ML for the
same driver ("drm: mxsfb: Fix crash when provided invalid DT bindings").

--
Stefan

>> ---
>> Changes since v1:
>> - Improved comments/fixed typo
>>
>>  drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 11 +++++++++--
>>  1 file changed, 9 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
>> index 3770dd2..5556e53 100644
>> --- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
>> +++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
>> @@ -195,9 +195,16 @@ static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)
>>  		vdctrl0 |= VDCTRL0_HSYNC_ACT_HIGH;
>>  	if (m->flags & DRM_MODE_FLAG_PVSYNC)
>>  		vdctrl0 |= VDCTRL0_VSYNC_ACT_HIGH;
>> -	if (bus_flags & DRM_BUS_FLAG_DE_HIGH)
>> +	/* Make sure Data Enable is high active by default */
>> +	if (!(bus_flags & DRM_BUS_FLAG_DE_LOW))
>>  		vdctrl0 |= VDCTRL0_ENABLE_ACT_HIGH;
>> -	if (bus_flags & DRM_BUS_FLAG_PIXDATA_NEGEDGE)
>> +	/*
>> +	 * DRM_BUS_FLAG_PIXDATA_ defines are controller centric,
>> +	 * controllers VDCTRL0_DOTCLK is display centric.
>> +	 * Drive on positive edge       -> display samples on falling edge
>> +	 * DRM_BUS_FLAG_PIXDATA_POSEDGE -> VDCTRL0_DOTCLK_ACT_FALLING
>> +	 */
>> +	if (bus_flags & DRM_BUS_FLAG_PIXDATA_POSEDGE)
>>  		vdctrl0 |= VDCTRL0_DOTCLK_ACT_FALLING;
>>
>>  	writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0);
>>

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH v2] drm/mxsfb: fix pixel clock polarity
  2017-02-08  5:19   ` Stefan Agner
@ 2017-02-08  7:19     ` Daniel Vetter
  2017-02-08 10:19       ` Marek Vasut
  0 siblings, 1 reply; 5+ messages in thread
From: Daniel Vetter @ 2017-02-08  7:19 UTC (permalink / raw)
  To: Stefan Agner
  Cc: Marek Vasut, Dave Airlie, Linux Kernel Mailing List, dri-devel

On Wed, Feb 8, 2017 at 6:19 AM, Stefan Agner <stefan@agner.ch> wrote:
> On 2016-12-14 13:25, Marek Vasut wrote:
>> On 12/14/2016 09:48 PM, Stefan Agner wrote:
>>> The DRM subsystem specifies the pixel clock polarity from a
>>> controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
>>> the controller drives the data on pixel clocks falling edge.
>>> That is the controllers DOTCLK_POL=0 (Default is data launched
>>> at negative edge).
>>>
>>> Also change the data enable logic to be high active by default
>>> and only change if explicitly requested via bus_flags. With
>>> that defaults are:
>>> - Data enable: high active
>>> - Pixel clock polarity: controller drives data on negative edge
>>>
>>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>>
>> Acked-by: Marek Vasut <marex@denx.de>
>>
>
> This seems not have made into drm-next yet. Not sure what the plan is
> here, who will pick this up? There is also another fix on ML for the
> same driver ("drm: mxsfb: Fix crash when provided invalid DT bindings").

By default, driver maintainers are expected to pick up driver patches.
Exception is trivial patches by newcomers, to get them on board fast
(and avoid frustration when a maintainer isn't around). drm-misc and
Dave by default don't pick up anything.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH v2] drm/mxsfb: fix pixel clock polarity
  2017-02-08  7:19     ` Daniel Vetter
@ 2017-02-08 10:19       ` Marek Vasut
  0 siblings, 0 replies; 5+ messages in thread
From: Marek Vasut @ 2017-02-08 10:19 UTC (permalink / raw)
  To: Daniel Vetter, Stefan Agner
  Cc: Dave Airlie, Linux Kernel Mailing List, dri-devel

On 02/08/2017 08:19 AM, Daniel Vetter wrote:
> On Wed, Feb 8, 2017 at 6:19 AM, Stefan Agner <stefan@agner.ch> wrote:
>> On 2016-12-14 13:25, Marek Vasut wrote:
>>> On 12/14/2016 09:48 PM, Stefan Agner wrote:
>>>> The DRM subsystem specifies the pixel clock polarity from a
>>>> controllers perspective: DRM_BUS_FLAG_PIXDATA_NEGEDGE means
>>>> the controller drives the data on pixel clocks falling edge.
>>>> That is the controllers DOTCLK_POL=0 (Default is data launched
>>>> at negative edge).
>>>>
>>>> Also change the data enable logic to be high active by default
>>>> and only change if explicitly requested via bus_flags. With
>>>> that defaults are:
>>>> - Data enable: high active
>>>> - Pixel clock polarity: controller drives data on negative edge
>>>>
>>>> Signed-off-by: Stefan Agner <stefan@agner.ch>
>>>
>>> Acked-by: Marek Vasut <marex@denx.de>
>>>
>>
>> This seems not have made into drm-next yet. Not sure what the plan is
>> here, who will pick this up? There is also another fix on ML for the
>> same driver ("drm: mxsfb: Fix crash when provided invalid DT bindings").
> 
> By default, driver maintainers are expected to pick up driver patches.
> Exception is trivial patches by newcomers, to get them on board fast
> (and avoid frustration when a maintainer isn't around). drm-misc and
> Dave by default don't pick up anything.

Aha, OK.

-- 
Best regards,
Marek Vasut

^ permalink raw reply	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2017-02-08 11:15 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2016-12-14 20:48 [PATCH v2] drm/mxsfb: fix pixel clock polarity Stefan Agner
2016-12-14 21:25 ` Marek Vasut
2017-02-08  5:19   ` Stefan Agner
2017-02-08  7:19     ` Daniel Vetter
2017-02-08 10:19       ` Marek Vasut

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