* [PATCH 1/2] video: ipuv3: use closest fractional divider
@ 2018-11-12 16:22 Lucas Stach
2018-11-12 16:22 ` [PATCH 2/2] video: ipuv3: use non-fractional clock for parallel display Lucas Stach
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Lucas Stach @ 2018-11-12 16:22 UTC (permalink / raw)
To: barebox
Currently the divider is always rounded down, which may lead to a
rather big overshoot of the display clock. Try to match the clock
better by rounding to closest.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
drivers/video/imx-ipu-v3/ipu-di.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/drivers/video/imx-ipu-v3/ipu-di.c b/drivers/video/imx-ipu-v3/ipu-di.c
index b6e64fe16a85..5751c678b28e 100644
--- a/drivers/video/imx-ipu-v3/ipu-di.c
+++ b/drivers/video/imx-ipu-v3/ipu-di.c
@@ -140,10 +140,7 @@ static int ipu_di_clk_calc_div(unsigned long inrate, unsigned long outrate)
int div;
tmp *= 16;
-
- do_div(tmp, outrate);
-
- div = tmp;
+ div = DIV_ROUND_CLOSEST(tmp, outrate);
if (div < 0x10)
div = 0x10;
--
2.19.1
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/2] video: ipuv3: use non-fractional clock for parallel display
2018-11-12 16:22 [PATCH 1/2] video: ipuv3: use closest fractional divider Lucas Stach
@ 2018-11-12 16:22 ` Lucas Stach
2018-11-14 8:59 ` [PATCH 1/2] video: ipuv3: use closest fractional divider Sascha Hauer
2018-11-19 10:05 ` Sascha Hauer
2 siblings, 0 replies; 4+ messages in thread
From: Lucas Stach @ 2018-11-12 16:22 UTC (permalink / raw)
To: barebox
There is no need to keep DI and parent clock in sync for the parallel
display interface, but some displays really don't like the jitter
introduced by using a fractional clock.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
---
drivers/video/imx-ipu-v3/imx-pd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/imx-ipu-v3/imx-pd.c b/drivers/video/imx-ipu-v3/imx-pd.c
index 09d8a3ae2a84..601be35880ac 100644
--- a/drivers/video/imx-ipu-v3/imx-pd.c
+++ b/drivers/video/imx-ipu-v3/imx-pd.c
@@ -45,7 +45,7 @@ static int imx_pd_ioctl(struct vpl *vpl, unsigned int port,
case IMX_IPU_VPL_DI_MODE:
mode = data;
- mode->di_clkflags = IPU_DI_CLKMODE_SYNC;
+ mode->di_clkflags = IPU_DI_CLKMODE_NON_FRACTIONAL;
mode->bus_format = imx_pd->bus_format;
return 0;
--
2.19.1
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] video: ipuv3: use closest fractional divider
2018-11-12 16:22 [PATCH 1/2] video: ipuv3: use closest fractional divider Lucas Stach
2018-11-12 16:22 ` [PATCH 2/2] video: ipuv3: use non-fractional clock for parallel display Lucas Stach
@ 2018-11-14 8:59 ` Sascha Hauer
2018-11-19 10:05 ` Sascha Hauer
2 siblings, 0 replies; 4+ messages in thread
From: Sascha Hauer @ 2018-11-14 8:59 UTC (permalink / raw)
To: Lucas Stach; +Cc: barebox
On Mon, Nov 12, 2018 at 05:22:56PM +0100, Lucas Stach wrote:
> Currently the divider is always rounded down, which may lead to a
> rather big overshoot of the display clock. Try to match the clock
> better by rounding to closest.
>
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> drivers/video/imx-ipu-v3/ipu-di.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
Applied, thanks
Sascha
>
> diff --git a/drivers/video/imx-ipu-v3/ipu-di.c b/drivers/video/imx-ipu-v3/ipu-di.c
> index b6e64fe16a85..5751c678b28e 100644
> --- a/drivers/video/imx-ipu-v3/ipu-di.c
> +++ b/drivers/video/imx-ipu-v3/ipu-di.c
> @@ -140,10 +140,7 @@ static int ipu_di_clk_calc_div(unsigned long inrate, unsigned long outrate)
> int div;
>
> tmp *= 16;
> -
> - do_div(tmp, outrate);
> -
> - div = tmp;
> + div = DIV_ROUND_CLOSEST(tmp, outrate);
>
> if (div < 0x10)
> div = 0x10;
> --
> 2.19.1
>
>
> _______________________________________________
> barebox mailing list
> barebox@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/barebox
>
--
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Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] video: ipuv3: use closest fractional divider
2018-11-12 16:22 [PATCH 1/2] video: ipuv3: use closest fractional divider Lucas Stach
2018-11-12 16:22 ` [PATCH 2/2] video: ipuv3: use non-fractional clock for parallel display Lucas Stach
2018-11-14 8:59 ` [PATCH 1/2] video: ipuv3: use closest fractional divider Sascha Hauer
@ 2018-11-19 10:05 ` Sascha Hauer
2 siblings, 0 replies; 4+ messages in thread
From: Sascha Hauer @ 2018-11-19 10:05 UTC (permalink / raw)
To: Lucas Stach; +Cc: barebox
On Mon, Nov 12, 2018 at 05:22:56PM +0100, Lucas Stach wrote:
> Currently the divider is always rounded down, which may lead to a
> rather big overshoot of the display clock. Try to match the clock
> better by rounding to closest.
>
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> ---
> drivers/video/imx-ipu-v3/ipu-di.c | 5 +----
> 1 file changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/drivers/video/imx-ipu-v3/ipu-di.c b/drivers/video/imx-ipu-v3/ipu-di.c
> index b6e64fe16a85..5751c678b28e 100644
> --- a/drivers/video/imx-ipu-v3/ipu-di.c
> +++ b/drivers/video/imx-ipu-v3/ipu-di.c
> @@ -140,10 +140,7 @@ static int ipu_di_clk_calc_div(unsigned long inrate, unsigned long outrate)
> int div;
>
> tmp *= 16;
> -
> - do_div(tmp, outrate);
> -
> - div = tmp;
> + div = DIV_ROUND_CLOSEST(tmp, outrate);
>
On ARM32 this fails with:
undefined reference to `__aeabi_uldivmod'
Fixed up like this:
----------------------------8<-------------------------
From 6b14328204f3978abeb91e8e779f6444c3c74df8 Mon Sep 17 00:00:00 2001
From: Lucas Stach <l.stach@pengutronix.de>
Date: Mon, 12 Nov 2018 17:22:56 +0100
Subject: [PATCH] video: ipuv3: use closest fractional divider
Currently the divider is always rounded down, which may lead to a
rather big overshoot of the display clock. Try to match the clock
better by rounding to closest.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
drivers/video/imx-ipu-v3/ipu-di.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/video/imx-ipu-v3/ipu-di.c b/drivers/video/imx-ipu-v3/ipu-di.c
index b6e64fe16a..b4302412e0 100644
--- a/drivers/video/imx-ipu-v3/ipu-di.c
+++ b/drivers/video/imx-ipu-v3/ipu-di.c
@@ -140,6 +140,7 @@ static int ipu_di_clk_calc_div(unsigned long inrate, unsigned long outrate)
int div;
tmp *= 16;
+ tmp += outrate / 2;
do_div(tmp, outrate);
--
2.19.1
--
Pengutronix e.K. | |
Industrial Linux Solutions | http://www.pengutronix.de/ |
Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 |
Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |
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2018-11-12 16:22 [PATCH 1/2] video: ipuv3: use closest fractional divider Lucas Stach
2018-11-12 16:22 ` [PATCH 2/2] video: ipuv3: use non-fractional clock for parallel display Lucas Stach
2018-11-14 8:59 ` [PATCH 1/2] video: ipuv3: use closest fractional divider Sascha Hauer
2018-11-19 10:05 ` Sascha Hauer
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