* [U-Boot] iMX6 IPU configuration by EDID
@ 2015-03-17 10:04 Luca Ellero
2015-03-17 14:25 ` Eric Nelson
0 siblings, 1 reply; 3+ messages in thread
From: Luca Ellero @ 2015-03-17 10:04 UTC (permalink / raw)
To: u-boot
Hi all,
I'm trying to configure IPU on a iMX6 based platform by reading EDID
from the external monitor.
Everything seem to work fine except for the pixelclock. In particular my
monitor has a standard resolution of 1280x1024 at 60 (108 MHz pixelclock).
When the function ipu_init_sync_panel (file ipu_disp.c) is called it
correctly receive 108 MHz as pixelclock. but during the execution of
this function it gets rounded to 130 MHz.
I can see that the function calls clk_round_rate to round the clock to
130 MHz but it's not clear for me how it works.
Can someone please tell me how to get the exact pixelclock I would like
to achieve? I've carefully read the iMX6 manual but it's not very useful
in this case.
Another doubt that I have regards the field "ext_clk" of parameter
"ipu_di_signal_cfg_t sig". In this case, is it better to set it or not?
Thanks
Regards
Luca
--
Luca Ellero
E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com
^ permalink raw reply [flat|nested] 3+ messages in thread
* [U-Boot] iMX6 IPU configuration by EDID
2015-03-17 10:04 [U-Boot] iMX6 IPU configuration by EDID Luca Ellero
@ 2015-03-17 14:25 ` Eric Nelson
2015-03-18 8:26 ` Luca Ellero
0 siblings, 1 reply; 3+ messages in thread
From: Eric Nelson @ 2015-03-17 14:25 UTC (permalink / raw)
To: u-boot
Hi Luca,
On 03/17/2015 03:04 AM, Luca Ellero wrote:
> Hi all,
>
> I'm trying to configure IPU on a iMX6 based platform by reading EDID
> from the external monitor.
>
> Everything seem to work fine except for the pixelclock. In particular my
> monitor has a standard resolution of 1280x1024 at 60 (108 MHz pixelclock).
>
> When the function ipu_init_sync_panel (file ipu_disp.c) is called it
> correctly receive 108 MHz as pixelclock. but during the execution of
> this function it gets rounded to 130 MHz.
>
> I can see that the function calls clk_round_rate to round the clock to
> 130 MHz but it's not clear for me how it works.
>
It's been a while since I've looked at this, but I believe there's
a hidden fixed clock somewhere in the IPU driver.
http://lists.denx.de/pipermail/u-boot/2014-January/thread.html#170363
> Can someone please tell me how to get the exact pixelclock I would like
> to achieve? I've carefully read the iMX6 manual but it's not very useful
> in this case.
>
> Another doubt that I have regards the field "ext_clk" of parameter
> "ipu_di_signal_cfg_t sig". In this case, is it better to set it or not?
>
I believe this is supposed to be set for HDMI, such that the IPU
clock is derived from the HDMI PHY clock and it's best to use
the Linux driver as a guide.
Regards,
Eric
^ permalink raw reply [flat|nested] 3+ messages in thread
* [U-Boot] iMX6 IPU configuration by EDID
2015-03-17 14:25 ` Eric Nelson
@ 2015-03-18 8:26 ` Luca Ellero
0 siblings, 0 replies; 3+ messages in thread
From: Luca Ellero @ 2015-03-18 8:26 UTC (permalink / raw)
To: u-boot
On 17/03/2015 15:25, Eric Nelson wrote:
> Hi Luca,
>
> On 03/17/2015 03:04 AM, Luca Ellero wrote:
>> Hi all,
>>
>> I'm trying to configure IPU on a iMX6 based platform by reading EDID
>> from the external monitor.
>>
>> Everything seem to work fine except for the pixelclock. In particular my
>> monitor has a standard resolution of 1280x1024 at 60 (108 MHz pixelclock).
>>
>> When the function ipu_init_sync_panel (file ipu_disp.c) is called it
>> correctly receive 108 MHz as pixelclock. but during the execution of
>> this function it gets rounded to 130 MHz.
>>
>> I can see that the function calls clk_round_rate to round the clock to
>> 130 MHz but it's not clear for me how it works.
>>
>
> It's been a while since I've looked at this, but I believe there's
> a hidden fixed clock somewhere in the IPU driver.
>
> http://lists.denx.de/pipermail/u-boot/2014-January/thread.html#170363
>
>> Can someone please tell me how to get the exact pixelclock I would like
>> to achieve? I've carefully read the iMX6 manual but it's not very useful
>> in this case.
>>
>> Another doubt that I have regards the field "ext_clk" of parameter
>> "ipu_di_signal_cfg_t sig". In this case, is it better to set it or not?
>>
>
> I believe this is supposed to be set for HDMI, such that the IPU
> clock is derived from the HDMI PHY clock and it's best to use
> the Linux driver as a guide.
>
Hi Eric,
thank you for your reply.
I'll try to investigate the Linux driver then.
Kind regards
Luca
--
Luca Ellero
E-mail: luca.ellero at brickedbrain.com
Internet: www.brickedbrain.com
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-03-17 10:04 [U-Boot] iMX6 IPU configuration by EDID Luca Ellero
2015-03-17 14:25 ` Eric Nelson
2015-03-18 8:26 ` Luca Ellero
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