omap4: how to get the HDMI core IRQ?

Tomi Valkeinen tomi.valkeinen at ti.com
Wed Mar 30 10:37:45 UTC 2016


Hi Hans,

On 24/03/16 23:20, Hans Verkuil wrote:
> Hi Tomi,
> 
> I hope you (or someone else on this list) can help me find the problem in this code.
> 
> I am working on a kernel framework for HDMI CEC (see https://lwn.net/Articles/680942/).
> In order to get as much experience with different devices as possible I am trying to
> implement it on my omap4430 Pandaboard. The big problem I am facing is that the CEC
> interrupts come in through the HDMI_IRQ_CORE interrupt, and that just refuses to
> trigger.
> 
> The code below adds support for this core interrupt and it is supposed to trigger it
> using the Software Induced interrupt to keep the code as simple as possible.

So this irq is just for testing?

> On boot I get this debug line from the pr_info in my code:
> 
> irqstat 02000000 wp_irq 06000001 raw 20010000 intr_state 00000001 intr1 00000080 unmask1 00000080 intr_ctrl 0000000a
> 
> As far as I can see everything looks perfectly fine, except for the fact that bit 0
> of the irqstat is stubbornly 0.
> 
> This is using kernel 4.5 with only this patch applied.
> 
> What am I missing?

Set SYS_CTRL1:PD to 1 (I presume you have the NDA HDMI TRM?).

Apparently we set it always to 0 in
hdmi4_core.c:hdmi_core_powerdown_disable(), but never enable it. I guess
it only affects core irqs, so there have been no side effects.

But it would make sense to either have a matching call in the enable
path, or then just set it to 0 when initializing the IP.

> 
> The reward for the right answer will be HDMI CEC support for omap4 (and any other TI device
> with the same CEC IP).

Ok. When is it ready? ;)

 Tomi

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