[PATCH 1/8] arm: omap4: enable CEC pin for Pandaboard A4 and ES

Tony Lindgren tony at atomide.com
Sat Apr 29 20:21:04 UTC 2017

* Tony Lindgren <tony at atomide.com> [170428 11:57]:
> The pull seems to be enabled in the Android kernel too:
> # rwmem -s16 0x4a10009a
> 0x4a10009a = 0x0118
> So needs to be tested, what's the simplest test to check the CEC?

So on droid 4, with the internal pull enabled cec-ctl -m does not
show anything. With the internal pull disabled, cec-ctl -m produces
the following with a lapdock:

Initial Event: State Change: PA:, LA mask: 0x4000

Event: State Change: PA: f.f.f.f, LA mask: 0x0000

Event: State Change: PA:, LA mask: 0x0000
Transmitted by Specific to Specific (14 to 14): CEC_MSG_POLL
        Tx, Not Acknowledged (4), Max Retries

Event: State Change: PA:, LA mask: 0x4000
Transmitted by Specific to all (14 to 15): CEC_MSG_REPORT_FEATURES (0xa6):
        cec-version: version-2-0 (0x06)
        all-device-types: switch (0x04)
        rc-profile: tv-profile-none (0x00)
        dev-features: 0 (0x00)
Transmitted by Specific to all (14 to 15): CEC_MSG_REPORT_PHYSICAL_ADDR (0x84):
        prim-devtype: processor (0x07)

And looking at the ifixit.com board picture, there seems to be a
IP4791CZ12 chip on droid 4. And it's docs seem to hint it has a
pull in the IP4791CZ12.

So yeah my guess is the cec internal pull should be disabled on
all omap4 devices with HDMI. I'll send a follow-up patch for that.

> Hmm I wonder if disabling the internal pull also allows removing
> the "regulator-always-on" hack for hdmi_regulator there? Without
> regulator-always-on I noticed that HDMI panel resolutions are not
> detected. This I can test easily..

The regulator-fixed is still needed, I think this GPIO regulator
powers the IP4791CZ12 which has no control channel. Not sure if
we should still have encoder-ip4791cz12.c driver for it just to
manage the regulator?



More information about the dri-devel mailing list