From: Hans Verkuil hans.verkuil@cisco.com
This patch series adds support for the OMAP4 HDMI CEC IP core.
Most of the patches leading up to the actual CEC implementation make changes to the HDMI core support. The reason for this is that CEC has to be enabled even if the HPD is low: some displays will set the HPD low when they go into standby or when they switch to another input, but CEC is still available and able to wake up/change input for such a display.
This corner case is explicitly allowed by the CEC standard, and such displays really exist, even in modern displays.
So CEC has to be able to wake up the HDMI core, even when there is no HPD.
I also looked at implementing CEC monitoring (i.e. 'snooping' the CEC bus for messages between other CEC devices), but I couldn't figure that out. The omap4 datasheet does not give sufficient information on how it is supposed to work. There is a CEC_SN bit in CEC_DBG_3 and a 'CEC Snoop Initiator' field in CEC_DBG_2, but no information on how to use those registers. Trying to enable CEC_SN gave me weird results, so I decided to leave that feature out.
Links to CEC documentation and utilities:
Public API:
https://www.linuxtv.org/downloads/v4l-dvb-apis-new/uapi/cec/cec-api.html
Kernel API:
https://www.linuxtv.org/downloads/v4l-dvb-apis-new/kapi/cec-core.html
CEC utilities (esp. cec-ctl):
https://git.linuxtv.org/v4l-utils.git/ (master branch)
To test:
First configure the CEC adapter as a playback device:
cec-ctl --playback
Then detect and query any other CEC devices, such as a CEC-enabled display:
cec-ctl -S
Regards,
Hans
Hans Verkuil (8): arm: omap4: enable CEC pin for Pandaboard A4 and ES omapdrm: encoder-tpd12s015: keep ls_oe_gpio high if CEC is enabled omapdrm: hdmi.h: extend hdmi_core_data with CEC fields omapdrm: hdmi4: make low-level functions available omapdrm: hdmi4: prepare irq handling for HDMI CEC support omapdrm: hdmi4: refcount hdmi_power_on/off_core omapdrm: hdmi4_cec: add OMAP4 HDMI CEC support omapdrm: hdmi4: hook up the HDMI CEC support
arch/arm/boot/dts/omap4-panda-a4.dts | 2 +- arch/arm/boot/dts/omap4-panda-es.dts | 2 +- .../gpu/drm/omapdrm/displays/encoder-tpd12s015.c | 8 + drivers/gpu/drm/omapdrm/dss/Kconfig | 9 + drivers/gpu/drm/omapdrm/dss/Makefile | 1 + drivers/gpu/drm/omapdrm/dss/hdmi.h | 6 +- drivers/gpu/drm/omapdrm/dss/hdmi4.c | 58 +++- drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c | 381 +++++++++++++++++++++ drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h | 55 +++ drivers/gpu/drm/omapdrm/dss/hdmi4_core.c | 6 +- drivers/gpu/drm/omapdrm/dss/hdmi4_core.h | 4 + 11 files changed, 513 insertions(+), 19 deletions(-) create mode 100644 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.c create mode 100644 drivers/gpu/drm/omapdrm/dss/hdmi4_cec.h