diff options
Diffstat (limited to 'drivers/gpu/drm/vc4/vc4_hdmi.c')
| -rw-r--r-- | drivers/gpu/drm/vc4/vc4_hdmi.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c index 93d5994f3a04..1be1e8304720 100644 --- a/drivers/gpu/drm/vc4/vc4_hdmi.c +++ b/drivers/gpu/drm/vc4/vc4_hdmi.c @@ -20,9 +20,26 @@ /** * DOC: VC4 Falcon HDMI module * - * The HDMI core has a state machine and a PHY. Most of the unit - * operates off of the HSM clock from CPRMAN. It also internally uses - * the PLLH_PIX clock for the PHY. + * The HDMI core has a state machine and a PHY. On BCM2835, most of + * the unit operates off of the HSM clock from CPRMAN. It also + * internally uses the PLLH_PIX clock for the PHY. + * + * HDMI infoframes are kept within a small packet ram, where each + * packet can be individually enabled for including in a frame. + * + * HDMI audio is implemented entirely within the HDMI IP block. A + * register in the HDMI encoder takes SPDIF frames from the DMA engine + * and transfers them over an internal MAI (multi-channel audio + * interconnect) bus to the encoder side for insertion into the video + * blank regions. + * + * The driver's HDMI encoder does not yet support power management. + * The HDMI encoder's power domain and the HSM/pixel clocks are kept + * continuously running, and only the HDMI logic and packet ram are + * powered off/on at disable/enable time. + * + * The driver does not yet support CEC control, though the HDMI + * encoder block has CEC support. */ #include "drm_atomic_helper.h" |