drm/vc4: Extend and edit documentation for output from the RST
I had written most of my comments as if I was describing the
individual code files the way I used to for doxygen, while for RST we
want to describe things in a more chapter/section way where there's no
obvious relation to .c files.
Additionally, several of the files had stub descriptions that I've
taken this opportunity to extend.
Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170227201144.10970-4-eric@anholt.net
diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index 93d5994..1be1e83 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"