Add NTSC composite output for the iPod Classic 6G/7G using the
S5L8702 video processor, mixer, and encoder. Reconstruct the setup used
by the original firmware and mirror the 320x240 LCD in a centered
648x432 viewport.
Expose the driver through HAVE_COMPOSITE_VIDEO_OUT and a
target-neutral videoout interface. Keep the S5L8702 MMIO layout and
register definitions with the other SoC definitions in s5l87xx.h.
Convert LCD updates from RGB565 to planar YUV420. MPEG playback copies
decoded YUV420 planes directly, avoiding an RGB round trip. Hold output
clocks and CPU boost only while the memory-backed layer is active, and
restore them on disable or power-off.
Defer dock identification out of the serial tick because the accessory
resistor ADC path sleeps. Auto detection recognizes the measured Philips
DCP750/37 resistor range; manual mode can qualify other attached docks.
Leave interrupts enabled during the encoder's 10 ms reset wait so PCM
DMA can service linked-buffer completions when a dock is inserted during
audio playback. Keep reset assertion, reset release, all SVID register
writes, and pipeline start atomic so the composite setup cannot
interleave.
Hardware tested on an iPod Classic 6G/7G with a Philips DCP750/37 for
correct colors and geometry, stable UI mirroring, and full-screen MPEG
playback.
Change-Id: I669f2477d5cc707b48f7d24384c713d874a80e3f
d2ae775f0a