mmc: bcm2835-sdhost: Support underclocking
authorPhil Elwell <phil@raspberrypi.org>
Mon, 22 Jan 2018 12:17:27 +0000 (12:17 +0000)
committerRaspbian kernel package updater <root@raspbian.org>
Sat, 31 Mar 2018 14:57:29 +0000 (15:57 +0100)
commite5f4d98cf8de121db0569bf059a52155b803f1bd
tree46d4ae5972b3d03bfc6991908006a261f3c0728a
parent8c385f36dcd5abdc4013b8191d65afb20ceaad85
mmc: bcm2835-sdhost: Support underclocking

Support underclocking of the SD bus in two ways:
1. using the max-frequency DT property (which currently has no DT
   parameter), and
2. using the exiting sd_overclock parameter.

The two methods differ slightly - in the former the MMC subsystem is
aware of the underclocking, while in the latter it isn't - but the
end results should be the same.

See: https://github.com/raspberrypi/linux/issues/2350

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
drivers/mmc/host/bcm2835-sdhost.c