For debugging power management features it is convenient to have the
possibility of changing the MMC host controller clock at runtime. This
patch adds a 'clock' file for this under the MMC host root of debugfs.
Usage is as follows:
# cat /sys/kernel/debug/mmc0/clock
52000000
# echo "1000000000" > /sys/kernel/debug/mmc0/clock
# cat /sys/kernel/debug/mmc0/clock
52000000
# echo "48000000" > /sys/kernel/debug/mmc0/clock
# cat /sys/kernel/debug/mmc0/clock
48000000
The middle example shows limits being applied by the host driver.
Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com>
Cc: Adrian Hunter <adrian.hunter@nokia.com>
[cjb: modify changelog language]
Signed-off-by: Chris Ball <cjb@laptop.org>
703aae3d09