mmc: add a file to debugfs for changing host clock at runtime
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>
1 file changed