diff options
Diffstat (limited to 'Documentation/mmc')
| -rw-r--r-- | Documentation/mmc/mmc-dev-attrs.txt | 10 | ||||
| -rw-r--r-- | Documentation/mmc/mmc-dev-parts.txt | 13 |
2 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/mmc/mmc-dev-attrs.txt b/Documentation/mmc/mmc-dev-attrs.txt index 8898a95b41e..22ae8441489 100644 --- a/Documentation/mmc/mmc-dev-attrs.txt +++ b/Documentation/mmc/mmc-dev-attrs.txt @@ -64,3 +64,13 @@ Note on Erase Size and Preferred Erase Size: size specified by the card. "preferred_erase_size" is in bytes. + +SD/MMC/SDIO Clock Gating Attribute +================================== + +Read and write access is provided to following attribute. +This attribute appears only if CONFIG_MMC_CLKGATE is enabled. + + clkgate_delay Tune the clock gating delay with desired value in milliseconds. + +echo <desired delay> > /sys/class/mmc_host/mmcX/clkgate_delay diff --git a/Documentation/mmc/mmc-dev-parts.txt b/Documentation/mmc/mmc-dev-parts.txt index 2db28b8e662..f08d078d43c 100644 --- a/Documentation/mmc/mmc-dev-parts.txt +++ b/Documentation/mmc/mmc-dev-parts.txt @@ -25,3 +25,16 @@ echo 0 > /sys/block/mmcblkXbootY/force_ro To re-enable read-only access: echo 1 > /sys/block/mmcblkXbootY/force_ro + +The boot partitions can also be locked read only until the next power on, +with: + +echo 1 > /sys/block/mmcblkXbootY/ro_lock_until_next_power_on + +This is a feature of the card and not of the kernel. If the card does +not support boot partition locking, the file will not exist. If the +feature has been disabled on the card, the file will be read-only. + +The boot partitions can also be locked permanently, but this feature is +not accessible through sysfs in order to avoid accidental or malicious +bricking. |