aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation/mmc
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/mmc')
-rw-r--r--Documentation/mmc/mmc-dev-attrs.txt10
-rw-r--r--Documentation/mmc/mmc-dev-parts.txt13
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.