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authorClemens Ladisch <clemens@ladisch.de>2011-02-16 08:02:38 -0500
committerGuenter Roeck <guenter.roeck@ericsson.com>2011-02-16 08:18:33 -0800
commit2c6315da6a1657a49e03970a4084dc3d1958ad70 (patch)
treee2b8f4639578e4f81e9371778c6f45faabe3c87e /Documentation
parentd5622f5b6c4671d1588ccc9056705366d4eb312a (diff)
downloadlinux-linaro-android-2c6315da6a1657a49e03970a4084dc3d1958ad70.tar.gz
hwmon: (jc42) do not allow writing to locked registers
On systems where the temperature sensor is actually used, the BIOS is likely to have locked the alarm registers. In that case, all writes through the corresponding sysfs files would be silently ignored. To prevent this, detect the locks and make the affected sysfs files read-only. Signed-off-by: Clemens Ladisch <clemens@ladisch.de> Cc: stable@kernel.org Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/hwmon/jc4212
1 files changed, 8 insertions, 4 deletions
diff --git a/Documentation/hwmon/jc42 b/Documentation/hwmon/jc42
index 2a0924003f9..a22ecf48f25 100644
--- a/Documentation/hwmon/jc42
+++ b/Documentation/hwmon/jc42
@@ -86,15 +86,19 @@ limits. The chip supports only a single register to configure the hysteresis,
which applies to all limits. This register can be written by writing into
temp1_crit_hyst. Other hysteresis attributes are read-only.
+If the BIOS has configured the sensor for automatic temperature management, it
+is likely that it has locked the registers, i.e., that the temperature limits
+cannot be changed.
+
Sysfs entries
-------------
temp1_input Temperature (RO)
-temp1_min Minimum temperature (RW)
-temp1_max Maximum temperature (RW)
-temp1_crit Critical high temperature (RW)
+temp1_min Minimum temperature (RO or RW)
+temp1_max Maximum temperature (RO or RW)
+temp1_crit Critical high temperature (RO or RW)
-temp1_crit_hyst Critical hysteresis temperature (RW)
+temp1_crit_hyst Critical hysteresis temperature (RO or RW)
temp1_max_hyst Maximum hysteresis temperature (RO)
temp1_min_alarm Temperature low alarm