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authorGuenter Roeck <linux@roeck-us.net>2014-02-22 17:17:34 +0100
committerGuenter Roeck <linux@roeck-us.net>2014-03-03 17:01:06 +0100
commita41a8927e7adfa5de607d5bd43fa8fbbef44d6f2 (patch)
tree04582a857933f67aacc261595530049f51a64634
parenthwmon: (lm95245) Convert to use devm_hwmon_device_register_with_groups (diff)
downloadlinux-a41a8927e7adfa5de607d5bd43fa8fbbef44d6f2.tar.xz
linux-a41a8927e7adfa5de607d5bd43fa8fbbef44d6f2.zip
hwmon: (lm95245) Make temp2_crit_hyst read-only
The hysteresis register is shared among both temperature sensors. This means changing one also affects the other. To avoid confusion, established way to express this is to make only the first instance writable and keep all other instances as read-only. Otherwise users may be confused that changing the second writable value also affects the first, while it is more obvious that a writable value may affect a different read-only value. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Jean Delvare <jdelvare@suse.de>
-rw-r--r--Documentation/hwmon/lm952458
-rw-r--r--drivers/hwmon/lm95245.c3
2 files changed, 7 insertions, 4 deletions
diff --git a/Documentation/hwmon/lm95245 b/Documentation/hwmon/lm95245
index cbd8aeab7124..77eaf2812d25 100644
--- a/Documentation/hwmon/lm95245
+++ b/Documentation/hwmon/lm95245
@@ -24,8 +24,12 @@ is given within a range of -127 to +127.875 degrees. Remote temperatures are
given within a range of -127 to +255 degrees. Resolution depends on
temperature input and range.
-Each sensor has its own critical limit, but the hysteresis is common to all
-two channels.
+Each sensor has its own critical limit. Additionally, there is a relative
+hysteresis value common to both critical limits. To make life easier to
+user-space applications, two absolute values are exported, one for each
+channel, but these values are of course linked. Only the local hysteresis
+can be set from user-space, and the same delta applies to the remote
+hysteresis.
The lm95245 driver can change its update interval to a fixed set of values.
It will round up to the next selectable interval. See the datasheet for exact
diff --git a/drivers/hwmon/lm95245.c b/drivers/hwmon/lm95245.c
index acf36794e7e3..0ae0dfdafdff 100644
--- a/drivers/hwmon/lm95245.c
+++ b/drivers/hwmon/lm95245.c
@@ -395,8 +395,7 @@ static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL,
static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_input, NULL, 2);
static SENSOR_DEVICE_ATTR(temp2_crit, S_IWUSR | S_IRUGO, show_limit,
set_limit, 7);
-static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IWUSR | S_IRUGO, show_crit_hyst,
- set_crit_hyst, 7);
+static SENSOR_DEVICE_ATTR(temp2_crit_hyst, S_IRUGO, show_crit_hyst, NULL, 7);
static SENSOR_DEVICE_ATTR(temp2_crit_alarm, S_IRUGO, show_alarm, NULL,
STATUS1_RTCRIT);
static SENSOR_DEVICE_ATTR(temp2_type, S_IWUSR | S_IRUGO, show_type,