[PATCH 3.14 16/66] hwmon: (adm1031) Fix writes to limit registers

Greg Kroah-Hartman
2014-07-16T00:04:32Z

From: Guenter Roeck <linux@roeck-us.net>

commit 145e74a4e5022225adb84f4e5d4fff7938475c35 upstream.

Upper limit for write operations to temperature limit registers
was clamped to a fractional value. However, limit registers do
not support fractional values. As a result, upper limits of 127.5
degrees C or higher resulted in a rounded limit of 128 degrees C.
Since limit registers are signed, this was stored as -128 degrees C.
Clamp limits to (-55, +127) degrees C to solve the problem.

Value on writes to auto_temp[12]_min and auto_temp[12]_max were not
clamped at all, but masked. As a result, out-of-range writes resulted
in a more or less arbitrary limit. Clamp those attributes to (0, 127)
degrees C for more predictable results.

Cc: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/hwmon/adm1031.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

--- a/drivers/hwmon/adm1031.c
+++ b/drivers/hwmon/adm1031.c
@@ -365,6 +365,7 @@ set_auto_temp_min(struct device *dev, st
if (ret)
return ret;

+ val = clamp_val(val, 0, 127000);
mutex_lock(&data->update_lock);
data->auto_temp[nr] = AUTO_TEMP_MIN_TO_REG(val, data->auto_temp[nr]);
adm1031_write_value(client, ADM1031_REG_AUTO_TEMP(nr),
@@ -394,6 +395,7 @@ set_auto_temp_max(struct device *dev, st
if (ret)
return ret;

+ val = clamp_val(val, 0, 127000);
mutex_lock(&data->update_lock);
data->temp_max[nr] = AUTO_TEMP_MAX_TO_REG(val, data->auto_temp[nr],
data->pwm[nr]);
@@ -696,7 +698,7 @@ static ssize_t set_temp_min(struct devic
if (ret)
return ret;

- val = clamp_val(val, -55000, nr == 0 ? 127750 : 127875);
+ val = clamp_val(val, -55000, 127000);
mutex_lock(&data->update_lock);
data->temp_min[nr] = TEMP_TO_REG(val);
adm1031_write_value(client, ADM1031_REG_TEMP_MIN(nr),
@@ -717,7 +719,7 @@ static ssize_t set_temp_max(struct devic
if (ret)
return ret;

- val = clamp_val(val, -55000, nr == 0 ? 127750 : 127875);
+ val = clamp_val(val, -55000, 127000);
mutex_lock(&data->update_lock);
data->temp_max[nr] = TEMP_TO_REG(val);
adm1031_write_value(client, ADM1031_REG_TEMP_MAX(nr),
@@ -738,7 +740,7 @@ static ssize_t set_temp_crit(struct devi
if (ret)
return ret;

- val = clamp_val(val, -55000, nr == 0 ? 127750 : 127875);
+ val = clamp_val(val, -55000, 127000);
mutex_lock(&data->update_lock);
data->temp_crit[nr] = TEMP_TO_REG(val);
adm1031_write_value(client, ADM1031_REG_TEMP_CRIT(nr),