1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index da6c9306ca5f..b7a442a80bde 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -74,6 +74,7 @@ I2C_CLIENT_INSMOD_1(adt7470);
 #define ADT7470_REG_PWM12_CFG                   0x68
 #define         ADT7470_PWM2_AUTO_MASK          0x40
 #define         ADT7470_PWM1_AUTO_MASK          0x80
+#define         ADT7470_PWM_AUTO_MASK           0xC0
 #define ADT7470_REG_PWM34_CFG                   0x69
 #define         ADT7470_PWM3_AUTO_MASK          0x40
 #define         ADT7470_PWM4_AUTO_MASK          0x80
@@ -223,7 +224,7 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
         struct i2c_client *client = to_i2c_client(dev);
         struct adt7470_data *data = i2c_get_clientdata(client);
         unsigned long local_jiffies = jiffies;
-        u8 cfg;
+        u8 cfg, pwm[4], pwm_cfg[2];
         int i;
 
         mutex_lock(&data->lock);
@@ -232,6 +233,24 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
                 && data->sensors_valid)
                 goto no_sensor_update;
 
+        /* save pwm[1-4] config register */
+        pwm_cfg[0] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM_CFG(0));
+        pwm_cfg[1] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM_CFG(2));
+
+        /* set manual pwm to whatever it is set to now */
+        for (i = 0; i < ADT7470_FAN_COUNT; i++)
+                pwm[i] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM(i));
+
+        /* put pwm in manual mode */
+        i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(0),
+                pwm_cfg[0] & ~(ADT7470_PWM_AUTO_MASK));
+        i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(2),
+                pwm_cfg[1] & ~(ADT7470_PWM_AUTO_MASK));
+
+        /* write pwm control to whatever it was */
+        for (i = 0; i < ADT7470_FAN_COUNT; i++)
+                i2c_smbus_write_byte_data(client, ADT7470_REG_PWM(i), pwm[i]);
+
         /* start reading temperature sensors */
         cfg = i2c_smbus_read_byte_data(client, ADT7470_REG_CFG);
         cfg |= 0x80;
@@ -249,6 +268,10 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
         cfg &= ~0x80;
         i2c_smbus_write_byte_data(client, ADT7470_REG_CFG, cfg);
 
+        /* restore pwm[1-4] config registers */
+        i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(0), pwm_cfg[0]);
+        i2c_smbus_write_byte_data(client, ADT7470_REG_PWM_CFG(2), pwm_cfg[1]);
+
         for (i = 0; i < ADT7470_TEMP_COUNT; i++)
                 data->temp[i] = i2c_smbus_read_byte_data(client,
                                                 ADT7470_TEMP_REG(i));