hwmon: (adt7411) Improve locking

Add proper locking for the cached variables. Also get rid of
ref_is_vdd, which became obsolete.

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 14 insertions, 7 deletions

diff --git a/drivers/hwmon/adt7411.c b/drivers/hwmon/adt7411.c
index 9e9246fe2245..3471884e42d2 100644
--- a/drivers/hwmon/adt7411.c
+++ b/drivers/hwmon/adt7411.c
@@ -48,9 +48,9 @@ static const unsigned short normal_i2c[] = { 0x48, 0x4a, 0x4b, I2C_CLIENT_END };
 
 struct adt7411_data {
         struct mutex device_lock;       /* for "atomic" device accesses */
+        struct mutex update_lock;
         unsigned long next_update;
         int vref_cached;
-        bool ref_is_vdd;
         struct device *hwmon_dev;
 };
 
@@ -142,18 +142,18 @@ static ssize_t adt7411_show_input(struct device *dev,
         int val;
         u8 lsb_reg, lsb_shift;
 
+        mutex_lock(&data->update_lock);
         if (time_after_eq(jiffies, data->next_update)) {
                 val = i2c_smbus_read_byte_data(client, ADT7411_REG_CFG3);
                 if (val < 0)
-                        return val;
-                data->ref_is_vdd = val & ADT7411_CFG3_REF_VDD;
+                        goto exit_unlock;
 
-                if (data->ref_is_vdd) {
+                if (val & ADT7411_CFG3_REF_VDD) {
                         val = adt7411_read_10_bit(client,
                                         ADT7411_REG_INT_TEMP_VDD_LSB,
                                         ADT7411_REG_VDD_MSB, 2);
                         if (val < 0)
-                                return val;
+                                goto exit_unlock;
 
                         data->vref_cached = val * 7000 / 1024;
                 } else {
@@ -167,9 +167,13 @@ static ssize_t adt7411_show_input(struct device *dev,
         lsb_shift = 2 * (nr & 0x03);
         val = adt7411_read_10_bit(client, lsb_reg,
                         ADT7411_REG_EXT_TEMP_AIN1_MSB + nr, lsb_shift);
+        if (val < 0)
+                goto exit_unlock;
 
-        return val < 0 ? val :
-                        sprintf(buf, "%u\n", val * data->vref_cached / 1024);
+        val = sprintf(buf, "%u\n", val * data->vref_cached / 1024);
+ exit_unlock:
+        mutex_unlock(&data->update_lock);
+        return val;
 }
 
 static ssize_t adt7411_show_bit(struct device *dev,
@@ -199,7 +203,9 @@ static ssize_t adt7411_set_bit(struct device *dev,
         ret = adt7411_modify_bit(client, s_attr2->index, s_attr2->nr, flag);
 
         /* force update */
+        mutex_lock(&data->update_lock);
         data->next_update = jiffies;
+        mutex_unlock(&data->update_lock);
 
         return ret < 0 ? ret : count;
 }
@@ -282,6 +288,7 @@ static int __devinit adt7411_probe(struct i2c_client *client,
 
         i2c_set_clientdata(client, data);
         mutex_init(&data->device_lock);
+        mutex_init(&data->update_lock);
 
         ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
                                  ADT7411_CFG1_START_MONITOR, 1);