hwmon: (emc6w201) Properly handle all errors
Jean Delvare [Sun, 3 Jul 2011 11:32:53 +0000 (13:32 +0200)]
Handle errors on 8-bit register reads and writes too. Also use likely
and unlikely to make the functions faster on success.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

drivers/hwmon/emc6w201.c

index e0ef323..0064432 100644 (file)
@@ -78,8 +78,9 @@ static u16 emc6w201_read16(struct i2c_client *client, u8 reg)
 
        lsb = i2c_smbus_read_byte_data(client, reg);
        msb = i2c_smbus_read_byte_data(client, reg + 1);
-       if (lsb < 0 || msb < 0) {
-               dev_err(&client->dev, "16-bit read failed at 0x%02x\n", reg);
+       if (unlikely(lsb < 0 || msb < 0)) {
+               dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
+                       16, "read", reg);
                return 0xFFFF;  /* Arbitrary value */
        }
 
@@ -95,10 +96,39 @@ static int emc6w201_write16(struct i2c_client *client, u8 reg, u16 val)
        int err;
 
        err = i2c_smbus_write_byte_data(client, reg, val & 0xff);
-       if (!err)
+       if (likely(!err))
                err = i2c_smbus_write_byte_data(client, reg + 1, val >> 8);
-       if (err < 0)
-               dev_err(&client->dev, "16-bit write failed at 0x%02x\n", reg);
+       if (unlikely(err < 0))
+               dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
+                       16, "write", reg);
+
+       return err;
+}
+
+/* Read 8-bit value from register */
+static u8 emc6w201_read8(struct i2c_client *client, u8 reg)
+{
+       int val;
+
+       val = i2c_smbus_read_byte_data(client, reg);
+       if (unlikely(val < 0)) {
+               dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
+                       8, "read", reg);
+               return 0x00;    /* Arbitrary value */
+       }
+
+       return val;
+}
+
+/* Write 8-bit value to register */
+static int emc6w201_write8(struct i2c_client *client, u8 reg, u8 val)
+{
+       int err;
+
+       err = i2c_smbus_write_byte_data(client, reg, val);
+       if (unlikely(err < 0))
+               dev_err(&client->dev, "%d-bit %s failed at 0x%02x\n",
+                       8, "write", reg);
 
        return err;
 }
@@ -114,25 +144,25 @@ static struct emc6w201_data *emc6w201_update_device(struct device *dev)
        if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
                for (nr = 0; nr < 6; nr++) {
                        data->in[input][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_IN(nr));
                        data->in[min][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_IN_LOW(nr));
                        data->in[max][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_IN_HIGH(nr));
                }
 
                for (nr = 0; nr < 6; nr++) {
                        data->temp[input][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_TEMP(nr));
                        data->temp[min][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_TEMP_LOW(nr));
                        data->temp[max][nr] =
-                               i2c_smbus_read_byte_data(client,
+                               emc6w201_read8(client,
                                                EMC6W201_REG_TEMP_HIGH(nr));
                }
 
@@ -192,7 +222,7 @@ static ssize_t set_in(struct device *dev, struct device_attribute *devattr,
 
        mutex_lock(&data->update_lock);
        data->in[sf][nr] = SENSORS_LIMIT(val, 0, 255);
-       err = i2c_smbus_write_byte_data(client, reg, data->in[sf][nr]);
+       err = emc6w201_write8(client, reg, data->in[sf][nr]);
        mutex_unlock(&data->update_lock);
 
        return err < 0 ? err : count;
@@ -229,7 +259,7 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
 
        mutex_lock(&data->update_lock);
        data->temp[sf][nr] = SENSORS_LIMIT(val, -127, 128);
-       err = i2c_smbus_write_byte_data(client, reg, data->temp[sf][nr]);
+       err = emc6w201_write8(client, reg, data->temp[sf][nr]);
        mutex_unlock(&data->update_lock);
 
        return err < 0 ? err : count;
@@ -444,7 +474,7 @@ static int emc6w201_detect(struct i2c_client *client,
 
        /* Check configuration */
        config = i2c_smbus_read_byte_data(client, EMC6W201_REG_CONFIG);
-       if ((config & 0xF4) != 0x04)
+       if (config < 0 || (config & 0xF4) != 0x04)
                return -ENODEV;
        if (!(config & 0x01)) {
                dev_err(&client->dev, "Monitoring not enabled\n");