[PATCH] hwmon: Separate the lm90 register read function

Preparatory patch to add PEC support to the lm90 driver. We need a
centralized function to read register values, where the PEC code will
be later inserted. A positive side effect is that read errors are now
handled properly.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index dad0f10..5acc12a 100644 (file)
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -349,6 +349,22 @@ static DEVICE_ATTR(alarms, S_IRUGO, show_alarms, NULL);
  * Real code
  */
 
+static int lm90_read_reg(struct i2c_client* client, u8 reg, u8 *value)
+{
+       int err;
+
+       err = i2c_smbus_read_byte_data(client, reg);
+
+       if (err < 0) {
+               dev_warn(&client->dev, "Register %#02x read failed (%d)\n",
+                        reg, err);
+               return err;
+       }
+       *value = err;
+
+       return 0;
+}
+
 static int lm90_attach_adapter(struct i2c_adapter *adapter)
 {
        if (!(adapter->class & I2C_CLASS_HWMON))
@@ -402,20 +418,22 @@ static int lm90_detect(struct i2c_adapter *adapter, int address, int kind)
        if (kind < 0) { /* detection and identification */
                u8 man_id, chip_id, reg_config1, reg_convrate;
 
-               man_id = i2c_smbus_read_byte_data(new_client,
-                        LM90_REG_R_MAN_ID);
-               chip_id = i2c_smbus_read_byte_data(new_client,
-                         LM90_REG_R_CHIP_ID);
-               reg_config1 = i2c_smbus_read_byte_data(new_client,
-                             LM90_REG_R_CONFIG1);
-               reg_convrate = i2c_smbus_read_byte_data(new_client,
-                              LM90_REG_R_CONVRATE);
+               if (lm90_read_reg(new_client, LM90_REG_R_MAN_ID,
+                                 &man_id) < 0
+                || lm90_read_reg(new_client, LM90_REG_R_CHIP_ID,
+                                 &chip_id) < 0
+                || lm90_read_reg(new_client, LM90_REG_R_CONFIG1,
+                                 &reg_config1) < 0
+                || lm90_read_reg(new_client, LM90_REG_R_CONVRATE,
+                                 &reg_convrate) < 0)
+                       goto exit_free;
                
                if (man_id == 0x01) { /* National Semiconductor */
                        u8 reg_config2;
 
-                       reg_config2 = i2c_smbus_read_byte_data(new_client,
-                                     LM90_REG_R_CONFIG2);
+                       if (lm90_read_reg(new_client, LM90_REG_R_CONFIG2,
+                                         &reg_config2) < 0)
+                               goto exit_free;
 
                        if ((reg_config1 & 0x2A) == 0x00
                         && (reg_config2 & 0xF8) == 0x00
@@ -547,7 +565,10 @@ static void lm90_init_client(struct i2c_client *client)
         */
        i2c_smbus_write_byte_data(client, LM90_REG_W_CONVRATE,
                                  5); /* 2 Hz */
-       config = i2c_smbus_read_byte_data(client, LM90_REG_R_CONFIG1);
+       if (lm90_read_reg(client, LM90_REG_R_CONFIG1, &config) < 0) {
+               dev_warn(&client->dev, "Initialization failed!\n");
+               return;
+       }
        if (config & 0x40)
                i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
                                          config & 0xBF); /* run */
@@ -575,21 +596,15 @@ static struct lm90_data *lm90_update_device(struct device *dev)
        down(&data->update_lock);
 
        if (time_after(jiffies, data->last_updated + HZ * 2) || !data->valid) {
-               u8 oldh, newh;
+               u8 oldh, newh, l;
 
                dev_dbg(&client->dev, "Updating lm90 data.\n");
-               data->temp8[0] = i2c_smbus_read_byte_data(client,
-                                LM90_REG_R_LOCAL_TEMP);
-               data->temp8[1] = i2c_smbus_read_byte_data(client,
-                                LM90_REG_R_LOCAL_LOW);
-               data->temp8[2] = i2c_smbus_read_byte_data(client,
-                                LM90_REG_R_LOCAL_HIGH);
-               data->temp8[3] = i2c_smbus_read_byte_data(client,
-                                LM90_REG_R_LOCAL_CRIT);
-               data->temp8[4] = i2c_smbus_read_byte_data(client,
-                                LM90_REG_R_REMOTE_CRIT);
-               data->temp_hyst = i2c_smbus_read_byte_data(client,
-                                 LM90_REG_R_TCRIT_HYST);
+               lm90_read_reg(client, LM90_REG_R_LOCAL_TEMP, &data->temp8[0]);
+               lm90_read_reg(client, LM90_REG_R_LOCAL_LOW, &data->temp8[1]);
+               lm90_read_reg(client, LM90_REG_R_LOCAL_HIGH, &data->temp8[2]);
+               lm90_read_reg(client, LM90_REG_R_LOCAL_CRIT, &data->temp8[3]);
+               lm90_read_reg(client, LM90_REG_R_REMOTE_CRIT, &data->temp8[4]);
+               lm90_read_reg(client, LM90_REG_R_TCRIT_HYST, &data->temp_hyst);
 
                /*
                 * There is a trick here. We have to read two registers to
@@ -605,36 +620,20 @@ static struct lm90_data *lm90_update_device(struct device *dev)
                 * then we have a valid reading. Else we have to read the low
                 * byte again, and now we believe we have a correct reading.
                 */
-               oldh = i2c_smbus_read_byte_data(client,
-                      LM90_REG_R_REMOTE_TEMPH);
-               data->temp11[0] = i2c_smbus_read_byte_data(client,
-                                 LM90_REG_R_REMOTE_TEMPL);
-               newh = i2c_smbus_read_byte_data(client,
-                      LM90_REG_R_REMOTE_TEMPH);
-               if (newh != oldh) {
-                       data->temp11[0] = i2c_smbus_read_byte_data(client,
-                                         LM90_REG_R_REMOTE_TEMPL);
-#ifdef DEBUG
-                       oldh = i2c_smbus_read_byte_data(client,
-                              LM90_REG_R_REMOTE_TEMPH);
-                       /* oldh is actually newer */
-                       if (newh != oldh)
-                               dev_warn(&client->dev, "Remote temperature may be "
-                                        "wrong.\n");
-#endif
-               }
-               data->temp11[0] |= (newh << 8);
-
-               data->temp11[1] = (i2c_smbus_read_byte_data(client,
-                                  LM90_REG_R_REMOTE_LOWH) << 8) +
-                                  i2c_smbus_read_byte_data(client,
-                                  LM90_REG_R_REMOTE_LOWL);
-               data->temp11[2] = (i2c_smbus_read_byte_data(client,
-                                  LM90_REG_R_REMOTE_HIGHH) << 8) +
-                                  i2c_smbus_read_byte_data(client,
-                                  LM90_REG_R_REMOTE_HIGHL);
-               data->alarms = i2c_smbus_read_byte_data(client,
-                              LM90_REG_R_STATUS);
+               if (lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &oldh) == 0
+                && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0
+                && lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPH, &newh) == 0
+                && (newh == oldh
+                 || lm90_read_reg(client, LM90_REG_R_REMOTE_TEMPL, &l) == 0))
+                       data->temp11[0] = (newh << 8) | l;
+
+               if (lm90_read_reg(client, LM90_REG_R_REMOTE_LOWH, &newh) == 0
+                && lm90_read_reg(client, LM90_REG_R_REMOTE_LOWL, &l) == 0)
+                       data->temp11[1] = (newh << 8) | l;
+               if (lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHH, &newh) == 0
+                && lm90_read_reg(client, LM90_REG_R_REMOTE_HIGHL, &l) == 0)
+                       data->temp11[2] = (newh << 8) | l;
+               lm90_read_reg(client, LM90_REG_R_STATUS, &data->alarms);
 
                data->last_updated = jiffies;
                data->valid = 1;