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hwmon: (ds1621) Clean up register access 

Fix a few oddities in how the ds1621 driver accesses the registers:
* We don't need a wrapper to access the configuration register.
* Check for error before calling swab16. Error checking isn't
  complete yet, but that's a start.
* Device-specific read functions should never be called during
  detection, as by definition we don't know what device we are talking
  to at that point.
* Likewise, don't assume that register reads succeed during detection.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Jean Delvare 2009-03-30 21:46:40 +02:00
parent 9202add674
commit 594592dc6f
1 changed files with 24 additions and 24 deletions
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48
drivers/hwmon/ds1621.c
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@ -81,28 +81,27 @@ struct ds1621_data {
u8 conf; /* Register encoding, combined */
};
/* All registers are word-sized, except for the configuration register.
/* Temperature registers are word-sized.
DS1621 uses a high-byte first convention, which is exactly opposite to
the SMBus standard. */
static int ds1621_read_value(struct i2c_client *client, u8 reg)
static int ds1621_read_temp(struct i2c_client *client, u8 reg)
{
if (reg == DS1621_REG_CONF)
return i2c_smbus_read_byte_data(client, reg);
else
return swab16(i2c_smbus_read_word_data(client, reg));
int ret;
ret = i2c_smbus_read_word_data(client, reg);
if (ret < 0)
return ret;
return swab16(ret);
}
static int ds1621_write_value(struct i2c_client *client, u8 reg, u16 value)
static int ds1621_write_temp(struct i2c_client *client, u8 reg, u16 value)
{
if (reg == DS1621_REG_CONF)
return i2c_smbus_write_byte_data(client, reg, value);
else
return i2c_smbus_write_word_data(client, reg, swab16(value));
return i2c_smbus_write_word_data(client, reg, swab16(value));
}
static void ds1621_init_client(struct i2c_client *client)
{
int reg = ds1621_read_value(client, DS1621_REG_CONF);
int reg = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
/* switch to continuous conversion mode */
reg &= ~ DS1621_REG_CONFIG_1SHOT;
@ -112,7 +111,7 @@ static void ds1621_init_client(struct i2c_client *client)
else if (polarity == 1)
reg |= DS1621_REG_CONFIG_POLARITY;
ds1621_write_value(client, DS1621_REG_CONF, reg);
i2c_smbus_write_byte_data(client, DS1621_REG_CONF, reg);
/* start conversion */
i2c_smbus_write_byte(client, DS1621_COM_START);
@ -132,11 +131,11 @@ static struct ds1621_data *ds1621_update_client(struct device *dev)
dev_dbg(&client->dev, "Starting ds1621 update\n");
data->conf = ds1621_read_value(client, DS1621_REG_CONF);
data->conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
for (i = 0; i < ARRAY_SIZE(data->temp); i++)
data->temp[i] = ds1621_read_value(client,
DS1621_REG_TEMP[i]);
data->temp[i] = ds1621_read_temp(client,
DS1621_REG_TEMP[i]);
/* reset alarms if necessary */
new_conf = data->conf;
@ -145,8 +144,8 @@ static struct ds1621_data *ds1621_update_client(struct device *dev)
if (data->temp[0] < data->temp[2]) /* input < max */
new_conf &= ~DS1621_ALARM_TEMP_HIGH;
if (data->conf != new_conf)
ds1621_write_value(client, DS1621_REG_CONF,
new_conf);
i2c_smbus_write_byte_data(client, DS1621_REG_CONF,
new_conf);
data->last_updated = jiffies;
data->valid = 1;
@ -176,8 +175,8 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *da,
mutex_lock(&data->update_lock);
data->temp[attr->index] = val;
ds1621_write_value(client, DS1621_REG_TEMP[attr->index],
data->temp[attr->index]);
ds1621_write_temp(client, DS1621_REG_TEMP[attr->index],
data->temp[attr->index]);
mutex_unlock(&data->update_lock);
return count;
}
@ -239,13 +238,14 @@ static int ds1621_detect(struct i2c_client *client, int kind,
/* The NVB bit should be low if no EEPROM write has been
requested during the latest 10ms, which is highly
improbable in our case. */
conf = ds1621_read_value(client, DS1621_REG_CONF);
if (conf & DS1621_REG_CONFIG_NVB)
conf = i2c_smbus_read_byte_data(client, DS1621_REG_CONF);
if (conf < 0 || conf & DS1621_REG_CONFIG_NVB)
return -ENODEV;
/* The 7 lowest bits of a temperature should always be 0. */
for (i = 0; i < ARRAY_SIZE(DS1621_REG_TEMP); i++) {
temp = ds1621_read_value(client, DS1621_REG_TEMP[i]);
if (temp & 0x007f)
temp = i2c_smbus_read_word_data(client,
DS1621_REG_TEMP[i]);
if (temp < 0 || (temp & 0x7f00))
return -ENODEV;
}
}