From: Jean Delvare Date: Mon, 30 Mar 2009 19:46:40 +0000 (+0200) Subject: hwmon: (ds1621) Clean up register access X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=594592dc6f68356a3b7278eb4d260a50a66f0a06;p=linux-2.6-omap-h63xx.git 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 Cc: Aurelien Jarno --- diff --git a/drivers/hwmon/ds1621.c b/drivers/hwmon/ds1621.c index e688798e115..fe160c54b95 100644 --- a/drivers/hwmon/ds1621.c +++ b/drivers/hwmon/ds1621.c @@ -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; } }