Commit 594592dc authored by Jean Delvare's avatar Jean Delvare
Browse files

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: default avatarJean Delvare <khali@linux-fr.org>
Cc: Aurelien Jarno <aurelien@aurel32.net>
parent 9202add6

drivers/hwmon/ds1621.c

+24 −24
Original line number Diff line number Diff line
@@ -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));

}



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);
@@ -132,10 +131,10 @@ 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,

			data->temp[i] = ds1621_read_temp(client,

							 DS1621_REG_TEMP[i]);



		/* reset alarms if necessary */
@@ -145,7 +144,7 @@ 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,

			i2c_smbus_write_byte_data(client, DS1621_REG_CONF,

						  new_conf);



		data->last_updated = jiffies;
@@ -176,7 +175,7 @@ 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],

	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;

		}

	}

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