Patchwork [RESEND,v4] hwmon: (lm90) split set&show temp as common codes

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Submitter lightning314
Date Aug. 6, 2013, 10:36 a.m.
Message ID <1375785417-13650-1-git-send-email-wni@nvidia.com>
Download mbox | patch
Permalink /patch/264990/
State Not Applicable, archived
Headers show

Comments

lightning314 - Aug. 6, 2013, 10:36 a.m.
Split set&show temp codes as common functions, so we can use it
directly when implement linux thermal framework.
And handle error return value for the lm90_select_remote_channel
and write_tempx, then set_temp8 and set_temp11 could return it
to user-space.

Signed-off-by: Wei Ni <wni@nvidia.com>
---
 drivers/hwmon/lm90.c |  150 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 99 insertions(+), 51 deletions(-)
lightning314 - Aug. 6, 2013, 10:43 a.m.
This patch is separated from my previous v3 series, which is in
http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg466772.html

Changes from v3:
1. Add error handler for lm90_select_remote_channel(), set_temp8(), and
set_temp11().

Wei.

On 08/06/2013 06:36 PM, Wei Ni wrote:
> Split set&show temp codes as common functions, so we can use it
> directly when implement linux thermal framework.
> And handle error return value for the lm90_select_remote_channel
> and write_tempx, then set_temp8 and set_temp11 could return it
> to user-space.
> 
> Signed-off-by: Wei Ni <wni@nvidia.com>
> ---
>  drivers/hwmon/lm90.c |  150 +++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 99 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> index cdff742..6de8e01 100644
> --- a/drivers/hwmon/lm90.c
> +++ b/drivers/hwmon/lm90.c
> @@ -422,20 +422,29 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
>   * various registers have different meanings as a result of selecting a
>   * non-default remote channel.
>   */
> -static inline void lm90_select_remote_channel(struct i2c_client *client,
> +static inline int lm90_select_remote_channel(struct i2c_client *client,
>  					      struct lm90_data *data,
>  					      int channel)
>  {
>  	u8 config;
> +	int err = 0;
>  
>  	if (data->kind == max6696) {
>  		lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
>  		config &= ~0x08;
>  		if (channel)
>  			config |= 0x08;
> -		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> -					  config);
> +		err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> +						config);
> +		if (err < 0) {
> +			dev_err(&client->dev,
> +				"Failed to select remote channel %d, err %d\n",
> +				channel, err);
> +			return err;
> +		}
>  	}
> +
> +	return err;
>  }
>  
>  /*
> @@ -702,29 +711,34 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
>   * Sysfs stuff
>   */
>  
> -static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> -			  char *buf)
> +static int read_temp8(struct device *dev, int index)
>  {
> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>  	struct lm90_data *data = lm90_update_device(dev);
>  	int temp;
>  
>  	if (data->kind == adt7461)
> -		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
> +		temp = temp_from_u8_adt7461(data, data->temp8[index]);
>  	else if (data->kind == max6646)
> -		temp = temp_from_u8(data->temp8[attr->index]);
> +		temp = temp_from_u8(data->temp8[index]);
>  	else
> -		temp = temp_from_s8(data->temp8[attr->index]);
> +		temp = temp_from_s8(data->temp8[index]);
>  
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 && attr->index == 3)
> +	if (data->kind == lm99 && index == 3)
>  		temp += 16000;
>  
> -	return sprintf(buf, "%d\n", temp);
> +	return temp;
>  }
>  
> -static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> -			 const char *buf, size_t count)
> +static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> +			  char *buf)
> +{
> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +
> +	return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
> +}
> +
> +static int write_temp8(struct device *dev, int index, long val)
>  {
>  	static const u8 reg[8] = {
>  		LM90_REG_W_LOCAL_LOW,
> @@ -737,60 +751,79 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>  		MAX6659_REG_W_REMOTE_EMERG,
>  	};
>  
> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct lm90_data *data = i2c_get_clientdata(client);
> -	int nr = attr->index;
> -	long val;
>  	int err;
>  
> -	err = kstrtol(buf, 10, &val);
> -	if (err < 0)
> -		return err;
> -
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 && attr->index == 3)
> +	if (data->kind == lm99 && index == 3)
>  		val -= 16000;
>  
>  	mutex_lock(&data->update_lock);
>  	if (data->kind == adt7461)
> -		data->temp8[nr] = temp_to_u8_adt7461(data, val);
> +		data->temp8[index] = temp_to_u8_adt7461(data, val);
>  	else if (data->kind == max6646)
> -		data->temp8[nr] = temp_to_u8(val);
> +		data->temp8[index] = temp_to_u8(val);
>  	else
> -		data->temp8[nr] = temp_to_s8(val);
> -
> -	lm90_select_remote_channel(client, data, nr >= 6);
> -	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
> -	lm90_select_remote_channel(client, data, 0);
> +		data->temp8[index] = temp_to_s8(val);
>  
> +	err = lm90_select_remote_channel(client, data, index >= 6);
> +	err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
> +	err |= lm90_select_remote_channel(client, data, 0);
> +	if (err)
> +		dev_err(dev, "write_temp8 failed!\n");
>  	mutex_unlock(&data->update_lock);
> +
> +	return err;
> +}
> +
> +static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> +			 const char *buf, size_t count)
> +{
> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +	int index = attr->index;
> +	long val;
> +	int err;
> +
> +	err = kstrtol(buf, 10, &val);
> +	if (err < 0)
> +		return err;
> +
> +	err = write_temp8(dev, index, val);
> +	if (err < 0)
> +		return err;
> +
>  	return count;
>  }
>  
> -static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> -			   char *buf)
> +static int read_temp11(struct device *dev, int index)
>  {
> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>  	struct lm90_data *data = lm90_update_device(dev);
>  	int temp;
>  
>  	if (data->kind == adt7461)
> -		temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
> +		temp = temp_from_u16_adt7461(data, data->temp11[index]);
>  	else if (data->kind == max6646)
> -		temp = temp_from_u16(data->temp11[attr->index]);
> +		temp = temp_from_u16(data->temp11[index]);
>  	else
> -		temp = temp_from_s16(data->temp11[attr->index]);
> +		temp = temp_from_s16(data->temp11[index]);
>  
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 &&  attr->index <= 2)
> +	if (data->kind == lm99 && index <= 2)
>  		temp += 16000;
>  
> -	return sprintf(buf, "%d\n", temp);
> +	return temp;
>  }
>  
> -static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> -			  const char *buf, size_t count)
> +static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> +			   char *buf)
> +{
> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> +
> +	return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
> +}
> +
> +static int write_temp11(struct device *dev, int nr, int index, long val)
>  {
>  	struct {
>  		u8 high;
> @@ -804,18 +837,10 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>  		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
>  	};
>  
> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct lm90_data *data = i2c_get_clientdata(client);
> -	int nr = attr->nr;
> -	int index = attr->index;
> -	long val;
>  	int err;
>  
> -	err = kstrtol(buf, 10, &val);
> -	if (err < 0)
> -		return err;
> -
>  	/* +16 degrees offset for temp2 for the LM99 */
>  	if (data->kind == lm99 && index <= 2)
>  		val -= 16000;
> @@ -830,15 +855,38 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>  	else
>  		data->temp11[index] = temp_to_s8(val) << 8;
>  
> -	lm90_select_remote_channel(client, data, reg[nr].channel);
> -	i2c_smbus_write_byte_data(client, reg[nr].high,
> +	err = lm90_select_remote_channel(client, data, reg[nr].channel);
> +	err |= i2c_smbus_write_byte_data(client, reg[nr].high,
>  				  data->temp11[index] >> 8);
>  	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
> -		i2c_smbus_write_byte_data(client, reg[nr].low,
> -					  data->temp11[index] & 0xff);
> -	lm90_select_remote_channel(client, data, 0);
> +		err |= i2c_smbus_write_byte_data(client, reg[nr].low,
> +						data->temp11[index] & 0xff);
> +	err |= lm90_select_remote_channel(client, data, 0);
> +	if (err)
> +		dev_err(dev, "write_temp11 failed !\n");
>  
>  	mutex_unlock(&data->update_lock);
> +
> +	return err;
> +}
> +
> +static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> +			  const char *buf, size_t count)
> +{
> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> +	int nr = attr->nr;
> +	int index = attr->index;
> +	long val;
> +	int err;
> +
> +	err = kstrtol(buf, 10, &val);
> +	if (err < 0)
> +		return err;
> +
> +	err = write_temp11(dev, nr, index, val);
> +	if (err < 0)
> +		return err;
> +
>  	return count;
>  }
>  
> 

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lightning314 - Sept. 9, 2013, 6:15 a.m.
Hi, Jean
Do you have any more suggestions on this patch ?

Thanks.
Wei.

On 08/06/2013 06:43 PM, Wei Ni wrote:
> This patch is separated from my previous v3 series, which is in
> http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg466772.html
> 
> Changes from v3:
> 1. Add error handler for lm90_select_remote_channel(), set_temp8(), and
> set_temp11().
> 
> Wei.
> 
> On 08/06/2013 06:36 PM, Wei Ni wrote:
>> Split set&show temp codes as common functions, so we can use it
>> directly when implement linux thermal framework.
>> And handle error return value for the lm90_select_remote_channel
>> and write_tempx, then set_temp8 and set_temp11 could return it
>> to user-space.
>>
>> Signed-off-by: Wei Ni <wni@nvidia.com>
>> ---
>>  drivers/hwmon/lm90.c |  150 +++++++++++++++++++++++++++++++++-----------------
>>  1 file changed, 99 insertions(+), 51 deletions(-)
>>
>> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
>> index cdff742..6de8e01 100644
>> --- a/drivers/hwmon/lm90.c
>> +++ b/drivers/hwmon/lm90.c
>> @@ -422,20 +422,29 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
>>   * various registers have different meanings as a result of selecting a
>>   * non-default remote channel.
>>   */
>> -static inline void lm90_select_remote_channel(struct i2c_client *client,
>> +static inline int lm90_select_remote_channel(struct i2c_client *client,
>>  					      struct lm90_data *data,
>>  					      int channel)
>>  {
>>  	u8 config;
>> +	int err = 0;
>>  
>>  	if (data->kind == max6696) {
>>  		lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
>>  		config &= ~0x08;
>>  		if (channel)
>>  			config |= 0x08;
>> -		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
>> -					  config);
>> +		err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
>> +						config);
>> +		if (err < 0) {
>> +			dev_err(&client->dev,
>> +				"Failed to select remote channel %d, err %d\n",
>> +				channel, err);
>> +			return err;
>> +		}
>>  	}
>> +
>> +	return err;
>>  }
>>  
>>  /*
>> @@ -702,29 +711,34 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
>>   * Sysfs stuff
>>   */
>>  
>> -static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
>> -			  char *buf)
>> +static int read_temp8(struct device *dev, int index)
>>  {
>> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>>  	struct lm90_data *data = lm90_update_device(dev);
>>  	int temp;
>>  
>>  	if (data->kind == adt7461)
>> -		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
>> +		temp = temp_from_u8_adt7461(data, data->temp8[index]);
>>  	else if (data->kind == max6646)
>> -		temp = temp_from_u8(data->temp8[attr->index]);
>> +		temp = temp_from_u8(data->temp8[index]);
>>  	else
>> -		temp = temp_from_s8(data->temp8[attr->index]);
>> +		temp = temp_from_s8(data->temp8[index]);
>>  
>>  	/* +16 degrees offset for temp2 for the LM99 */
>> -	if (data->kind == lm99 && attr->index == 3)
>> +	if (data->kind == lm99 && index == 3)
>>  		temp += 16000;
>>  
>> -	return sprintf(buf, "%d\n", temp);
>> +	return temp;
>>  }
>>  
>> -static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>> -			 const char *buf, size_t count)
>> +static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
>> +			  char *buf)
>> +{
>> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>> +
>> +	return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
>> +}
>> +
>> +static int write_temp8(struct device *dev, int index, long val)
>>  {
>>  	static const u8 reg[8] = {
>>  		LM90_REG_W_LOCAL_LOW,
>> @@ -737,60 +751,79 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>>  		MAX6659_REG_W_REMOTE_EMERG,
>>  	};
>>  
>> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>>  	struct i2c_client *client = to_i2c_client(dev);
>>  	struct lm90_data *data = i2c_get_clientdata(client);
>> -	int nr = attr->index;
>> -	long val;
>>  	int err;
>>  
>> -	err = kstrtol(buf, 10, &val);
>> -	if (err < 0)
>> -		return err;
>> -
>>  	/* +16 degrees offset for temp2 for the LM99 */
>> -	if (data->kind == lm99 && attr->index == 3)
>> +	if (data->kind == lm99 && index == 3)
>>  		val -= 16000;
>>  
>>  	mutex_lock(&data->update_lock);
>>  	if (data->kind == adt7461)
>> -		data->temp8[nr] = temp_to_u8_adt7461(data, val);
>> +		data->temp8[index] = temp_to_u8_adt7461(data, val);
>>  	else if (data->kind == max6646)
>> -		data->temp8[nr] = temp_to_u8(val);
>> +		data->temp8[index] = temp_to_u8(val);
>>  	else
>> -		data->temp8[nr] = temp_to_s8(val);
>> -
>> -	lm90_select_remote_channel(client, data, nr >= 6);
>> -	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
>> -	lm90_select_remote_channel(client, data, 0);
>> +		data->temp8[index] = temp_to_s8(val);
>>  
>> +	err = lm90_select_remote_channel(client, data, index >= 6);
>> +	err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
>> +	err |= lm90_select_remote_channel(client, data, 0);
>> +	if (err)
>> +		dev_err(dev, "write_temp8 failed!\n");
>>  	mutex_unlock(&data->update_lock);
>> +
>> +	return err;
>> +}
>> +
>> +static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>> +			 const char *buf, size_t count)
>> +{
>> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>> +	int index = attr->index;
>> +	long val;
>> +	int err;
>> +
>> +	err = kstrtol(buf, 10, &val);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = write_temp8(dev, index, val);
>> +	if (err < 0)
>> +		return err;
>> +
>>  	return count;
>>  }
>>  
>> -static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
>> -			   char *buf)
>> +static int read_temp11(struct device *dev, int index)
>>  {
>> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>>  	struct lm90_data *data = lm90_update_device(dev);
>>  	int temp;
>>  
>>  	if (data->kind == adt7461)
>> -		temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
>> +		temp = temp_from_u16_adt7461(data, data->temp11[index]);
>>  	else if (data->kind == max6646)
>> -		temp = temp_from_u16(data->temp11[attr->index]);
>> +		temp = temp_from_u16(data->temp11[index]);
>>  	else
>> -		temp = temp_from_s16(data->temp11[attr->index]);
>> +		temp = temp_from_s16(data->temp11[index]);
>>  
>>  	/* +16 degrees offset for temp2 for the LM99 */
>> -	if (data->kind == lm99 &&  attr->index <= 2)
>> +	if (data->kind == lm99 && index <= 2)
>>  		temp += 16000;
>>  
>> -	return sprintf(buf, "%d\n", temp);
>> +	return temp;
>>  }
>>  
>> -static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>> -			  const char *buf, size_t count)
>> +static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
>> +			   char *buf)
>> +{
>> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>> +
>> +	return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
>> +}
>> +
>> +static int write_temp11(struct device *dev, int nr, int index, long val)
>>  {
>>  	struct {
>>  		u8 high;
>> @@ -804,18 +837,10 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>>  		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
>>  	};
>>  
>> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>>  	struct i2c_client *client = to_i2c_client(dev);
>>  	struct lm90_data *data = i2c_get_clientdata(client);
>> -	int nr = attr->nr;
>> -	int index = attr->index;
>> -	long val;
>>  	int err;
>>  
>> -	err = kstrtol(buf, 10, &val);
>> -	if (err < 0)
>> -		return err;
>> -
>>  	/* +16 degrees offset for temp2 for the LM99 */
>>  	if (data->kind == lm99 && index <= 2)
>>  		val -= 16000;
>> @@ -830,15 +855,38 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>>  	else
>>  		data->temp11[index] = temp_to_s8(val) << 8;
>>  
>> -	lm90_select_remote_channel(client, data, reg[nr].channel);
>> -	i2c_smbus_write_byte_data(client, reg[nr].high,
>> +	err = lm90_select_remote_channel(client, data, reg[nr].channel);
>> +	err |= i2c_smbus_write_byte_data(client, reg[nr].high,
>>  				  data->temp11[index] >> 8);
>>  	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
>> -		i2c_smbus_write_byte_data(client, reg[nr].low,
>> -					  data->temp11[index] & 0xff);
>> -	lm90_select_remote_channel(client, data, 0);
>> +		err |= i2c_smbus_write_byte_data(client, reg[nr].low,
>> +						data->temp11[index] & 0xff);
>> +	err |= lm90_select_remote_channel(client, data, 0);
>> +	if (err)
>> +		dev_err(dev, "write_temp11 failed !\n");
>>  
>>  	mutex_unlock(&data->update_lock);
>> +
>> +	return err;
>> +}
>> +
>> +static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>> +			  const char *buf, size_t count)
>> +{
>> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>> +	int nr = attr->nr;
>> +	int index = attr->index;
>> +	long val;
>> +	int err;
>> +
>> +	err = kstrtol(buf, 10, &val);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	err = write_temp11(dev, nr, index, val);
>> +	if (err < 0)
>> +		return err;
>> +
>>  	return count;
>>  }
>>  
>>
> 

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Jean Delvare - Sept. 16, 2013, 7:29 p.m.
Hi Wei,

On Tue, 6 Aug 2013 18:36:57 +0800, Wei Ni wrote:
> Split set&show temp codes as common functions, so we can use it
> directly when implement linux thermal framework.
> And handle error return value for the lm90_select_remote_channel
> and write_tempx, then set_temp8 and set_temp11 could return it
> to user-space.
> 
> Signed-off-by: Wei Ni <wni@nvidia.com>
> ---
>  drivers/hwmon/lm90.c |  150 +++++++++++++++++++++++++++++++++-----------------
>  1 file changed, 99 insertions(+), 51 deletions(-)
> 
> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
> index cdff742..6de8e01 100644
> --- a/drivers/hwmon/lm90.c
> +++ b/drivers/hwmon/lm90.c
> @@ -422,20 +422,29 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
>   * various registers have different meanings as a result of selecting a
>   * non-default remote channel.
>   */
> -static inline void lm90_select_remote_channel(struct i2c_client *client,
> +static inline int lm90_select_remote_channel(struct i2c_client *client,
>  					      struct lm90_data *data,
>  					      int channel)
>  {
>  	u8 config;
> +	int err = 0;

You don't have to initialize err, as you return immediately when an
error happens. You can just...

>  
>  	if (data->kind == max6696) {
>  		lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
>  		config &= ~0x08;
>  		if (channel)
>  			config |= 0x08;
> -		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> -					  config);
> +		err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
> +						config);
> +		if (err < 0) {
> +			dev_err(&client->dev,
> +				"Failed to select remote channel %d, err %d\n",
> +				channel, err);
> +			return err;
> +		}
>  	}
> +
> +	return err;

... return 0 here.

>  }
>  
>  /*
> @@ -702,29 +711,34 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
>   * Sysfs stuff
>   */
>  
> -static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> -			  char *buf)
> +static int read_temp8(struct device *dev, int index)
>  {
> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>  	struct lm90_data *data = lm90_update_device(dev);
>  	int temp;
>  
>  	if (data->kind == adt7461)
> -		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
> +		temp = temp_from_u8_adt7461(data, data->temp8[index]);
>  	else if (data->kind == max6646)
> -		temp = temp_from_u8(data->temp8[attr->index]);
> +		temp = temp_from_u8(data->temp8[index]);
>  	else
> -		temp = temp_from_s8(data->temp8[attr->index]);
> +		temp = temp_from_s8(data->temp8[index]);
>  
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 && attr->index == 3)
> +	if (data->kind == lm99 && index == 3)
>  		temp += 16000;
>  
> -	return sprintf(buf, "%d\n", temp);
> +	return temp;
>  }
>  
> -static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> -			 const char *buf, size_t count)
> +static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
> +			  char *buf)
> +{
> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +
> +	return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
> +}
> +
> +static int write_temp8(struct device *dev, int index, long val)
>  {
>  	static const u8 reg[8] = {
>  		LM90_REG_W_LOCAL_LOW,
> @@ -737,60 +751,79 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>  		MAX6659_REG_W_REMOTE_EMERG,
>  	};
>  
> -	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct lm90_data *data = i2c_get_clientdata(client);
> -	int nr = attr->index;
> -	long val;
>  	int err;
>  
> -	err = kstrtol(buf, 10, &val);
> -	if (err < 0)
> -		return err;
> -
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 && attr->index == 3)
> +	if (data->kind == lm99 && index == 3)
>  		val -= 16000;
>  
>  	mutex_lock(&data->update_lock);
>  	if (data->kind == adt7461)
> -		data->temp8[nr] = temp_to_u8_adt7461(data, val);
> +		data->temp8[index] = temp_to_u8_adt7461(data, val);
>  	else if (data->kind == max6646)
> -		data->temp8[nr] = temp_to_u8(val);
> +		data->temp8[index] = temp_to_u8(val);
>  	else
> -		data->temp8[nr] = temp_to_s8(val);
> -
> -	lm90_select_remote_channel(client, data, nr >= 6);
> -	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
> -	lm90_select_remote_channel(client, data, 0);
> +		data->temp8[index] = temp_to_s8(val);
>  
> +	err = lm90_select_remote_channel(client, data, index >= 6);
> +	err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
> +	err |= lm90_select_remote_channel(client, data, 0);

You can't use |= for error codes. Imagine that
lm90_select_remote_channel() returns -EIO (-5) and
i2c_smbus_write_byte_data() returns -EAGAIN (-11), err will have value
-EPERM (-1) which makes no sense. You have to report errors as soon as
they happen so that the error code isn't lost.

What you can do is:

	if ((err = f1(...)) ||
	    (err = f2(...)) ||
	    (err = f3(...))) {
		dev_err(...);
		return err;
	}

I think checkpatch will complain about that construct but me, I'm fine
with it.

> +	if (err)
> +		dev_err(dev, "write_temp8 failed!\n");
>  	mutex_unlock(&data->update_lock);
> +
> +	return err;
> +}
> +
> +static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
> +			 const char *buf, size_t count)
> +{
> +	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
> +	int index = attr->index;
> +	long val;
> +	int err;
> +
> +	err = kstrtol(buf, 10, &val);
> +	if (err < 0)
> +		return err;
> +
> +	err = write_temp8(dev, index, val);
> +	if (err < 0)
> +		return err;
> +
>  	return count;
>  }
>  
> -static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> -			   char *buf)
> +static int read_temp11(struct device *dev, int index)
>  {
> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>  	struct lm90_data *data = lm90_update_device(dev);
>  	int temp;
>  
>  	if (data->kind == adt7461)
> -		temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
> +		temp = temp_from_u16_adt7461(data, data->temp11[index]);
>  	else if (data->kind == max6646)
> -		temp = temp_from_u16(data->temp11[attr->index]);
> +		temp = temp_from_u16(data->temp11[index]);
>  	else
> -		temp = temp_from_s16(data->temp11[attr->index]);
> +		temp = temp_from_s16(data->temp11[index]);
>  
>  	/* +16 degrees offset for temp2 for the LM99 */
> -	if (data->kind == lm99 &&  attr->index <= 2)
> +	if (data->kind == lm99 && index <= 2)
>  		temp += 16000;
>  
> -	return sprintf(buf, "%d\n", temp);
> +	return temp;
>  }
>  
> -static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> -			  const char *buf, size_t count)
> +static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
> +			   char *buf)
> +{
> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> +
> +	return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
> +}
> +
> +static int write_temp11(struct device *dev, int nr, int index, long val)
>  {
>  	struct {
>  		u8 high;
> @@ -804,18 +837,10 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>  		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
>  	};
>  
> -	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>  	struct i2c_client *client = to_i2c_client(dev);
>  	struct lm90_data *data = i2c_get_clientdata(client);
> -	int nr = attr->nr;
> -	int index = attr->index;
> -	long val;
>  	int err;
>  
> -	err = kstrtol(buf, 10, &val);
> -	if (err < 0)
> -		return err;
> -
>  	/* +16 degrees offset for temp2 for the LM99 */
>  	if (data->kind == lm99 && index <= 2)
>  		val -= 16000;
> @@ -830,15 +855,38 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>  	else
>  		data->temp11[index] = temp_to_s8(val) << 8;
>  
> -	lm90_select_remote_channel(client, data, reg[nr].channel);
> -	i2c_smbus_write_byte_data(client, reg[nr].high,
> +	err = lm90_select_remote_channel(client, data, reg[nr].channel);
> +	err |= i2c_smbus_write_byte_data(client, reg[nr].high,
>  				  data->temp11[index] >> 8);
>  	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
> -		i2c_smbus_write_byte_data(client, reg[nr].low,
> -					  data->temp11[index] & 0xff);
> -	lm90_select_remote_channel(client, data, 0);
> +		err |= i2c_smbus_write_byte_data(client, reg[nr].low,
> +						data->temp11[index] & 0xff);
> +	err |= lm90_select_remote_channel(client, data, 0);
> +	if (err)
> +		dev_err(dev, "write_temp11 failed !\n");

Same here, you can't use |=.

Also, no space needed before exclamation marks in English.

>  
>  	mutex_unlock(&data->update_lock);
> +
> +	return err;
> +}
> +
> +static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
> +			  const char *buf, size_t count)
> +{
> +	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
> +	int nr = attr->nr;
> +	int index = attr->index;
> +	long val;
> +	int err;
> +
> +	err = kstrtol(buf, 10, &val);
> +	if (err < 0)
> +		return err;
> +
> +	err = write_temp11(dev, nr, index, val);
> +	if (err < 0)
> +		return err;
> +
>  	return count;
>  }
>
lightning314 - Sept. 17, 2013, 7:04 a.m.
On 09/17/2013 03:29 AM, Jean Delvare wrote:
> Hi Wei,
> 
> On Tue, 6 Aug 2013 18:36:57 +0800, Wei Ni wrote:
>> Split set&show temp codes as common functions, so we can use it
>> directly when implement linux thermal framework.
>> And handle error return value for the lm90_select_remote_channel
>> and write_tempx, then set_temp8 and set_temp11 could return it
>> to user-space.
>>
>> Signed-off-by: Wei Ni <wni@nvidia.com>
>> ---
>>  drivers/hwmon/lm90.c |  150 +++++++++++++++++++++++++++++++++-----------------
>>  1 file changed, 99 insertions(+), 51 deletions(-)
>>
>> diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
>> index cdff742..6de8e01 100644
>> --- a/drivers/hwmon/lm90.c
>> +++ b/drivers/hwmon/lm90.c
>> @@ -422,20 +422,29 @@ static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
>>   * various registers have different meanings as a result of selecting a
>>   * non-default remote channel.
>>   */
>> -static inline void lm90_select_remote_channel(struct i2c_client *client,
>> +static inline int lm90_select_remote_channel(struct i2c_client *client,
>>                                             struct lm90_data *data,
>>                                             int channel)
>>  {
>>       u8 config;
>> +     int err = 0;
> 
> You don't have to initialize err, as you return immediately when an
> error happens. You can just...

Got it, I will change it.

> 
>>
>>       if (data->kind == max6696) {
>>               lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
>>               config &= ~0x08;
>>               if (channel)
>>                       config |= 0x08;
>> -             i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
>> -                                       config);
>> +             err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
>> +                                             config);
>> +             if (err < 0) {
>> +                     dev_err(&client->dev,
>> +                             "Failed to select remote channel %d, err %d\n",
>> +                             channel, err);
>> +                     return err;
>> +             }
>>       }
>> +
>> +     return err;
> 
> ... return 0 here.
> 
>>  }
>>
>>  /*
>> @@ -702,29 +711,34 @@ static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
>>   * Sysfs stuff
>>   */
>>
>> -static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
>> -                       char *buf)
>> +static int read_temp8(struct device *dev, int index)
>>  {
>> -     struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>>       struct lm90_data *data = lm90_update_device(dev);
>>       int temp;
>>
>>       if (data->kind == adt7461)
>> -             temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
>> +             temp = temp_from_u8_adt7461(data, data->temp8[index]);
>>       else if (data->kind == max6646)
>> -             temp = temp_from_u8(data->temp8[attr->index]);
>> +             temp = temp_from_u8(data->temp8[index]);
>>       else
>> -             temp = temp_from_s8(data->temp8[attr->index]);
>> +             temp = temp_from_s8(data->temp8[index]);
>>
>>       /* +16 degrees offset for temp2 for the LM99 */
>> -     if (data->kind == lm99 && attr->index == 3)
>> +     if (data->kind == lm99 && index == 3)
>>               temp += 16000;
>>
>> -     return sprintf(buf, "%d\n", temp);
>> +     return temp;
>>  }
>>
>> -static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>> -                      const char *buf, size_t count)
>> +static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
>> +                       char *buf)
>> +{
>> +     struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>> +
>> +     return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
>> +}
>> +
>> +static int write_temp8(struct device *dev, int index, long val)
>>  {
>>       static const u8 reg[8] = {
>>               LM90_REG_W_LOCAL_LOW,
>> @@ -737,60 +751,79 @@ static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>>               MAX6659_REG_W_REMOTE_EMERG,
>>       };
>>
>> -     struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>>       struct i2c_client *client = to_i2c_client(dev);
>>       struct lm90_data *data = i2c_get_clientdata(client);
>> -     int nr = attr->index;
>> -     long val;
>>       int err;
>>
>> -     err = kstrtol(buf, 10, &val);
>> -     if (err < 0)
>> -             return err;
>> -
>>       /* +16 degrees offset for temp2 for the LM99 */
>> -     if (data->kind == lm99 && attr->index == 3)
>> +     if (data->kind == lm99 && index == 3)
>>               val -= 16000;
>>
>>       mutex_lock(&data->update_lock);
>>       if (data->kind == adt7461)
>> -             data->temp8[nr] = temp_to_u8_adt7461(data, val);
>> +             data->temp8[index] = temp_to_u8_adt7461(data, val);
>>       else if (data->kind == max6646)
>> -             data->temp8[nr] = temp_to_u8(val);
>> +             data->temp8[index] = temp_to_u8(val);
>>       else
>> -             data->temp8[nr] = temp_to_s8(val);
>> -
>> -     lm90_select_remote_channel(client, data, nr >= 6);
>> -     i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
>> -     lm90_select_remote_channel(client, data, 0);
>> +             data->temp8[index] = temp_to_s8(val);
>>
>> +     err = lm90_select_remote_channel(client, data, index >= 6);
>> +     err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
>> +     err |= lm90_select_remote_channel(client, data, 0);
> 
> You can't use |= for error codes. Imagine that
> lm90_select_remote_channel() returns -EIO (-5) and
> i2c_smbus_write_byte_data() returns -EAGAIN (-11), err will have value
> -EPERM (-1) which makes no sense. You have to report errors as soon as
> they happen so that the error code isn't lost.
> 
> What you can do is:
> 
>         if ((err = f1(...)) ||
>             (err = f2(...)) ||
>             (err = f3(...))) {
>                 dev_err(...);
>                 return err;
>         }
> 
> I think checkpatch will complain about that construct but me, I'm fine
> with it.

Ok, I will do it.

> 
>> +     if (err)
>> +             dev_err(dev, "write_temp8 failed!\n");
>>       mutex_unlock(&data->update_lock);
>> +
>> +     return err;
>> +}
>> +
>> +static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
>> +                      const char *buf, size_t count)
>> +{
>> +     struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
>> +     int index = attr->index;
>> +     long val;
>> +     int err;
>> +
>> +     err = kstrtol(buf, 10, &val);
>> +     if (err < 0)
>> +             return err;
>> +
>> +     err = write_temp8(dev, index, val);
>> +     if (err < 0)
>> +             return err;
>> +
>>       return count;
>>  }
>>
>> -static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
>> -                        char *buf)
>> +static int read_temp11(struct device *dev, int index)
>>  {
>> -     struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>>       struct lm90_data *data = lm90_update_device(dev);
>>       int temp;
>>
>>       if (data->kind == adt7461)
>> -             temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
>> +             temp = temp_from_u16_adt7461(data, data->temp11[index]);
>>       else if (data->kind == max6646)
>> -             temp = temp_from_u16(data->temp11[attr->index]);
>> +             temp = temp_from_u16(data->temp11[index]);
>>       else
>> -             temp = temp_from_s16(data->temp11[attr->index]);
>> +             temp = temp_from_s16(data->temp11[index]);
>>
>>       /* +16 degrees offset for temp2 for the LM99 */
>> -     if (data->kind == lm99 &&  attr->index <= 2)
>> +     if (data->kind == lm99 && index <= 2)
>>               temp += 16000;
>>
>> -     return sprintf(buf, "%d\n", temp);
>> +     return temp;
>>  }
>>
>> -static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>> -                       const char *buf, size_t count)
>> +static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
>> +                        char *buf)
>> +{
>> +     struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>> +
>> +     return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
>> +}
>> +
>> +static int write_temp11(struct device *dev, int nr, int index, long val)
>>  {
>>       struct {
>>               u8 high;
>> @@ -804,18 +837,10 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>>               { LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
>>       };
>>
>> -     struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>>       struct i2c_client *client = to_i2c_client(dev);
>>       struct lm90_data *data = i2c_get_clientdata(client);
>> -     int nr = attr->nr;
>> -     int index = attr->index;
>> -     long val;
>>       int err;
>>
>> -     err = kstrtol(buf, 10, &val);
>> -     if (err < 0)
>> -             return err;
>> -
>>       /* +16 degrees offset for temp2 for the LM99 */
>>       if (data->kind == lm99 && index <= 2)
>>               val -= 16000;
>> @@ -830,15 +855,38 @@ static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>>       else
>>               data->temp11[index] = temp_to_s8(val) << 8;
>>
>> -     lm90_select_remote_channel(client, data, reg[nr].channel);
>> -     i2c_smbus_write_byte_data(client, reg[nr].high,
>> +     err = lm90_select_remote_channel(client, data, reg[nr].channel);
>> +     err |= i2c_smbus_write_byte_data(client, reg[nr].high,
>>                                 data->temp11[index] >> 8);
>>       if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
>> -             i2c_smbus_write_byte_data(client, reg[nr].low,
>> -                                       data->temp11[index] & 0xff);
>> -     lm90_select_remote_channel(client, data, 0);
>> +             err |= i2c_smbus_write_byte_data(client, reg[nr].low,
>> +                                             data->temp11[index] & 0xff);
>> +     err |= lm90_select_remote_channel(client, data, 0);
>> +     if (err)
>> +             dev_err(dev, "write_temp11 failed !\n");
> 
> Same here, you can't use |=.
> 
> Also, no space needed before exclamation marks in English.

Oh, you reviewed so carefully, thanks.

> 
>>
>>       mutex_unlock(&data->update_lock);
>> +
>> +     return err;
>> +}
>> +
>> +static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
>> +                       const char *buf, size_t count)
>> +{
>> +     struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
>> +     int nr = attr->nr;
>> +     int index = attr->index;
>> +     long val;
>> +     int err;
>> +
>> +     err = kstrtol(buf, 10, &val);
>> +     if (err < 0)
>> +             return err;
>> +
>> +     err = write_temp11(dev, nr, index, val);
>> +     if (err < 0)
>> +             return err;
>> +
>>       return count;
>>  }
>>
> 
> --
> Jean Delvare
> --
> To unsubscribe from this list: send the line "unsubscribe linux-tegra" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

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Patch

diff --git a/drivers/hwmon/lm90.c b/drivers/hwmon/lm90.c
index cdff742..6de8e01 100644
--- a/drivers/hwmon/lm90.c
+++ b/drivers/hwmon/lm90.c
@@ -422,20 +422,29 @@  static int lm90_read16(struct i2c_client *client, u8 regh, u8 regl, u16 *value)
  * various registers have different meanings as a result of selecting a
  * non-default remote channel.
  */
-static inline void lm90_select_remote_channel(struct i2c_client *client,
+static inline int lm90_select_remote_channel(struct i2c_client *client,
 					      struct lm90_data *data,
 					      int channel)
 {
 	u8 config;
+	int err = 0;
 
 	if (data->kind == max6696) {
 		lm90_read_reg(client, LM90_REG_R_CONFIG1, &config);
 		config &= ~0x08;
 		if (channel)
 			config |= 0x08;
-		i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
-					  config);
+		err = i2c_smbus_write_byte_data(client, LM90_REG_W_CONFIG1,
+						config);
+		if (err < 0) {
+			dev_err(&client->dev,
+				"Failed to select remote channel %d, err %d\n",
+				channel, err);
+			return err;
+		}
 	}
+
+	return err;
 }
 
 /*
@@ -702,29 +711,34 @@  static u16 temp_to_u16_adt7461(struct lm90_data *data, long val)
  * Sysfs stuff
  */
 
-static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
-			  char *buf)
+static int read_temp8(struct device *dev, int index)
 {
-	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 	struct lm90_data *data = lm90_update_device(dev);
 	int temp;
 
 	if (data->kind == adt7461)
-		temp = temp_from_u8_adt7461(data, data->temp8[attr->index]);
+		temp = temp_from_u8_adt7461(data, data->temp8[index]);
 	else if (data->kind == max6646)
-		temp = temp_from_u8(data->temp8[attr->index]);
+		temp = temp_from_u8(data->temp8[index]);
 	else
-		temp = temp_from_s8(data->temp8[attr->index]);
+		temp = temp_from_s8(data->temp8[index]);
 
 	/* +16 degrees offset for temp2 for the LM99 */
-	if (data->kind == lm99 && attr->index == 3)
+	if (data->kind == lm99 && index == 3)
 		temp += 16000;
 
-	return sprintf(buf, "%d\n", temp);
+	return temp;
 }
 
-static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
-			 const char *buf, size_t count)
+static ssize_t show_temp8(struct device *dev, struct device_attribute *devattr,
+			  char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+
+	return sprintf(buf, "%d\n", read_temp8(dev, attr->index));
+}
+
+static int write_temp8(struct device *dev, int index, long val)
 {
 	static const u8 reg[8] = {
 		LM90_REG_W_LOCAL_LOW,
@@ -737,60 +751,79 @@  static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
 		MAX6659_REG_W_REMOTE_EMERG,
 	};
 
-	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct lm90_data *data = i2c_get_clientdata(client);
-	int nr = attr->index;
-	long val;
 	int err;
 
-	err = kstrtol(buf, 10, &val);
-	if (err < 0)
-		return err;
-
 	/* +16 degrees offset for temp2 for the LM99 */
-	if (data->kind == lm99 && attr->index == 3)
+	if (data->kind == lm99 && index == 3)
 		val -= 16000;
 
 	mutex_lock(&data->update_lock);
 	if (data->kind == adt7461)
-		data->temp8[nr] = temp_to_u8_adt7461(data, val);
+		data->temp8[index] = temp_to_u8_adt7461(data, val);
 	else if (data->kind == max6646)
-		data->temp8[nr] = temp_to_u8(val);
+		data->temp8[index] = temp_to_u8(val);
 	else
-		data->temp8[nr] = temp_to_s8(val);
-
-	lm90_select_remote_channel(client, data, nr >= 6);
-	i2c_smbus_write_byte_data(client, reg[nr], data->temp8[nr]);
-	lm90_select_remote_channel(client, data, 0);
+		data->temp8[index] = temp_to_s8(val);
 
+	err = lm90_select_remote_channel(client, data, index >= 6);
+	err |= i2c_smbus_write_byte_data(client, reg[index], data->temp8[index]);
+	err |= lm90_select_remote_channel(client, data, 0);
+	if (err)
+		dev_err(dev, "write_temp8 failed!\n");
 	mutex_unlock(&data->update_lock);
+
+	return err;
+}
+
+static ssize_t set_temp8(struct device *dev, struct device_attribute *devattr,
+			 const char *buf, size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+	int index = attr->index;
+	long val;
+	int err;
+
+	err = kstrtol(buf, 10, &val);
+	if (err < 0)
+		return err;
+
+	err = write_temp8(dev, index, val);
+	if (err < 0)
+		return err;
+
 	return count;
 }
 
-static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
-			   char *buf)
+static int read_temp11(struct device *dev, int index)
 {
-	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
 	struct lm90_data *data = lm90_update_device(dev);
 	int temp;
 
 	if (data->kind == adt7461)
-		temp = temp_from_u16_adt7461(data, data->temp11[attr->index]);
+		temp = temp_from_u16_adt7461(data, data->temp11[index]);
 	else if (data->kind == max6646)
-		temp = temp_from_u16(data->temp11[attr->index]);
+		temp = temp_from_u16(data->temp11[index]);
 	else
-		temp = temp_from_s16(data->temp11[attr->index]);
+		temp = temp_from_s16(data->temp11[index]);
 
 	/* +16 degrees offset for temp2 for the LM99 */
-	if (data->kind == lm99 &&  attr->index <= 2)
+	if (data->kind == lm99 && index <= 2)
 		temp += 16000;
 
-	return sprintf(buf, "%d\n", temp);
+	return temp;
 }
 
-static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
-			  const char *buf, size_t count)
+static ssize_t show_temp11(struct device *dev, struct device_attribute *devattr,
+			   char *buf)
+{
+	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
+
+	return sprintf(buf, "%d\n", read_temp11(dev, attr->index));
+}
+
+static int write_temp11(struct device *dev, int nr, int index, long val)
 {
 	struct {
 		u8 high;
@@ -804,18 +837,10 @@  static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
 		{ LM90_REG_W_REMOTE_HIGHH, LM90_REG_W_REMOTE_HIGHL, 1 }
 	};
 
-	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct lm90_data *data = i2c_get_clientdata(client);
-	int nr = attr->nr;
-	int index = attr->index;
-	long val;
 	int err;
 
-	err = kstrtol(buf, 10, &val);
-	if (err < 0)
-		return err;
-
 	/* +16 degrees offset for temp2 for the LM99 */
 	if (data->kind == lm99 && index <= 2)
 		val -= 16000;
@@ -830,15 +855,38 @@  static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
 	else
 		data->temp11[index] = temp_to_s8(val) << 8;
 
-	lm90_select_remote_channel(client, data, reg[nr].channel);
-	i2c_smbus_write_byte_data(client, reg[nr].high,
+	err = lm90_select_remote_channel(client, data, reg[nr].channel);
+	err |= i2c_smbus_write_byte_data(client, reg[nr].high,
 				  data->temp11[index] >> 8);
 	if (data->flags & LM90_HAVE_REM_LIMIT_EXT)
-		i2c_smbus_write_byte_data(client, reg[nr].low,
-					  data->temp11[index] & 0xff);
-	lm90_select_remote_channel(client, data, 0);
+		err |= i2c_smbus_write_byte_data(client, reg[nr].low,
+						data->temp11[index] & 0xff);
+	err |= lm90_select_remote_channel(client, data, 0);
+	if (err)
+		dev_err(dev, "write_temp11 failed !\n");
 
 	mutex_unlock(&data->update_lock);
+
+	return err;
+}
+
+static ssize_t set_temp11(struct device *dev, struct device_attribute *devattr,
+			  const char *buf, size_t count)
+{
+	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
+	int nr = attr->nr;
+	int index = attr->index;
+	long val;
+	int err;
+
+	err = kstrtol(buf, 10, &val);
+	if (err < 0)
+		return err;
+
+	err = write_temp11(dev, nr, index, val);
+	if (err < 0)
+		return err;
+
 	return count;
 }