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

[Wei Ni <wni-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

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-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
>> ---
>>  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
> --
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