Re: [PATCH]iio:humidity:si7020: cleanup read_raw and probe

[Jonathan Cameron <jic23@kernel.org>]

On 25/10/14 20:34, Jonathan Cameron wrote:
> On 25/10/14 18:34, Hartmut Knaack wrote:
>> Jonathan Cameron schrieb am 25.10.2014 12:02:
>>> On 18/10/14 20:46, Hartmut Knaack wrote:
>>>> In si7020_read_raw() the pointer to the i2c client was obtained as second level pointer, although a simple pointer would be sufficient. Cleaned this.
>>>> When reading temperature or humidity values, a right-shift of two bits needs to be applied, and only for the humidity channel a mask of the lower 12 bits needs to be applied. This reduces code repetition.
>>>> During probe, i2c_set_clientdata() was used, although its counterpart was not, so drop it.
>>>>
>>>> Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
>>> I think the incorrect pointer is a bug (rather than simply unnecessary).
>> Could you give me some infos, why you assess this issue as a bug?
> Fair point.  It's a bug with no effect whatsoever.
> I didn't really follow that through other than going
> "Gah it has the wrong type, we'll dereference it once too many and it will
> eat babies!"
> 
> Clearly it just gets passed on wards thus two bugs cancel each other out.

I take it back. Just taken a look at your updated patch. The dereference will
mean that instead of passing a pointer into the read, we will be passing whatever
is the start of an actual i2c_client structure.


> 
>>> The other stuff is a cleanup (sensible but not stable material).
>>>
>>> Please split the patch into two.
>> No problem at all.
> I'll probably just take them both through togreg anyway so would have
> been fine in the first place.  Sorry about that.
> 
> J
>>>
>>> Thanks,
>>>
>>> Jonathan
>>>> ---
>>>> diff --git a/drivers/iio/humidity/si7020.c b/drivers/iio/humidity/si7020.c
>>>> index e336af7..b541646 100644
>>>> --- a/drivers/iio/humidity/si7020.c
>>>> +++ b/drivers/iio/humidity/si7020.c
>>>> @@ -45,21 +45,20 @@ static int si7020_read_raw(struct iio_dev *indio_dev,
>>>>  			   struct iio_chan_spec const *chan, int *val,
>>>>  			   int *val2, long mask)
>>>>  {
>>>> -	struct i2c_client **client = iio_priv(indio_dev);
>>>> +	struct i2c_client *client = iio_priv(indio_dev);
>>>>  	int ret;
>>>>
>>>>  	switch (mask) {
>>>>  	case IIO_CHAN_INFO_RAW:
>>>> -		ret = i2c_smbus_read_word_data(*client,
>>>> +		ret = i2c_smbus_read_word_data(client,
>>>>  					       chan->type == IIO_TEMP ?
>>>>  					       SI7020CMD_TEMP_HOLD :
>>>>  					       SI7020CMD_RH_HOLD);
>>>>  		if (ret < 0)
>>>>  			return ret;
>>>> -		if (chan->type == IIO_TEMP)
>>>> -			*val = ret >> 2;
>>>> -		else
>>>> -			*val = (ret & 0x3FFF) >> 2;
>>>> +		*val = ret >> 2;
>>>> +		if (chan->type == IIO_HUMIDITYRELATIVE)
>>>> +			*val &= GENMASK(11, 0);
>>>>  		return IIO_VAL_INT;
>>>>  	case IIO_CHAN_INFO_SCALE:
>>>>  		if (chan->type == IIO_TEMP)
>>>> @@ -133,7 +132,6 @@ static int si7020_probe(struct i2c_client *client,
>>>>
>>>>  	data = iio_priv(indio_dev);
>>>>  	*data = client;
>>>> -	i2c_set_clientdata(client, indio_dev);
>>>>
>>>>  	indio_dev->dev.parent = &client->dev;
>>>>  	indio_dev->name = dev_name(&client->dev);
>>>> --
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>>>
>>
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