Re: [PATCH] staging/iio/meter: fix the coding style problem

[Lars-Peter Clausen]

On 05/01/2012 09:56 AM, Jonathan Cameron wrote:
> On 4/30/2012 9:01 PM, Lars-Peter Clausen wrote:
>> On 04/30/2012 09:26 PM, joseph daniel wrote:
>>> Signed-off-by: joseph daniel<josephdanielwalter@xxxxxxxxx>
>>> ---
>>> Hi Lars,
>>>     Thanks for review. how about the below change?
>>>   drivers/staging/iio/meter/ade7854-i2c.c |    6 +++++-
>>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/staging/iio/meter/ade7854-i2c.c
>>> b/drivers/staging/iio/meter/ade7854-i2c.c
>>> index 1e1faa0..52bdb05 100644
>>> --- a/drivers/staging/iio/meter/ade7854-i2c.c
>>> +++ b/drivers/staging/iio/meter/ade7854-i2c.c
>>> @@ -181,6 +181,7 @@ static int ade7854_i2c_read_reg_32(struct device
>>> *dev,
>>>   {
>>>       struct iio_dev *indio_dev = dev_get_drvdata(dev);
>>>       struct ade7854_state *st = iio_priv(indio_dev);
>>> +    uint32_t value;
>>>       int ret;
>>>
>>>       mutex_lock(&st->buf_lock);
>>> @@ -195,7 +196,10 @@ static int ade7854_i2c_read_reg_32(struct device
>>> *dev,
>>>       if (ret)
>>>           goto out;
>>>
>>> -    *val = (st->rx[0]<<  24) | (st->rx[1]<<  16) | (st->rx[2]<<  8)
>>> | st->rx[3];
>>> +    memcpy(&value, st->rx, sizeof(uint32_t));
>>> +
>> Uhm, yes, you are right st->rx is unaligned. The memcpy is not
>> necessary though
>> if you use get_unaligned_be32. Sorry for the pointer to the wrong
>> function.
> Or we could just force the alignment of st->rx? Might not be worth
> bothering.

Yes, but be32_to_cpu wants a be32 and there is another functions which only
does a 16 bit access on rx, so we'd need to cast and things get messy. Also for
tx we store first a 16bit value and then a 32bit value and while it is possible
to get this properly aligned this gets a bit messy too. I think we are fine
with {get,set}_unaligned for now.
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