Re: [PATCH 7/8] staging:iio:dac:ad5446: Consolidate store_sample and store_pwr_down functions

[Lars-Peter Clausen <lars@metafoo.de>]

On 04/24/2012 10:06 AM, Jonathan Cameron wrote:
> On 4/23/2012 6:51 PM, Lars-Peter Clausen wrote:
>> The devices supported by this drivers only have a single shift register,
>> which
>> contains both the power down mode and the output sample. So writing the power
>> down mode and the output sample can be done by the same function. The two
>> power
>> down bits are always placed ontop of the msb of the output sample, so we can
>> easily calculate their position by adding the channels shift to the channels
>> realbits.
> I wonder if the change in logic here slightly hides what is going on.
> Perhaps simply renaming store_sample to something that indicates it's dual
> purpose
> will make things clearer in the resulting code?

I had initially renamed it to simply 'write', but well reverted it again. Do
you think renaming it to 'write' will work?

> 
> Also does this mean you can kill of store_pwr_down in the structure?
> Given nothing sets it this should be fine!
> 

Uhm, yes, that was actually the plan, looks like I missed it though. Good catch.

Thanks,
- Lars

>>
>> Signed-off-by: Lars-Peter Clausen<lars@metafoo.de>
>> ---
>>   drivers/staging/iio/dac/ad5446.c |   38
>> ++++++++++----------------------------
>>   1 file changed, 10 insertions(+), 28 deletions(-)
>>
>> diff --git a/drivers/staging/iio/dac/ad5446.c
>> b/drivers/staging/iio/dac/ad5446.c
>> index c767024..90461b2 100644
>> --- a/drivers/staging/iio/dac/ad5446.c
>> +++ b/drivers/staging/iio/dac/ad5446.c
>> @@ -31,21 +31,6 @@ static void ad5446_store_sample(struct ad5446_state
>> *st, unsigned val)
>>
>>   static void ad5660_store_sample(struct ad5446_state *st, unsigned val)
>>   {
>> -    val |= AD5660_LOAD;
>> -    st->data.d24[0] = (val>>  16)&  0xFF;
>> -    st->data.d24[1] = (val>>  8)&  0xFF;
>> -    st->data.d24[2] = val&  0xFF;
>> -}
>> -
>> -static void ad5620_store_pwr_down(struct ad5446_state *st, unsigned mode)
>> -{
>> -    st->data.d16 = cpu_to_be16(mode<<  14);
>> -}
>> -
>> -static void ad5660_store_pwr_down(struct ad5446_state *st, unsigned mode)
>> -{
>> -    unsigned val = mode<<  16;
>> -
>>       st->data.d24[0] = (val>>  16)&  0xFF;
>>       st->data.d24[1] = (val>>  8)&  0xFF;
>>       st->data.d24[2] = val&  0xFF;
>> @@ -105,6 +90,8 @@ static ssize_t ad5446_write_dac_powerdown(struct
>> iio_dev *indio_dev,
>>                           const char *buf, size_t len)
>>   {
>>       struct ad5446_state *st = iio_priv(indio_dev);
>> +    unsigned int shift;
>> +    unsigned int val;
>>       bool powerdown;
>>       int ret;
>>
>> @@ -115,10 +102,14 @@ static ssize_t ad5446_write_dac_powerdown(struct
>> iio_dev *indio_dev,
>>       mutex_lock(&indio_dev->mlock);
>>       st->pwr_down = powerdown;
>>
>> -    if (st->pwr_down)
>> -        st->chip_info->store_pwr_down(st, st->pwr_down_mode);
>> -    else
>> -        st->chip_info->store_sample(st, st->cached_val);
>> +    if (st->pwr_down) {
>> +        shift = chan->scan_type.realbits + chan->scan_type.shift;
>> +        val = st->pwr_down_mode<<  shift;
>> +    } else {
>> +        val = st->cached_val;
>> +    }
>> +
>> +    st->chip_info->store_sample(st, val);
>>
>>       ret = spi_sync(st->spi,&st->msg);
>>       mutex_unlock(&indio_dev->mlock);
>> @@ -186,53 +177,44 @@ static const struct ad5446_chip_info
>> ad5446_chip_info_tbl[] = {
>>       [ID_AD5601] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(8, 16, 6),
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5611] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(10, 16, 4),
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5621] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5620_2500] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
>>           .int_vref_mv = 2500,
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5620_1250] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(12, 16, 2),
>>           .int_vref_mv = 1250,
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5640_2500] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(14, 16, 0),
>>           .int_vref_mv = 2500,
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5640_1250] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(14, 16, 0),
>>           .int_vref_mv = 1250,
>>           .store_sample = ad5446_store_sample,
>> -        .store_pwr_down = ad5620_store_pwr_down,
>>       },
>>       [ID_AD5660_2500] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(16, 16, 0),
>>           .int_vref_mv = 2500,
>>           .store_sample = ad5660_store_sample,
>> -        .store_pwr_down = ad5660_store_pwr_down,
>>       },
>>       [ID_AD5660_1250] = {
>>           .channel = AD5446_CHANNEL_POWERDOWN(16, 16, 0),
>>           .int_vref_mv = 1250,
>>           .store_sample = ad5660_store_sample,
>> -        .store_pwr_down = ad5660_store_pwr_down,
>>       },
>>   };
>>