Re: [PATCH 3/4] staging:iio:adc:spear_adc use info_mask_shared_by_all for samp freq

[Jonathan Cameron <jic23@kernel.org>]

On 15/03/14 21:26, Hartmut Knaack wrote:
> Jonathan Cameron schrieb:
>> Using the core support makes this element available to in kernel users as
>> well as to userspace under exactly the same interface as before.  The
>> intent is to move all sampling frequency control to this approach
>> throughout IIO.
>>
>> Drop unused clk_high and clk_low whilst we are at it.
>>
>> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
>> Acked-by: Stefan Roese <sr@denx.de>
>> ---
>>   drivers/staging/iio/adc/spear_adc.c | 96 ++++++++++++++-----------------------
>>   1 file changed, 37 insertions(+), 59 deletions(-)
>>
>> diff --git a/drivers/staging/iio/adc/spear_adc.c b/drivers/staging/iio/adc/spear_adc.c
>> index fa1e2b2..18a0a40 100644
>> --- a/drivers/staging/iio/adc/spear_adc.c
>> +++ b/drivers/staging/iio/adc/spear_adc.c
>> @@ -168,16 +168,52 @@ static int spear_read_raw(struct iio_dev *indio_dev,
>>   		*val = info->vref_external;
>>   		*val2 = SPEAR_ADC_DATA_BITS;
>>   		return IIO_VAL_FRACTIONAL_LOG2;
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		*val = info->current_clk;
>> +		return IIO_VAL_INT;
>>   	}
>>
>>   	return -EINVAL;
>>   }
>>
>> +static int spear_adc_write_raw(struct iio_dev *indio_dev,
>> +			       struct iio_chan_spec const *chan,
>> +			       int val,
>> +			       int val2,
>> +			       long mask)
>> +{
>> +	struct spear_adc_info *info = iio_priv(indio_dev);
>> +	u32 count;
>> +	u32 apb_clk = clk_get_rate(info->clk);
>> +	int ret = 0;
>> +
>> +	if (mask != IIO_CHAN_INFO_SAMP_FREQ)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&indio_dev->mlock);
>> +
>> +	if ((val < SPEAR_ADC_CLK_MIN) ||
>> +		(val > SPEAR_ADC_CLK_MAX) ||
>> +		(val2 != 0)) {
>> +		ret = -EINVAL;
>> +		goto out;
>> +	}
>> +
>> +	count = (apb_clk + val - 1) / val;
>> +	info->current_clk = apb_clk / count;
>> +	spear_adc_set_clk(info, val);
> It's me again, same spot, but this time on caffeine and sugar ;-)
> This time I got curious about what spear_adc_set_clk actually does.
> And guess what (make sure to be seated): it does the same calculation
> of count and info->current_clk. So these two lines can leave, as
> well. My thoughts about that function will follow in patch 4.
Gah!  I should have been less lazy and actually taken a look at what
was going on myself.

Anyhow, will fix this up for the next version.
>> +
>> +out:
>> +	mutex_unlock(&indio_dev->mlock);
>> +	return ret;
>> +}
>> +
>>   #define SPEAR_ADC_CHAN(idx) {				\
>>   	.type = IIO_VOLTAGE,				\
>>   	.indexed = 1,					\
>>   	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),	\
>>   	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),	\
>> +	.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),\
>>   	.channel = idx,					\
>>   }
>>
>> @@ -219,67 +255,9 @@ static int spear_adc_configure(struct spear_adc_info *info)
>>   	return 0;
>>   }
>>
>> -static ssize_t spear_adc_read_frequency(struct device *dev,
>> -					struct device_attribute *attr,
>> -					char *buf)
>> -{
>> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>> -	struct spear_adc_info *info = iio_priv(indio_dev);
>> -
>> -	return sprintf(buf, "%d\n", info->current_clk);
>> -}
>> -
>> -static ssize_t spear_adc_write_frequency(struct device *dev,
>> -					 struct device_attribute *attr,
>> -					 const char *buf,
>> -					 size_t len)
>> -{
>> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>> -	struct spear_adc_info *info = iio_priv(indio_dev);
>> -	u32 clk_high, clk_low, count;
>> -	u32 apb_clk = clk_get_rate(info->clk);
>> -	unsigned long lval;
>> -	int ret;
>> -
>> -	ret = kstrtoul(buf, 10, &lval);
>> -	if (ret)
>> -		return ret;
>> -
>> -	mutex_lock(&indio_dev->mlock);
>> -
>> -	if ((lval < SPEAR_ADC_CLK_MIN) || (lval > SPEAR_ADC_CLK_MAX)) {
>> -		ret = -EINVAL;
>> -		goto out;
>> -	}
>> -
>> -	count = (apb_clk + lval - 1) / lval;
>> -	clk_low = count / 2;
>> -	clk_high = count - clk_low;
>> -	info->current_clk = apb_clk / count;
>> -	spear_adc_set_clk(info, lval);
>> -
>> -out:
>> -	mutex_unlock(&indio_dev->mlock);
>> -
>> -	return ret ? ret : len;
>> -}
>> -
>> -static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
>> -			      spear_adc_read_frequency,
>> -			      spear_adc_write_frequency);
>> -
>> -static struct attribute *spear_attributes[] = {
>> -	&iio_dev_attr_sampling_frequency.dev_attr.attr,
>> -	NULL
>> -};
>> -
>> -static const struct attribute_group spear_attribute_group = {
>> -	.attrs = spear_attributes,
>> -};
>> -
>>   static const struct iio_info spear_adc_iio_info = {
>>   	.read_raw = &spear_read_raw,
>> -	.attrs = &spear_attribute_group,
>> +	.write_raw = &spear_adc_write_raw,
>>   	.driver_module = THIS_MODULE,
>>   };
>>
>
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