Re: [PATCH 5/5] iio: ad7152: Update sample rate, conversion time, digital filter handling

[Jonathan Cameron <jic23@cam.ac.uk>]

On 08/24/11 13:45, michael.hennerich@analog.com wrote:
> From: Michael Hennerich <michael.hennerich@analog.com>
> 
> Rename attribute, use sampling_frequency instead.
> Attribute now accepts values in Hz.
> Delay readout accordingly.

Thanks for this excellent series. Another driver we can add to our
list of 'good' ones :)
> 
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>

> ---
>  drivers/staging/iio/adc/ad7152.c |   39 ++++++++++++++++++++++++++++---------
>  1 files changed, 29 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/staging/iio/adc/ad7152.c b/drivers/staging/iio/adc/ad7152.c
> index bf26d38..41c3102 100644
> --- a/drivers/staging/iio/adc/ad7152.c
> +++ b/drivers/staging/iio/adc/ad7152.c
> @@ -66,6 +66,9 @@
>  #define AD7152_CAPDAC_DACEN		(1 << 7)
>  #define AD7152_CAPDAC_DACP(x)		((x) & 0x1F)
>  
> +/* CFG2 Register Bit Designations (AD7152_REG_CFG2) */
> +#define AD7152_CFG2_OSR(x)		(((x) & 0x3) << 4)
> +
>  enum {
>  	AD7152_DATA,
>  	AD7152_OFFS,
> @@ -156,8 +159,10 @@ static IIO_DEVICE_ATTR(in_capacitance0_calibscale_calibration,
>  static IIO_DEVICE_ATTR(in_capacitance1_calibscale_calibration,
>  		       S_IWUSR, NULL, ad7152_start_gain_calib, 1);
>  
> -#define IIO_DEV_ATTR_FILTER_RATE_SETUP(_mode, _show, _store)              \
> -	IIO_DEVICE_ATTR(filter_rate_setup, _mode, _show, _store, 0)
> +/* Values are Update Rate (Hz), Conversion Time (ms) */
> +static const unsigned char ad7152_filter_rate_table[][2] = {
> +	{200, 5}, {50, 20}, {20, 50}, {17, 60},
> +};
>  
>  static ssize_t ad7152_show_filter_rate_setup(struct device *dev,
>  		struct device_attribute *attr,
> @@ -166,7 +171,8 @@ static ssize_t ad7152_show_filter_rate_setup(struct device *dev,
>  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad7152_chip_info *chip = iio_priv(indio_dev);
>  
> -	return sprintf(buf, "0x%02x\n", chip->filter_rate_setup);
> +	return sprintf(buf, "%d\n",
> +		       ad7152_filter_rate_table[chip->filter_rate_setup][0]);
>  }
>  
>  static ssize_t ad7152_store_filter_rate_setup(struct device *dev,
> @@ -177,37 +183,50 @@ static ssize_t ad7152_store_filter_rate_setup(struct device *dev,
>  	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>  	struct ad7152_chip_info *chip = iio_priv(indio_dev);
>  	u8 data;
> -	int ret;
> +	int ret, i;
>  
>  	ret = kstrtou8(buf, 10, &data);
>  	if (ret < 0)
>  		return ret;
>  
> +	for (i = 0; i < ARRAY_SIZE(ad7152_filter_rate_table); i++)
> +		if (data >= ad7152_filter_rate_table[i][0])
> +			break;
> +
> +	if (i >= ARRAY_SIZE(ad7152_filter_rate_table))
> +		i = ARRAY_SIZE(ad7152_filter_rate_table) - 1;
> +
>  	mutex_lock(&indio_dev->mlock);
> -	ret = i2c_smbus_write_byte_data(chip->client, AD7152_REG_CFG2, data);
> -	if (ret < 0)
> +	ret = i2c_smbus_write_byte_data(chip->client,
> +			AD7152_REG_CFG2, AD7152_CFG2_OSR(i));
> +	if (ret < 0) {
> +		mutex_unlock(&indio_dev->mlock);
>  		return ret;
> +	}
>  
> -	chip->filter_rate_setup = data;
> +	chip->filter_rate_setup = i;
>  	mutex_unlock(&indio_dev->mlock);
>  
>  	return len;
>  }
>  
> -static IIO_DEV_ATTR_FILTER_RATE_SETUP(S_IRUGO | S_IWUSR,
> +static IIO_DEV_ATTR_SAMP_FREQ(S_IRUGO | S_IWUSR,
>  		ad7152_show_filter_rate_setup,
>  		ad7152_store_filter_rate_setup);
>  
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("200 50 20 17");
> +
>  static IIO_CONST_ATTR(in_capacitance_scale_available,
>  		      "0.000061050 0.000030525 0.000015263 0.000007631");
>  
>  static struct attribute *ad7152_attributes[] = {
> -	&iio_dev_attr_filter_rate_setup.dev_attr.attr,
> +	&iio_dev_attr_sampling_frequency.dev_attr.attr,
>  	&iio_dev_attr_in_capacitance0_calibbias_calibration.dev_attr.attr,
>  	&iio_dev_attr_in_capacitance1_calibbias_calibration.dev_attr.attr,
>  	&iio_dev_attr_in_capacitance0_calibscale_calibration.dev_attr.attr,
>  	&iio_dev_attr_in_capacitance1_calibscale_calibration.dev_attr.attr,
>  	&iio_const_attr_in_capacitance_scale_available.dev_attr.attr,
> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
>  	NULL,
>  };
>  
> @@ -339,7 +358,7 @@ static int ad7152_read_raw(struct iio_dev *indio_dev,
>  		if (ret < 0)
>  			goto out;
>  
> -		msleep(60); /* Slowest conversion time */
> +		msleep(ad7152_filter_rate_table[chip->filter_rate_setup][1]);
>  		/* Now read the actual register */
>  		ret = i2c_smbus_read_word_data(chip->client,
>  				ad7152_addresses[chan->channel][AD7152_DATA]);