Re: [PATCH 4/4] iio: accel: adxl345: add sampling frequency support

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 17 Jun 2018 00:04:43 +0900
Akinobu Mita <akinobu.mita@gmail.com> wrote:

> The ADXL345 provides selectable output data rate.  This adds the iio
> channel information for the sampling frequency with that feature.
> 
> Cc: Eva Rachel Retuya <eraretuya@gmail.com>
> Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
> Cc: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Looks good to me will pick up once patch 3 discussion is sorted.

Thanks,

Jonathan

> ---
>  drivers/iio/accel/adxl345_core.c | 61 ++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 61 insertions(+)
> 
> diff --git a/drivers/iio/accel/adxl345_core.c b/drivers/iio/accel/adxl345_core.c
> index a392f9e..80e60c5 100644
> --- a/drivers/iio/accel/adxl345_core.c
> +++ b/drivers/iio/accel/adxl345_core.c
> @@ -14,6 +14,7 @@
>  #include <linux/regmap.h>
>  
>  #include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
>  
>  #include "adxl345.h"
>  
> @@ -21,12 +22,15 @@
>  #define ADXL345_REG_OFSX		0x1e
>  #define ADXL345_REG_OFSY		0x1f
>  #define ADXL345_REG_OFSZ		0x20
> +#define ADXL345_REG_BW_RATE		0x2C
>  #define ADXL345_REG_POWER_CTL		0x2D
>  #define ADXL345_REG_DATA_FORMAT		0x31
>  #define ADXL345_REG_DATAX0		0x32
>  #define ADXL345_REG_DATAY0		0x34
>  #define ADXL345_REG_DATAZ0		0x36
>  
> +#define ADXL345_BW_RATE			GENMASK(3, 0)
> +
>  #define ADXL345_POWER_CTL_MEASURE	BIT(3)
>  #define ADXL345_POWER_CTL_STANDBY	0x00
>  
> @@ -59,6 +63,7 @@ struct adxl345_data {
>  	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |			\
>  		BIT(IIO_CHAN_INFO_CALIBBIAS),				\
>  	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |		\
> +		BIT(IIO_CHAN_INFO_SAMP_FREQ) |				\
>  		BIT(IIO_CHAN_INFO_CALIBSCALE),				\
>  	.scan_index = si,						\
>  }
> @@ -69,6 +74,28 @@ static const struct iio_chan_spec adxl345_channels[] = {
>  	ADXL345_CHANNEL(2, Z),
>  };
>  
> +static const struct {
> +	int val;
> +	int val2;
> +} adxl345_samp_freq_table[] = {
> +	{ 0, 97656 },
> +	{ 0, 195313 },
> +	{ 0, 390625 },
> +	{ 0, 781250 },
> +	{ 1, 562500 },
> +	{ 3, 125000 },
> +	{ 6, 250000 },
> +	{ 12, 500000 },
> +	{ 25, 0 },
> +	{ 50, 0 },
> +	{ 100, 0 },
> +	{ 200, 0 },
> +	{ 400, 0 },
> +	{ 800, 0 },
> +	{ 1600, 0 },
> +	{ 3200, 0 },
> +};
> +
>  static int adxl345_read_raw(struct iio_dev *indio_dev,
>  			    struct iio_chan_spec const *chan,
>  			    int *val, int *val2, long mask)
> @@ -114,6 +141,15 @@ static int adxl345_read_raw(struct iio_dev *indio_dev,
>  		*val2 = adxl345_uscale * 4;
>  
>  		return IIO_VAL_INT_PLUS_MICRO;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		ret = regmap_read(data->regmap, ADXL345_REG_BW_RATE, &regval);
> +		if (ret < 0)
> +			return ret;
> +		regval &= ADXL345_BW_RATE;
> +		*val = adxl345_samp_freq_table[regval].val;
> +		*val2 = adxl345_samp_freq_table[regval].val2;
> +
> +		return IIO_VAL_INT_PLUS_MICRO;
>  	}
>  
>  	return -EINVAL;
> @@ -125,18 +161,43 @@ static int adxl345_write_raw(struct iio_dev *indio_dev,
>  {
>  	struct adxl345_data *data = iio_priv(indio_dev);
>  	int ret;
> +	int i;
>  
>  	switch (mask) {
>  	case IIO_CHAN_INFO_CALIBBIAS:
>  		ret = regmap_write(data->regmap,
>  				   ADXL345_REG_OFSX + chan->scan_index, val);
>  		return ret;
> +	case IIO_CHAN_INFO_SAMP_FREQ:
> +		for (i = 0; i < ARRAY_SIZE(adxl345_samp_freq_table); i++) {
> +			if (adxl345_samp_freq_table[i].val == val &&
> +			    adxl345_samp_freq_table[i].val2 == val2) {
> +				return regmap_update_bits(data->regmap,
> +							ADXL345_REG_BW_RATE,
> +							ADXL345_BW_RATE, i);
> +			}
> +		}
> +		return -EINVAL;
>  	}
>  
>  	return -EINVAL;
>  }
>  
> +static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(
> +"0.097656 0.195313 0.390625 0.78125 1.5625 3.125 6.25 12.5 25 50 100 200 400 800 1600 3200"
> +);
> +
> +static struct attribute *adxl345_attrs[] = {
> +	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
> +	NULL,
> +};
> +
> +static const struct attribute_group adxl345_attrs_group = {
> +	.attrs = adxl345_attrs,
> +};
> +
>  static const struct iio_info adxl345_info = {
> +	.attrs		= &adxl345_attrs_group,
>  	.read_raw	= adxl345_read_raw,
>  	.write_raw	= adxl345_write_raw,
>  };