Re: [PATCH v2 7/7] iio: light: vcnl4000: Add calibration bias for 4040/4200

[Jonathan Cameron <jic23@kernel.org>]

On Tue, 9 May 2023 16:01:53 +0200
Astrid Rost <astrid.rost@axis.com> wrote:

> The calibration bias is setting the LED current to change
> the detection distance.
> Add read/write attribute for proximity calibration bias and read
> attribute for available values.
> This is supported for vcnl4040 and vcnl4200.
Another interesting mapping onto standard ABI.
I guess it sort of ends up mapping to calibbias so I think I'm fine with this
one if other reviewers agree.

From a quick look (run out of time again today!) this looks fine to me.
Will take another look at v3.

Thanks,

Jonathan

> 
> Signed-off-by: Astrid Rost <astrid.rost@axis.com>
> ---
>  drivers/iio/light/vcnl4000.c | 97 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 94 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index 1fd1eaaa4620..f0bf078dcdbe 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -91,6 +91,7 @@
>  #define VCNL4040_CONF1_PS_PERS	GENMASK(5, 4) /* Proximity interrupt persistence setting */
>  #define VCNL4040_PS_CONF2_PS_INT	GENMASK(9, 8) /* Proximity interrupt mode */
>  #define VCNL4040_PS_CONF3_MPS		GENMASK(6, 5) /* Proximity multi pulse number */
> +#define VCNL4040_PS_MS_LED_I		GENMASK(10, 8) /* Proximity current */
>  #define VCNL4040_PS_IF_AWAY		BIT(8) /* Proximity event cross low threshold */
>  #define VCNL4040_PS_IF_CLOSE		BIT(9) /* Proximity event cross high threshold */
>  #define VCNL4040_ALS_RISING		BIT(12) /* Ambient Light cross high threshold */
> @@ -157,6 +158,17 @@ static const int vcnl4200_als_it_times[][2] = {
>  	{0, 400000},
>  };
>  
> +static const int vcnl4040_ps_calibbias_ua[][2] = {
> +	{0, 50000},
> +	{0, 75000},
> +	{0, 100000},
> +	{0, 120000},
> +	{0, 140000},
> +	{0, 160000},
> +	{0, 180000},
> +	{0, 200000},
> +};
> +
>  static const int vcnl4040_als_debounce_count[] = {1, 2, 4, 8};
>  static const int vcnl4040_ps_debounce_count[] = {1, 2, 3, 4};
>  static const int vcnl4040_ps_oversampling_ratio[] = {1, 2, 4, 8};
> @@ -838,6 +850,57 @@ static ssize_t vcnl4040_write_ps_oversampling_ratio(struct vcnl4000_data *data,
>  	return ret;
>  }
>  
> +static ssize_t vcnl4040_read_ps_calibbias(struct vcnl4000_data *data, int *val, int *val2)
> +{
> +	int ret;
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF3);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = FIELD_GET(VCNL4040_PS_MS_LED_I, ret);
> +
> +	if (ret >= ARRAY_SIZE(vcnl4040_ps_calibbias_ua))
> +		return -EINVAL;
> +
> +	*val = vcnl4040_ps_calibbias_ua[ret][0];
> +	*val2 = vcnl4040_ps_calibbias_ua[ret][1];
> +
> +	return ret;
> +}
> +
> +static ssize_t vcnl4040_write_ps_calibbias(struct vcnl4000_data *data, int val)
> +{
> +	unsigned int i;
> +	int ret, index = -1;
> +	u16 regval;
> +
> +	for (i = 0; i < ARRAY_SIZE(vcnl4040_ps_calibbias_ua); i++) {
> +		if (val == vcnl4040_ps_calibbias_ua[i][1]) {
> +			index = i;
> +			break;
> +		}
> +	}
> +
> +	if (index < 0)
> +		return -EINVAL;
> +
> +	mutex_lock(&data->vcnl4000_lock);
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF3);
> +	if (ret < 0)
> +		goto out;
> +
> +	regval = (ret & ~VCNL4040_PS_MS_LED_I) |
> +	    FIELD_PREP(VCNL4040_PS_MS_LED_I, index);
> +	ret = i2c_smbus_write_word_data(data->client, VCNL4200_PS_CONF3,
> +					regval);
> +
> +out:
> +	mutex_unlock(&data->vcnl4000_lock);
> +	return ret;
> +}
> +
>  static int vcnl4000_read_raw(struct iio_dev *indio_dev,
>  				struct iio_chan_spec const *chan,
>  				int *val, int *val2, long mask)
> @@ -912,7 +975,16 @@ static int vcnl4000_read_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> -
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		switch (chan->type) {
> +		case IIO_PROXIMITY:
> +			ret = vcnl4040_read_ps_calibbias(data, val, val2);
> +			if (ret < 0)
> +				return ret;
> +			return IIO_VAL_INT_PLUS_MICRO;
> +		default:
> +			return -EINVAL;
> +		}
>  	default:
>  		return -EINVAL;
>  	}
> @@ -952,6 +1024,13 @@ static int vcnl4040_write_raw(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		switch (chan->type) {
> +		case IIO_PROXIMITY:
> +			return vcnl4040_write_ps_calibbias(data, val2);
> +		default:
> +			return -EINVAL;
> +		}
>  	default:
>  		return -EINVAL;
>  	}
> @@ -1015,6 +1094,16 @@ static int vcnl4040_read_avail(struct iio_dev *indio_dev,
>  		default:
>  			return -EINVAL;
>  		}
> +	case IIO_CHAN_INFO_CALIBBIAS:
> +		switch (chan->type) {
> +		case IIO_PROXIMITY:
> +			*vals = (int *)vcnl4040_ps_calibbias_ua;
> +			*length = 2 * ARRAY_SIZE(vcnl4040_ps_calibbias_ua);
> +			*type = IIO_VAL_INT_PLUS_MICRO;
> +			return IIO_AVAIL_LIST;
> +		default:
> +			return -EINVAL;
> +	}
>  	default:
>  		return -EINVAL;
>  	}
> @@ -1739,10 +1828,12 @@ static const struct iio_chan_spec vcnl4040_channels[] = {
>  		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>  			BIT(IIO_CHAN_INFO_INT_TIME) |
>  			BIT(IIO_CHAN_INFO_DEBOUNCE_COUNT) |
> -			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> +			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
> +			BIT(IIO_CHAN_INFO_CALIBBIAS),
>  		.info_mask_separate_available = BIT(IIO_CHAN_INFO_INT_TIME) |
>  			BIT(IIO_CHAN_INFO_DEBOUNCE_COUNT) |
> -			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> +			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO) |
> +			BIT(IIO_CHAN_INFO_CALIBBIAS),
>  		.ext_info = vcnl4000_ext_info,
>  		.event_spec = vcnl4040_event_spec,
>  		.num_event_specs = ARRAY_SIZE(vcnl4040_event_spec),