Re: [PATCH v2 07/11] staging: iio: tsl2x7x: support 2.72 and 2.73 ALS increments

[Jonathan Cameron <jic23@kernel.org>]

On Thu,  3 May 2018 22:53:15 -0400
Brian Masney <masneyb@onstation.org> wrote:

> The driver assumed that the ALS increment was 2.72 ms, and the upper
> range was 696 ms. Some other supported devices use 2.73 ms - 699 ms.
> This patch adds support for the multiple ranges.
> 
> Signed-off-by: Brian Masney <masneyb@onstation.org>

My problem here is that this isn't compatible with the ABI for
available.   Originally it could only be used if we had short
list of possible values.  We did add the (currently poorly documented
which is my fault ;() option of defining it with limits and
interval, but this doesn't obey that format either.
see iio_format_avail_range
[min step max]

Ideally perhaps actually set it up to use read_avail callback
as then you'll get that for free.  I've not pushed it that heavily
as a way to do things because we obviously have a 'lot' of driver
that predate that core support and I don't want a rush to move
them over where it isn't useful.

Jonathan
> ---
> I debated whether or not this change should even be included. I feel
> pretty confident that I can cleanly fold the tsl2583 driver into this
> driver once the staging graduation is done. Those devices have an ALS
> range of 2.7 ms - 688.5 ms.
> 
>  drivers/staging/iio/light/tsl2x7x.c | 50 +++++++++++++++++++++++++++++--------
>  1 file changed, 40 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/staging/iio/light/tsl2x7x.c b/drivers/staging/iio/light/tsl2x7x.c
> index 9b32054713fb..e3e37501829f 100644
> --- a/drivers/staging/iio/light/tsl2x7x.c
> +++ b/drivers/staging/iio/light/tsl2x7x.c
> @@ -209,9 +209,9 @@ static const struct tsl2x7x_lux *tsl2x7x_default_lux_table_group[] = {
>  };
>  
>  static const struct tsl2x7x_settings tsl2x7x_default_settings = {
> -	.als_time = 255, /* 2.73 ms */
> +	.als_time = 255, /* 2.72 / 2.73 ms */
>  	.als_gain = 0,
> -	.prox_time = 255, /* 2.73 ms */
> +	.prox_time = 255, /* 2.72 / 2.73 ms */
>  	.prox_gain = 0,
>  	.wait_time = 255,
>  	.als_prox_config = 0,
> @@ -245,6 +245,24 @@ static const s16 tsl2x7x_prox_gain[] = {
>  	8
>  };
>  
> +struct tsl2x7x_int_time {
> +	int increment_us;
> +	char *display_range;
> +};
> +
> +static const struct tsl2x7x_int_time tsl2x7x_int_time[] = {
> +	[tsl2571] = { 2720, "0.00272 - 0.696" },
> +	[tsl2671] = { 2720, "0.00272 - 0.696" },
> +	[tmd2671] = { 2720, "0.00272 - 0.696" },
> +	[tsl2771] = { 2720, "0.00272 - 0.696" },
> +	[tmd2771] = { 2720, "0.00272 - 0.696" },
> +	[tsl2572] = { 2730, "0.00273 - 0.699" },
> +	[tsl2672] = { 2730, "0.00273 - 0.699" },
> +	[tmd2672] = { 2730, "0.00273 - 0.699" },
> +	[tsl2772] = { 2730, "0.00273 - 0.699" },
> +	[tmd2772] = { 2730, "0.00273 - 0.699" },
> +};
> +
>  /* Channel variations */
>  enum {
>  	ALS,
> @@ -626,7 +644,7 @@ static int tsl2x7x_chip_on(struct iio_dev *indio_dev)
>  
>  	/* set chip time scaling and saturation */
>  	als_count = 256 - chip->settings.als_time;
> -	als_time_us = als_count * 2720;
> +	als_time_us = als_count * tsl2x7x_int_time[chip->id].increment_us;
>  	chip->als_saturation = als_count * 768; /* 75% of full scale */
>  	chip->als_gain_time_scale = als_time_us *
>  		tsl2x7x_als_gain[chip->settings.als_gain];
> @@ -764,8 +782,16 @@ static IIO_CONST_ATTR(in_intensity0_calibscale_available, "1 8 16 120");
>  
>  static IIO_CONST_ATTR(in_proximity0_calibscale_available, "1 2 4 8");
>  
> -static IIO_CONST_ATTR(in_intensity0_integration_time_available,
> -		".00272 - .696");
> +static ssize_t
> +in_intensity0_integration_time_available_show(struct device *dev,
> +					      struct device_attribute *attr,
> +					      char *buf)
> +{
> +	struct tsl2X7X_chip *chip = iio_priv(dev_to_iio_dev(dev));
> +
> +	return snprintf(buf, PAGE_SIZE, "%s\n",
> +			tsl2x7x_int_time[chip->id].display_range);
> +}
>  
>  static ssize_t in_illuminance0_target_input_show(struct device *dev,
>  						 struct device_attribute *attr,
> @@ -1124,7 +1150,8 @@ static int tsl2x7x_read_raw(struct iio_dev *indio_dev,
>  		break;
>  	case IIO_CHAN_INFO_INT_TIME:
>  		*val = 0;
> -		*val2 = (256 - chip->settings.als_time) * 2720;
> +		*val2 = (256 - chip->settings.als_time) *
> +			tsl2x7x_int_time[chip->id].increment_us;
>  		ret = IIO_VAL_INT_PLUS_MICRO;
>  		break;
>  	default:
> @@ -1184,7 +1211,8 @@ static int tsl2x7x_write_raw(struct iio_dev *indio_dev,
>  		chip->settings.als_gain_trim = val;
>  		break;
>  	case IIO_CHAN_INFO_INT_TIME:
> -		chip->settings.als_time = 256 - (val2 / 2720);
> +		chip->settings.als_time = 256 -
> +			(val2 / tsl2x7x_int_time[chip->id].increment_us);
>  		break;
>  	default:
>  		return -EINVAL;
> @@ -1193,6 +1221,8 @@ static int tsl2x7x_write_raw(struct iio_dev *indio_dev,
>  	return tsl2x7x_invoke_change(indio_dev);
>  }
>  
> +static DEVICE_ATTR_RO(in_intensity0_integration_time_available);
> +
>  static DEVICE_ATTR_RW(in_illuminance0_target_input);
>  
>  static DEVICE_ATTR_WO(in_illuminance0_calibrate);
> @@ -1266,7 +1296,7 @@ static irqreturn_t tsl2x7x_event_handler(int irq, void *private)
>  
>  static struct attribute *tsl2x7x_ALS_device_attrs[] = {
>  	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
> -	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
> +	&dev_attr_in_intensity0_integration_time_available.attr,
>  	&dev_attr_in_illuminance0_target_input.attr,
>  	&dev_attr_in_illuminance0_calibrate.attr,
>  	&dev_attr_in_illuminance0_lux_table.attr,
> @@ -1280,7 +1310,7 @@ static struct attribute *tsl2x7x_PRX_device_attrs[] = {
>  
>  static struct attribute *tsl2x7x_ALSPRX_device_attrs[] = {
>  	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
> -	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
> +	&dev_attr_in_intensity0_integration_time_available.attr,
>  	&dev_attr_in_illuminance0_target_input.attr,
>  	&dev_attr_in_illuminance0_calibrate.attr,
>  	&dev_attr_in_illuminance0_lux_table.attr,
> @@ -1295,7 +1325,7 @@ static struct attribute *tsl2x7x_PRX2_device_attrs[] = {
>  
>  static struct attribute *tsl2x7x_ALSPRX2_device_attrs[] = {
>  	&iio_const_attr_in_intensity0_calibscale_available.dev_attr.attr,
> -	&iio_const_attr_in_intensity0_integration_time_available.dev_attr.attr,
> +	&dev_attr_in_intensity0_integration_time_available.attr,
>  	&dev_attr_in_illuminance0_target_input.attr,
>  	&dev_attr_in_illuminance0_calibrate.attr,
>  	&dev_attr_in_illuminance0_lux_table.attr,