[PATCH v2 0/2] iio: light: Report the available lists via read_avail()

[PATCH v2 0/2] iio: light: Report the available lists via read_avail()

[Arka Mondal]

These are patches 1 and 3 of the v1 series. Patches 2, 4, 5 and 6 are
applied and are not resent.

Changes since v1:

- isl29125: the available bit goes in info_mask_shared_by_all_available
  instead of info_mask_shared_by_type_available, which is the sharing
  level that names the file scale_available, so the attribute keeps the
  name it has and no ABI changes. The Fixes: tag is gone with it, and
  the patch is a cleanup rather than a fix.

- max44009: the list is IIO_VAL_INT_PLUS_MICRO instead of
  IIO_VAL_INT_PLUS_NANO. All eight values are a whole number of
  microseconds, so three zeros go and nothing is rounded.

I loaded both drivers against CONFIG_I2C_STUB under qemu and read the
attributes. isl29125 shows in_intensity_scale and scale_available, no
in_intensity_scale_available, and scale_available still reads
0.005722 0.152590. max44009 shows in_illuminance_integration_time_available
reading 0.800000 0.400000 0.200000 0.100000 0.050000 0.025000 0.012500 0.006250,
and no unprefixed name.

Link: https://lore.kernel.org/r/20261102074700.63075-1-arka@arkamondal.net

Arka Mondal (2):
  iio: light: isl29125: Report the scale list via read_avail()
  iio: light: max44009: Report the integration time via read_avail()

 drivers/iio/light/isl29125.c | 29 +++++++++++++++-------
 drivers/iio/light/max44009.c | 48 ++++++++++++++++++++----------------
 2 files changed, 47 insertions(+), 30 deletions(-)


base-commit: d135ab453a7400a34930bdda1ef4bdc8acfac80e
-- 
2.56.0

[PATCH v2 1/2] iio: light: isl29125: Report the scale list via read_avail()

[Arka Mondal]

The scales the intensity channels accept are listed by a custom
attribute built with IIO_CONST_ATTR and named scale_available.

Report the two values through read_avail() and drop the attribute
group. The available bit goes in info_mask_shared_by_all_available,
the sharing level the core names scale_available, so the file keeps
the name it has. The scale itself stays in info_mask_shared_by_type
and is still in_intensity_scale. veml6030 and ti-ads1015 hold
IIO_CHAN_INFO_SCALE in info_mask_separate and list it under
info_mask_shared_by_all_available, so the pairing is already in use.

The two values and the text they print do not change.

Signed-off-by: Arka Mondal <arka@arkamondal.net>
---

Notes:
    No hardware available. Loaded against CONFIG_I2C_STUB under qemu:
    in_intensity_scale and scale_available are both present,
    in_intensity_scale_available is not, and scale_available reads
    0.005722 0.152590.

 drivers/iio/light/isl29125.c | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/light/isl29125.c b/drivers/iio/light/isl29125.c
index 9e0b7e6a3ecf..35a378cc3990 100644
--- a/drivers/iio/light/isl29125.c
+++ b/drivers/iio/light/isl29125.c
@@ -58,6 +58,7 @@ struct isl29125_data {
 	.modified = 1, \
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SCALE), \
 	.channel2 = IIO_MOD_LIGHT_##_color, \
 	.scan_index = _si, \
 	.scan_type = { \
@@ -198,21 +199,31 @@ static irqreturn_t isl29125_trigger_handler(int irq, void *p)
 	return IRQ_HANDLED;
 }
 
-static IIO_CONST_ATTR(scale_available, "0.005722 0.152590");
-
-static struct attribute *isl29125_attributes[] = {
-	&iio_const_attr_scale_available.dev_attr.attr,
-	NULL
+static const int isl29125_scale_avail[] = {
+	0, ISL29125_SENSING_RANGE_0,
+	0, ISL29125_SENSING_RANGE_1,
 };
 
-static const struct attribute_group isl29125_attribute_group = {
-	.attrs = isl29125_attributes,
-};
+static int isl29125_read_avail(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       const int **vals, int *type, int *length,
+			       long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		*vals = isl29125_scale_avail;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = ARRAY_SIZE(isl29125_scale_avail);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
 
 static const struct iio_info isl29125_info = {
 	.read_raw = isl29125_read_raw,
 	.write_raw = isl29125_write_raw,
-	.attrs = &isl29125_attribute_group,
+	.read_avail = isl29125_read_avail,
 };
 
 static int isl29125_buffer_postenable(struct iio_dev *indio_dev)
-- 
2.56.0

[PATCH v2 2/2] iio: light: max44009: Report the integration time via read_avail()

[Arka Mondal]

The integration times the light channel accepts are listed by a custom
attribute named illuminance_integration_time_available. That name has
no in_ prefix, so it is registered at the device level instead of
beside in_illuminance_integration_time, and userspace looking for
in_illuminance_integration_time_available finds nothing.

Report the list through read_avail() and drop the custom attribute.
All eight values are a whole number of microseconds, so they go in as
IIO_VAL_INT_PLUS_MICRO pairs with nothing rounded. The values do not
change; the core prints them with six decimals, so the attribute reads
0.800000 down to 0.006250 instead of 0.8 down to 0.00625. read_raw()
still reports the time itself as IIO_VAL_INT_PLUS_NANO.

Fixes: 6aef699a7d7e ("iio: light: add driver for MAX44009")
Signed-off-by: Arka Mondal <arka@arkamondal.net>
---

Notes:
    No hardware available. Loaded against CONFIG_I2C_STUB under qemu:
    in_illuminance_integration_time_available reads 0.800000 0.400000
    0.200000 0.100000 0.050000 0.025000 0.012500 0.006250, and the
    unprefixed name is gone.

 drivers/iio/light/max44009.c | 48 ++++++++++++++++++++----------------
 1 file changed, 27 insertions(+), 21 deletions(-)

diff --git a/drivers/iio/light/max44009.c b/drivers/iio/light/max44009.c
index 82b8a806c5fa..8a57b9812f7f 100644
--- a/drivers/iio/light/max44009.c
+++ b/drivers/iio/light/max44009.c
@@ -66,15 +66,16 @@ static const u32 max44009_int_time_ns_array[] = {
 	6250000,  /* Manual mode only */
 };
 
-static const char max44009_int_time_str[] =
-	"0.8 "
-	"0.4 "
-	"0.2 "
-	"0.1 "
-	"0.05 "
-	"0.025 "
-	"0.0125 "
-	"0.00625";
+static const int max44009_int_time_avail[] = {
+	0, 800000,
+	0, 400000,
+	0, 200000,
+	0, 100000,
+	0, 50000,
+	0, 25000,
+	0, 12500,
+	0, 6250,
+};
 
 struct max44009_data {
 	struct i2c_client *client;
@@ -101,6 +102,7 @@ static const struct iio_chan_spec max44009_channels[] = {
 		.type = IIO_LIGHT,
 		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
 				      BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_INT_TIME),
 		.event_spec = max44009_event_spec,
 		.num_event_specs = ARRAY_SIZE(max44009_event_spec),
 	},
@@ -284,17 +286,21 @@ static int max44009_read_raw(struct iio_dev *indio_dev,
 	}
 }
 
-static IIO_CONST_ATTR(illuminance_integration_time_available,
-		      max44009_int_time_str);
-
-static struct attribute *max44009_attributes[] = {
-	&iio_const_attr_illuminance_integration_time_available.dev_attr.attr,
-	NULL,
-};
-
-static const struct attribute_group max44009_attribute_group = {
-	.attrs = max44009_attributes,
-};
+static int max44009_read_avail(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       const int **vals, int *type, int *length,
+			       long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		*vals = max44009_int_time_avail;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = ARRAY_SIZE(max44009_int_time_avail);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
 
 static int max44009_threshold_byte_from_fraction(int integral, int fractional)
 {
@@ -464,7 +470,7 @@ static const struct iio_info max44009_info = {
 	.read_event_config = max44009_read_event_config,
 	.write_event_value = max44009_write_event_value,
 	.write_event_config = max44009_write_event_config,
-	.attrs = &max44009_attribute_group,
+	.read_avail = max44009_read_avail,
 };
 
 static irqreturn_t max44009_threaded_irq_handler(int irq, void *p)
-- 
2.56.0

Re: [PATCH v2 2/2] iio: light: max44009: Report the integration time via read_avail()

[Andy Shevchenko]

On Mon, Nov 09, 2026 at 02:07:38PM +0900, Arka Mondal wrote:
> The integration times the light channel accepts are listed by a custom
> attribute named illuminance_integration_time_available. That name has
> no in_ prefix, so it is registered at the device level instead of
> beside in_illuminance_integration_time, and userspace looking for
> in_illuminance_integration_time_available finds nothing.
> 
> Report the list through read_avail() and drop the custom attribute.

Will break it user space?

> All eight values are a whole number of microseconds, so they go in as
> IIO_VAL_INT_PLUS_MICRO pairs with nothing rounded. The values do not
> change; the core prints them with six decimals, so the attribute reads
> 0.800000 down to 0.006250 instead of 0.8 down to 0.00625. read_raw()
> still reports the time itself as IIO_VAL_INT_PLUS_NANO.

...

> +static const int max44009_int_time_avail[] = {
> +	0, 800000,
> +	0, 400000,
> +	0, 200000,
> +	0, 100000,
> +	0, 50000,
> +	0, 25000,
> +	0, 12500,
> +	0, 6250,
> +};

Make it 2d array.

-- 
With Best Regards,
Andy Shevchenko