iio: core: add function to retrieve active_scan_mask index

Add a function to retrieve the index of the active scan mask inside the
available scan masks array.

As in iio_scan_mask_match and iio_sanity_check_avail_scan_masks,
this function does not handle multi-long masks correctly.
It only checks the first long to be zero, and will use such mask
as a terminator even if there was bits set after the first long.

This should be fine since the available_scan_mask has already been
sanity tested using iio_sanity_check_avail_scan_masks.

See iio_scan_mask_match and iio_sanity_check_avail_scan_masks for
more details

Signed-off-by: Julien Stephan <jstephan@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240731-ad7380-add-single-ended-chips-v2-2-cd63bf05744c@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index e6fad8a6a1fc6d9f0aa2863b9c7476ea67c6f22b..f18f48c7eb037299f625a1061557aa1765ebc4d9 100644 (file)
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1965,6 +1965,49 @@ static void iio_sanity_check_avail_scan_masks(struct iio_dev *indio_dev)
        }
 }
 
+/**
+ * iio_active_scan_mask_index - Get index of the active scan mask inside the
+ * available scan masks array
+ * @indio_dev: the IIO device containing the active and available scan masks
+ *
+ * Returns: the index or -EINVAL if  active_scan_mask is not set
+ */
+int iio_active_scan_mask_index(struct iio_dev *indio_dev)
+
+{
+       const unsigned long *av_masks;
+       unsigned int masklength = iio_get_masklength(indio_dev);
+       int i = 0;
+
+       if (!indio_dev->active_scan_mask)
+               return -EINVAL;
+
+       /*
+        * As in iio_scan_mask_match and iio_sanity_check_avail_scan_masks,
+        * the condition here do not handle multi-long masks correctly.
+        * It only checks the first long to be zero, and will use such mask
+        * as a terminator even if there was bits set after the first long.
+        *
+        * This should be fine since the available_scan_mask has already been
+        * sanity tested using iio_sanity_check_avail_scan_masks.
+        *
+        * See iio_scan_mask_match and iio_sanity_check_avail_scan_masks for
+        * more details
+        */
+       av_masks = indio_dev->available_scan_masks;
+       while (*av_masks) {
+               if (indio_dev->active_scan_mask == av_masks)
+                       return i;
+               av_masks += BITS_TO_LONGS(masklength);
+               i++;
+       }
+
+       dev_warn(indio_dev->dev.parent,
+                "active scan mask is not part of the avaialable scan masks\n");
+       return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(iio_active_scan_mask_index);
+
 int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod)
 {
        struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index f6c0499853bbae6bdae53191923a0d20e4a2a21a..3a735a9a9eae4e2f142858428e693fd0c499590f 100644 (file)
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -864,6 +864,8 @@ static inline unsigned int iio_get_masklength(const struct iio_dev *indio_dev)
        return ACCESS_PRIVATE(indio_dev, masklength);
 }
 
+int iio_active_scan_mask_index(struct iio_dev *indio_dev);
+
 /**
  * iio_for_each_active_channel - Iterated over active channels
  * @indio_dev: the IIO device