diff options
Diffstat (limited to 'drivers/iio')
| -rw-r--r-- | drivers/iio/industrialio-core.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c index c77745b594bd..34e1f8d0071c 100644 --- a/drivers/iio/industrialio-core.c +++ b/drivers/iio/industrialio-core.c @@ -1896,6 +1896,66 @@ static int iio_check_extended_name(const struct iio_dev *indio_dev) static const struct iio_buffer_setup_ops noop_ring_setup_ops; +static void iio_sanity_check_avail_scan_masks(struct iio_dev *indio_dev) +{ + unsigned int num_masks, masklength, longs_per_mask; + const unsigned long *av_masks; + int i; + + av_masks = indio_dev->available_scan_masks; + masklength = indio_dev->masklength; + longs_per_mask = BITS_TO_LONGS(masklength); + + /* + * The code determining how many available_scan_masks is in the array + * will be assuming the end of masks when first long with all bits + * zeroed is encountered. This is incorrect for masks where mask + * consists of more than one long, and where some of the available masks + * has long worth of bits zeroed (but has subsequent bit(s) set). This + * is a safety measure against bug where array of masks is terminated by + * a single zero while mask width is greater than width of a long. + */ + if (longs_per_mask > 1) + dev_warn(indio_dev->dev.parent, + "multi long available scan masks not fully supported\n"); + + if (bitmap_empty(av_masks, masklength)) + dev_warn(indio_dev->dev.parent, "empty scan mask\n"); + + for (num_masks = 0; *av_masks; num_masks++) + av_masks += longs_per_mask; + + if (num_masks < 2) + return; + + av_masks = indio_dev->available_scan_masks; + + /* + * Go through all the masks from first to one before the last, and see + * that no mask found later from the available_scan_masks array is a + * subset of mask found earlier. If this happens, then the mask found + * later will never get used because scanning the array is stopped when + * the first suitable mask is found. Drivers should order the array of + * available masks in the order of preference (presumably the least + * costy to access masks first). + */ + for (i = 0; i < num_masks - 1; i++) { + const unsigned long *mask1; + int j; + + mask1 = av_masks + i * longs_per_mask; + for (j = i + 1; j < num_masks; j++) { + const unsigned long *mask2; + + mask2 = av_masks + j * longs_per_mask; + if (bitmap_subset(mask2, mask1, masklength)) + dev_warn(indio_dev->dev.parent, + "available_scan_mask %d subset of %d. Never used\n", + j, i); + } + } +} + 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); @@ -1934,6 +1994,9 @@ int __iio_device_register(struct iio_dev *indio_dev, struct module *this_mod) goto error_unreg_debugfs; } + if (indio_dev->available_scan_masks) + iio_sanity_check_avail_scan_masks(indio_dev); + ret = iio_device_register_sysfs(indio_dev); if (ret) { dev_err(indio_dev->dev.parent, |