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author | Lars-Peter Clausen <lars@metafoo.de> | 2012-07-09 09:00:00 (GMT) |
---|---|---|
committer | Jonathan Cameron <jic23@kernel.org> | 2012-07-09 17:18:15 (GMT) |
commit | 939546d1a9f47ed169554c711e1e05965b84ffe1 (patch) | |
tree | 80ee898547145c1b202a77d3ca5f642809ba9778 /drivers/iio/industrialio-buffer.c | |
parent | c732a24c5a9392cf3738f5957e0d97d37c09e6e1 (diff) | |
download | linux-fsl-qoriq-939546d1a9f47ed169554c711e1e05965b84ffe1.tar.xz |
iio: Add callback to check whether a scan mask is valid
This is useful for cases where the number of valid scan masks grows
exponentially, but it is rather easy to check whether a mask is valid or not
programmatically.
An example of such a case is a device with multiple ADCs where each ADC has a
upstream MUX, which allows to select from a number of physical channels.
+-------+ +-------+
| | | | --- Channel 1
| ADC 1 |---| MUX 1 | --- ...
| | | | --- Channel M
+-------+ +-------+
. . .
. . .
. . .
+-------+ +-------+
| | | | --- Channel M * N + 1
| ADC N |---| MUX N | --- ...
| | | | --- Channel M * N + M
+-------+ +-------+
The number of necessary scan masks for this case is (M+1)**N - 1, on the other
hand it is easy to check whether subsets for each ADC of the scanmask have only
one bit set.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'drivers/iio/industrialio-buffer.c')
-rw-r--r-- | drivers/iio/industrialio-buffer.c | 27 |
1 files changed, 20 insertions, 7 deletions
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index 3d8d187..cc5db36 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -570,6 +570,15 @@ int iio_sw_buffer_preenable(struct iio_dev *indio_dev) } EXPORT_SYMBOL(iio_sw_buffer_preenable); +static bool iio_validate_scan_mask(struct iio_dev *indio_dev, + const unsigned long *mask) +{ + if (!indio_dev->setup_ops->validate_scan_mask) + return true; + + return indio_dev->setup_ops->validate_scan_mask(indio_dev, mask); +} + /** * iio_scan_mask_set() - set particular bit in the scan mask * @buffer: the buffer whose scan mask we are interested in @@ -589,27 +598,31 @@ int iio_scan_mask_set(struct iio_dev *indio_dev, return -ENOMEM; if (!indio_dev->masklength) { WARN_ON("trying to set scanmask prior to registering buffer\n"); - kfree(trialmask); - return -EINVAL; + goto err_invalid_mask; } bitmap_copy(trialmask, buffer->scan_mask, indio_dev->masklength); set_bit(bit, trialmask); + if (!iio_validate_scan_mask(indio_dev, trialmask)) + goto err_invalid_mask; + if (indio_dev->available_scan_masks) { mask = iio_scan_mask_match(indio_dev->available_scan_masks, indio_dev->masklength, trialmask); - if (!mask) { - kfree(trialmask); - return -EINVAL; - } + if (!mask) + goto err_invalid_mask; } bitmap_copy(buffer->scan_mask, trialmask, indio_dev->masklength); kfree(trialmask); return 0; -}; + +err_invalid_mask: + kfree(trialmask); + return -EINVAL; +} EXPORT_SYMBOL_GPL(iio_scan_mask_set); int iio_scan_mask_query(struct iio_dev *indio_dev, |