On 07/09/2012 10:00 AM, Lars-Peter Clausen wrote:
> 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.
>
merged first 5 to togreg branch. Pull request may be a few days.
Jonathan
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
>
> ---
> No changes since v1
> ---
> drivers/iio/industrialio-buffer.c | 27 ++++++++++++++++++++-------
> include/linux/iio/iio.h | 4 ++++
> 2 files changed, 24 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,
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index 2afbb6f..be82936 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -363,12 +363,16 @@ struct iio_info {
> * @predisable: [DRIVER] function to run prior to marking buffer
> * disabled
> * @postdisable: [DRIVER] function to run after marking buffer disabled
> + * @validate_scan_mask: [DRIVER] function callback to check whether a given
> + * scan mask is valid for the device.
> */
> struct iio_buffer_setup_ops {
> int (*preenable)(struct iio_dev *);
> int (*postenable)(struct iio_dev *);
> int (*predisable)(struct iio_dev *);
> int (*postdisable)(struct iio_dev *);
> + bool (*validate_scan_mask)(struct iio_dev *indio_dev,
> + const unsigned long *scan_mask);
> };
>
> /**
>
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