This 2nd patch set brings a new approach to hadware buffers, as a result of the feedback from the first patch set. It also fixes a few issues in the bmc150 refactor patches found during the review. It builds on the patch of Josselin and Yannick but with the timeout parameter removed, as the poll timeout can be used instead (for non-blocking reads). In order to provide support for hardware buffers a driver must expose a watermark trigger, a function to set the watermark level in hadware and a function to flush the hardware buffers. It must also expose the maximum number of samples that the hardware buffer can hold. When the watermark trigger is set the driver must make sure that the hardware buffer is operational so that we can hold samples until the watermark level is reached. When the watermark level is reached (the watermark triggered is activated) and when the flush operation is called, the driver must read all of the entries from the hardware buffers and store then in the device buffer. >From the userspace point of view, to enable hardware buffers, the application must set the device buffer and the watermark level to an appropriate value then switch to using the watermark trigger. At that point the data will be hold in the hadware buffer and the processor will not be interrupted until the hadware buffer level reaches the watermark level. The application can force a flush operation when reading from the device and there is not enough data available to satisfy the request. This allows the application to balance power-consumption and latency by setting a poll timeout and forcing a non-blocking read when the poll timeout expires which allows the application to retrieve any samples stored in the hardware buffer. Josselin Costanzi (1): iio: add watermark logic to iio read and poll Octavian Purdila (10): iio: buffer: fix custom buffer attributes copy iio: buffer: refactor buffer attributes setup iio: add support for hardware fifo iio: bmc150: refactor slope duration and threshold update iio: bmc150: refactor interrupt enabling iio: bmc150: exit early if event / trigger state is not changed iio: bmc150: introduce bmc150_accel_interrupt iio: bmc150: introduce bmc150_accel_trigger iio: bmc150: introduce bmc150_accel_event iio: bmc150: add support for hardware fifo Documentation/ABI/testing/sysfs-bus-iio | 32 ++ drivers/iio/accel/bmc150-accel.c | 919 ++++++++++++++++++++----------- drivers/iio/industrialio-buffer.c | 179 ++++-- drivers/iio/kfifo_buf.c | 11 +- drivers/staging/iio/accel/sca3000_ring.c | 4 +- include/linux/iio/buffer.h | 9 +- include/linux/iio/iio.h | 17 + 7 files changed, 819 insertions(+), 352 deletions(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
