diff options
Diffstat (limited to 'drivers/iio/dummy/iio_simple_dummy_buffer.c')
-rw-r--r-- | drivers/iio/dummy/iio_simple_dummy_buffer.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/iio/dummy/iio_simple_dummy_buffer.c b/drivers/iio/dummy/iio_simple_dummy_buffer.c new file mode 100644 index 0000000000..9b2f99449a --- /dev/null +++ b/drivers/iio/dummy/iio_simple_dummy_buffer.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2011 Jonathan Cameron + * + * Buffer handling elements of industrial I/O reference driver. + * Uses the kfifo buffer. + * + * To test without hardware use the sysfs trigger. + */ + +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/irq.h> +#include <linux/bitmap.h> + +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/trigger_consumer.h> +#include <linux/iio/triggered_buffer.h> + +#include "iio_simple_dummy.h" + +/* Some fake data */ + +static const s16 fakedata[] = { + [DUMMY_INDEX_VOLTAGE_0] = 7, + [DUMMY_INDEX_DIFFVOLTAGE_1M2] = -33, + [DUMMY_INDEX_DIFFVOLTAGE_3M4] = -2, + [DUMMY_INDEX_ACCELX] = 344, +}; + +/** + * iio_simple_dummy_trigger_h() - the trigger handler function + * @irq: the interrupt number + * @p: private data - always a pointer to the poll func. + * + * This is the guts of buffered capture. On a trigger event occurring, + * if the pollfunc is attached then this handler is called as a threaded + * interrupt (and hence may sleep). It is responsible for grabbing data + * from the device and pushing it into the associated buffer. + */ +static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p) +{ + struct iio_poll_func *pf = p; + struct iio_dev *indio_dev = pf->indio_dev; + int i = 0, j; + u16 *data; + + data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL); + if (!data) + goto done; + + /* + * Three common options here: + * hardware scans: + * certain combinations of channels make up a fast read. The capture + * will consist of all of them. Hence we just call the grab data + * function and fill the buffer without processing. + * software scans: + * can be considered to be random access so efficient reading is just + * a case of minimal bus transactions. + * software culled hardware scans: + * occasionally a driver may process the nearest hardware scan to avoid + * storing elements that are not desired. This is the fiddliest option + * by far. + * Here let's pretend we have random access. And the values are in the + * constant table fakedata. + */ + for_each_set_bit(j, indio_dev->active_scan_mask, indio_dev->masklength) + data[i++] = fakedata[j]; + + iio_push_to_buffers_with_timestamp(indio_dev, data, + iio_get_time_ns(indio_dev)); + + kfree(data); + +done: + /* + * Tell the core we are done with this trigger and ready for the + * next one. + */ + iio_trigger_notify_done(indio_dev->trig); + + return IRQ_HANDLED; +} + +static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = { +}; + +int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev) +{ + return iio_triggered_buffer_setup(indio_dev, NULL, + iio_simple_dummy_trigger_h, + &iio_simple_dummy_buffer_setup_ops); +} + +/** + * iio_simple_dummy_unconfigure_buffer() - release buffer resources + * @indio_dev: device instance state + */ +void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev) +{ + iio_triggered_buffer_cleanup(indio_dev); +} |