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