107 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (c) 2011 Jonathan Cameron4 *5 * Buffer handling elements of industrial I/O reference driver.6 * Uses the kfifo buffer.7 *8 * To test without hardware use the sysfs trigger.9 */10 11#include <linux/kernel.h>12#include <linux/export.h>13#include <linux/slab.h>14#include <linux/interrupt.h>15#include <linux/irq.h>16#include <linux/bitmap.h>17 18#include <linux/iio/iio.h>19#include <linux/iio/buffer.h>20#include <linux/iio/trigger_consumer.h>21#include <linux/iio/triggered_buffer.h>22 23#include "iio_simple_dummy.h"24 25/* Some fake data */26 27static const s16 fakedata[] = {28 [DUMMY_INDEX_VOLTAGE_0] = 7,29 [DUMMY_INDEX_DIFFVOLTAGE_1M2] = -33,30 [DUMMY_INDEX_DIFFVOLTAGE_3M4] = -2,31 [DUMMY_INDEX_ACCELX] = 344,32};33 34/**35 * iio_simple_dummy_trigger_h() - the trigger handler function36 * @irq: the interrupt number37 * @p: private data - always a pointer to the poll func.38 *39 * This is the guts of buffered capture. On a trigger event occurring,40 * if the pollfunc is attached then this handler is called as a threaded41 * interrupt (and hence may sleep). It is responsible for grabbing data42 * from the device and pushing it into the associated buffer.43 */44static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)45{46 struct iio_poll_func *pf = p;47 struct iio_dev *indio_dev = pf->indio_dev;48 int i = 0, j;49 u16 *data;50 51 data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);52 if (!data)53 goto done;54 55 /*56 * Three common options here:57 * hardware scans:58 * certain combinations of channels make up a fast read. The capture59 * will consist of all of them. Hence we just call the grab data60 * function and fill the buffer without processing.61 * software scans:62 * can be considered to be random access so efficient reading is just63 * a case of minimal bus transactions.64 * software culled hardware scans:65 * occasionally a driver may process the nearest hardware scan to avoid66 * storing elements that are not desired. This is the fiddliest option67 * by far.68 * Here let's pretend we have random access. And the values are in the69 * constant table fakedata.70 */71 iio_for_each_active_channel(indio_dev, j)72 data[i++] = fakedata[j];73 74 iio_push_to_buffers_with_timestamp(indio_dev, data,75 iio_get_time_ns(indio_dev));76 77 kfree(data);78 79done:80 /*81 * Tell the core we are done with this trigger and ready for the82 * next one.83 */84 iio_trigger_notify_done(indio_dev->trig);85 86 return IRQ_HANDLED;87}88 89static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = {90};91 92int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)93{94 return iio_triggered_buffer_setup(indio_dev, NULL,95 iio_simple_dummy_trigger_h,96 &iio_simple_dummy_buffer_setup_ops);97}98 99/**100 * iio_simple_dummy_unconfigure_buffer() - release buffer resources101 * @indio_dev: device instance state102 */103void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)104{105 iio_triggered_buffer_cleanup(indio_dev);106}107