staging:iio:dummy Add buffered reading support

Very simple buffered reading.  Did not provide a trigger as
the sysfs trigger already meets that requirement.

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jonathan Cameron 2011-10-14 16:34:15 +01:00 committed by Greg Kroah-Hartman
parent e6477000fc
commit 9ad2e2e1d6
5 changed files with 303 additions and 9 deletions

View File

@ -89,6 +89,11 @@ config IIO_SIMPLE_DUMMY_EVENTS
help
Add some dummy events to the simple dummy driver.
config IIO_SIMPLE_DUMMY_BUFFER
boolean "Buffered capture support"
depends on IIO_KFIFO_BUF
help
Add buffered data capture to the simple dummy driver.
endif # IIO_SIMPLE_DUMMY

View File

@ -13,6 +13,7 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
obj-$(CONFIG_IIO_SIMPLE_DUMMY) += iio_dummy.o
iio_dummy-y := iio_simple_dummy.o
iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_EVENTS) += iio_simple_dummy_events.o
iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o

View File

@ -21,6 +21,7 @@
#include "iio.h"
#include "sysfs.h"
#include "buffer_generic.h"
#include "iio_simple_dummy.h"
/*
@ -82,7 +83,14 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* when converting to standard units (microvolts)
*/
(1 << IIO_CHAN_INFO_SCALE_SEPARATE),
/* The ordering of elements in the buffer via an enum */
.scan_index = voltage0,
.scan_type = { /* Description of storage in buffer */
.sign = 'u', /* unsigned */
.realbits = 13, /* 13 bits */
.storagebits = 16, /* 16 bits used for storage */
.shift = 0, /* zero shift */
},
#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
/*
* simple event - triggered when value rises above
@ -110,6 +118,13 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* input channels of type IIO_VOLTAGE.
*/
(1 << IIO_CHAN_INFO_SCALE_SHARED),
.scan_index = diffvoltage1m2,
.scan_type = { /* Description of storage in buffer */
.sign = 's', /* signed */
.realbits = 12, /* 12 bits */
.storagebits = 16, /* 16 bits used for storage */
.shift = 0, /* zero shift */
},
},
/* Differential ADC channel in_voltage3-voltage4_raw etc*/
{
@ -120,13 +135,13 @@ static struct iio_chan_spec iio_dummy_channels[] = {
.channel2 = 4,
.info_mask =
(1 << IIO_CHAN_INFO_SCALE_SHARED),
},
/* DAC channel out_voltage0_raw */
{
.type = IIO_VOLTAGE,
.output = 1,
.indexed = 1,
.channel = 0,
.scan_index = diffvoltage3m4,
.scan_type = {
.sign = 's',
.realbits = 11,
.storagebits = 16,
.shift = 0,
},
},
/*
* 'modified' (i.e. axis specified) acceleration channel
@ -145,6 +160,25 @@ static struct iio_chan_spec iio_dummy_channels[] = {
* calibration.
*/
(1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE),
.scan_index = accelx,
.scan_type = { /* Description of storage in buffer */
.sign = 's', /* signed */
.realbits = 16, /* 12 bits */
.storagebits = 16, /* 16 bits used for storage */
.shift = 0, /* zero shift */
},
},
/*
* Convenience macro for timestamps. 4 is the index in
* the buffer.
*/
IIO_CHAN_SOFT_TIMESTAMP(4),
/* DAC channel out_voltage0_raw */
{
.type = IIO_VOLTAGE,
.output = 1,
.indexed = 1,
.channel = 0,
},
};
@ -391,11 +425,29 @@ static int __devinit iio_dummy_probe(int index)
ret = iio_simple_dummy_events_register(indio_dev);
if (ret < 0)
goto error_free_device;
ret = iio_device_register(indio_dev);
/* Configure buffered capture support. */
ret = iio_simple_dummy_configure_buffer(indio_dev);
if (ret < 0)
goto error_unregister_events;
/*
* Register the channels with the buffer, but avoid the output
* channel being registered by reducing the number of channels by 1.
*/
ret = iio_buffer_register(indio_dev, iio_dummy_channels, 5);
if (ret < 0)
goto error_unconfigure_buffer;
ret = iio_device_register(indio_dev);
if (ret < 0)
goto error_unregister_buffer;
return 0;
error_unregister_buffer:
iio_buffer_unregister(indio_dev);
error_unconfigure_buffer:
iio_simple_dummy_unconfigure_buffer(indio_dev);
error_unregister_events:
iio_simple_dummy_events_unregister(indio_dev);
error_free_device:
@ -429,6 +481,9 @@ static int iio_dummy_remove(int index)
/* Device specific code to power down etc */
/* Buffered capture related cleanup */
iio_buffer_unregister(indio_dev);
iio_simple_dummy_unconfigure_buffer(indio_dev);
ret = iio_simple_dummy_events_unregister(indio_dev);
if (ret)

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@ -78,4 +78,31 @@ iio_simple_dummy_events_unregister(struct iio_dev *indio_dev)
#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS*/
/**
* enum iio_simple_dummy_scan_elements - scan index enum
* @voltage0: the single ended voltage channel
* @diffvoltage1m2: first differential channel
* @diffvoltage3m4: second differenial channel
* @accelx: acceleration channel
*
* Enum provides convenient numbering for the scan index.
*/
enum iio_simple_dummy_scan_elements {
voltage0,
diffvoltage1m2,
diffvoltage3m4,
accelx,
};
#ifdef CONFIG_IIO_SIMPLE_DUMMY_BUFFER
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev);
void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev);
#else
static inline int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
{
return 0;
};
static inline
void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
{};
#endif /* CONFIG_IIO_SIMPLE_DUMMY_BUFFER */

View File

@ -0,0 +1,206 @@
/**
* Copyright (c) 2011 Jonathan Cameron
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* 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/slab.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/bitmap.h>
#include "iio.h"
#include "trigger_consumer.h"
#include "kfifo_buf.h"
#include "iio_simple_dummy.h"
/* Some fake data */
static const s16 fakedata[] = {
[voltage0] = 7,
[diffvoltage1m2] = -33,
[diffvoltage3m4] = -2,
[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 occuring,
* 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;
struct iio_buffer *buffer = indio_dev->buffer;
int len = 0;
/*
* The datasize is obtained from the buffer. It was stored when
* the preenable setup function was called.
*/
size_t datasize = buffer->access->get_bytes_per_datum(buffer);
u16 *data = kmalloc(datasize, GFP_KERNEL);
if (data == NULL)
return -ENOMEM;
if (buffer->scan_count) {
/*
* 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.
* sofware 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 fidliest option by far.
* Here lets pretend we have random access. And the values are
* in the constant table fakedata.
*/
int i, j;
for (i = 0, j = 0; i < buffer->scan_count; i++) {
j = find_next_bit(buffer->scan_mask,
indio_dev->masklength, j + 1);
/* random access read form the 'device' */
data[i] = fakedata[j];
len += 2;
}
}
/* Store a timestampe at an 8 byte boundary */
if (buffer->scan_timestamp)
*(s64 *)(((phys_addr_t)data + len
+ sizeof(s64) - 1) & ~(sizeof(s64) - 1))
= iio_get_time_ns();
buffer->access->store_to(buffer, (u8 *)data, pf->timestamp);
kfree(data);
/*
* 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 = {
/*
* iio_sw_buffer_preenable:
* Generic function for equal sized ring elements + 64 bit timestamp
* Assumes that any combination of channels can be enabled.
* Typically replaced to implement restrictions on what combinations
* can be captured (hardware scan modes).
*/
.preenable = &iio_sw_buffer_preenable,
/*
* iio_triggered_buffer_postenable:
* Generic function that simply attaches the pollfunc to the trigger.
* Replace this to mess with hardware state before we attach the
* trigger.
*/
.postenable = &iio_triggered_buffer_postenable,
/*
* iio_triggered_buffer_predisable:
* Generic function that simple detaches the pollfunc from the trigger.
* Replace this to put hardware state back again after the trigger is
* detached but before userspace knows we have disabled the ring.
*/
.predisable = &iio_triggered_buffer_predisable,
};
int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev)
{
int ret;
struct iio_buffer *buffer;
/* Allocate a buffer to use - here a kfifo */
buffer = iio_kfifo_allocate(indio_dev);
if (buffer == NULL) {
ret = -ENOMEM;
goto error_ret;
}
indio_dev->buffer = buffer;
/* Tell the core how to access the buffer */
buffer->access = &kfifo_access_funcs;
/* Number of bytes per element */
buffer->bpe = 2;
/* Enable timestamps by default */
buffer->scan_timestamp = true;
/*
* Tell the core what device type specific functions should
* be run on either side of buffer capture enable / disable.
*/
buffer->setup_ops = &iio_simple_dummy_buffer_setup_ops;
buffer->owner = THIS_MODULE;
/*
* Configure a polling function.
* When a trigger event with this polling function connected
* occurs, this function is run. Typically this grabs data
* from the device.
*
* NULL for the top half. This is normally implemented only if we
* either want to ping a capture now pin (no sleeping) or grab
* a timestamp as close as possible to a data ready trigger firing.
*
* IRQF_ONESHOT ensures irqs are masked such that only one instance
* of the handler can run at a time.
*
* "iio_simple_dummy_consumer%d" formatting string for the irq 'name'
* as seen under /proc/interrupts. Remaining parameters as per printk.
*/
indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
&iio_simple_dummy_trigger_h,
IRQF_ONESHOT,
indio_dev,
"iio_simple_dummy_consumer%d",
indio_dev->id);
if (indio_dev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_free_buffer;
}
/*
* Notify the core that this device is capable of buffered capture
* driven by a trigger.
*/
indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
return 0;
error_free_buffer:
iio_kfifo_free(indio_dev->buffer);
error_ret:
return ret;
}
/**
* iio_simple_dummy_unconfigure_buffer() - release buffer resources
* @indo_dev: device instance state
*/
void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev)
{
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_kfifo_free(indio_dev->buffer);
}