1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
|
/**
* 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/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/trigger_consumer.h>
#include <linux/iio/kfifo_buf.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 len = 0;
u16 *data;
data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
if (!data)
goto done;
if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) {
/*
* 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.
*/
int i, j;
for (i = 0, j = 0;
i < bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength);
i++, j++) {
j = find_next_bit(indio_dev->active_scan_mask,
indio_dev->masklength, j);
/* random access read from the 'device' */
data[i] = fakedata[j];
len += 2;
}
}
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 = {
/*
* 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();
if (!buffer) {
ret = -ENOMEM;
goto error_ret;
}
iio_device_attach_buffer(indio_dev, buffer);
/* 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.
*/
indio_dev->setup_ops = &iio_simple_dummy_buffer_setup_ops;
/*
* 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 bottom 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) {
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);
}
|
