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
194
195
196
197
198
199
200
201
202
203
204
205
206
207
|
/*
* Copyright 2010 Analog Devices Inc.
* Copyright (C) 2008 Jonathan Cameron
*
* Licensed under the GPL-2 or later.
*
* ad7476_ring.c
*/
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/workqueue.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include <linux/list.h>
#include <linux/spi/spi.h>
#include "../iio.h"
#include "../ring_generic.h"
#include "../ring_sw.h"
#include "../trigger.h"
#include "../sysfs.h"
#include "ad7476.h"
static IIO_SCAN_EL_C(in0, 0, 0, NULL);
static ssize_t ad7476_show_type(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_ring_buffer *ring = dev_get_drvdata(dev);
struct iio_dev *indio_dev = ring->indio_dev;
struct ad7476_state *st = indio_dev->dev_data;
return sprintf(buf, "%c%d/%d>>%d\n", st->chip_info->sign,
st->chip_info->bits, st->chip_info->storagebits,
st->chip_info->res_shift);
}
static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7476_show_type, NULL, 0);
static struct attribute *ad7476_scan_el_attrs[] = {
&iio_scan_el_in0.dev_attr.attr,
&iio_const_attr_in0_index.dev_attr.attr,
&iio_dev_attr_in_type.dev_attr.attr,
NULL,
};
static struct attribute_group ad7476_scan_el_group = {
.name = "scan_elements",
.attrs = ad7476_scan_el_attrs,
};
int ad7476_scan_from_ring(struct ad7476_state *st)
{
struct iio_ring_buffer *ring = st->indio_dev->ring;
int ret;
u8 *ring_data;
ring_data = kmalloc(ring->access.get_bytes_per_datum(ring), GFP_KERNEL);
if (ring_data == NULL) {
ret = -ENOMEM;
goto error_ret;
}
ret = ring->access.read_last(ring, ring_data);
if (ret)
goto error_free_ring_data;
ret = (ring_data[0] << 8) | ring_data[1];
error_free_ring_data:
kfree(ring_data);
error_ret:
return ret;
}
/**
* ad7476_ring_preenable() setup the parameters of the ring before enabling
*
* The complex nature of the setting of the nuber of bytes per datum is due
* to this driver currently ensuring that the timestamp is stored at an 8
* byte boundary.
**/
static int ad7476_ring_preenable(struct iio_dev *indio_dev)
{
struct ad7476_state *st = indio_dev->dev_data;
size_t d_size;
if (indio_dev->ring->access.set_bytes_per_datum) {
d_size = st->chip_info->storagebits / 8 + sizeof(s64);
if (d_size % 8)
d_size += 8 - (d_size % 8);
indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
d_size);
}
return 0;
}
/**
* ad7476_poll_func_th() th of trigger launched polling to ring buffer
*
* As sampling only occurs on i2c comms occuring, leave timestamping until
* then. Some triggers will generate their own time stamp. Currently
* there is no way of notifying them when no one cares.
**/
static void ad7476_poll_func_th(struct iio_dev *indio_dev, s64 time)
{
struct ad7476_state *st = indio_dev->dev_data;
schedule_work(&st->poll_work);
return;
}
/**
* ad7476_poll_bh_to_ring() bh of trigger launched polling to ring buffer
* @work_s: the work struct through which this was scheduled
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
* I think the one copy of this at a time was to avoid problems if the
* trigger was set far too high and the reads then locked up the computer.
**/
static void ad7476_poll_bh_to_ring(struct work_struct *work_s)
{
struct ad7476_state *st = container_of(work_s, struct ad7476_state,
poll_work);
struct iio_dev *indio_dev = st->indio_dev;
struct iio_sw_ring_buffer *sw_ring = iio_to_sw_ring(indio_dev->ring);
s64 time_ns;
__u8 *rxbuf;
int b_sent;
size_t d_size;
/* Ensure the timestamp is 8 byte aligned */
d_size = st->chip_info->storagebits / 8 + sizeof(s64);
if (d_size % sizeof(s64))
d_size += sizeof(s64) - (d_size % sizeof(s64));
/* Ensure only one copy of this function running at a time */
if (atomic_inc_return(&st->protect_ring) > 1)
return;
rxbuf = kzalloc(d_size, GFP_KERNEL);
if (rxbuf == NULL)
return;
b_sent = spi_read(st->spi, rxbuf, st->chip_info->storagebits / 8);
if (b_sent < 0)
goto done;
time_ns = iio_get_time_ns();
memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
indio_dev->ring->access.store_to(&sw_ring->buf, rxbuf, time_ns);
done:
kfree(rxbuf);
atomic_dec(&st->protect_ring);
}
int ad7476_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
struct ad7476_state *st = indio_dev->dev_data;
int ret = 0;
indio_dev->ring = iio_sw_rb_allocate(indio_dev);
if (!indio_dev->ring) {
ret = -ENOMEM;
goto error_ret;
}
/* Effectively select the ring buffer implementation */
iio_ring_sw_register_funcs(&indio_dev->ring->access);
ret = iio_alloc_pollfunc(indio_dev, NULL, &ad7476_poll_func_th);
if (ret)
goto error_deallocate_sw_rb;
/* Ring buffer functions - here trigger setup related */
indio_dev->ring->preenable = &ad7476_ring_preenable;
indio_dev->ring->postenable = &iio_triggered_ring_postenable;
indio_dev->ring->predisable = &iio_triggered_ring_predisable;
indio_dev->ring->scan_el_attrs = &ad7476_scan_el_group;
INIT_WORK(&st->poll_work, &ad7476_poll_bh_to_ring);
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_RING_TRIGGERED;
return 0;
error_deallocate_sw_rb:
iio_sw_rb_free(indio_dev->ring);
error_ret:
return ret;
}
void ad7476_ring_cleanup(struct iio_dev *indio_dev)
{
/* ensure that the trigger has been detached */
if (indio_dev->trig) {
iio_put_trigger(indio_dev->trig);
iio_trigger_dettach_poll_func(indio_dev->trig,
indio_dev->pollfunc);
}
kfree(indio_dev->pollfunc);
iio_sw_rb_free(indio_dev->ring);
}
|
