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
|
/*
* AD7298 SPI ADC driver
*
* Copyright 2011 Analog Devices Inc.
*
* Licensed under the GPL-2.
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include "../iio.h"
#include "../buffer.h"
#include "../ring_sw.h"
#include "../trigger_consumer.h"
#include "ad7298.h"
/**
* ad7298_ring_preenable() setup the parameters of the ring before enabling
*
* The complex nature of the setting of the number of bytes per datum is due
* to this driver currently ensuring that the timestamp is stored at an 8
* byte boundary.
**/
static int ad7298_ring_preenable(struct iio_dev *indio_dev)
{
struct ad7298_state *st = iio_priv(indio_dev);
struct iio_buffer *ring = indio_dev->buffer;
size_t d_size;
int i, m;
unsigned short command;
int scan_count = bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength);
d_size = scan_count * (AD7298_STORAGE_BITS / 8);
if (ring->scan_timestamp) {
d_size += sizeof(s64);
if (d_size % sizeof(s64))
d_size += sizeof(s64) - (d_size % sizeof(s64));
}
if (ring->access->set_bytes_per_datum)
ring->access->set_bytes_per_datum(ring, d_size);
st->d_size = d_size;
command = AD7298_WRITE | st->ext_ref;
for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
if (test_bit(i, indio_dev->active_scan_mask))
command |= m;
st->tx_buf[0] = cpu_to_be16(command);
/* build spi ring message */
st->ring_xfer[0].tx_buf = &st->tx_buf[0];
st->ring_xfer[0].len = 2;
st->ring_xfer[0].cs_change = 1;
st->ring_xfer[1].tx_buf = &st->tx_buf[1];
st->ring_xfer[1].len = 2;
st->ring_xfer[1].cs_change = 1;
spi_message_init(&st->ring_msg);
spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
for (i = 0; i < scan_count; i++) {
st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
st->ring_xfer[i + 2].len = 2;
st->ring_xfer[i + 2].cs_change = 1;
spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
}
/* make sure last transfer cs_change is not set */
st->ring_xfer[i + 1].cs_change = 0;
return 0;
}
/**
* ad7298_trigger_handler() bh of trigger launched polling to ring buffer
*
* Currently there is no option in this driver to disable the saving of
* timestamps within the ring.
**/
static irqreturn_t ad7298_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *indio_dev = pf->indio_dev;
struct ad7298_state *st = iio_priv(indio_dev);
struct iio_buffer *ring = indio_dev->buffer;
s64 time_ns;
__u16 buf[16];
int b_sent, i;
b_sent = spi_sync(st->spi, &st->ring_msg);
if (b_sent)
return b_sent;
if (ring->scan_timestamp) {
time_ns = iio_get_time_ns();
memcpy((u8 *)buf + st->d_size - sizeof(s64),
&time_ns, sizeof(time_ns));
}
for (i = 0; i < bitmap_weight(indio_dev->active_scan_mask,
indio_dev->masklength); i++)
buf[i] = be16_to_cpu(st->rx_buf[i]);
indio_dev->buffer->access->store_to(ring, (u8 *)buf, time_ns);
iio_trigger_notify_done(indio_dev->trig);
return IRQ_HANDLED;
}
static const struct iio_buffer_setup_ops ad7298_ring_setup_ops = {
.preenable = &ad7298_ring_preenable,
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
};
int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
{
int ret;
indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
if (!indio_dev->buffer) {
ret = -ENOMEM;
goto error_ret;
}
/* Effectively select the ring buffer implementation */
indio_dev->buffer->access = &ring_sw_access_funcs;
indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
&ad7298_trigger_handler,
IRQF_ONESHOT,
indio_dev,
"ad7298_consumer%d",
indio_dev->id);
if (indio_dev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_deallocate_sw_rb;
}
/* Ring buffer functions - here trigger setup related */
indio_dev->setup_ops = &ad7298_ring_setup_ops;
indio_dev->buffer->scan_timestamp = true;
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
return 0;
error_deallocate_sw_rb:
iio_sw_rb_free(indio_dev->buffer);
error_ret:
return ret;
}
void ad7298_ring_cleanup(struct iio_dev *indio_dev)
{
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_sw_rb_free(indio_dev->buffer);
}
|
