1 /*
2 * Copyright 2011-2012 Analog Devices Inc.
3 *
4 * Licensed under the GPL-2.
5 *
6 */
7
8 #include <linux/interrupt.h>
9 #include <linux/gpio.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13
14 #include <linux/iio/iio.h>
15 #include <linux/iio/buffer.h>
16 #include <linux/iio/trigger_consumer.h>
17 #include <linux/iio/triggered_buffer.h>
18
19 #include "ad7606.h"
20
21 /**
22 * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
23 *
24 **/
ad7606_trigger_handler_th_bh(int irq,void * p)25 static irqreturn_t ad7606_trigger_handler_th_bh(int irq, void *p)
26 {
27 struct iio_poll_func *pf = p;
28 struct ad7606_state *st = iio_priv(pf->indio_dev);
29
30 gpio_set_value(st->pdata->gpio_convst, 1);
31
32 return IRQ_HANDLED;
33 }
34
35 /**
36 * ad7606_poll_bh_to_ring() bh of trigger launched polling to ring buffer
37 * @work_s: the work struct through which this was scheduled
38 *
39 * Currently there is no option in this driver to disable the saving of
40 * timestamps within the ring.
41 * I think the one copy of this at a time was to avoid problems if the
42 * trigger was set far too high and the reads then locked up the computer.
43 **/
ad7606_poll_bh_to_ring(struct work_struct * work_s)44 static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
45 {
46 struct ad7606_state *st = container_of(work_s, struct ad7606_state,
47 poll_work);
48 struct iio_dev *indio_dev = iio_priv_to_dev(st);
49 s64 time_ns;
50 __u8 *buf;
51 int ret;
52
53 buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
54 if (buf == NULL)
55 return;
56
57 if (gpio_is_valid(st->pdata->gpio_frstdata)) {
58 ret = st->bops->read_block(st->dev, 1, buf);
59 if (ret)
60 goto done;
61 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
62 /* This should never happen. However
63 * some signal glitch caused by bad PCB desgin or
64 * electrostatic discharge, could cause an extra read
65 * or clock. This allows recovery.
66 */
67 ad7606_reset(st);
68 goto done;
69 }
70 ret = st->bops->read_block(st->dev,
71 st->chip_info->num_channels - 1, buf + 2);
72 if (ret)
73 goto done;
74 } else {
75 ret = st->bops->read_block(st->dev,
76 st->chip_info->num_channels, buf);
77 if (ret)
78 goto done;
79 }
80
81 time_ns = iio_get_time_ns();
82
83 if (indio_dev->scan_timestamp)
84 *((s64 *)(buf + indio_dev->scan_bytes - sizeof(s64))) = time_ns;
85
86 iio_push_to_buffers(indio_dev, buf);
87 done:
88 gpio_set_value(st->pdata->gpio_convst, 0);
89 iio_trigger_notify_done(indio_dev->trig);
90 kfree(buf);
91 }
92
ad7606_register_ring_funcs_and_init(struct iio_dev * indio_dev)93 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
94 {
95 struct ad7606_state *st = iio_priv(indio_dev);
96
97 INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
98
99 return iio_triggered_buffer_setup(indio_dev,
100 &ad7606_trigger_handler_th_bh, &ad7606_trigger_handler_th_bh,
101 NULL);
102 }
103
ad7606_ring_cleanup(struct iio_dev * indio_dev)104 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
105 {
106 iio_triggered_buffer_cleanup(indio_dev);
107 }
108