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 __u8 *buf;
50 int ret;
51
52 buf = kzalloc(indio_dev->scan_bytes, GFP_KERNEL);
53 if (!buf)
54 return;
55
56 if (gpio_is_valid(st->pdata->gpio_frstdata)) {
57 ret = st->bops->read_block(st->dev, 1, buf);
58 if (ret)
59 goto done;
60 if (!gpio_get_value(st->pdata->gpio_frstdata)) {
61 /* This should never happen. However
62 * some signal glitch caused by bad PCB desgin or
63 * electrostatic discharge, could cause an extra read
64 * or clock. This allows recovery.
65 */
66 ad7606_reset(st);
67 goto done;
68 }
69 ret = st->bops->read_block(st->dev,
70 st->chip_info->num_channels - 1, buf + 2);
71 if (ret)
72 goto done;
73 } else {
74 ret = st->bops->read_block(st->dev,
75 st->chip_info->num_channels, buf);
76 if (ret)
77 goto done;
78 }
79
80 iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
81 done:
82 gpio_set_value(st->pdata->gpio_convst, 0);
83 iio_trigger_notify_done(indio_dev->trig);
84 kfree(buf);
85 }
86
ad7606_register_ring_funcs_and_init(struct iio_dev * indio_dev)87 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev)
88 {
89 struct ad7606_state *st = iio_priv(indio_dev);
90
91 INIT_WORK(&st->poll_work, &ad7606_poll_bh_to_ring);
92
93 return iio_triggered_buffer_setup(indio_dev,
94 &ad7606_trigger_handler_th_bh, &ad7606_trigger_handler_th_bh,
95 NULL);
96 }
97
ad7606_ring_cleanup(struct iio_dev * indio_dev)98 void ad7606_ring_cleanup(struct iio_dev *indio_dev)
99 {
100 iio_triggered_buffer_cleanup(indio_dev);
101 }
102