1 /*
2 * Copyright (C) 2010 Michael Hennerich, Analog Devices Inc.
3 * Copyright (C) 2008-2010 Jonathan Cameron
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * ad799x_ring.c
10 */
11
12 #include <linux/interrupt.h>
13 #include <linux/slab.h>
14 #include <linux/kernel.h>
15 #include <linux/list.h>
16 #include <linux/i2c.h>
17 #include <linux/bitops.h>
18
19 #include "../iio.h"
20 #include "../buffer.h"
21 #include "../ring_sw.h"
22 #include "../trigger_consumer.h"
23
24 #include "ad799x.h"
25
26 /**
27 * ad799x_ring_preenable() setup the parameters of the ring before enabling
28 *
29 * The complex nature of the setting of the nuber of bytes per datum is due
30 * to this driver currently ensuring that the timestamp is stored at an 8
31 * byte boundary.
32 **/
ad799x_ring_preenable(struct iio_dev * indio_dev)33 static int ad799x_ring_preenable(struct iio_dev *indio_dev)
34 {
35 struct iio_buffer *ring = indio_dev->buffer;
36 struct ad799x_state *st = iio_priv(indio_dev);
37
38 /*
39 * Need to figure out the current mode based upon the requested
40 * scan mask in iio_dev
41 */
42
43 if (st->id == ad7997 || st->id == ad7998)
44 ad7997_8_set_scan_mode(st, *indio_dev->active_scan_mask);
45
46 st->d_size = bitmap_weight(indio_dev->active_scan_mask,
47 indio_dev->masklength) * 2;
48
49 if (ring->scan_timestamp) {
50 st->d_size += sizeof(s64);
51
52 if (st->d_size % sizeof(s64))
53 st->d_size += sizeof(s64) - (st->d_size % sizeof(s64));
54 }
55
56 if (indio_dev->buffer->access->set_bytes_per_datum)
57 indio_dev->buffer->access->
58 set_bytes_per_datum(indio_dev->buffer, st->d_size);
59
60 return 0;
61 }
62
63 /**
64 * ad799x_trigger_handler() bh of trigger launched polling to ring buffer
65 *
66 * Currently there is no option in this driver to disable the saving of
67 * timestamps within the ring.
68 **/
69
ad799x_trigger_handler(int irq,void * p)70 static irqreturn_t ad799x_trigger_handler(int irq, void *p)
71 {
72 struct iio_poll_func *pf = p;
73 struct iio_dev *indio_dev = pf->indio_dev;
74 struct ad799x_state *st = iio_priv(indio_dev);
75 struct iio_buffer *ring = indio_dev->buffer;
76 s64 time_ns;
77 __u8 *rxbuf;
78 int b_sent;
79 u8 cmd;
80
81 rxbuf = kmalloc(st->d_size, GFP_KERNEL);
82 if (rxbuf == NULL)
83 goto out;
84
85 switch (st->id) {
86 case ad7991:
87 case ad7995:
88 case ad7999:
89 cmd = st->config |
90 (*indio_dev->active_scan_mask << AD799X_CHANNEL_SHIFT);
91 break;
92 case ad7992:
93 case ad7993:
94 case ad7994:
95 cmd = (*indio_dev->active_scan_mask << AD799X_CHANNEL_SHIFT) |
96 AD7998_CONV_RES_REG;
97 break;
98 case ad7997:
99 case ad7998:
100 cmd = AD7997_8_READ_SEQUENCE | AD7998_CONV_RES_REG;
101 break;
102 default:
103 cmd = 0;
104 }
105
106 b_sent = i2c_smbus_read_i2c_block_data(st->client,
107 cmd, bitmap_weight(indio_dev->active_scan_mask,
108 indio_dev->masklength) * 2, rxbuf);
109 if (b_sent < 0)
110 goto done;
111
112 time_ns = iio_get_time_ns();
113
114 if (ring->scan_timestamp)
115 memcpy(rxbuf + st->d_size - sizeof(s64),
116 &time_ns, sizeof(time_ns));
117
118 ring->access->store_to(indio_dev->buffer, rxbuf, time_ns);
119 done:
120 kfree(rxbuf);
121 if (b_sent < 0)
122 return b_sent;
123 out:
124 iio_trigger_notify_done(indio_dev->trig);
125
126 return IRQ_HANDLED;
127 }
128
129 static const struct iio_buffer_setup_ops ad799x_buf_setup_ops = {
130 .preenable = &ad799x_ring_preenable,
131 .postenable = &iio_triggered_buffer_postenable,
132 .predisable = &iio_triggered_buffer_predisable,
133 };
134
ad799x_register_ring_funcs_and_init(struct iio_dev * indio_dev)135 int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
136 {
137 int ret = 0;
138
139 indio_dev->buffer = iio_sw_rb_allocate(indio_dev);
140 if (!indio_dev->buffer) {
141 ret = -ENOMEM;
142 goto error_ret;
143 }
144 /* Effectively select the ring buffer implementation */
145 indio_dev->buffer->access = &ring_sw_access_funcs;
146 indio_dev->pollfunc = iio_alloc_pollfunc(NULL,
147 &ad799x_trigger_handler,
148 IRQF_ONESHOT,
149 indio_dev,
150 "%s_consumer%d",
151 indio_dev->name,
152 indio_dev->id);
153 if (indio_dev->pollfunc == NULL) {
154 ret = -ENOMEM;
155 goto error_deallocate_sw_rb;
156 }
157
158 /* Ring buffer functions - here trigger setup related */
159 indio_dev->setup_ops = &ad799x_buf_setup_ops;
160 indio_dev->buffer->scan_timestamp = true;
161
162 /* Flag that polled ring buffering is possible */
163 indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
164 return 0;
165
166 error_deallocate_sw_rb:
167 iio_sw_rb_free(indio_dev->buffer);
168 error_ret:
169 return ret;
170 }
171
ad799x_ring_cleanup(struct iio_dev * indio_dev)172 void ad799x_ring_cleanup(struct iio_dev *indio_dev)
173 {
174 iio_dealloc_pollfunc(indio_dev->pollfunc);
175 iio_sw_rb_free(indio_dev->buffer);
176 }
177