1 /* The industrial I/O callback buffer
2  *
3  * This program is free software; you can redistribute it and/or modify it
4  * under the terms of the GNU General Public License version 2 as published by
5  * the Free Software Foundation.
6  */
7 
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/slab.h>
11 #include <linux/err.h>
12 #include <linux/export.h>
13 #include <linux/iio/iio.h>
14 #include <linux/iio/buffer_impl.h>
15 #include <linux/iio/consumer.h>
16 
17 struct iio_cb_buffer {
18 	struct iio_buffer buffer;
19 	int (*cb)(const void *data, void *private);
20 	void *private;
21 	struct iio_channel *channels;
22 	struct iio_dev *indio_dev;
23 };
24 
25 static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer)
26 {
27 	return container_of(buffer, struct iio_cb_buffer, buffer);
28 }
29 
30 static int iio_buffer_cb_store_to(struct iio_buffer *buffer, const void *data)
31 {
32 	struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
33 	return cb_buff->cb(data, cb_buff->private);
34 }
35 
36 static void iio_buffer_cb_release(struct iio_buffer *buffer)
37 {
38 	struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer);
39 	kfree(cb_buff->buffer.scan_mask);
40 	kfree(cb_buff);
41 }
42 
43 static const struct iio_buffer_access_funcs iio_cb_access = {
44 	.store_to = &iio_buffer_cb_store_to,
45 	.release = &iio_buffer_cb_release,
46 
47 	.modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED,
48 };
49 
50 struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev,
51 					     int (*cb)(const void *data,
52 						       void *private),
53 					     void *private)
54 {
55 	int ret;
56 	struct iio_cb_buffer *cb_buff;
57 	struct iio_channel *chan;
58 
59 	cb_buff = kzalloc(sizeof(*cb_buff), GFP_KERNEL);
60 	if (cb_buff == NULL)
61 		return ERR_PTR(-ENOMEM);
62 
63 	iio_buffer_init(&cb_buff->buffer);
64 
65 	cb_buff->private = private;
66 	cb_buff->cb = cb;
67 	cb_buff->buffer.access = &iio_cb_access;
68 	INIT_LIST_HEAD(&cb_buff->buffer.demux_list);
69 
70 	cb_buff->channels = iio_channel_get_all(dev);
71 	if (IS_ERR(cb_buff->channels)) {
72 		ret = PTR_ERR(cb_buff->channels);
73 		goto error_free_cb_buff;
74 	}
75 
76 	cb_buff->indio_dev = cb_buff->channels[0].indio_dev;
77 	cb_buff->buffer.scan_mask
78 		= kcalloc(BITS_TO_LONGS(cb_buff->indio_dev->masklength),
79 			  sizeof(long), GFP_KERNEL);
80 	if (cb_buff->buffer.scan_mask == NULL) {
81 		ret = -ENOMEM;
82 		goto error_release_channels;
83 	}
84 	chan = &cb_buff->channels[0];
85 	while (chan->indio_dev) {
86 		if (chan->indio_dev != cb_buff->indio_dev) {
87 			ret = -EINVAL;
88 			goto error_free_scan_mask;
89 		}
90 		set_bit(chan->channel->scan_index,
91 			cb_buff->buffer.scan_mask);
92 		chan++;
93 	}
94 
95 	return cb_buff;
96 
97 error_free_scan_mask:
98 	kfree(cb_buff->buffer.scan_mask);
99 error_release_channels:
100 	iio_channel_release_all(cb_buff->channels);
101 error_free_cb_buff:
102 	kfree(cb_buff);
103 	return ERR_PTR(ret);
104 }
105 EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
106 
107 int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buff,
108 					size_t watermark)
109 {
110 	if (!watermark)
111 		return -EINVAL;
112 	cb_buff->buffer.watermark = watermark;
113 
114 	return 0;
115 }
116 EXPORT_SYMBOL_GPL(iio_channel_cb_set_buffer_watermark);
117 
118 int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
119 {
120 	return iio_update_buffers(cb_buff->indio_dev, &cb_buff->buffer,
121 				  NULL);
122 }
123 EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
124 
125 void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
126 {
127 	iio_update_buffers(cb_buff->indio_dev, NULL, &cb_buff->buffer);
128 }
129 EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
130 
131 void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
132 {
133 	iio_channel_release_all(cb_buff->channels);
134 	iio_buffer_put(&cb_buff->buffer);
135 }
136 EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
137 
138 struct iio_channel
139 *iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
140 {
141 	return cb_buffer->channels;
142 }
143 EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
144 
145 struct iio_dev
146 *iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer)
147 {
148 	return cb_buffer->indio_dev;
149 }
150 EXPORT_SYMBOL_GPL(iio_channel_cb_get_iio_dev);
151 
152 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
153 MODULE_DESCRIPTION("Industrial I/O callback buffer");
154 MODULE_LICENSE("GPL");
155