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9ad2e2e1 JC |
1 | /** |
2 | * Copyright (c) 2011 Jonathan Cameron | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License version 2 as published by | |
6 | * the Free Software Foundation. | |
7 | * | |
8 | * Buffer handling elements of industrial I/O reference driver. | |
9 | * Uses the kfifo buffer. | |
10 | * | |
11 | * To test without hardware use the sysfs trigger. | |
12 | */ | |
13 | ||
14 | #include <linux/kernel.h> | |
8e336a72 | 15 | #include <linux/export.h> |
9ad2e2e1 JC |
16 | #include <linux/slab.h> |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/irq.h> | |
19 | #include <linux/bitmap.h> | |
20 | ||
06458e27 JC |
21 | #include <linux/iio/iio.h> |
22 | #include <linux/iio/trigger_consumer.h> | |
23 | #include <linux/iio/kfifo_buf.h> | |
9ad2e2e1 JC |
24 | |
25 | #include "iio_simple_dummy.h" | |
26 | ||
27 | /* Some fake data */ | |
28 | ||
29 | static const s16 fakedata[] = { | |
30 | [voltage0] = 7, | |
31 | [diffvoltage1m2] = -33, | |
32 | [diffvoltage3m4] = -2, | |
33 | [accelx] = 344, | |
34 | }; | |
35 | /** | |
36 | * iio_simple_dummy_trigger_h() - the trigger handler function | |
37 | * @irq: the interrupt number | |
38 | * @p: private data - always a pointer to the poll func. | |
39 | * | |
99de0c2b | 40 | * This is the guts of buffered capture. On a trigger event occurring, |
9ad2e2e1 JC |
41 | * if the pollfunc is attached then this handler is called as a threaded |
42 | * interrupt (and hence may sleep). It is responsible for grabbing data | |
43 | * from the device and pushing it into the associated buffer. | |
44 | */ | |
45 | static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p) | |
46 | { | |
47 | struct iio_poll_func *pf = p; | |
48 | struct iio_dev *indio_dev = pf->indio_dev; | |
9ad2e2e1 | 49 | int len = 0; |
420fe2e9 JC |
50 | u16 *data; |
51 | ||
52 | data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL); | |
9ad2e2e1 | 53 | if (data == NULL) |
a1bdeefd | 54 | goto done; |
9ad2e2e1 | 55 | |
550268ca | 56 | if (!bitmap_empty(indio_dev->active_scan_mask, indio_dev->masklength)) { |
9ad2e2e1 JC |
57 | /* |
58 | * Three common options here: | |
59 | * hardware scans: certain combinations of channels make | |
60 | * up a fast read. The capture will consist of all of them. | |
61 | * Hence we just call the grab data function and fill the | |
62 | * buffer without processing. | |
99de0c2b | 63 | * software scans: can be considered to be random access |
9ad2e2e1 JC |
64 | * so efficient reading is just a case of minimal bus |
65 | * transactions. | |
66 | * software culled hardware scans: | |
67 | * occasionally a driver may process the nearest hardware | |
68 | * scan to avoid storing elements that are not desired. This | |
25c38aa3 PM |
69 | * is the fiddliest option by far. |
70 | * Here let's pretend we have random access. And the values are | |
9ad2e2e1 JC |
71 | * in the constant table fakedata. |
72 | */ | |
73 | int i, j; | |
550268ca JC |
74 | for (i = 0, j = 0; |
75 | i < bitmap_weight(indio_dev->active_scan_mask, | |
76 | indio_dev->masklength); | |
708706ff | 77 | i++, j++) { |
84b36ce5 | 78 | j = find_next_bit(indio_dev->active_scan_mask, |
708706ff | 79 | indio_dev->masklength, j); |
d163a19d | 80 | /* random access read from the 'device' */ |
9ad2e2e1 JC |
81 | data[i] = fakedata[j]; |
82 | len += 2; | |
83 | } | |
84 | } | |
09a799d0 LPC |
85 | |
86 | iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns()); | |
9ad2e2e1 JC |
87 | |
88 | kfree(data); | |
89 | ||
a1bdeefd | 90 | done: |
9ad2e2e1 JC |
91 | /* |
92 | * Tell the core we are done with this trigger and ready for the | |
93 | * next one. | |
94 | */ | |
95 | iio_trigger_notify_done(indio_dev->trig); | |
96 | ||
97 | return IRQ_HANDLED; | |
98 | } | |
99 | ||
100 | static const struct iio_buffer_setup_ops iio_simple_dummy_buffer_setup_ops = { | |
9ad2e2e1 JC |
101 | /* |
102 | * iio_triggered_buffer_postenable: | |
103 | * Generic function that simply attaches the pollfunc to the trigger. | |
104 | * Replace this to mess with hardware state before we attach the | |
105 | * trigger. | |
106 | */ | |
107 | .postenable = &iio_triggered_buffer_postenable, | |
108 | /* | |
109 | * iio_triggered_buffer_predisable: | |
110 | * Generic function that simple detaches the pollfunc from the trigger. | |
111 | * Replace this to put hardware state back again after the trigger is | |
112 | * detached but before userspace knows we have disabled the ring. | |
113 | */ | |
114 | .predisable = &iio_triggered_buffer_predisable, | |
115 | }; | |
116 | ||
3fff2274 LPC |
117 | int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev, |
118 | const struct iio_chan_spec *channels, unsigned int num_channels) | |
9ad2e2e1 JC |
119 | { |
120 | int ret; | |
121 | struct iio_buffer *buffer; | |
122 | ||
123 | /* Allocate a buffer to use - here a kfifo */ | |
124 | buffer = iio_kfifo_allocate(indio_dev); | |
125 | if (buffer == NULL) { | |
126 | ret = -ENOMEM; | |
127 | goto error_ret; | |
128 | } | |
129 | ||
9e69c935 | 130 | iio_device_attach_buffer(indio_dev, buffer); |
9ad2e2e1 | 131 | |
9ad2e2e1 JC |
132 | /* Enable timestamps by default */ |
133 | buffer->scan_timestamp = true; | |
134 | ||
135 | /* | |
136 | * Tell the core what device type specific functions should | |
137 | * be run on either side of buffer capture enable / disable. | |
138 | */ | |
1612244f | 139 | indio_dev->setup_ops = &iio_simple_dummy_buffer_setup_ops; |
9ad2e2e1 JC |
140 | |
141 | /* | |
142 | * Configure a polling function. | |
143 | * When a trigger event with this polling function connected | |
144 | * occurs, this function is run. Typically this grabs data | |
145 | * from the device. | |
146 | * | |
569c4ac2 | 147 | * NULL for the bottom half. This is normally implemented only if we |
9ad2e2e1 JC |
148 | * either want to ping a capture now pin (no sleeping) or grab |
149 | * a timestamp as close as possible to a data ready trigger firing. | |
150 | * | |
151 | * IRQF_ONESHOT ensures irqs are masked such that only one instance | |
152 | * of the handler can run at a time. | |
153 | * | |
154 | * "iio_simple_dummy_consumer%d" formatting string for the irq 'name' | |
155 | * as seen under /proc/interrupts. Remaining parameters as per printk. | |
156 | */ | |
157 | indio_dev->pollfunc = iio_alloc_pollfunc(NULL, | |
158 | &iio_simple_dummy_trigger_h, | |
159 | IRQF_ONESHOT, | |
160 | indio_dev, | |
161 | "iio_simple_dummy_consumer%d", | |
162 | indio_dev->id); | |
163 | ||
164 | if (indio_dev->pollfunc == NULL) { | |
165 | ret = -ENOMEM; | |
166 | goto error_free_buffer; | |
167 | } | |
168 | ||
169 | /* | |
170 | * Notify the core that this device is capable of buffered capture | |
171 | * driven by a trigger. | |
172 | */ | |
173 | indio_dev->modes |= INDIO_BUFFER_TRIGGERED; | |
3fff2274 LPC |
174 | |
175 | ret = iio_buffer_register(indio_dev, channels, num_channels); | |
176 | if (ret) | |
177 | goto error_dealloc_pollfunc; | |
178 | ||
9ad2e2e1 JC |
179 | return 0; |
180 | ||
3fff2274 LPC |
181 | error_dealloc_pollfunc: |
182 | iio_dealloc_pollfunc(indio_dev->pollfunc); | |
9ad2e2e1 JC |
183 | error_free_buffer: |
184 | iio_kfifo_free(indio_dev->buffer); | |
185 | error_ret: | |
186 | return ret; | |
187 | ||
188 | } | |
189 | ||
190 | /** | |
191 | * iio_simple_dummy_unconfigure_buffer() - release buffer resources | |
192 | * @indo_dev: device instance state | |
193 | */ | |
194 | void iio_simple_dummy_unconfigure_buffer(struct iio_dev *indio_dev) | |
195 | { | |
3fff2274 | 196 | iio_buffer_unregister(indio_dev); |
9ad2e2e1 JC |
197 | iio_dealloc_pollfunc(indio_dev->pollfunc); |
198 | iio_kfifo_free(indio_dev->buffer); | |
199 | } |