xref: /linux/drivers/iio/gyro/itg3200_buffer.c (revision bd628c1bed7902ec1f24ba0fe70758949146abbe)
1 /*
2  * itg3200_buffer.c -- support InvenSense ITG3200
3  *                     Digital 3-Axis Gyroscope driver
4  *
5  * Copyright (c) 2011 Christian Strobel <christian.strobel@iis.fraunhofer.de>
6  * Copyright (c) 2011 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
7  * Copyright (c) 2012 Thorsten Nowak <thorsten.nowak@iis.fraunhofer.de>
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/slab.h>
15 #include <linux/i2c.h>
16 #include <linux/interrupt.h>
17 
18 #include <linux/iio/iio.h>
19 #include <linux/iio/buffer.h>
20 #include <linux/iio/trigger.h>
21 #include <linux/iio/trigger_consumer.h>
22 #include <linux/iio/triggered_buffer.h>
23 #include <linux/iio/gyro/itg3200.h>
24 
25 
26 static int itg3200_read_all_channels(struct i2c_client *i2c, __be16 *buf)
27 {
28 	u8 tx = 0x80 | ITG3200_REG_TEMP_OUT_H;
29 	struct i2c_msg msg[2] = {
30 		{
31 			.addr = i2c->addr,
32 			.flags = i2c->flags,
33 			.len = 1,
34 			.buf = &tx,
35 		},
36 		{
37 			.addr = i2c->addr,
38 			.flags = i2c->flags | I2C_M_RD,
39 			.len = ITG3200_SCAN_ELEMENTS * sizeof(s16),
40 			.buf = (char *)&buf,
41 		},
42 	};
43 
44 	return i2c_transfer(i2c->adapter, msg, 2);
45 }
46 
47 static irqreturn_t itg3200_trigger_handler(int irq, void *p)
48 {
49 	struct iio_poll_func *pf = p;
50 	struct iio_dev *indio_dev = pf->indio_dev;
51 	struct itg3200 *st = iio_priv(indio_dev);
52 	__be16 buf[ITG3200_SCAN_ELEMENTS + sizeof(s64)/sizeof(u16)];
53 
54 	int ret = itg3200_read_all_channels(st->i2c, buf);
55 	if (ret < 0)
56 		goto error_ret;
57 
58 	iio_push_to_buffers_with_timestamp(indio_dev, buf, pf->timestamp);
59 
60 	iio_trigger_notify_done(indio_dev->trig);
61 
62 error_ret:
63 	return IRQ_HANDLED;
64 }
65 
66 int itg3200_buffer_configure(struct iio_dev *indio_dev)
67 {
68 	return iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
69 		itg3200_trigger_handler, NULL);
70 }
71 
72 void itg3200_buffer_unconfigure(struct iio_dev *indio_dev)
73 {
74 	iio_triggered_buffer_cleanup(indio_dev);
75 }
76 
77 
78 static int itg3200_data_rdy_trigger_set_state(struct iio_trigger *trig,
79 		bool state)
80 {
81 	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
82 	int ret;
83 	u8 msc;
84 
85 	ret = itg3200_read_reg_8(indio_dev, ITG3200_REG_IRQ_CONFIG, &msc);
86 	if (ret)
87 		goto error_ret;
88 
89 	if (state)
90 		msc |= ITG3200_IRQ_DATA_RDY_ENABLE;
91 	else
92 		msc &= ~ITG3200_IRQ_DATA_RDY_ENABLE;
93 
94 	ret = itg3200_write_reg_8(indio_dev, ITG3200_REG_IRQ_CONFIG, msc);
95 	if (ret)
96 		goto error_ret;
97 
98 error_ret:
99 	return ret;
100 
101 }
102 
103 static const struct iio_trigger_ops itg3200_trigger_ops = {
104 	.set_trigger_state = &itg3200_data_rdy_trigger_set_state,
105 };
106 
107 int itg3200_probe_trigger(struct iio_dev *indio_dev)
108 {
109 	int ret;
110 	struct itg3200 *st = iio_priv(indio_dev);
111 
112 	st->trig = iio_trigger_alloc("%s-dev%d", indio_dev->name,
113 				     indio_dev->id);
114 	if (!st->trig)
115 		return -ENOMEM;
116 
117 	ret = request_irq(st->i2c->irq,
118 			  &iio_trigger_generic_data_rdy_poll,
119 			  IRQF_TRIGGER_RISING,
120 			  "itg3200_data_rdy",
121 			  st->trig);
122 	if (ret)
123 		goto error_free_trig;
124 
125 
126 	st->trig->dev.parent = &st->i2c->dev;
127 	st->trig->ops = &itg3200_trigger_ops;
128 	iio_trigger_set_drvdata(st->trig, indio_dev);
129 	ret = iio_trigger_register(st->trig);
130 	if (ret)
131 		goto error_free_irq;
132 
133 	/* select default trigger */
134 	indio_dev->trig = iio_trigger_get(st->trig);
135 
136 	return 0;
137 
138 error_free_irq:
139 	free_irq(st->i2c->irq, st->trig);
140 error_free_trig:
141 	iio_trigger_free(st->trig);
142 	return ret;
143 }
144 
145 void itg3200_remove_trigger(struct iio_dev *indio_dev)
146 {
147 	struct itg3200 *st = iio_priv(indio_dev);
148 
149 	iio_trigger_unregister(st->trig);
150 	free_irq(st->i2c->irq, st->trig);
151 	iio_trigger_free(st->trig);
152 }
153