1 /*
2  * STMicroelectronics sensors buffer library driver
3  *
4  * Copyright 2012-2013 STMicroelectronics Inc.
5  *
6  * Denis Ciocca <denis.ciocca@st.com>
7  *
8  * Licensed under the GPL-2.
9  */
10 
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/slab.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/trigger.h>
16 #include <linux/interrupt.h>
17 #include <linux/iio/buffer.h>
18 #include <linux/iio/trigger_consumer.h>
19 #include <linux/iio/triggered_buffer.h>
20 #include <linux/irqreturn.h>
21 
22 #include <linux/iio/common/st_sensors.h>
23 
24 
25 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
26 {
27 	int i;
28 	struct st_sensor_data *sdata = iio_priv(indio_dev);
29 	unsigned int num_data_channels = sdata->num_data_channels;
30 
31 	for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
32 		const struct iio_chan_spec *channel = &indio_dev->channels[i];
33 		unsigned int bytes_to_read =
34 			DIV_ROUND_UP(channel->scan_type.realbits +
35 				     channel->scan_type.shift, 8);
36 		unsigned int storage_bytes =
37 			channel->scan_type.storagebits >> 3;
38 
39 		buf = PTR_ALIGN(buf, storage_bytes);
40 		if (sdata->tf->read_multiple_byte(&sdata->tb, sdata->dev,
41 						  channel->address,
42 						  bytes_to_read, buf,
43 						  sdata->multiread_bit) <
44 		    bytes_to_read)
45 			return -EIO;
46 
47 		/* Advance the buffer pointer */
48 		buf += storage_bytes;
49 	}
50 
51 	return 0;
52 }
53 
54 irqreturn_t st_sensors_trigger_handler(int irq, void *p)
55 {
56 	int len;
57 	struct iio_poll_func *pf = p;
58 	struct iio_dev *indio_dev = pf->indio_dev;
59 	struct st_sensor_data *sdata = iio_priv(indio_dev);
60 	s64 timestamp;
61 
62 	/*
63 	 * If we do timetamping here, do it before reading the values, because
64 	 * once we've read the values, new interrupts can occur (when using
65 	 * the hardware trigger) and the hw_timestamp may get updated.
66 	 * By storing it in a local variable first, we are safe.
67 	 */
68 	if (iio_trigger_using_own(indio_dev))
69 		timestamp = sdata->hw_timestamp;
70 	else
71 		timestamp = iio_get_time_ns(indio_dev);
72 
73 	len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
74 	if (len < 0)
75 		goto st_sensors_get_buffer_element_error;
76 
77 	iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
78 					   timestamp);
79 
80 st_sensors_get_buffer_element_error:
81 	iio_trigger_notify_done(indio_dev->trig);
82 
83 	return IRQ_HANDLED;
84 }
85 EXPORT_SYMBOL(st_sensors_trigger_handler);
86 
87 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
88 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer");
89 MODULE_LICENSE("GPL v2");
90