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 int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
26 {
27 	int i, len;
28 	int total = 0;
29 	struct st_sensor_data *sdata = iio_priv(indio_dev);
30 	unsigned int num_data_channels = sdata->num_data_channels;
31 
32 	for (i = 0; i < num_data_channels; i++) {
33 		unsigned int bytes_to_read;
34 
35 		if (test_bit(i, indio_dev->active_scan_mask)) {
36 			bytes_to_read = indio_dev->channels[i].scan_type.storagebits >> 3;
37 			len = sdata->tf->read_multiple_byte(&sdata->tb,
38 				sdata->dev, indio_dev->channels[i].address,
39 				bytes_to_read,
40 				buf + total, sdata->multiread_bit);
41 
42 			if (len < bytes_to_read)
43 				return -EIO;
44 
45 			/* Advance the buffer pointer */
46 			total += len;
47 		}
48 	}
49 
50 	return total;
51 }
52 EXPORT_SYMBOL(st_sensors_get_buffer_element);
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 
61 	/* If we have a status register, check if this IRQ came from us */
62 	if (sdata->sensor_settings->drdy_irq.addr_stat_drdy) {
63 		u8 status;
64 
65 		len = sdata->tf->read_byte(&sdata->tb, sdata->dev,
66 			   sdata->sensor_settings->drdy_irq.addr_stat_drdy,
67 			   &status);
68 		if (len < 0)
69 			dev_err(sdata->dev, "could not read channel status\n");
70 
71 		/*
72 		 * If this was not caused by any channels on this sensor,
73 		 * return IRQ_NONE
74 		 */
75 		if (!(status & (u8)indio_dev->active_scan_mask[0]))
76 			return IRQ_NONE;
77 	}
78 
79 	len = st_sensors_get_buffer_element(indio_dev, sdata->buffer_data);
80 	if (len < 0)
81 		goto st_sensors_get_buffer_element_error;
82 
83 	iio_push_to_buffers_with_timestamp(indio_dev, sdata->buffer_data,
84 		pf->timestamp);
85 
86 st_sensors_get_buffer_element_error:
87 	iio_trigger_notify_done(indio_dev->trig);
88 
89 	return IRQ_HANDLED;
90 }
91 EXPORT_SYMBOL(st_sensors_trigger_handler);
92 
93 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
94 MODULE_DESCRIPTION("STMicroelectronics ST-sensors buffer");
95 MODULE_LICENSE("GPL v2");
96