2 * AD7298 SPI ADC driver
4 * Copyright 2011-2012 Analog Devices Inc.
6 * Licensed under the GPL-2.
9 #include <linux/interrupt.h>
10 #include <linux/kernel.h>
11 #include <linux/slab.h>
12 #include <linux/spi/spi.h>
14 #include <linux/iio/iio.h>
15 #include <linux/iio/buffer.h>
16 #include <linux/iio/trigger_consumer.h>
17 #include <linux/iio/triggered_buffer.h>
22 * ad7298_update_scan_mode() setup the spi transfer buffer for the new scan mask
24 int ad7298_update_scan_mode(struct iio_dev *indio_dev,
25 const unsigned long *active_scan_mask)
27 struct ad7298_state *st = iio_priv(indio_dev);
29 unsigned short command;
32 /* Now compute overall size */
33 scan_count = bitmap_weight(active_scan_mask, indio_dev->masklength);
35 command = AD7298_WRITE | st->ext_ref;
37 for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
38 if (test_bit(i, active_scan_mask))
41 st->tx_buf[0] = cpu_to_be16(command);
43 /* build spi ring message */
44 st->ring_xfer[0].tx_buf = &st->tx_buf[0];
45 st->ring_xfer[0].len = 2;
46 st->ring_xfer[0].cs_change = 1;
47 st->ring_xfer[1].tx_buf = &st->tx_buf[1];
48 st->ring_xfer[1].len = 2;
49 st->ring_xfer[1].cs_change = 1;
51 spi_message_init(&st->ring_msg);
52 spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
53 spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
55 for (i = 0; i < scan_count; i++) {
56 st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
57 st->ring_xfer[i + 2].len = 2;
58 st->ring_xfer[i + 2].cs_change = 1;
59 spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
61 /* make sure last transfer cs_change is not set */
62 st->ring_xfer[i + 1].cs_change = 0;
68 * ad7298_trigger_handler() bh of trigger launched polling to ring buffer
70 * Currently there is no option in this driver to disable the saving of
71 * timestamps within the ring.
73 static irqreturn_t ad7298_trigger_handler(int irq, void *p)
75 struct iio_poll_func *pf = p;
76 struct iio_dev *indio_dev = pf->indio_dev;
77 struct ad7298_state *st = iio_priv(indio_dev);
78 struct iio_buffer *ring = indio_dev->buffer;
83 b_sent = spi_sync(st->spi, &st->ring_msg);
87 if (indio_dev->scan_timestamp) {
88 time_ns = iio_get_time_ns();
89 memcpy((u8 *)buf + indio_dev->scan_bytes - sizeof(s64),
90 &time_ns, sizeof(time_ns));
93 for (i = 0; i < bitmap_weight(indio_dev->active_scan_mask,
94 indio_dev->masklength); i++)
95 buf[i] = be16_to_cpu(st->rx_buf[i]);
97 indio_dev->buffer->access->store_to(ring, (u8 *)buf, time_ns);
100 iio_trigger_notify_done(indio_dev->trig);
105 int ad7298_register_ring_funcs_and_init(struct iio_dev *indio_dev)
107 return iio_triggered_buffer_setup(indio_dev, NULL,
108 &ad7298_trigger_handler, NULL);
111 void ad7298_ring_cleanup(struct iio_dev *indio_dev)
113 iio_triggered_buffer_cleanup(indio_dev);