194 lines
4.6 KiB
C
194 lines
4.6 KiB
C
/*
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* Copyright 2010-2011 Analog Devices Inc.
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* Copyright (C) 2008 Jonathan Cameron
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*
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* Licensed under the GPL-2.
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*
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* ad7887_ring.c
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*/
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/spi/spi.h>
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#include "../iio.h"
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#include "../ring_generic.h"
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#include "../ring_sw.h"
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#include "../trigger_consumer.h"
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#include "ad7887.h"
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int ad7887_scan_from_ring(struct ad7887_state *st, long mask)
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{
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struct iio_ring_buffer *ring = iio_priv_to_dev(st)->ring;
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int count = 0, ret;
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u16 *ring_data;
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if (!(ring->scan_mask & mask)) {
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ret = -EBUSY;
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goto error_ret;
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}
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ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
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GFP_KERNEL);
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if (ring_data == NULL) {
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ret = -ENOMEM;
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goto error_ret;
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}
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ret = ring->access->read_last(ring, (u8 *) ring_data);
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if (ret)
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goto error_free_ring_data;
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/* for single channel scan the result is stored with zero offset */
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if ((ring->scan_mask == ((1 << 1) | (1 << 0))) && (mask == (1 << 1)))
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count = 1;
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ret = be16_to_cpu(ring_data[count]);
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error_free_ring_data:
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kfree(ring_data);
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error_ret:
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return ret;
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}
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/**
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* ad7887_ring_preenable() setup the parameters of the ring before enabling
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*
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* The complex nature of the setting of the nuber of bytes per datum is due
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* to this driver currently ensuring that the timestamp is stored at an 8
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* byte boundary.
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**/
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static int ad7887_ring_preenable(struct iio_dev *indio_dev)
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{
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struct ad7887_state *st = iio_priv(indio_dev);
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struct iio_ring_buffer *ring = indio_dev->ring;
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st->d_size = ring->scan_count *
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st->chip_info->channel[0].scan_type.storagebits / 8;
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if (ring->scan_timestamp) {
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st->d_size += sizeof(s64);
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if (st->d_size % sizeof(s64))
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st->d_size += sizeof(s64) - (st->d_size % sizeof(s64));
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}
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if (indio_dev->ring->access->set_bytes_per_datum)
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indio_dev->ring->access->set_bytes_per_datum(indio_dev->ring,
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st->d_size);
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switch (ring->scan_mask) {
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case (1 << 0):
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st->ring_msg = &st->msg[AD7887_CH0];
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break;
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case (1 << 1):
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st->ring_msg = &st->msg[AD7887_CH1];
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/* Dummy read: push CH1 setting down to hardware */
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spi_sync(st->spi, st->ring_msg);
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break;
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case ((1 << 1) | (1 << 0)):
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st->ring_msg = &st->msg[AD7887_CH0_CH1];
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break;
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}
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return 0;
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}
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static int ad7887_ring_postdisable(struct iio_dev *indio_dev)
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{
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struct ad7887_state *st = iio_priv(indio_dev);
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/* dummy read: restore default CH0 settin */
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return spi_sync(st->spi, &st->msg[AD7887_CH0]);
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}
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/**
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* ad7887_trigger_handler() bh of trigger launched polling to ring buffer
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*
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* Currently there is no option in this driver to disable the saving of
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* timestamps within the ring.
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**/
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static irqreturn_t ad7887_trigger_handler(int irq, void *p)
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{
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struct iio_poll_func *pf = p;
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struct iio_dev *indio_dev = pf->indio_dev;
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struct ad7887_state *st = iio_priv(indio_dev);
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struct iio_ring_buffer *ring = indio_dev->ring;
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s64 time_ns;
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__u8 *buf;
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int b_sent;
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unsigned int bytes = ring->scan_count *
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st->chip_info->channel[0].scan_type.storagebits / 8;
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buf = kzalloc(st->d_size, GFP_KERNEL);
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if (buf == NULL)
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return -ENOMEM;
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b_sent = spi_sync(st->spi, st->ring_msg);
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if (b_sent)
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goto done;
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time_ns = iio_get_time_ns();
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memcpy(buf, st->data, bytes);
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if (ring->scan_timestamp)
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memcpy(buf + st->d_size - sizeof(s64),
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&time_ns, sizeof(time_ns));
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indio_dev->ring->access->store_to(indio_dev->ring, buf, time_ns);
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done:
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kfree(buf);
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iio_trigger_notify_done(indio_dev->trig);
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return IRQ_HANDLED;
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}
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static const struct iio_ring_setup_ops ad7887_ring_setup_ops = {
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.preenable = &ad7887_ring_preenable,
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.postenable = &iio_triggered_ring_postenable,
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.predisable = &iio_triggered_ring_predisable,
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.postdisable = &ad7887_ring_postdisable,
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};
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int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
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{
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int ret;
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indio_dev->ring = iio_sw_rb_allocate(indio_dev);
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if (!indio_dev->ring) {
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ret = -ENOMEM;
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goto error_ret;
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}
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/* Effectively select the ring buffer implementation */
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indio_dev->ring->access = &ring_sw_access_funcs;
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indio_dev->pollfunc = iio_alloc_pollfunc(&iio_pollfunc_store_time,
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&ad7887_trigger_handler,
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IRQF_ONESHOT,
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indio_dev,
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"ad7887_consumer%d",
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indio_dev->id);
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if (indio_dev->pollfunc == NULL) {
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ret = -ENOMEM;
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goto error_deallocate_sw_rb;
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}
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/* Ring buffer functions - here trigger setup related */
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indio_dev->ring->setup_ops = &ad7887_ring_setup_ops;
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/* Flag that polled ring buffering is possible */
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indio_dev->modes |= INDIO_RING_TRIGGERED;
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return 0;
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error_deallocate_sw_rb:
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iio_sw_rb_free(indio_dev->ring);
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error_ret:
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return ret;
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}
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void ad7887_ring_cleanup(struct iio_dev *indio_dev)
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{
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iio_dealloc_pollfunc(indio_dev->pollfunc);
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iio_sw_rb_free(indio_dev->ring);
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}
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