195 lines
4.6 KiB
C
195 lines
4.6 KiB
C
/*
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* AD7298 SPI ADC driver
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*
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* Copyright 2011 Analog Devices Inc.
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*
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* Licensed under the GPL-2.
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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 "ad7298.h"
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int ad7298_scan_from_ring(struct iio_dev *dev_info, long ch)
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{
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struct iio_ring_buffer *ring = dev_info->ring;
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int ret;
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u16 *ring_data;
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if (!(ring->scan_mask & (1 << ch))) {
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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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ret = be16_to_cpu(ring_data[ch]);
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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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* ad7298_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 number 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 ad7298_ring_preenable(struct iio_dev *indio_dev)
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{
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struct ad7298_state *st = iio_priv(indio_dev);
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struct iio_ring_buffer *ring = indio_dev->ring;
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size_t d_size;
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int i, m;
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unsigned short command;
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d_size = ring->scan_count * (AD7298_STORAGE_BITS / 8);
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if (ring->scan_timestamp) {
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d_size += sizeof(s64);
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if (d_size % sizeof(s64))
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d_size += sizeof(s64) - (d_size % sizeof(s64));
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}
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if (ring->access->set_bytes_per_datum)
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ring->access->set_bytes_per_datum(ring, d_size);
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st->d_size = d_size;
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command = AD7298_WRITE | st->ext_ref;
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for (i = 0, m = AD7298_CH(0); i < AD7298_MAX_CHAN; i++, m >>= 1)
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if (ring->scan_mask & (1 << i))
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command |= m;
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st->tx_buf[0] = cpu_to_be16(command);
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/* build spi ring message */
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st->ring_xfer[0].tx_buf = &st->tx_buf[0];
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st->ring_xfer[0].len = 2;
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st->ring_xfer[0].cs_change = 1;
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st->ring_xfer[1].tx_buf = &st->tx_buf[1];
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st->ring_xfer[1].len = 2;
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st->ring_xfer[1].cs_change = 1;
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spi_message_init(&st->ring_msg);
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spi_message_add_tail(&st->ring_xfer[0], &st->ring_msg);
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spi_message_add_tail(&st->ring_xfer[1], &st->ring_msg);
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for (i = 0; i < ring->scan_count; i++) {
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st->ring_xfer[i + 2].rx_buf = &st->rx_buf[i];
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st->ring_xfer[i + 2].len = 2;
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st->ring_xfer[i + 2].cs_change = 1;
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spi_message_add_tail(&st->ring_xfer[i + 2], &st->ring_msg);
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}
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/* make sure last transfer cs_change is not set */
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st->ring_xfer[i + 1].cs_change = 0;
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return 0;
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}
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/**
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* ad7298_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 ad7298_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 ad7298_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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__u16 buf[16];
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int b_sent, i;
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b_sent = spi_sync(st->spi, &st->ring_msg);
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if (b_sent)
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return b_sent;
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if (ring->scan_timestamp) {
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time_ns = iio_get_time_ns();
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memcpy((u8 *)buf + st->d_size - sizeof(s64),
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&time_ns, sizeof(time_ns));
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}
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for (i = 0; i < ring->scan_count; i++)
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buf[i] = be16_to_cpu(st->rx_buf[i]);
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indio_dev->ring->access->store_to(ring, (u8 *)buf, time_ns);
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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 ad7298_ring_setup_ops = {
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.preenable = &ad7298_ring_preenable,
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.postenable = &iio_triggered_ring_postenable,
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.predisable = &iio_triggered_ring_predisable,
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};
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int ad7298_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(NULL,
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&ad7298_trigger_handler,
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IRQF_ONESHOT,
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indio_dev,
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"ad7298_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 = &ad7298_ring_setup_ops;
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indio_dev->ring->scan_timestamp = true;
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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 ad7298_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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