![Peter Meerwald](/assets/img/avatar_default.png)
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net> Acked-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
370 lines
8.7 KiB
C
370 lines
8.7 KiB
C
/*
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* AD7887 SPI ADC driver
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*
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* Copyright 2010-2011 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/device.h>
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#include <linux/kernel.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/spi/spi.h>
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#include <linux/regulator/consumer.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/bitops.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/trigger_consumer.h>
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#include <linux/iio/triggered_buffer.h>
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#include <linux/platform_data/ad7887.h>
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#define AD7887_REF_DIS BIT(5) /* on-chip reference disable */
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#define AD7887_DUAL BIT(4) /* dual-channel mode */
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#define AD7887_CH_AIN1 BIT(3) /* convert on channel 1, DUAL=1 */
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#define AD7887_CH_AIN0 0 /* convert on channel 0, DUAL=0,1 */
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#define AD7887_PM_MODE1 0 /* CS based shutdown */
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#define AD7887_PM_MODE2 1 /* full on */
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#define AD7887_PM_MODE3 2 /* auto shutdown after conversion */
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#define AD7887_PM_MODE4 3 /* standby mode */
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enum ad7887_channels {
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AD7887_CH0,
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AD7887_CH0_CH1,
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AD7887_CH1,
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};
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/**
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* struct ad7887_chip_info - chip specifc information
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* @int_vref_mv: the internal reference voltage
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* @channel: channel specification
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*/
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struct ad7887_chip_info {
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u16 int_vref_mv;
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struct iio_chan_spec channel[3];
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};
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struct ad7887_state {
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struct spi_device *spi;
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const struct ad7887_chip_info *chip_info;
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struct regulator *reg;
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struct spi_transfer xfer[4];
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struct spi_message msg[3];
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struct spi_message *ring_msg;
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unsigned char tx_cmd_buf[4];
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/*
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* DMA (thus cache coherency maintenance) requires the
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* transfer buffers to live in their own cache lines.
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* Buffer needs to be large enough to hold two 16 bit samples and a
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* 64 bit aligned 64 bit timestamp.
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*/
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unsigned char data[ALIGN(4, sizeof(s64)) + sizeof(s64)]
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____cacheline_aligned;
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};
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enum ad7887_supported_device_ids {
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ID_AD7887
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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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/* We know this is a single long so can 'cheat' */
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switch (*indio_dev->active_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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int b_sent;
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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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iio_push_to_buffers_with_timestamp(indio_dev, st->data,
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iio_get_time_ns());
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done:
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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_buffer_setup_ops ad7887_ring_setup_ops = {
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.preenable = &ad7887_ring_preenable,
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.postenable = &iio_triggered_buffer_postenable,
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.predisable = &iio_triggered_buffer_predisable,
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.postdisable = &ad7887_ring_postdisable,
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};
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static int ad7887_scan_direct(struct ad7887_state *st, unsigned ch)
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{
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int ret = spi_sync(st->spi, &st->msg[ch]);
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if (ret)
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return ret;
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return (st->data[(ch * 2)] << 8) | st->data[(ch * 2) + 1];
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}
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static int ad7887_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val,
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int *val2,
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long m)
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{
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int ret;
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struct ad7887_state *st = iio_priv(indio_dev);
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switch (m) {
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case IIO_CHAN_INFO_RAW:
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mutex_lock(&indio_dev->mlock);
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if (iio_buffer_enabled(indio_dev))
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ret = -EBUSY;
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else
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ret = ad7887_scan_direct(st, chan->address);
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mutex_unlock(&indio_dev->mlock);
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if (ret < 0)
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return ret;
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*val = ret >> chan->scan_type.shift;
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*val &= GENMASK(chan->scan_type.realbits - 1, 0);
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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if (st->reg) {
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*val = regulator_get_voltage(st->reg);
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if (*val < 0)
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return *val;
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*val /= 1000;
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} else {
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*val = st->chip_info->int_vref_mv;
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}
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*val2 = chan->scan_type.realbits;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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return -EINVAL;
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}
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static const struct ad7887_chip_info ad7887_chip_info_tbl[] = {
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/*
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* More devices added in future
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*/
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[ID_AD7887] = {
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.channel[0] = {
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.type = IIO_VOLTAGE,
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.indexed = 1,
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.channel = 1,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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.address = 1,
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.scan_index = 1,
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.scan_type = {
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.sign = 'u',
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.realbits = 12,
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.storagebits = 16,
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.shift = 0,
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.endianness = IIO_BE,
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},
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},
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.channel[1] = {
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.type = IIO_VOLTAGE,
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.indexed = 1,
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.channel = 0,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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.address = 0,
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.scan_index = 0,
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.scan_type = {
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.sign = 'u',
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.realbits = 12,
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.storagebits = 16,
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.shift = 0,
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.endianness = IIO_BE,
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},
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},
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.channel[2] = IIO_CHAN_SOFT_TIMESTAMP(2),
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.int_vref_mv = 2500,
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},
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};
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static const struct iio_info ad7887_info = {
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.read_raw = &ad7887_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int ad7887_probe(struct spi_device *spi)
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{
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struct ad7887_platform_data *pdata = spi->dev.platform_data;
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struct ad7887_state *st;
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struct iio_dev *indio_dev;
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uint8_t mode;
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int ret;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
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if (indio_dev == NULL)
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return -ENOMEM;
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st = iio_priv(indio_dev);
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if (!pdata || !pdata->use_onchip_ref) {
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st->reg = devm_regulator_get(&spi->dev, "vref");
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if (IS_ERR(st->reg))
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return PTR_ERR(st->reg);
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ret = regulator_enable(st->reg);
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if (ret)
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return ret;
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}
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st->chip_info =
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&ad7887_chip_info_tbl[spi_get_device_id(spi)->driver_data];
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spi_set_drvdata(spi, indio_dev);
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st->spi = spi;
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/* Estabilish that the iio_dev is a child of the spi device */
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indio_dev->dev.parent = &spi->dev;
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->info = &ad7887_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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/* Setup default message */
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mode = AD7887_PM_MODE4;
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if (!pdata || !pdata->use_onchip_ref)
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mode |= AD7887_REF_DIS;
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if (pdata && pdata->en_dual)
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mode |= AD7887_DUAL;
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st->tx_cmd_buf[0] = AD7887_CH_AIN0 | mode;
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st->xfer[0].rx_buf = &st->data[0];
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st->xfer[0].tx_buf = &st->tx_cmd_buf[0];
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st->xfer[0].len = 2;
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spi_message_init(&st->msg[AD7887_CH0]);
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spi_message_add_tail(&st->xfer[0], &st->msg[AD7887_CH0]);
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if (pdata && pdata->en_dual) {
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st->tx_cmd_buf[2] = AD7887_CH_AIN1 | mode;
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st->xfer[1].rx_buf = &st->data[0];
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st->xfer[1].tx_buf = &st->tx_cmd_buf[2];
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st->xfer[1].len = 2;
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st->xfer[2].rx_buf = &st->data[2];
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st->xfer[2].tx_buf = &st->tx_cmd_buf[0];
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st->xfer[2].len = 2;
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spi_message_init(&st->msg[AD7887_CH0_CH1]);
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spi_message_add_tail(&st->xfer[1], &st->msg[AD7887_CH0_CH1]);
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spi_message_add_tail(&st->xfer[2], &st->msg[AD7887_CH0_CH1]);
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st->xfer[3].rx_buf = &st->data[2];
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st->xfer[3].tx_buf = &st->tx_cmd_buf[2];
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st->xfer[3].len = 2;
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spi_message_init(&st->msg[AD7887_CH1]);
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spi_message_add_tail(&st->xfer[3], &st->msg[AD7887_CH1]);
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indio_dev->channels = st->chip_info->channel;
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indio_dev->num_channels = 3;
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} else {
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indio_dev->channels = &st->chip_info->channel[1];
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indio_dev->num_channels = 2;
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}
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ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
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&ad7887_trigger_handler, &ad7887_ring_setup_ops);
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if (ret)
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goto error_disable_reg;
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_unregister_ring;
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return 0;
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error_unregister_ring:
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iio_triggered_buffer_cleanup(indio_dev);
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error_disable_reg:
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if (st->reg)
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regulator_disable(st->reg);
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return ret;
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}
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static int ad7887_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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struct ad7887_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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iio_triggered_buffer_cleanup(indio_dev);
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if (st->reg)
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regulator_disable(st->reg);
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return 0;
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}
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static const struct spi_device_id ad7887_id[] = {
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{"ad7887", ID_AD7887},
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{}
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};
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MODULE_DEVICE_TABLE(spi, ad7887_id);
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static struct spi_driver ad7887_driver = {
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.driver = {
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.name = "ad7887",
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.owner = THIS_MODULE,
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},
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.probe = ad7887_probe,
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.remove = ad7887_remove,
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.id_table = ad7887_id,
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};
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module_spi_driver(ad7887_driver);
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MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
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MODULE_DESCRIPTION("Analog Devices AD7887 ADC");
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MODULE_LICENSE("GPL v2");
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