300 lines
6.9 KiB
C
300 lines
6.9 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/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/delay.h>
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#include <linux/module.h>
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#include "../iio.h"
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#include "../sysfs.h"
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#include "../ring_generic.h"
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#include "ad7298.h"
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static struct iio_chan_spec ad7298_channels[] = {
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IIO_CHAN(IIO_TEMP, 0, 1, 0, NULL, 0, 0,
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(1 << IIO_CHAN_INFO_SCALE_SEPARATE),
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9, AD7298_CH_TEMP, IIO_ST('s', 32, 32, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 0, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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0, 0, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 1, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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1, 1, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 2, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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2, 2, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 3, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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3, 3, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 4, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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4, 4, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 5, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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5, 5, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 6, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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6, 6, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN(IIO_IN, 0, 1, 0, NULL, 7, 0,
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(1 << IIO_CHAN_INFO_SCALE_SHARED),
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7, 7, IIO_ST('u', 12, 16, 0), 0),
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IIO_CHAN_SOFT_TIMESTAMP(8),
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};
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static int ad7298_scan_direct(struct ad7298_state *st, unsigned ch)
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{
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int ret;
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st->tx_buf[0] = cpu_to_be16(AD7298_WRITE | st->ext_ref |
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(AD7298_CH(0) >> ch));
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ret = spi_sync(st->spi, &st->scan_single_msg);
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if (ret)
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return ret;
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return be16_to_cpu(st->rx_buf[0]);
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}
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static int ad7298_scan_temp(struct ad7298_state *st, int *val)
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{
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int tmp, ret;
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tmp = cpu_to_be16(AD7298_WRITE | AD7298_TSENSE |
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AD7298_TAVG | st->ext_ref);
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ret = spi_write(st->spi, (u8 *)&tmp, 2);
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if (ret)
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return ret;
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tmp = 0;
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ret = spi_write(st->spi, (u8 *)&tmp, 2);
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if (ret)
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return ret;
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usleep_range(101, 1000); /* sleep > 100us */
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ret = spi_read(st->spi, (u8 *)&tmp, 2);
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if (ret)
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return ret;
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tmp = be16_to_cpu(tmp) & RES_MASK(AD7298_BITS);
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/*
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* One LSB of the ADC corresponds to 0.25 deg C.
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* The temperature reading is in 12-bit twos complement format
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*/
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if (tmp & (1 << (AD7298_BITS - 1))) {
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tmp = (4096 - tmp) * 250;
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tmp -= (2 * tmp);
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} else {
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tmp *= 250; /* temperature in milli degrees Celsius */
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}
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*val = tmp;
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return 0;
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}
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static int ad7298_read_raw(struct iio_dev *dev_info,
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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 ad7298_state *st = iio_priv(dev_info);
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unsigned int scale_uv;
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switch (m) {
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case 0:
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mutex_lock(&dev_info->mlock);
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if (iio_ring_enabled(dev_info)) {
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if (chan->address == AD7298_CH_TEMP)
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ret = -ENODEV;
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else
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ret = ad7298_scan_from_ring(dev_info,
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chan->address);
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} else {
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if (chan->address == AD7298_CH_TEMP)
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ret = ad7298_scan_temp(st, val);
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else
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ret = ad7298_scan_direct(st, chan->address);
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}
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mutex_unlock(&dev_info->mlock);
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if (ret < 0)
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return ret;
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if (chan->address != AD7298_CH_TEMP)
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*val = ret & RES_MASK(AD7298_BITS);
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return IIO_VAL_INT;
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case (1 << IIO_CHAN_INFO_SCALE_SHARED):
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scale_uv = (st->int_vref_mv * 1000) >> AD7298_BITS;
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*val = scale_uv / 1000;
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*val2 = (scale_uv % 1000) * 1000;
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return IIO_VAL_INT_PLUS_MICRO;
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case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
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*val = 1;
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*val2 = 0;
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return IIO_VAL_INT_PLUS_MICRO;
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}
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return -EINVAL;
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}
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static const struct iio_info ad7298_info = {
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.read_raw = &ad7298_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int __devinit ad7298_probe(struct spi_device *spi)
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{
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struct ad7298_platform_data *pdata = spi->dev.platform_data;
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struct ad7298_state *st;
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int ret, regdone = 0;
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struct iio_dev *indio_dev = iio_allocate_device(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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st->reg = regulator_get(&spi->dev, "vcc");
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if (!IS_ERR(st->reg)) {
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ret = regulator_enable(st->reg);
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if (ret)
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goto error_put_reg;
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}
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spi_set_drvdata(spi, indio_dev);
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st->spi = spi;
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indio_dev->name = spi_get_device_id(spi)->name;
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indio_dev->dev.parent = &spi->dev;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ad7298_channels;
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indio_dev->num_channels = ARRAY_SIZE(ad7298_channels);
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indio_dev->info = &ad7298_info;
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/* Setup default message */
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st->scan_single_xfer[0].tx_buf = &st->tx_buf[0];
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st->scan_single_xfer[0].len = 2;
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st->scan_single_xfer[0].cs_change = 1;
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st->scan_single_xfer[1].tx_buf = &st->tx_buf[1];
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st->scan_single_xfer[1].len = 2;
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st->scan_single_xfer[1].cs_change = 1;
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st->scan_single_xfer[2].rx_buf = &st->rx_buf[0];
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st->scan_single_xfer[2].len = 2;
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spi_message_init(&st->scan_single_msg);
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spi_message_add_tail(&st->scan_single_xfer[0], &st->scan_single_msg);
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spi_message_add_tail(&st->scan_single_xfer[1], &st->scan_single_msg);
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spi_message_add_tail(&st->scan_single_xfer[2], &st->scan_single_msg);
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if (pdata && pdata->vref_mv) {
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st->int_vref_mv = pdata->vref_mv;
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st->ext_ref = AD7298_EXTREF;
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} else {
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st->int_vref_mv = AD7298_INTREF_mV;
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}
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ret = ad7298_register_ring_funcs_and_init(indio_dev);
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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_disable_reg;
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regdone = 1;
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ret = iio_ring_buffer_register(indio_dev,
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&ad7298_channels[1], /* skip temp0 */
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ARRAY_SIZE(ad7298_channels) - 1);
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if (ret)
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goto error_cleanup_ring;
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return 0;
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error_cleanup_ring:
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ad7298_ring_cleanup(indio_dev);
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error_disable_reg:
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if (!IS_ERR(st->reg))
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regulator_disable(st->reg);
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error_put_reg:
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if (!IS_ERR(st->reg))
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regulator_put(st->reg);
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if (regdone)
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iio_device_unregister(indio_dev);
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else
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iio_free_device(indio_dev);
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return ret;
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}
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static int __devexit ad7298_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 ad7298_state *st = iio_priv(indio_dev);
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iio_ring_buffer_unregister(indio_dev);
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ad7298_ring_cleanup(indio_dev);
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iio_device_unregister(indio_dev);
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if (!IS_ERR(st->reg)) {
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regulator_disable(st->reg);
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regulator_put(st->reg);
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}
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iio_device_unregister(indio_dev);
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return 0;
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}
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static const struct spi_device_id ad7298_id[] = {
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{"ad7298", 0},
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{}
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};
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static struct spi_driver ad7298_driver = {
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.driver = {
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.name = "ad7298",
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.bus = &spi_bus_type,
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.owner = THIS_MODULE,
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},
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.probe = ad7298_probe,
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.remove = __devexit_p(ad7298_remove),
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.id_table = ad7298_id,
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};
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static int __init ad7298_init(void)
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{
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return spi_register_driver(&ad7298_driver);
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}
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module_init(ad7298_init);
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static void __exit ad7298_exit(void)
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{
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spi_unregister_driver(&ad7298_driver);
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}
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module_exit(ad7298_exit);
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MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
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MODULE_DESCRIPTION("Analog Devices AD7298 ADC");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("spi:ad7298");
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