mirror of https://gitee.com/openkylin/linux.git
303 lines
6.8 KiB
C
303 lines
6.8 KiB
C
/*
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* AD7303 Digital to analog converters driver
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*
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* Copyright 2013 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/err.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/spi/spi.h>
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#include <linux/slab.h>
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#include <linux/sysfs.h>
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#include <linux/regulator/consumer.h>
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#include <linux/of.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/platform_data/ad7303.h>
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#define AD7303_CFG_EXTERNAL_VREF BIT(15)
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#define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
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#define AD7303_CFG_ADDR_OFFSET 10
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#define AD7303_CMD_UPDATE_DAC (0x3 << 8)
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/**
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* struct ad7303_state - driver instance specific data
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* @spi: the device for this driver instance
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* @config: cached config register value
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* @dac_cache: current DAC raw value (chip does not support readback)
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* @data: spi transfer buffer
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*/
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struct ad7303_state {
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struct spi_device *spi;
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uint16_t config;
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uint8_t dac_cache[2];
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struct regulator *vdd_reg;
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struct regulator *vref_reg;
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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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*/
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__be16 data ____cacheline_aligned;
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};
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static int ad7303_write(struct ad7303_state *st, unsigned int chan,
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uint8_t val)
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{
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st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC |
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(chan << AD7303_CFG_ADDR_OFFSET) |
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st->config | val);
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return spi_write(st->spi, &st->data, sizeof(st->data));
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}
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static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
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uintptr_t private, const struct iio_chan_spec *chan, char *buf)
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{
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struct ad7303_state *st = iio_priv(indio_dev);
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return sprintf(buf, "%d\n", (bool)(st->config &
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AD7303_CFG_POWER_DOWN(chan->channel)));
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}
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static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
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uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
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size_t len)
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{
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struct ad7303_state *st = iio_priv(indio_dev);
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bool pwr_down;
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int ret;
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ret = strtobool(buf, &pwr_down);
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if (ret)
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return ret;
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mutex_lock(&indio_dev->mlock);
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if (pwr_down)
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st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
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else
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st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);
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/* There is no noop cmd which allows us to only update the powerdown
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* mode, so just write one of the DAC channels again */
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ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
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mutex_unlock(&indio_dev->mlock);
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return ret ? ret : len;
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}
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static int ad7303_get_vref(struct ad7303_state *st,
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struct iio_chan_spec const *chan)
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{
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int ret;
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if (st->config & AD7303_CFG_EXTERNAL_VREF)
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return regulator_get_voltage(st->vref_reg);
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ret = regulator_get_voltage(st->vdd_reg);
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if (ret < 0)
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return ret;
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return ret / 2;
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}
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static int ad7303_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val, int *val2, long info)
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{
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struct ad7303_state *st = iio_priv(indio_dev);
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int vref_uv;
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switch (info) {
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case IIO_CHAN_INFO_RAW:
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*val = st->dac_cache[chan->channel];
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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vref_uv = ad7303_get_vref(st, chan);
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if (vref_uv < 0)
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return vref_uv;
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*val = 2 * vref_uv / 1000;
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*val2 = chan->scan_type.realbits;
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return IIO_VAL_FRACTIONAL_LOG2;
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default:
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break;
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}
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return -EINVAL;
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}
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static int ad7303_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val, int val2, long mask)
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{
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struct ad7303_state *st = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (val >= (1 << chan->scan_type.realbits) || val < 0)
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return -EINVAL;
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mutex_lock(&indio_dev->mlock);
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ret = ad7303_write(st, chan->address, val);
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if (ret == 0)
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st->dac_cache[chan->channel] = val;
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mutex_unlock(&indio_dev->mlock);
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break;
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default:
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ret = -EINVAL;
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}
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return ret;
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}
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static const struct iio_info ad7303_info = {
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.read_raw = ad7303_read_raw,
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.write_raw = ad7303_write_raw,
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.driver_module = THIS_MODULE,
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};
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static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
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{
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.name = "powerdown",
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.read = ad7303_read_dac_powerdown,
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.write = ad7303_write_dac_powerdown,
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},
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{ },
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};
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#define AD7303_CHANNEL(chan) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.output = 1, \
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.channel = (chan), \
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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 = (chan), \
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.scan_type = { \
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.sign = 'u', \
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.realbits = '8', \
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.storagebits = '8', \
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.shift = '0', \
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}, \
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.ext_info = ad7303_ext_info, \
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}
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static const struct iio_chan_spec ad7303_channels[] = {
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AD7303_CHANNEL(0),
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AD7303_CHANNEL(1),
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};
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static int ad7303_probe(struct spi_device *spi)
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{
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const struct spi_device_id *id = spi_get_device_id(spi);
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struct iio_dev *indio_dev;
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struct ad7303_state *st;
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bool ext_ref;
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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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spi_set_drvdata(spi, indio_dev);
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st->spi = spi;
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st->vdd_reg = devm_regulator_get(&spi->dev, "Vdd");
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if (IS_ERR(st->vdd_reg))
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return PTR_ERR(st->vdd_reg);
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ret = regulator_enable(st->vdd_reg);
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if (ret)
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return ret;
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if (spi->dev.of_node) {
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ext_ref = of_property_read_bool(spi->dev.of_node,
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"REF-supply");
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} else {
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struct ad7303_platform_data *pdata = spi->dev.platform_data;
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if (pdata && pdata->use_external_ref)
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ext_ref = true;
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else
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ext_ref = false;
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}
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if (ext_ref) {
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st->vref_reg = devm_regulator_get(&spi->dev, "REF");
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if (IS_ERR(st->vref_reg)) {
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ret = PTR_ERR(st->vref_reg);
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goto err_disable_vdd_reg;
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}
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ret = regulator_enable(st->vref_reg);
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if (ret)
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goto err_disable_vdd_reg;
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st->config |= AD7303_CFG_EXTERNAL_VREF;
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}
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indio_dev->dev.parent = &spi->dev;
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indio_dev->name = id->name;
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indio_dev->info = &ad7303_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ad7303_channels;
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indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);
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ret = iio_device_register(indio_dev);
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if (ret)
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goto err_disable_vref_reg;
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return 0;
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err_disable_vref_reg:
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if (st->vref_reg)
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regulator_disable(st->vref_reg);
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err_disable_vdd_reg:
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regulator_disable(st->vdd_reg);
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return ret;
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}
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static int ad7303_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 ad7303_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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if (st->vref_reg)
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regulator_disable(st->vref_reg);
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regulator_disable(st->vdd_reg);
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return 0;
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}
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static const struct spi_device_id ad7303_spi_ids[] = {
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{ "ad7303", 0 },
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{}
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};
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MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);
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static struct spi_driver ad7303_driver = {
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.driver = {
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.name = "ad7303",
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.owner = THIS_MODULE,
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},
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.probe = ad7303_probe,
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.remove = ad7303_remove,
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.id_table = ad7303_spi_ids,
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};
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module_spi_driver(ad7303_driver);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
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MODULE_LICENSE("GPL v2");
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