311 lines
6.6 KiB
C
311 lines
6.6 KiB
C
/*
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* AD7780/AD7781 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/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/sched.h>
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#include <linux/gpio.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include "ad7780.h"
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#define AD7780_RDY (1 << 7)
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#define AD7780_FILTER (1 << 6)
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#define AD7780_ERR (1 << 5)
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#define AD7780_ID1 (1 << 4)
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#define AD7780_ID0 (1 << 3)
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#define AD7780_GAIN (1 << 2)
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#define AD7780_PAT1 (1 << 1)
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#define AD7780_PAT0 (1 << 0)
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struct ad7780_chip_info {
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struct iio_chan_spec channel;
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};
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struct ad7780_state {
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struct spi_device *spi;
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const struct ad7780_chip_info *chip_info;
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struct regulator *reg;
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struct ad7780_platform_data *pdata;
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wait_queue_head_t wq_data_avail;
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bool done;
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u16 int_vref_mv;
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struct spi_transfer xfer;
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struct spi_message msg;
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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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unsigned int data ____cacheline_aligned;
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};
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enum ad7780_supported_device_ids {
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ID_AD7780,
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ID_AD7781,
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};
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static int ad7780_read(struct ad7780_state *st, int *val)
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{
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int ret;
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spi_bus_lock(st->spi->master);
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enable_irq(st->spi->irq);
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st->done = false;
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gpio_set_value(st->pdata->gpio_pdrst, 1);
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ret = wait_event_interruptible(st->wq_data_avail, st->done);
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disable_irq_nosync(st->spi->irq);
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if (ret)
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goto out;
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ret = spi_sync_locked(st->spi, &st->msg);
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*val = be32_to_cpu(st->data);
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out:
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gpio_set_value(st->pdata->gpio_pdrst, 0);
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spi_bus_unlock(st->spi->master);
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return ret;
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}
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static int ad7780_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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struct ad7780_state *st = iio_priv(indio_dev);
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struct iio_chan_spec channel = st->chip_info->channel;
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int ret, smpl = 0;
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unsigned long scale_uv;
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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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ret = ad7780_read(st, &smpl);
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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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if ((smpl & AD7780_ERR) ||
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!((smpl & AD7780_PAT0) && !(smpl & AD7780_PAT1)))
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return -EIO;
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*val = (smpl >> channel.scan_type.shift) &
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((1 << (channel.scan_type.realbits)) - 1);
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*val -= (1 << (channel.scan_type.realbits - 1));
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if (!(smpl & AD7780_GAIN))
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*val *= 128;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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scale_uv = (st->int_vref_mv * 100000)
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>> (channel.scan_type.realbits - 1);
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*val = scale_uv / 100000;
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*val2 = (scale_uv % 100000) * 10;
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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 ad7780_chip_info ad7780_chip_info_tbl[] = {
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[ID_AD7780] = {
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.channel = {
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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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
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IIO_CHAN_INFO_SCALE_SHARED_BIT,
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.scan_type = {
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.sign = 's',
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.realbits = 24,
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.storagebits = 32,
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.shift = 8,
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},
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},
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},
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[ID_AD7781] = {
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.channel = {
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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 = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
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IIO_CHAN_INFO_SCALE_SHARED_BIT,
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.scan_type = {
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.sign = 's',
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.realbits = 20,
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.storagebits = 32,
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.shift = 12,
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},
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},
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},
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};
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/**
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* Interrupt handler
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*/
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static irqreturn_t ad7780_interrupt(int irq, void *dev_id)
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{
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struct ad7780_state *st = dev_id;
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st->done = true;
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wake_up_interruptible(&st->wq_data_avail);
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return IRQ_HANDLED;
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};
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static const struct iio_info ad7780_info = {
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.read_raw = &ad7780_read_raw,
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.driver_module = THIS_MODULE,
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};
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static int __devinit ad7780_probe(struct spi_device *spi)
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{
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struct ad7780_platform_data *pdata = spi->dev.platform_data;
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struct ad7780_state *st;
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struct iio_dev *indio_dev;
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int ret, voltage_uv = 0;
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if (!pdata) {
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dev_dbg(&spi->dev, "no platform data?\n");
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return -ENODEV;
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}
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indio_dev = iio_device_alloc(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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voltage_uv = regulator_get_voltage(st->reg);
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}
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st->chip_info =
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&ad7780_chip_info_tbl[spi_get_device_id(spi)->driver_data];
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st->pdata = pdata;
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if (pdata && pdata->vref_mv)
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st->int_vref_mv = pdata->vref_mv;
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else if (voltage_uv)
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st->int_vref_mv = voltage_uv / 1000;
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else
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dev_warn(&spi->dev, "reference voltage unspecified\n");
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spi_set_drvdata(spi, indio_dev);
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st->spi = spi;
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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->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = &st->chip_info->channel;
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indio_dev->num_channels = 1;
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indio_dev->info = &ad7780_info;
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init_waitqueue_head(&st->wq_data_avail);
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/* Setup default message */
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st->xfer.rx_buf = &st->data;
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st->xfer.len = st->chip_info->channel.scan_type.storagebits / 8;
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spi_message_init(&st->msg);
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spi_message_add_tail(&st->xfer, &st->msg);
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ret = gpio_request_one(st->pdata->gpio_pdrst, GPIOF_OUT_INIT_LOW,
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"AD7780 /PDRST");
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if (ret) {
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dev_err(&spi->dev, "failed to request GPIO PDRST\n");
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goto error_disable_reg;
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}
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ret = request_irq(spi->irq, ad7780_interrupt,
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IRQF_TRIGGER_FALLING, spi_get_device_id(spi)->name, st);
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if (ret)
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goto error_free_gpio;
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disable_irq(spi->irq);
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ret = iio_device_register(indio_dev);
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if (ret)
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goto error_free_irq;
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return 0;
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error_free_irq:
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free_irq(spi->irq, st);
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error_free_gpio:
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gpio_free(st->pdata->gpio_pdrst);
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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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iio_device_free(indio_dev);
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return ret;
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}
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static int ad7780_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 ad7780_state *st = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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free_irq(spi->irq, st);
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gpio_free(st->pdata->gpio_pdrst);
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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_free(indio_dev);
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return 0;
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}
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static const struct spi_device_id ad7780_id[] = {
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{"ad7780", ID_AD7780},
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{"ad7781", ID_AD7781},
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{}
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};
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MODULE_DEVICE_TABLE(spi, ad7780_id);
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static struct spi_driver ad7780_driver = {
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.driver = {
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.name = "ad7780",
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.owner = THIS_MODULE,
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},
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.probe = ad7780_probe,
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.remove = __devexit_p(ad7780_remove),
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.id_table = ad7780_id,
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};
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module_spi_driver(ad7780_driver);
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MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
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MODULE_DESCRIPTION("Analog Devices AD7780/1 ADC");
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MODULE_LICENSE("GPL v2");
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