staging: iio: LPC32xx: ADC driver
This patch adds a 3-channel ADC driver for the LPC32xx ARM SoC Signed-off-by: Roland Stigge <stigge@antcom.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Roland Stigge
committed by
Greg Kroah-Hartman
Greg Kroah-Hartman
parent
413db8c1c7
commit
906ecf69ad
@@ -193,4 +193,13 @@ config MAX1363_RING_BUFFER
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Say yes here to include ring buffer support in the MAX1363
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ADC driver.
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config LPC32XX_ADC
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tristate "NXP LPC32XX ADC"
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depends on ARCH_LPC32XX && !TOUCHSCREEN_LPC32XX
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help
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Say yes here to build support for the integrated ADC inside the
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LPC32XX SoC. Note that this feature uses the same hardware as the
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touchscreen driver, so you can only select one of the two drivers
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(lpc32xx_adc or lpc32xx_ts). Provides direct access via sysfs.
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endmenu
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@@ -37,3 +37,4 @@ obj-$(CONFIG_AD7192) += ad7192.o
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obj-$(CONFIG_ADT7310) += adt7310.o
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obj-$(CONFIG_ADT7410) += adt7410.o
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obj-$(CONFIG_AD7280) += ad7280a.o
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obj-$(CONFIG_LPC32XX_ADC) += lpc32xx_adc.o
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@@ -0,0 +1,237 @@
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/*
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* lpc32xx_adc.c - Support for ADC in LPC32XX
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*
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* 3-channel, 10-bit ADC
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*
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* Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/platform_device.h>
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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/io.h>
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/completion.h>
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#include "../iio.h"
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#include "../sysfs.h"
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/*
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* LPC32XX registers definitions
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*/
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#define LPC32XX_ADC_SELECT(x) ((x) + 0x04)
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#define LPC32XX_ADC_CTRL(x) ((x) + 0x08)
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#define LPC32XX_ADC_VALUE(x) ((x) + 0x48)
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/* Bit definitions for LPC32XX_ADC_SELECT: */
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#define AD_REFm 0x00000200 /* constant, always write this value! */
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#define AD_REFp 0x00000080 /* constant, always write this value! */
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#define AD_IN 0x00000010 /* multiple of this is the */
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/* channel number: 0, 1, 2 */
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#define AD_INTERNAL 0x00000004 /* constant, always write this value! */
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/* Bit definitions for LPC32XX_ADC_CTRL: */
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#define AD_STROBE 0x00000002
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#define AD_PDN_CTRL 0x00000004
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/* Bit definitions for LPC32XX_ADC_VALUE: */
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#define ADC_VALUE_MASK 0x000003FF
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#define MOD_NAME "lpc32xx-adc"
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struct lpc32xx_adc_info {
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void __iomem *adc_base;
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struct clk *clk;
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struct completion completion;
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u32 value;
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};
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static int lpc32xx_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 mask)
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{
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struct lpc32xx_adc_info *info = iio_priv(indio_dev);
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if (mask == 0) {
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mutex_lock(&indio_dev->mlock);
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clk_enable(info->clk);
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/* Measurement setup */
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__raw_writel(AD_INTERNAL | (chan->address) | AD_REFp | AD_REFm,
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LPC32XX_ADC_SELECT(info->adc_base));
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/* Trigger conversion */
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__raw_writel(AD_PDN_CTRL | AD_STROBE,
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LPC32XX_ADC_CTRL(info->adc_base));
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wait_for_completion(&info->completion); /* set by ISR */
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clk_disable(info->clk);
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*val = info->value;
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mutex_unlock(&indio_dev->mlock);
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return IIO_VAL_INT;
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}
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return -EINVAL;
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}
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static const struct iio_info lpc32xx_adc_iio_info = {
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.read_raw = &lpc32xx_read_raw,
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.driver_module = THIS_MODULE,
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};
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#define LPC32XX_ADC_CHANNEL(_index) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.channel = _index, \
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.address = AD_IN * _index, \
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.scan_index = _index, \
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}
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static struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
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LPC32XX_ADC_CHANNEL(0),
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LPC32XX_ADC_CHANNEL(1),
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LPC32XX_ADC_CHANNEL(2),
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};
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static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
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{
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struct lpc32xx_adc_info *info = (struct lpc32xx_adc_info *) dev_id;
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/* Read value and clear irq */
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info->value = __raw_readl(LPC32XX_ADC_VALUE(info->adc_base)) &
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ADC_VALUE_MASK;
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complete(&info->completion);
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return IRQ_HANDLED;
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}
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static int __devinit lpc32xx_adc_probe(struct platform_device *pdev)
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{
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struct lpc32xx_adc_info *info = NULL;
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struct resource *res;
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int retval = -ENODEV;
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struct iio_dev *iodev = NULL;
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int irq;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "failed to get platform I/O memory\n");
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retval = -EBUSY;
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goto errout1;
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}
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iodev = iio_allocate_device(sizeof(struct lpc32xx_adc_info));
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if (!iodev) {
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dev_err(&pdev->dev, "failed allocating iio device\n");
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retval = -ENOMEM;
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goto errout1;
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}
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info = iio_priv(iodev);
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info->adc_base = ioremap(res->start, res->end - res->start + 1);
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if (!info->adc_base) {
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dev_err(&pdev->dev, "failed mapping memory\n");
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retval = -EBUSY;
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goto errout2;
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}
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info->clk = clk_get(&pdev->dev, NULL);
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if (IS_ERR(info->clk)) {
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dev_err(&pdev->dev, "failed getting clock\n");
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goto errout3;
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}
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irq = platform_get_irq(pdev, 0);
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if ((irq < 0) || (irq >= NR_IRQS)) {
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dev_err(&pdev->dev, "failed getting interrupt resource\n");
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retval = -EINVAL;
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goto errout4;
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}
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retval = request_irq(irq, lpc32xx_adc_isr, 0, MOD_NAME, info);
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if (retval < 0) {
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dev_err(&pdev->dev, "failed requesting interrupt\n");
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goto errout4;
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}
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platform_set_drvdata(pdev, iodev);
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init_completion(&info->completion);
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iodev->name = MOD_NAME;
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iodev->dev.parent = &pdev->dev;
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iodev->info = &lpc32xx_adc_iio_info;
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iodev->modes = INDIO_DIRECT_MODE;
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iodev->channels = lpc32xx_adc_iio_channels;
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iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
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retval = iio_device_register(iodev);
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if (retval)
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goto errout5;
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dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);
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return 0;
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errout5:
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free_irq(irq, iodev);
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errout4:
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clk_put(info->clk);
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errout3:
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iounmap(info->adc_base);
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errout2:
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iio_free_device(iodev);
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errout1:
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return retval;
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}
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static int __devexit lpc32xx_adc_remove(struct platform_device *pdev)
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{
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struct iio_dev *iodev = platform_get_drvdata(pdev);
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struct lpc32xx_adc_info *info = iio_priv(iodev);
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int irq = platform_get_irq(pdev, 0);
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iio_device_unregister(iodev);
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free_irq(irq, iodev);
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platform_set_drvdata(pdev, NULL);
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clk_put(info->clk);
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iounmap(info->adc_base);
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iio_free_device(iodev);
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return 0;
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}
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static struct platform_driver lpc32xx_adc_driver = {
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.probe = lpc32xx_adc_probe,
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.remove = __devexit_p(lpc32xx_adc_remove),
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.driver = {
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.name = MOD_NAME,
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.owner = THIS_MODULE,
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},
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};
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module_platform_driver(lpc32xx_adc_driver);
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MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
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MODULE_DESCRIPTION("LPC32XX ADC driver");
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MODULE_LICENSE("GPL");
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