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/*
* lpc32xx_adc.c - Support for ADC in LPC32XX
*
* 3-channel, 10-bit ADC
*
* Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
/*
* LPC32XX registers definitions
*/
#define LPC32XXAD_SELECT(x) ((x) + 0x04)
#define LPC32XXAD_CTRL(x) ((x) + 0x08)
#define LPC32XXAD_VALUE(x) ((x) + 0x48)
/* Bit definitions for LPC32XXAD_SELECT: */
/* constant, always write this value! */
#define LPC32XXAD_REFm 0x00000200
/* constant, always write this value! */
#define LPC32XXAD_REFp 0x00000080
/* multiple of this is the channel number: 0, 1, 2 */
#define LPC32XXAD_IN 0x00000010
/* constant, always write this value! */
#define LPC32XXAD_INTERNAL 0x00000004
/* Bit definitions for LPC32XXAD_CTRL: */
#define LPC32XXAD_STROBE 0x00000002
#define LPC32XXAD_PDN_CTRL 0x00000004
/* Bit definitions for LPC32XXAD_VALUE: */
#define LPC32XXAD_VALUE_MASK 0x000003FF
#define LPC32XXAD_NAME "lpc32xx-adc"
struct lpc32xx_adc_state {
void __iomem *adc_base;
struct clk *clk;
struct completion completion;
u32 value;
};
static int lpc32xx_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long mask)
{
struct lpc32xx_adc_state *st = iio_priv(indio_dev);
int ret;
if (mask == IIO_CHAN_INFO_RAW) {
mutex_lock(&indio_dev->mlock);
ret = clk_prepare_enable(st->clk);
if (ret) {
mutex_unlock(&indio_dev->mlock);
return ret;
}
/* Measurement setup */
__raw_writel(LPC32XXAD_INTERNAL | (chan->address) |
LPC32XXAD_REFp | LPC32XXAD_REFm,
LPC32XXAD_SELECT(st->adc_base));
/* Trigger conversion */
__raw_writel(LPC32XXAD_PDN_CTRL | LPC32XXAD_STROBE,
LPC32XXAD_CTRL(st->adc_base));
wait_for_completion(&st->completion); /* set by ISR */
clk_disable_unprepare(st->clk);
*val = st->value;
mutex_unlock(&indio_dev->mlock);
return IIO_VAL_INT;
}
return -EINVAL;
}
static const struct iio_info lpc32xx_adc_iio_info = {
.read_raw = &lpc32xx_read_raw,
.driver_module = THIS_MODULE,
};
#define LPC32XX_ADC_CHANNEL(_index) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = _index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.address = LPC32XXAD_IN * _index, \
.scan_index = _index, \
}
static const struct iio_chan_spec lpc32xx_adc_iio_channels[] = {
LPC32XX_ADC_CHANNEL(0),
LPC32XX_ADC_CHANNEL(1),
LPC32XX_ADC_CHANNEL(2),
};
static irqreturn_t lpc32xx_adc_isr(int irq, void *dev_id)
{
struct lpc32xx_adc_state *st = dev_id;
/* Read value and clear irq */
st->value = __raw_readl(LPC32XXAD_VALUE(st->adc_base)) &
LPC32XXAD_VALUE_MASK;
complete(&st->completion);
return IRQ_HANDLED;
}
static int lpc32xx_adc_probe(struct platform_device *pdev)
{
struct lpc32xx_adc_state *st = NULL;
struct resource *res;
int retval = -ENODEV;
struct iio_dev *iodev = NULL;
int irq;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(&pdev->dev, "failed to get platform I/O memory\n");
return -ENXIO;
}
iodev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
if (!iodev)
return -ENOMEM;
st = iio_priv(iodev);
st->adc_base = devm_ioremap(&pdev->dev, res->start,
resource_size(res));
if (!st->adc_base) {
dev_err(&pdev->dev, "failed mapping memory\n");
return -EBUSY;
}
st->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(st->clk)) {
dev_err(&pdev->dev, "failed getting clock\n");
return PTR_ERR(st->clk);
}
irq = platform_get_irq(pdev, 0);
if (irq <= 0) {
dev_err(&pdev->dev, "failed getting interrupt resource\n");
return -ENXIO;
}
retval = devm_request_irq(&pdev->dev, irq, lpc32xx_adc_isr, 0,
LPC32XXAD_NAME, st);
if (retval < 0) {
dev_err(&pdev->dev, "failed requesting interrupt\n");
return retval;
}
platform_set_drvdata(pdev, iodev);
init_completion(&st->completion);
iodev->name = LPC32XXAD_NAME;
iodev->dev.parent = &pdev->dev;
iodev->info = &lpc32xx_adc_iio_info;
iodev->modes = INDIO_DIRECT_MODE;
iodev->channels = lpc32xx_adc_iio_channels;
iodev->num_channels = ARRAY_SIZE(lpc32xx_adc_iio_channels);
retval = devm_iio_device_register(&pdev->dev, iodev);
if (retval)
return retval;
dev_info(&pdev->dev, "LPC32XX ADC driver loaded, IRQ %d\n", irq);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id lpc32xx_adc_match[] = {
{ .compatible = "nxp,lpc3220-adc" },
{},
};
MODULE_DEVICE_TABLE(of, lpc32xx_adc_match);
#endif
static struct platform_driver lpc32xx_adc_driver = {
.probe = lpc32xx_adc_probe,
.driver = {
.name = LPC32XXAD_NAME,
.of_match_table = of_match_ptr(lpc32xx_adc_match),
},
};
module_platform_driver(lpc32xx_adc_driver);
MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
MODULE_DESCRIPTION("LPC32XX ADC driver");
MODULE_LICENSE("GPL");
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