linux-imx

// SPDX-License-Identifier: GPL-2.0+

/*

 *  lpc32xx_adc.c - Support for ADC in LPC32XX

 *

 *  3-channel, 10-bit ADC

 *

 *  Copyright (C) 2011, 2012 Roland Stigge <stigge@antcom.de>

 */

​

#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 = {