Linux 4.19.133

[linux/fpc-iii.git] / drivers / iio / adc / vf610_adc.c

/*
 * Freescale Vybrid vf610 ADC driver
 *
 * Copyright 2013 Freescale Semiconductor, Inc.
 *
 * 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/delay.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/regulator/consumer.h>
#include <linux/of_platform.h>
#include <linux/err.h>

#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

/* This will be the driver name the kernel reports */
#define DRIVER_NAME "vf610-adc"

/* Vybrid/IMX ADC registers */
#define VF610_REG_ADC_HC0               0x00
#define VF610_REG_ADC_HC1               0x04
#define VF610_REG_ADC_HS                0x08
#define VF610_REG_ADC_R0                0x0c
#define VF610_REG_ADC_R1                0x10
#define VF610_REG_ADC_CFG               0x14
#define VF610_REG_ADC_GC                0x18
#define VF610_REG_ADC_GS                0x1c
#define VF610_REG_ADC_CV                0x20
#define VF610_REG_ADC_OFS               0x24
#define VF610_REG_ADC_CAL               0x28
#define VF610_REG_ADC_PCTL              0x30

/* Configuration register field define */
#define VF610_ADC_MODE_BIT8             0x00
#define VF610_ADC_MODE_BIT10            0x04
#define VF610_ADC_MODE_BIT12            0x08
#define VF610_ADC_MODE_MASK             0x0c
#define VF610_ADC_BUSCLK2_SEL           0x01
#define VF610_ADC_ALTCLK_SEL            0x02
#define VF610_ADC_ADACK_SEL             0x03
#define VF610_ADC_ADCCLK_MASK           0x03
#define VF610_ADC_CLK_DIV2              0x20
#define VF610_ADC_CLK_DIV4              0x40
#define VF610_ADC_CLK_DIV8              0x60
#define VF610_ADC_CLK_MASK              0x60
#define VF610_ADC_ADLSMP_LONG           0x10
#define VF610_ADC_ADSTS_SHORT   0x100
#define VF610_ADC_ADSTS_NORMAL  0x200
#define VF610_ADC_ADSTS_LONG    0x300
#define VF610_ADC_ADSTS_MASK            0x300
#define VF610_ADC_ADLPC_EN              0x80
#define VF610_ADC_ADHSC_EN              0x400
#define VF610_ADC_REFSEL_VALT           0x800
#define VF610_ADC_REFSEL_VBG            0x1000
#define VF610_ADC_ADTRG_HARD            0x2000
#define VF610_ADC_AVGS_8                0x4000
#define VF610_ADC_AVGS_16               0x8000
#define VF610_ADC_AVGS_32               0xC000
#define VF610_ADC_AVGS_MASK             0xC000
#define VF610_ADC_OVWREN                0x10000

/* General control register field define */
#define VF610_ADC_ADACKEN               0x1
#define VF610_ADC_DMAEN                 0x2
#define VF610_ADC_ACREN                 0x4
#define VF610_ADC_ACFGT                 0x8
#define VF610_ADC_ACFE                  0x10
#define VF610_ADC_AVGEN                 0x20
#define VF610_ADC_ADCON                 0x40
#define VF610_ADC_CAL                   0x80

/* Other field define */
#define VF610_ADC_ADCHC(x)              ((x) & 0x1F)
#define VF610_ADC_AIEN                  (0x1 << 7)
#define VF610_ADC_CONV_DISABLE          0x1F
#define VF610_ADC_HS_COCO0              0x1
#define VF610_ADC_CALF                  0x2
#define VF610_ADC_TIMEOUT               msecs_to_jiffies(100)

#define DEFAULT_SAMPLE_TIME             1000

/* V at 25°C of 696 mV */
#define VF610_VTEMP25_3V0               950
/* V at 25°C of 699 mV */
#define VF610_VTEMP25_3V3               867
/* Typical sensor slope coefficient at all temperatures */
#define VF610_TEMP_SLOPE_COEFF          1840

enum clk_sel {
        VF610_ADCIOC_BUSCLK_SET,
        VF610_ADCIOC_ALTCLK_SET,
        VF610_ADCIOC_ADACK_SET,
};

enum vol_ref {
        VF610_ADCIOC_VR_VREF_SET,
        VF610_ADCIOC_VR_VALT_SET,
        VF610_ADCIOC_VR_VBG_SET,
};

enum average_sel {
        VF610_ADC_SAMPLE_1,
        VF610_ADC_SAMPLE_4,
        VF610_ADC_SAMPLE_8,
        VF610_ADC_SAMPLE_16,
        VF610_ADC_SAMPLE_32,
};

enum conversion_mode_sel {
        VF610_ADC_CONV_NORMAL,
        VF610_ADC_CONV_HIGH_SPEED,
        VF610_ADC_CONV_LOW_POWER,
};

enum lst_adder_sel {
        VF610_ADCK_CYCLES_3,
        VF610_ADCK_CYCLES_5,
        VF610_ADCK_CYCLES_7,
        VF610_ADCK_CYCLES_9,
        VF610_ADCK_CYCLES_13,
        VF610_ADCK_CYCLES_17,
        VF610_ADCK_CYCLES_21,
        VF610_ADCK_CYCLES_25,
};

struct vf610_adc_feature {
        enum clk_sel    clk_sel;
        enum vol_ref    vol_ref;
        enum conversion_mode_sel conv_mode;

        int     clk_div;
        int     sample_rate;
        int     res_mode;
        u32 lst_adder_index;
        u32 default_sample_time;

        bool    calibration;
        bool    ovwren;
};

struct vf610_adc {
        struct device *dev;
        void __iomem *regs;
        struct clk *clk;

        u32 vref_uv;
        u32 value;
        struct regulator *vref;

        u32 max_adck_rate[3];
        struct vf610_adc_feature adc_feature;

        u32 sample_freq_avail[5];

        struct completion completion;
        u16 buffer[8];
};

static const u32 vf610_hw_avgs[] = { 1, 4, 8, 16, 32 };
static const u32 vf610_lst_adder[] = { 3, 5, 7, 9, 13, 17, 21, 25 };

static inline void vf610_adc_calculate_rates(struct vf610_adc *info)
{
        struct vf610_adc_feature *adc_feature = &info->adc_feature;
        unsigned long adck_rate, ipg_rate = clk_get_rate(info->clk);
        u32 adck_period, lst_addr_min;
        int divisor, i;

        adck_rate = info->max_adck_rate[adc_feature->conv_mode];

        if (adck_rate) {
                /* calculate clk divider which is within specification */
                divisor = ipg_rate / adck_rate;
                adc_feature->clk_div = 1 << fls(divisor + 1);
        } else {
                /* fall-back value using a safe divisor */
                adc_feature->clk_div = 8;
        }

        adck_rate = ipg_rate / adc_feature->clk_div;

        /*
         * Determine the long sample time adder value to be used based
         * on the default minimum sample time provided.
         */
        adck_period = NSEC_PER_SEC / adck_rate;
        lst_addr_min = adc_feature->default_sample_time / adck_period;
        for (i = 0; i < ARRAY_SIZE(vf610_lst_adder); i++) {
                if (vf610_lst_adder[i] > lst_addr_min) {
                        adc_feature->lst_adder_index = i;
                        break;
                }
        }

        /*
         * Calculate ADC sample frequencies
         * Sample time unit is ADCK cycles. ADCK clk source is ipg clock,
         * which is the same as bus clock.
         *
         * ADC conversion time = SFCAdder + AverageNum x (BCT + LSTAdder)
         * SFCAdder: fixed to 6 ADCK cycles
         * AverageNum: 1, 4, 8, 16, 32 samples for hardware average.
         * BCT (Base Conversion Time): fixed to 25 ADCK cycles for 12 bit mode
         * LSTAdder(Long Sample Time): 3, 5, 7, 9, 13, 17, 21, 25 ADCK cycles
         */
        for (i = 0; i < ARRAY_SIZE(vf610_hw_avgs); i++)
                info->sample_freq_avail[i] =
                        adck_rate / (6 + vf610_hw_avgs[i] *
                         (25 + vf610_lst_adder[adc_feature->lst_adder_index]));
}

static inline void vf610_adc_cfg_init(struct vf610_adc *info)
{
        struct vf610_adc_feature *adc_feature = &info->adc_feature;

        /* set default Configuration for ADC controller */
        adc_feature->clk_sel = VF610_ADCIOC_BUSCLK_SET;
        adc_feature->vol_ref = VF610_ADCIOC_VR_VREF_SET;

        adc_feature->calibration = true;
        adc_feature->ovwren = true;

        adc_feature->res_mode = 12;
        adc_feature->sample_rate = 1;

        adc_feature->conv_mode = VF610_ADC_CONV_LOW_POWER;

        vf610_adc_calculate_rates(info);
}

static void vf610_adc_cfg_post_set(struct vf610_adc *info)
{
        struct vf610_adc_feature *adc_feature = &info->adc_feature;
        int cfg_data = 0;
        int gc_data = 0;

        switch (adc_feature->clk_sel) {
        case VF610_ADCIOC_ALTCLK_SET:
                cfg_data |= VF610_ADC_ALTCLK_SEL;
                break;
        case VF610_ADCIOC_ADACK_SET:
                cfg_data |= VF610_ADC_ADACK_SEL;
                break;
        default:
                break;
        }

        /* low power set for calibration */
        cfg_data |= VF610_ADC_ADLPC_EN;

        /* enable high speed for calibration */
        cfg_data |= VF610_ADC_ADHSC_EN;

        /* voltage reference */
        switch (adc_feature->vol_ref) {
        case VF610_ADCIOC_VR_VREF_SET:
                break;
        case VF610_ADCIOC_VR_VALT_SET:
                cfg_data |= VF610_ADC_REFSEL_VALT;
                break;
        case VF610_ADCIOC_VR_VBG_SET:
                cfg_data |= VF610_ADC_REFSEL_VBG;
                break;
        default:
                dev_err(info->dev, "error voltage reference\n");
        }

        /* data overwrite enable */
        if (adc_feature->ovwren)
                cfg_data |= VF610_ADC_OVWREN;

        writel(cfg_data, info->regs + VF610_REG_ADC_CFG);
        writel(gc_data, info->regs + VF610_REG_ADC_GC);
}

static void vf610_adc_calibration(struct vf610_adc *info)
{
        int adc_gc, hc_cfg;

        if (!info->adc_feature.calibration)
                return;

        /* enable calibration interrupt */
        hc_cfg = VF610_ADC_AIEN | VF610_ADC_CONV_DISABLE;
        writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);

        adc_gc = readl(info->regs + VF610_REG_ADC_GC);
        writel(adc_gc | VF610_ADC_CAL, info->regs + VF610_REG_ADC_GC);

        if (!wait_for_completion_timeout(&info->completion, VF610_ADC_TIMEOUT))
                dev_err(info->dev, "Timeout for adc calibration\n");

        adc_gc = readl(info->regs + VF610_REG_ADC_GS);
        if (adc_gc & VF610_ADC_CALF)
                dev_err(info->dev, "ADC calibration failed\n");

        info->adc_feature.calibration = false;
}

static void vf610_adc_cfg_set(struct vf610_adc *info)
{
        struct vf610_adc_feature *adc_feature = &(info->adc_feature);
        int cfg_data;

        cfg_data = readl(info->regs + VF610_REG_ADC_CFG);

        cfg_data &= ~VF610_ADC_ADLPC_EN;
        if (adc_feature->conv_mode == VF610_ADC_CONV_LOW_POWER)
                cfg_data |= VF610_ADC_ADLPC_EN;

        cfg_data &= ~VF610_ADC_ADHSC_EN;
        if (adc_feature->conv_mode == VF610_ADC_CONV_HIGH_SPEED)
                cfg_data |= VF610_ADC_ADHSC_EN;

        writel(cfg_data, info->regs + VF610_REG_ADC_CFG);
}

static void vf610_adc_sample_set(struct vf610_adc *info)
{
        struct vf610_adc_feature *adc_feature = &(info->adc_feature);
        int cfg_data, gc_data;

        cfg_data = readl(info->regs + VF610_REG_ADC_CFG);
        gc_data = readl(info->regs + VF610_REG_ADC_GC);

        /* resolution mode */
        cfg_data &= ~VF610_ADC_MODE_MASK;
        switch (adc_feature->res_mode) {
        case 8:
                cfg_data |= VF610_ADC_MODE_BIT8;
                break;
        case 10:
                cfg_data |= VF610_ADC_MODE_BIT10;
                break;
        case 12:
                cfg_data |= VF610_ADC_MODE_BIT12;
                break;
        default:
                dev_err(info->dev, "error resolution mode\n");
                break;
        }

        /* clock select and clock divider */
        cfg_data &= ~(VF610_ADC_CLK_MASK | VF610_ADC_ADCCLK_MASK);
        switch (adc_feature->clk_div) {
        case 1:
                break;
        case 2:
                cfg_data |= VF610_ADC_CLK_DIV2;
                break;
        case 4:
                cfg_data |= VF610_ADC_CLK_DIV4;
                break;
        case 8:
                cfg_data |= VF610_ADC_CLK_DIV8;
                break;
        case 16:
                switch (adc_feature->clk_sel) {
                case VF610_ADCIOC_BUSCLK_SET:
                        cfg_data |= VF610_ADC_BUSCLK2_SEL | VF610_ADC_CLK_DIV8;
                        break;
                default:
                        dev_err(info->dev, "error clk divider\n");
                        break;
                }
                break;
        }

        /*
         * Set ADLSMP and ADSTS based on the Long Sample Time Adder value
         * determined.
         */
        switch (adc_feature->lst_adder_index) {
        case VF610_ADCK_CYCLES_3:
                break;
        case VF610_ADCK_CYCLES_5:
                cfg_data |= VF610_ADC_ADSTS_SHORT;
                break;
        case VF610_ADCK_CYCLES_7:
                cfg_data |= VF610_ADC_ADSTS_NORMAL;
                break;
        case VF610_ADCK_CYCLES_9:
                cfg_data |= VF610_ADC_ADSTS_LONG;
                break;
        case VF610_ADCK_CYCLES_13:
                cfg_data |= VF610_ADC_ADLSMP_LONG;
                break;
        case VF610_ADCK_CYCLES_17:
                cfg_data |= VF610_ADC_ADLSMP_LONG;
                cfg_data |= VF610_ADC_ADSTS_SHORT;
                break;
        case VF610_ADCK_CYCLES_21:
                cfg_data |= VF610_ADC_ADLSMP_LONG;
                cfg_data |= VF610_ADC_ADSTS_NORMAL;
                break;
        case VF610_ADCK_CYCLES_25:
                cfg_data |= VF610_ADC_ADLSMP_LONG;
                cfg_data |= VF610_ADC_ADSTS_NORMAL;
                break;
        default:
                dev_err(info->dev, "error in sample time select\n");
        }

        /* update hardware average selection */
        cfg_data &= ~VF610_ADC_AVGS_MASK;
        gc_data &= ~VF610_ADC_AVGEN;
        switch (adc_feature->sample_rate) {
        case VF610_ADC_SAMPLE_1:
                break;
        case VF610_ADC_SAMPLE_4:
                gc_data |= VF610_ADC_AVGEN;
                break;
        case VF610_ADC_SAMPLE_8:
                gc_data |= VF610_ADC_AVGEN;
                cfg_data |= VF610_ADC_AVGS_8;
                break;
        case VF610_ADC_SAMPLE_16:
                gc_data |= VF610_ADC_AVGEN;
                cfg_data |= VF610_ADC_AVGS_16;
                break;
        case VF610_ADC_SAMPLE_32:
                gc_data |= VF610_ADC_AVGEN;
                cfg_data |= VF610_ADC_AVGS_32;
                break;
        default:
                dev_err(info->dev,
                        "error hardware sample average select\n");
        }

        writel(cfg_data, info->regs + VF610_REG_ADC_CFG);
        writel(gc_data, info->regs + VF610_REG_ADC_GC);
}

static void vf610_adc_hw_init(struct vf610_adc *info)
{
        /* CFG: Feature set */
        vf610_adc_cfg_post_set(info);
        vf610_adc_sample_set(info);

        /* adc calibration */
        vf610_adc_calibration(info);

        /* CFG: power and speed set */
        vf610_adc_cfg_set(info);
}

static int vf610_set_conversion_mode(struct iio_dev *indio_dev,
                                     const struct iio_chan_spec *chan,
                                     unsigned int mode)
{
        struct vf610_adc *info = iio_priv(indio_dev);

        mutex_lock(&indio_dev->mlock);
        info->adc_feature.conv_mode = mode;
        vf610_adc_calculate_rates(info);
        vf610_adc_hw_init(info);
        mutex_unlock(&indio_dev->mlock);

        return 0;
}

static int vf610_get_conversion_mode(struct iio_dev *indio_dev,
                                     const struct iio_chan_spec *chan)
{
        struct vf610_adc *info = iio_priv(indio_dev);

        return info->adc_feature.conv_mode;
}

static const char * const vf610_conv_modes[] = { "normal", "high-speed",
                                                 "low-power" };

static const struct iio_enum vf610_conversion_mode = {
        .items = vf610_conv_modes,
        .num_items = ARRAY_SIZE(vf610_conv_modes),
        .get = vf610_get_conversion_mode,
        .set = vf610_set_conversion_mode,
};

static const struct iio_chan_spec_ext_info vf610_ext_info[] = {
        IIO_ENUM("conversion_mode", IIO_SHARED_BY_DIR, &vf610_conversion_mode),
        {},
};

#define VF610_ADC_CHAN(_idx, _chan_type) {                      \
        .type = (_chan_type),                                   \
        .indexed = 1,                                           \
        .channel = (_idx),                                      \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) |  \
                                BIT(IIO_CHAN_INFO_SAMP_FREQ),   \
        .ext_info = vf610_ext_info,                             \
        .scan_index = (_idx),                   \
        .scan_type = {                                  \
                .sign = 'u',                            \
                .realbits = 12,                         \
                .storagebits = 16,                      \
        },                                              \
}

#define VF610_ADC_TEMPERATURE_CHAN(_idx, _chan_type) {  \
        .type = (_chan_type),   \
        .channel = (_idx),              \
        .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),     \
        .scan_index = (_idx),                                   \
        .scan_type = {                                          \
                .sign = 'u',                                    \
                .realbits = 12,                                 \
                .storagebits = 16,                              \
        },                                                      \
}

static const struct iio_chan_spec vf610_adc_iio_channels[] = {
        VF610_ADC_CHAN(0, IIO_VOLTAGE),
        VF610_ADC_CHAN(1, IIO_VOLTAGE),
        VF610_ADC_CHAN(2, IIO_VOLTAGE),
        VF610_ADC_CHAN(3, IIO_VOLTAGE),
        VF610_ADC_CHAN(4, IIO_VOLTAGE),
        VF610_ADC_CHAN(5, IIO_VOLTAGE),
        VF610_ADC_CHAN(6, IIO_VOLTAGE),
        VF610_ADC_CHAN(7, IIO_VOLTAGE),
        VF610_ADC_CHAN(8, IIO_VOLTAGE),
        VF610_ADC_CHAN(9, IIO_VOLTAGE),
        VF610_ADC_CHAN(10, IIO_VOLTAGE),
        VF610_ADC_CHAN(11, IIO_VOLTAGE),
        VF610_ADC_CHAN(12, IIO_VOLTAGE),
        VF610_ADC_CHAN(13, IIO_VOLTAGE),
        VF610_ADC_CHAN(14, IIO_VOLTAGE),
        VF610_ADC_CHAN(15, IIO_VOLTAGE),
        VF610_ADC_TEMPERATURE_CHAN(26, IIO_TEMP),
        IIO_CHAN_SOFT_TIMESTAMP(32),
        /* sentinel */
};

static int vf610_adc_read_data(struct vf610_adc *info)
{
        int result;

        result = readl(info->regs + VF610_REG_ADC_R0);

        switch (info->adc_feature.res_mode) {
        case 8:
                result &= 0xFF;
                break;
        case 10:
                result &= 0x3FF;
                break;
        case 12:
                result &= 0xFFF;
                break;
        default:
                break;
        }

        return result;
}

static irqreturn_t vf610_adc_isr(int irq, void *dev_id)
{
        struct iio_dev *indio_dev = dev_id;
        struct vf610_adc *info = iio_priv(indio_dev);
        int coco;

        coco = readl(info->regs + VF610_REG_ADC_HS);
        if (coco & VF610_ADC_HS_COCO0) {
                info->value = vf610_adc_read_data(info);
                if (iio_buffer_enabled(indio_dev)) {
                        info->buffer[0] = info->value;
                        iio_push_to_buffers_with_timestamp(indio_dev,
                                        info->buffer,
                                        iio_get_time_ns(indio_dev));
                        iio_trigger_notify_done(indio_dev->trig);
                } else
                        complete(&info->completion);
        }

        return IRQ_HANDLED;
}

static ssize_t vf610_show_samp_freq_avail(struct device *dev,
                                struct device_attribute *attr, char *buf)
{
        struct vf610_adc *info = iio_priv(dev_to_iio_dev(dev));
        size_t len = 0;
        int i;

        for (i = 0; i < ARRAY_SIZE(info->sample_freq_avail); i++)
                len += scnprintf(buf + len, PAGE_SIZE - len,
                        "%u ", info->sample_freq_avail[i]);

        /* replace trailing space by newline */
        buf[len - 1] = '\n';

        return len;
}

static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(vf610_show_samp_freq_avail);

static struct attribute *vf610_attributes[] = {
        &iio_dev_attr_sampling_frequency_available.dev_attr.attr,
        NULL
};

static const struct attribute_group vf610_attribute_group = {
        .attrs = vf610_attributes,
};

static int vf610_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val,
                        int *val2,
                        long mask)
{
        struct vf610_adc *info = iio_priv(indio_dev);
        unsigned int hc_cfg;
        long ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
        case IIO_CHAN_INFO_PROCESSED:
                mutex_lock(&indio_dev->mlock);
                if (iio_buffer_enabled(indio_dev)) {
                        mutex_unlock(&indio_dev->mlock);
                        return -EBUSY;
                }

                reinit_completion(&info->completion);
                hc_cfg = VF610_ADC_ADCHC(chan->channel);
                hc_cfg |= VF610_ADC_AIEN;
                writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);
                ret = wait_for_completion_interruptible_timeout
                                (&info->completion, VF610_ADC_TIMEOUT);
                if (ret == 0) {
                        mutex_unlock(&indio_dev->mlock);
                        return -ETIMEDOUT;
                }
                if (ret < 0) {
                        mutex_unlock(&indio_dev->mlock);
                        return ret;
                }

                switch (chan->type) {
                case IIO_VOLTAGE:
                        *val = info->value;
                        break;
                case IIO_TEMP:
                        /*
                         * Calculate in degree Celsius times 1000
                         * Using the typical sensor slope of 1.84 mV/°C
                         * and VREFH_ADC at 3.3V, V at 25°C of 699 mV
                         */
                        *val = 25000 - ((int)info->value - VF610_VTEMP25_3V3) *
                                        1000000 / VF610_TEMP_SLOPE_COEFF;

                        break;
                default:
                        mutex_unlock(&indio_dev->mlock);
                        return -EINVAL;
                }

                mutex_unlock(&indio_dev->mlock);
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                *val = info->vref_uv / 1000;
                *val2 = info->adc_feature.res_mode;
                return IIO_VAL_FRACTIONAL_LOG2;

        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = info->sample_freq_avail[info->adc_feature.sample_rate];
                *val2 = 0;
                return IIO_VAL_INT;

        default:
                break;
        }

        return -EINVAL;
}

static int vf610_write_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int val,
                        int val2,
                        long mask)
{
        struct vf610_adc *info = iio_priv(indio_dev);
        int i;

        switch (mask) {
        case IIO_CHAN_INFO_SAMP_FREQ:
                for (i = 0;
                        i < ARRAY_SIZE(info->sample_freq_avail);
                        i++)
                        if (val == info->sample_freq_avail[i]) {
                                info->adc_feature.sample_rate = i;
                                vf610_adc_sample_set(info);
                                return 0;
                        }
                break;

        default:
                break;
        }

        return -EINVAL;
}

static int vf610_adc_buffer_postenable(struct iio_dev *indio_dev)
{
        struct vf610_adc *info = iio_priv(indio_dev);
        unsigned int channel;
        int ret;
        int val;

        ret = iio_triggered_buffer_postenable(indio_dev);
        if (ret)
                return ret;

        val = readl(info->regs + VF610_REG_ADC_GC);
        val |= VF610_ADC_ADCON;
        writel(val, info->regs + VF610_REG_ADC_GC);

        channel = find_first_bit(indio_dev->active_scan_mask,
                                                indio_dev->masklength);

        val = VF610_ADC_ADCHC(channel);
        val |= VF610_ADC_AIEN;

        writel(val, info->regs + VF610_REG_ADC_HC0);

        return 0;
}

static int vf610_adc_buffer_predisable(struct iio_dev *indio_dev)
{
        struct vf610_adc *info = iio_priv(indio_dev);
        unsigned int hc_cfg = 0;
        int val;

        val = readl(info->regs + VF610_REG_ADC_GC);
        val &= ~VF610_ADC_ADCON;
        writel(val, info->regs + VF610_REG_ADC_GC);

        hc_cfg |= VF610_ADC_CONV_DISABLE;
        hc_cfg &= ~VF610_ADC_AIEN;

        writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);

        return iio_triggered_buffer_predisable(indio_dev);
}

static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
        .postenable = &vf610_adc_buffer_postenable,
        .predisable = &vf610_adc_buffer_predisable,
        .validate_scan_mask = &iio_validate_scan_mask_onehot,
};

static int vf610_adc_reg_access(struct iio_dev *indio_dev,
                        unsigned reg, unsigned writeval,
                        unsigned *readval)
{
        struct vf610_adc *info = iio_priv(indio_dev);

        if ((readval == NULL) ||
                ((reg % 4) || (reg > VF610_REG_ADC_PCTL)))
                return -EINVAL;

        *readval = readl(info->regs + reg);

        return 0;
}

static const struct iio_info vf610_adc_iio_info = {
        .read_raw = &vf610_read_raw,
        .write_raw = &vf610_write_raw,
        .debugfs_reg_access = &vf610_adc_reg_access,
        .attrs = &vf610_attribute_group,
};

static const struct of_device_id vf610_adc_match[] = {
        { .compatible = "fsl,vf610-adc", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, vf610_adc_match);

static int vf610_adc_probe(struct platform_device *pdev)
{
        struct vf610_adc *info;
        struct iio_dev *indio_dev;
        struct resource *mem;
        int irq;
        int ret;

        indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(struct vf610_adc));
        if (!indio_dev) {
                dev_err(&pdev->dev, "Failed allocating iio device\n");
                return -ENOMEM;
        }

        info = iio_priv(indio_dev);
        info->dev = &pdev->dev;

        mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        info->regs = devm_ioremap_resource(&pdev->dev, mem);
        if (IS_ERR(info->regs))
                return PTR_ERR(info->regs);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(&pdev->dev, "no irq resource?\n");
                return irq;
        }

        ret = devm_request_irq(info->dev, irq,
                                vf610_adc_isr, 0,
                                dev_name(&pdev->dev), indio_dev);
        if (ret < 0) {
                dev_err(&pdev->dev, "failed requesting irq, irq = %d\n", irq);
                return ret;
        }

        info->clk = devm_clk_get(&pdev->dev, "adc");
        if (IS_ERR(info->clk)) {
                dev_err(&pdev->dev, "failed getting clock, err = %ld\n",
                                                PTR_ERR(info->clk));
                return PTR_ERR(info->clk);
        }

        info->vref = devm_regulator_get(&pdev->dev, "vref");
        if (IS_ERR(info->vref))
                return PTR_ERR(info->vref);

        ret = regulator_enable(info->vref);
        if (ret)
                return ret;

        info->vref_uv = regulator_get_voltage(info->vref);

        of_property_read_u32_array(pdev->dev.of_node, "fsl,adck-max-frequency",
                        info->max_adck_rate, 3);

        ret = of_property_read_u32(pdev->dev.of_node, "min-sample-time",
                        &info->adc_feature.default_sample_time);
        if (ret)
                info->adc_feature.default_sample_time = DEFAULT_SAMPLE_TIME;

        platform_set_drvdata(pdev, indio_dev);

        init_completion(&info->completion);

        indio_dev->name = dev_name(&pdev->dev);
        indio_dev->dev.parent = &pdev->dev;
        indio_dev->dev.of_node = pdev->dev.of_node;
        indio_dev->info = &vf610_adc_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = vf610_adc_iio_channels;
        indio_dev->num_channels = ARRAY_SIZE(vf610_adc_iio_channels);

        ret = clk_prepare_enable(info->clk);
        if (ret) {
                dev_err(&pdev->dev,
                        "Could not prepare or enable the clock.\n");
                goto error_adc_clk_enable;
        }

        vf610_adc_cfg_init(info);
        vf610_adc_hw_init(info);

        ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
                                        NULL, &iio_triggered_buffer_setup_ops);
        if (ret < 0) {
                dev_err(&pdev->dev, "Couldn't initialise the buffer\n");
                goto error_iio_device_register;
        }

        ret = iio_device_register(indio_dev);
        if (ret) {
                dev_err(&pdev->dev, "Couldn't register the device.\n");
                goto error_adc_buffer_init;
        }

        return 0;

error_adc_buffer_init:
        iio_triggered_buffer_cleanup(indio_dev);
error_iio_device_register:
        clk_disable_unprepare(info->clk);
error_adc_clk_enable:
        regulator_disable(info->vref);

        return ret;
}

static int vf610_adc_remove(struct platform_device *pdev)
{
        struct iio_dev *indio_dev = platform_get_drvdata(pdev);
        struct vf610_adc *info = iio_priv(indio_dev);

        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);
        regulator_disable(info->vref);
        clk_disable_unprepare(info->clk);

        return 0;
}

#ifdef CONFIG_PM_SLEEP
static int vf610_adc_suspend(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct vf610_adc *info = iio_priv(indio_dev);
        int hc_cfg;

        /* ADC controller enters to stop mode */
        hc_cfg = readl(info->regs + VF610_REG_ADC_HC0);
        hc_cfg |= VF610_ADC_CONV_DISABLE;
        writel(hc_cfg, info->regs + VF610_REG_ADC_HC0);

        clk_disable_unprepare(info->clk);
        regulator_disable(info->vref);

        return 0;
}

static int vf610_adc_resume(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct vf610_adc *info = iio_priv(indio_dev);
        int ret;

        ret = regulator_enable(info->vref);
        if (ret)
                return ret;

        ret = clk_prepare_enable(info->clk);
        if (ret)
                goto disable_reg;

        vf610_adc_hw_init(info);

        return 0;

disable_reg:
        regulator_disable(info->vref);
        return ret;
}
#endif

static SIMPLE_DEV_PM_OPS(vf610_adc_pm_ops, vf610_adc_suspend, vf610_adc_resume);

static struct platform_driver vf610_adc_driver = {
        .probe          = vf610_adc_probe,
        .remove         = vf610_adc_remove,
        .driver         = {
                .name   = DRIVER_NAME,
                .of_match_table = vf610_adc_match,
                .pm     = &vf610_adc_pm_ops,
        },
};

module_platform_driver(vf610_adc_driver);

MODULE_AUTHOR("Fugang Duan <B38611@freescale.com>");
MODULE_DESCRIPTION("Freescale VF610 ADC driver");
MODULE_LICENSE("GPL v2");