// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Freescale i.MX7D ADC driver
 *
 * Copyright (C) 2015 Freescale Semiconductor, Inc.
 */

#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

#include <linux/iio/iio.h>
#include <linux/iio/driver.h>
#include <linux/iio/sysfs.h>

/* ADC register */
#define IMX7D_REG_ADC_CH_A_CFG1                 0x00
#define IMX7D_REG_ADC_CH_A_CFG2                 0x10
#define IMX7D_REG_ADC_CH_B_CFG1                 0x20
#define IMX7D_REG_ADC_CH_B_CFG2                 0x30
#define IMX7D_REG_ADC_CH_C_CFG1                 0x40
#define IMX7D_REG_ADC_CH_C_CFG2                 0x50
#define IMX7D_REG_ADC_CH_D_CFG1                 0x60
#define IMX7D_REG_ADC_CH_D_CFG2                 0x70
#define IMX7D_REG_ADC_CH_SW_CFG                 0x80
#define IMX7D_REG_ADC_TIMER_UNIT                0x90
#define IMX7D_REG_ADC_DMA_FIFO                  0xa0
#define IMX7D_REG_ADC_FIFO_STATUS               0xb0
#define IMX7D_REG_ADC_INT_SIG_EN                0xc0
#define IMX7D_REG_ADC_INT_EN                    0xd0
#define IMX7D_REG_ADC_INT_STATUS                0xe0
#define IMX7D_REG_ADC_CHA_B_CNV_RSLT            0xf0
#define IMX7D_REG_ADC_CHC_D_CNV_RSLT            0x100
#define IMX7D_REG_ADC_CH_SW_CNV_RSLT            0x110
#define IMX7D_REG_ADC_DMA_FIFO_DAT              0x120
#define IMX7D_REG_ADC_ADC_CFG                   0x130

#define IMX7D_REG_ADC_CHANNEL_CFG2_BASE         0x10
#define IMX7D_EACH_CHANNEL_REG_OFFSET           0x20

#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN                        (0x1 << 31)
#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_SINGLE                    BIT(30)
#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_AVG_EN                    BIT(29)
#define IMX7D_REG_ADC_CH_CFG1_CHANNEL_SEL(x)                    ((x) << 24)

#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_4                         (0x0 << 12)
#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_8                         (0x1 << 12)
#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_16                        (0x2 << 12)
#define IMX7D_REG_ADC_CH_CFG2_AVG_NUM_32                        (0x3 << 12)

#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_4                      (0x0 << 29)
#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_8                      (0x1 << 29)
#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_16                     (0x2 << 29)
#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_32                     (0x3 << 29)
#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_64                     (0x4 << 29)
#define IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_128                    (0x5 << 29)

#define IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN                      BIT(31)
#define IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN                    BIT(1)
#define IMX7D_REG_ADC_ADC_CFG_ADC_EN                            BIT(0)

#define IMX7D_REG_ADC_INT_CHA_COV_INT_EN                        BIT(8)
#define IMX7D_REG_ADC_INT_CHB_COV_INT_EN                        BIT(9)
#define IMX7D_REG_ADC_INT_CHC_COV_INT_EN                        BIT(10)
#define IMX7D_REG_ADC_INT_CHD_COV_INT_EN                        BIT(11)
#define IMX7D_REG_ADC_INT_CHANNEL_INT_EN \
        (IMX7D_REG_ADC_INT_CHA_COV_INT_EN | \
         IMX7D_REG_ADC_INT_CHB_COV_INT_EN | \
         IMX7D_REG_ADC_INT_CHC_COV_INT_EN | \
         IMX7D_REG_ADC_INT_CHD_COV_INT_EN)
#define IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS             0xf00
#define IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT          0xf0000

#define IMX7D_ADC_TIMEOUT               msecs_to_jiffies(100)
#define IMX7D_ADC_INPUT_CLK             24000000

enum imx7d_adc_clk_pre_div {
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_4,
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_8,
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_16,
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_32,
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_64,
        IMX7D_ADC_ANALOG_CLK_PRE_DIV_128,
};

enum imx7d_adc_average_num {
        IMX7D_ADC_AVERAGE_NUM_4,
        IMX7D_ADC_AVERAGE_NUM_8,
        IMX7D_ADC_AVERAGE_NUM_16,
        IMX7D_ADC_AVERAGE_NUM_32,
};

struct imx7d_adc_feature {
        enum imx7d_adc_clk_pre_div clk_pre_div;
        enum imx7d_adc_average_num avg_num;

        u32 core_time_unit;     /* impact the sample rate */
};

struct imx7d_adc {
        struct device *dev;
        void __iomem *regs;
        struct clk *clk;
        /* lock to protect against multiple access to the device */
        struct mutex lock;
        u32 vref_uv;
        u32 value;
        u32 channel;
        u32 pre_div_num;

        struct regulator *vref;
        struct imx7d_adc_feature adc_feature;

        struct completion completion;
};

struct imx7d_adc_analogue_core_clk {
        u32 pre_div;
        u32 reg_config;
};

#define IMX7D_ADC_ANALOGUE_CLK_CONFIG(_pre_div, _reg_conf) {    \
        .pre_div = (_pre_div),                                  \
        .reg_config = (_reg_conf),                              \
}

static const struct imx7d_adc_analogue_core_clk imx7d_adc_analogue_clk[] = {
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(4, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_4),
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(8, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_8),
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(16, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_16),
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(32, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_32),
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(64, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_64),
        IMX7D_ADC_ANALOGUE_CLK_CONFIG(128, IMX7D_REG_ADC_TIMER_UNIT_PRE_DIV_128),
};

#define IMX7D_ADC_CHAN(_idx) {                                  \
        .type = IIO_VOLTAGE,                                    \
        .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),   \
}

static const struct iio_chan_spec imx7d_adc_iio_channels[] = {
        IMX7D_ADC_CHAN(0),
        IMX7D_ADC_CHAN(1),
        IMX7D_ADC_CHAN(2),
        IMX7D_ADC_CHAN(3),
        IMX7D_ADC_CHAN(4),
        IMX7D_ADC_CHAN(5),
        IMX7D_ADC_CHAN(6),
        IMX7D_ADC_CHAN(7),
        IMX7D_ADC_CHAN(8),
        IMX7D_ADC_CHAN(9),
        IMX7D_ADC_CHAN(10),
        IMX7D_ADC_CHAN(11),
        IMX7D_ADC_CHAN(12),
        IMX7D_ADC_CHAN(13),
        IMX7D_ADC_CHAN(14),
        IMX7D_ADC_CHAN(15),
};

static const u32 imx7d_adc_average_num[] = {
        IMX7D_REG_ADC_CH_CFG2_AVG_NUM_4,
        IMX7D_REG_ADC_CH_CFG2_AVG_NUM_8,
        IMX7D_REG_ADC_CH_CFG2_AVG_NUM_16,
        IMX7D_REG_ADC_CH_CFG2_AVG_NUM_32,
};

static void imx7d_adc_feature_config(struct imx7d_adc *info)
{
        info->adc_feature.clk_pre_div = IMX7D_ADC_ANALOG_CLK_PRE_DIV_4;
        info->adc_feature.avg_num = IMX7D_ADC_AVERAGE_NUM_32;
        info->adc_feature.core_time_unit = 1;
}

static void imx7d_adc_sample_rate_set(struct imx7d_adc *info)
{
        struct imx7d_adc_feature *adc_feature = &info->adc_feature;
        struct imx7d_adc_analogue_core_clk adc_analogure_clk;
        u32 i;
        u32 tmp_cfg1;
        u32 sample_rate = 0;

        /*
         * Before sample set, disable channel A,B,C,D. Here we
         * clear the bit 31 of register REG_ADC_CH_A\B\C\D_CFG1.
         */
        for (i = 0; i < 4; i++) {
                tmp_cfg1 =
                        readl(info->regs + i * IMX7D_EACH_CHANNEL_REG_OFFSET);
                tmp_cfg1 &= ~IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN;
                writel(tmp_cfg1,
                       info->regs + i * IMX7D_EACH_CHANNEL_REG_OFFSET);
        }

        adc_analogure_clk = imx7d_adc_analogue_clk[adc_feature->clk_pre_div];
        sample_rate |= adc_analogure_clk.reg_config;
        info->pre_div_num = adc_analogure_clk.pre_div;

        sample_rate |= adc_feature->core_time_unit;
        writel(sample_rate, info->regs + IMX7D_REG_ADC_TIMER_UNIT);
}

static void imx7d_adc_hw_init(struct imx7d_adc *info)
{
        u32 cfg;

        /* power up and enable adc analogue core */
        cfg = readl(info->regs + IMX7D_REG_ADC_ADC_CFG);
        cfg &= ~(IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN |
                 IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN);
        cfg |= IMX7D_REG_ADC_ADC_CFG_ADC_EN;
        writel(cfg, info->regs + IMX7D_REG_ADC_ADC_CFG);

        /* enable channel A,B,C,D interrupt */
        writel(IMX7D_REG_ADC_INT_CHANNEL_INT_EN,
               info->regs + IMX7D_REG_ADC_INT_SIG_EN);
        writel(IMX7D_REG_ADC_INT_CHANNEL_INT_EN,
               info->regs + IMX7D_REG_ADC_INT_EN);

        imx7d_adc_sample_rate_set(info);
}

static void imx7d_adc_channel_set(struct imx7d_adc *info)
{
        u32 cfg1 = 0;
        u32 cfg2;
        u32 channel;

        channel = info->channel;

        /* the channel choose single conversion, and enable average mode */
        cfg1 |= (IMX7D_REG_ADC_CH_CFG1_CHANNEL_EN |
                 IMX7D_REG_ADC_CH_CFG1_CHANNEL_SINGLE |
                 IMX7D_REG_ADC_CH_CFG1_CHANNEL_AVG_EN);

        /*
         * physical channel 0 chose logical channel A
         * physical channel 1 chose logical channel B
         * physical channel 2 chose logical channel C
         * physical channel 3 chose logical channel D
         */
        cfg1 |= IMX7D_REG_ADC_CH_CFG1_CHANNEL_SEL(channel);

        /*
         * read register REG_ADC_CH_A\B\C\D_CFG2, according to the
         * channel chosen
         */
        cfg2 = readl(info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel +
                     IMX7D_REG_ADC_CHANNEL_CFG2_BASE);

        cfg2 |= imx7d_adc_average_num[info->adc_feature.avg_num];

        /*
         * write the register REG_ADC_CH_A\B\C\D_CFG2, according to
         * the channel chosen
         */
        writel(cfg2, info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel +
               IMX7D_REG_ADC_CHANNEL_CFG2_BASE);
        writel(cfg1, info->regs + IMX7D_EACH_CHANNEL_REG_OFFSET * channel);
}

static u32 imx7d_adc_get_sample_rate(struct imx7d_adc *info)
{
        u32 analogue_core_clk;
        u32 core_time_unit = info->adc_feature.core_time_unit;
        u32 tmp;

        analogue_core_clk = IMX7D_ADC_INPUT_CLK / info->pre_div_num;
        tmp = (core_time_unit + 1) * 6;

        return analogue_core_clk / tmp;
}

static int imx7d_adc_read_raw(struct iio_dev *indio_dev,
                        struct iio_chan_spec const *chan,
                        int *val,
                        int *val2,
                        long mask)
{
        struct imx7d_adc *info = iio_priv(indio_dev);

        u32 channel;
        long ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                mutex_lock(&info->lock);
                reinit_completion(&info->completion);

                channel = chan->channel & 0x03;
                info->channel = channel;
                imx7d_adc_channel_set(info);

                ret = wait_for_completion_interruptible_timeout
                                (&info->completion, IMX7D_ADC_TIMEOUT);
                if (ret == 0) {
                        mutex_unlock(&info->lock);
                        return -ETIMEDOUT;
                }
                if (ret < 0) {
                        mutex_unlock(&info->lock);
                        return ret;
                }

                *val = info->value;
                mutex_unlock(&info->lock);
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                info->vref_uv = regulator_get_voltage(info->vref);
                *val = info->vref_uv / 1000;
                *val2 = 12;
                return IIO_VAL_FRACTIONAL_LOG2;

        case IIO_CHAN_INFO_SAMP_FREQ:
                *val = imx7d_adc_get_sample_rate(info);
                return IIO_VAL_INT;

        default:
                return -EINVAL;
        }
}

static int imx7d_adc_read_data(struct imx7d_adc *info)
{
        u32 channel;
        u32 value;

        channel = info->channel & 0x03;

        /*
         * channel A and B conversion result share one register,
         * bit[27~16] is the channel B conversion result,
         * bit[11~0] is the channel A conversion result.
         * channel C and D is the same.
         */
        if (channel < 2)
                value = readl(info->regs + IMX7D_REG_ADC_CHA_B_CNV_RSLT);
        else
                value = readl(info->regs + IMX7D_REG_ADC_CHC_D_CNV_RSLT);
        if (channel & 0x1)      /* channel B or D */
                value = (value >> 16) & 0xFFF;
        else                    /* channel A or C */
                value &= 0xFFF;

        return value;
}

static irqreturn_t imx7d_adc_isr(int irq, void *dev_id)
{
        struct imx7d_adc *info = dev_id;
        int status;

        status = readl(info->regs + IMX7D_REG_ADC_INT_STATUS);
        if (status & IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS) {
                info->value = imx7d_adc_read_data(info);
                complete(&info->completion);

                /*
                 * The register IMX7D_REG_ADC_INT_STATUS can't clear
                 * itself after read operation, need software to write
                 * 0 to the related bit. Here we clear the channel A/B/C/D
                 * conversion finished flag.
                 */
                status &= ~IMX7D_REG_ADC_INT_STATUS_CHANNEL_INT_STATUS;
                writel(status, info->regs + IMX7D_REG_ADC_INT_STATUS);
        }

        /*
         * If the channel A/B/C/D conversion timeout, report it and clear these
         * timeout flags.
         */
        if (status & IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT) {
                dev_err(info->dev,
                        "ADC got conversion time out interrupt: 0x%08x\n",
                        status);
                status &= ~IMX7D_REG_ADC_INT_STATUS_CHANNEL_CONV_TIME_OUT;
                writel(status, info->regs + IMX7D_REG_ADC_INT_STATUS);
        }

        return IRQ_HANDLED;
}

static int imx7d_adc_reg_access(struct iio_dev *indio_dev,
                        unsigned reg, unsigned writeval,
                        unsigned *readval)
{
        struct imx7d_adc *info = iio_priv(indio_dev);

        if (!readval || reg % 4 || reg > IMX7D_REG_ADC_ADC_CFG)
                return -EINVAL;

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

        return 0;
}

static const struct iio_info imx7d_adc_iio_info = {
        .read_raw = &imx7d_adc_read_raw,
        .debugfs_reg_access = &imx7d_adc_reg_access,
};

static const struct of_device_id imx7d_adc_match[] = {
        { .compatible = "fsl,imx7d-adc", },
        { }
};
MODULE_DEVICE_TABLE(of, imx7d_adc_match);

static void imx7d_adc_power_down(struct imx7d_adc *info)
{
        u32 adc_cfg;

        adc_cfg = readl(info->regs + IMX7D_REG_ADC_ADC_CFG);
        adc_cfg |= IMX7D_REG_ADC_ADC_CFG_ADC_CLK_DOWN |
                   IMX7D_REG_ADC_ADC_CFG_ADC_POWER_DOWN;
        adc_cfg &= ~IMX7D_REG_ADC_ADC_CFG_ADC_EN;
        writel(adc_cfg, info->regs + IMX7D_REG_ADC_ADC_CFG);
}

static int imx7d_adc_enable(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct imx7d_adc *info = iio_priv(indio_dev);
        int ret;

        ret = regulator_enable(info->vref);
        if (ret) {
                dev_err(info->dev,
                        "Can't enable adc reference top voltage, err = %d\n",
                        ret);
                return ret;
        }

        ret = clk_prepare_enable(info->clk);
        if (ret) {
                dev_err(info->dev,
                        "Could not prepare or enable clock.\n");
                regulator_disable(info->vref);
                return ret;
        }

        imx7d_adc_hw_init(info);

        return 0;
}

static int imx7d_adc_disable(struct device *dev)
{
        struct iio_dev *indio_dev = dev_get_drvdata(dev);
        struct imx7d_adc *info = iio_priv(indio_dev);

        imx7d_adc_power_down(info);

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

        return 0;
}

static void __imx7d_adc_disable(void *data)
{
        imx7d_adc_disable(data);
}

static int imx7d_adc_probe(struct platform_device *pdev)
{
        struct imx7d_adc *info;
        struct iio_dev *indio_dev;
        struct device *dev = &pdev->dev;
        int irq;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
        if (!indio_dev)
                return -ENOMEM;

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

        info->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(info->regs))
                return PTR_ERR(info->regs);

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        info->clk = devm_clk_get(dev, "adc");
        if (IS_ERR(info->clk))
                return dev_err_probe(dev, PTR_ERR(info->clk), "Failed getting clock\n");

        info->vref = devm_regulator_get(dev, "vref");
        if (IS_ERR(info->vref))
                return dev_err_probe(dev, PTR_ERR(info->vref),
                                     "Failed getting reference voltage\n");

        platform_set_drvdata(pdev, indio_dev);

        init_completion(&info->completion);

        indio_dev->name = dev_name(dev);
        indio_dev->info = &imx7d_adc_iio_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        indio_dev->channels = imx7d_adc_iio_channels;
        indio_dev->num_channels = ARRAY_SIZE(imx7d_adc_iio_channels);

        ret = devm_request_irq(dev, irq, imx7d_adc_isr, 0, dev_name(dev), info);
        if (ret < 0) {
                dev_err(dev, "Failed requesting irq, irq = %d\n", irq);
                return ret;
        }

        imx7d_adc_feature_config(info);

        ret = imx7d_adc_enable(dev);
        if (ret)
                return ret;

        ret = devm_add_action_or_reset(dev, __imx7d_adc_disable, dev);
        if (ret)
                return ret;

        mutex_init(&info->lock);

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

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(imx7d_adc_pm_ops, imx7d_adc_disable,
                                imx7d_adc_enable);

static struct platform_driver imx7d_adc_driver = {
        .probe          = imx7d_adc_probe,
        .driver         = {
                .name   = "imx7d_adc",
                .of_match_table = imx7d_adc_match,
                .pm     = pm_sleep_ptr(&imx7d_adc_pm_ops),
        },
};

module_platform_driver(imx7d_adc_driver);

MODULE_AUTHOR("Haibo Chen <haibo.chen@freescale.com>");
MODULE_DESCRIPTION("Freescale IMX7D ADC driver");
MODULE_LICENSE("GPL v2");