// SPDX-License-Identifier: GPL-2.0
/*
 * Renesas RZ/N1 ADC driver
 *
 * Copyright (C) 2025 Schneider-Electric
 *
 * Author: Herve Codina <herve.codina@bootlin.com>
 *
 * The RZ/N1 ADC controller can handle channels from its internal ADC1 and/or
 * ADC2 cores. The driver use ADC1 and/or ADC2 cores depending on the presence
 * of the related power supplies (AVDD and VREF) description in the device-tree.
 */

#include <linux/array_size.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/dev_printk.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/types.h>

#define RZN1_ADC_CONTROL_REG                    0x02c
#define RZN1_ADC_CONTROL_ADC_BUSY               BIT(6)

#define RZN1_ADC_FORCE_REG                      0x030
#define RZN1_ADC_SET_FORCE_REG                  0x034
#define RZN1_ADC_CLEAR_FORCE_REG                0x038
#define RZN1_ADC_FORCE_VC(_n)                   BIT(_n)

#define RZN1_ADC_CONFIG_REG                     0x040
#define RZN1_ADC_CONFIG_ADC_POWER_DOWN          BIT(3)

#define RZN1_ADC_VC_REG(_n)                     (0x0c0 + 4 * (_n))
#define RZN1_ADC_VC_ADC2_ENABLE                 BIT(16)
#define RZN1_ADC_VC_ADC1_ENABLE                 BIT(15)
#define RZN1_ADC_VC_ADC2_CHANNEL_SEL_MASK       GENMASK(5, 3)
#define RZN1_ADC_VC_ADC1_CHANNEL_SEL_MASK       GENMASK(2, 0)

#define RZN1_ADC_ADC1_DATA_REG(_n)              (0x100 + 4 * (_n))
#define RZN1_ADC_ADC2_DATA_REG(_n)              (0x140 + 4 * (_n))
#define RZN1_ADC_ADCX_DATA_DATA_MASK            GENMASK(11, 0)

#define RZN1_ADC_NO_CHANNEL     -1

#define RZN1_ADC_CHANNEL_SHARED_SCALE(_ch, _ds_name) {          \
        .type = IIO_VOLTAGE,                                    \
        .indexed = 1,                                           \
        .channel = (_ch),                                       \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
        .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
        .datasheet_name = (_ds_name),                           \
}

#define RZN1_ADC_CHANNEL_SEPARATED_SCALE(_ch, _ds_name) {       \
        .type = IIO_VOLTAGE,                                    \
        .indexed = 1,                                           \
        .channel = (_ch),                                       \
        .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
                              BIT(IIO_CHAN_INFO_SCALE),         \
        .datasheet_name = (_ds_name),                           \
}

/*
 * 8 ADC1_IN signals existed numbered 0..4, 6..8
 * ADCx_IN5 doesn't exist in RZ/N1 datasheet
 */
static struct iio_chan_spec rzn1_adc1_channels[] = {
        RZN1_ADC_CHANNEL_SHARED_SCALE(0, "ADC1_IN0"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(1, "ADC1_IN1"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(2, "ADC1_IN2"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(3, "ADC1_IN3"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(4, "ADC1_IN4"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(5, "ADC1_IN6"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(6, "ADC1_IN7"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(7, "ADC1_IN8"),
};

static struct iio_chan_spec rzn1_adc2_channels[] = {
        RZN1_ADC_CHANNEL_SHARED_SCALE(8,  "ADC2_IN0"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(9,  "ADC2_IN1"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(10, "ADC2_IN2"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(11, "ADC2_IN3"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(12, "ADC2_IN4"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(13, "ADC2_IN6"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(14, "ADC2_IN7"),
        RZN1_ADC_CHANNEL_SHARED_SCALE(15, "ADC2_IN8"),
};

/*
 * If both ADCs core are used, scale cannot be common. Indeed, scale is
 * based on Vref connected on each ADC core.
 */
static struct iio_chan_spec rzn1_adc1_adc2_channels[] = {
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(0, "ADC1_IN0"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(1, "ADC1_IN1"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(2, "ADC1_IN2"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(3, "ADC1_IN3"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(4, "ADC1_IN4"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(5, "ADC1_IN6"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(6, "ADC1_IN7"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(7, "ADC1_IN8"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(8,  "ADC2_IN0"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(9,  "ADC2_IN1"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(10, "ADC2_IN2"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(11, "ADC2_IN3"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(12, "ADC2_IN4"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(13, "ADC2_IN6"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(14, "ADC2_IN7"),
        RZN1_ADC_CHANNEL_SEPARATED_SCALE(15, "ADC2_IN8"),
};

struct rzn1_adc {
        struct device *dev;
        void __iomem *regs;
        struct mutex lock; /* ADC lock */
        int adc1_vref_mV; /* ADC1 Vref in mV. Negative if ADC1 is not used */
        int adc2_vref_mV; /* ADC2 Vref in mV. Negative if ADC2 is not used */
};

static int rzn1_adc_power(struct rzn1_adc *rzn1_adc, bool power)
{
        u32 v;

        writel(power ? 0 : RZN1_ADC_CONFIG_ADC_POWER_DOWN,
               rzn1_adc->regs + RZN1_ADC_CONFIG_REG);

        /* Wait for the ADC_BUSY to clear */
        return readl_poll_timeout_atomic(rzn1_adc->regs + RZN1_ADC_CONTROL_REG,
                                         v, !(v & RZN1_ADC_CONTROL_ADC_BUSY),
                                         0, 500);
}

static void rzn1_adc_vc_setup_conversion(struct rzn1_adc *rzn1_adc, u32 ch,
                                         int adc1_ch, int adc2_ch)
{
        u32 vc = 0;

        if (adc1_ch != RZN1_ADC_NO_CHANNEL)
                vc |= RZN1_ADC_VC_ADC1_ENABLE |
                      FIELD_PREP(RZN1_ADC_VC_ADC1_CHANNEL_SEL_MASK, adc1_ch);

        if (adc2_ch != RZN1_ADC_NO_CHANNEL)
                vc |= RZN1_ADC_VC_ADC2_ENABLE |
                      FIELD_PREP(RZN1_ADC_VC_ADC2_CHANNEL_SEL_MASK, adc2_ch);

        writel(vc, rzn1_adc->regs + RZN1_ADC_VC_REG(ch));
}

static int rzn1_adc_vc_start_conversion(struct rzn1_adc *rzn1_adc, u32 ch)
{
        u32 val;

        val = readl(rzn1_adc->regs + RZN1_ADC_FORCE_REG);
        if (val & RZN1_ADC_FORCE_VC(ch))
                return -EBUSY;

        writel(RZN1_ADC_FORCE_VC(ch), rzn1_adc->regs + RZN1_ADC_SET_FORCE_REG);

        return 0;
}

static void rzn1_adc_vc_stop_conversion(struct rzn1_adc *rzn1_adc, u32 ch)
{
        writel(RZN1_ADC_FORCE_VC(ch), rzn1_adc->regs + RZN1_ADC_CLEAR_FORCE_REG);
}

static int rzn1_adc_vc_wait_conversion(struct rzn1_adc *rzn1_adc, u32 ch,
                                       u32 *adc1_data, u32 *adc2_data)
{
        u32 data_reg;
        int ret;
        u32 v;

        /*
         * When a VC is selected, it needs 20 ADC clocks to perform the
         * conversion.
         *
         * The worst case is when the 16 VCs need to perform a conversion and
         * our VC is the lowest in term of priority.
         *
         * In that case, the conversion is performed in 16 * 20 ADC clocks.
         *
         * The ADC clock can be set from 4MHz to 20MHz. This leads to a worst
         * case of  16 * 20 * 1/4Mhz = 80us.
         *
         * Round it up to 100us.
         */

        /* Wait for the ADC_FORCE_VC(n) to clear */
        ret = readl_poll_timeout_atomic(rzn1_adc->regs + RZN1_ADC_FORCE_REG,
                                        v, !(v & RZN1_ADC_FORCE_VC(ch)),
                                        0, 100);
        if (ret)
                return ret;

        if (adc1_data) {
                data_reg = readl(rzn1_adc->regs + RZN1_ADC_ADC1_DATA_REG(ch));
                *adc1_data = FIELD_GET(RZN1_ADC_ADCX_DATA_DATA_MASK, data_reg);
        }

        if (adc2_data) {
                data_reg = readl(rzn1_adc->regs + RZN1_ADC_ADC2_DATA_REG(ch));
                *adc2_data = FIELD_GET(RZN1_ADC_ADCX_DATA_DATA_MASK, data_reg);
        }

        return 0;
}

static int rzn1_adc_read_raw_ch(struct rzn1_adc *rzn1_adc, unsigned int chan, int *val)
{
        u32 *adc1_data, *adc2_data;
        int adc1_ch, adc2_ch;
        u32 adc_data;
        int ret;

        /*
         * IIO chan are decoupled from chans used in rzn1_adc_vc_*() functions.
         * The RZ/N1 ADC VC controller can handle on a single VC chan one
         * channel from the ADC1 core and one channel from the ADC2 core.
         *
         * Even if IIO chans are mapped 1:1 to ADC core chans and so uses only
         * a chan from ADC1 or a chan from ADC2, future improvements can define
         * an IIO chan that uses one chan from ADC1 and one chan from ADC2.
         */

        if (chan < 8) {
                /* chan 0..7 used to get ADC1 ch 0..7 */
                adc1_ch = chan;
                adc1_data = &adc_data;
                adc2_ch = RZN1_ADC_NO_CHANNEL;
                adc2_data = NULL;
        } else if (chan < 16) {
                /* chan 8..15 used to get ADC2 ch 0..7 */
                adc1_ch = RZN1_ADC_NO_CHANNEL;
                adc1_data = NULL;
                adc2_ch = chan - 8;
                adc2_data = &adc_data;
        } else {
                return -EINVAL;
        }

        ACQUIRE(pm_runtime_active_auto_try_enabled, pm)(rzn1_adc->dev);
        ret = ACQUIRE_ERR(pm_runtime_active_auto_try_enabled, &pm);
        if (ret < 0)
                return ret;

        scoped_guard(mutex, &rzn1_adc->lock) {
                rzn1_adc_vc_setup_conversion(rzn1_adc, chan, adc1_ch, adc2_ch);

                ret = rzn1_adc_vc_start_conversion(rzn1_adc, chan);
                if (ret)
                        return ret;

                ret = rzn1_adc_vc_wait_conversion(rzn1_adc, chan, adc1_data, adc2_data);
                if (ret) {
                        rzn1_adc_vc_stop_conversion(rzn1_adc, chan);
                        return ret;
                }
        }

        *val = adc_data;
        ret = IIO_VAL_INT;

        return 0;
}

static int rzn1_adc_get_vref_mV(struct rzn1_adc *rzn1_adc, unsigned int chan)
{
        /* chan 0..7 use ADC1 ch 0..7. Vref related to ADC1 core */
        if (chan < 8)
                return rzn1_adc->adc1_vref_mV;

        /* chan 8..15 use ADC2 ch 0..7. Vref related to ADC2 core */
        if (chan < 16)
                return rzn1_adc->adc2_vref_mV;

        return -EINVAL;
}

static int rzn1_adc_read_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
                             int *val, int *val2, long mask)
{
        struct rzn1_adc *rzn1_adc = iio_priv(indio_dev);
        int ret;

        switch (mask) {
        case IIO_CHAN_INFO_RAW:
                ret = rzn1_adc_read_raw_ch(rzn1_adc, chan->channel, val);
                if (ret)
                        return ret;
                return IIO_VAL_INT;

        case IIO_CHAN_INFO_SCALE:
                ret = rzn1_adc_get_vref_mV(rzn1_adc, chan->channel);
                if (ret < 0)
                        return ret;
                *val = ret;
                *val2 = 12;
                return IIO_VAL_FRACTIONAL_LOG2;

        default:
                return -EINVAL;
        }
}

static const struct iio_info rzn1_adc_info = {
        .read_raw = &rzn1_adc_read_raw,
};

static int rzn1_adc_set_iio_dev_channels(struct rzn1_adc *rzn1_adc,
                                         struct iio_dev *indio_dev)
{
        /*
         * When an ADC core is not used, its related vref_mV is set to a
         * negative error code. Use the correct IIO channels table based on
         * those vref_mV values.
         */
        if (rzn1_adc->adc1_vref_mV >= 0) {
                if (rzn1_adc->adc2_vref_mV >= 0) {
                        indio_dev->channels = rzn1_adc1_adc2_channels;
                        indio_dev->num_channels = ARRAY_SIZE(rzn1_adc1_adc2_channels);
                } else {
                        indio_dev->channels = rzn1_adc1_channels;
                        indio_dev->num_channels = ARRAY_SIZE(rzn1_adc1_channels);
                }
                return 0;
        }

        if (rzn1_adc->adc2_vref_mV >= 0) {
                indio_dev->channels = rzn1_adc2_channels;
                indio_dev->num_channels = ARRAY_SIZE(rzn1_adc2_channels);
                return 0;
        }

        return dev_err_probe(rzn1_adc->dev, -ENODEV,
                             "Failed to set IIO channels, no ADC core used\n");
}

static int rzn1_adc_core_get_regulators(struct rzn1_adc *rzn1_adc,
                                        int *adc_vref_mV,
                                        const char *avdd_name, const char *vref_name)
{
        struct device *dev = rzn1_adc->dev;
        int ret;

        /*
         * For a given ADC core (ADC1 or ADC2), both regulators (AVDD and VREF)
         * must be available in order to have the ADC core used.
         *
         * We use the regulators presence to check the usage of the related
         * ADC core. If both regulators are available, the ADC core is used.
         * Otherwise, the ADC core is not used.
         *
         * The adc_vref_mV value is set to a negative error code (-ENODEV) when
         * the ADC core is not used. Otherwise it is set to the VRef mV value.
         */

        *adc_vref_mV = -ENODEV;

        ret = devm_regulator_get_enable_optional(dev, avdd_name);
        if (ret == -ENODEV)
                return 0;
        if (ret < 0)
                return dev_err_probe(dev, ret, "Failed to get '%s' regulator\n",
                                     avdd_name);

        ret = devm_regulator_get_enable_read_voltage(dev, vref_name);
        if (ret == -ENODEV)
                return 0;
        if (ret < 0)
                return dev_err_probe(dev, ret, "Failed to get '%s' regulator\n",
                                     vref_name);

        /*
         * Both regulators are available.
         * Set adc_vref_mV to the Vref value in mV. This, as the value set is
         * positive, also signals that the ADC is used.
         */
        *adc_vref_mV = ret / 1000;

        return 0;
}

static int rzn1_adc_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct iio_dev *indio_dev;
        struct rzn1_adc *rzn1_adc;
        struct clk *clk;
        int ret;

        indio_dev = devm_iio_device_alloc(dev, sizeof(*rzn1_adc));
        if (!indio_dev)
                return -ENOMEM;

        rzn1_adc = iio_priv(indio_dev);
        rzn1_adc->dev = dev;

        ret = devm_mutex_init(dev, &rzn1_adc->lock);
        if (ret)
                return ret;

        rzn1_adc->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(rzn1_adc->regs))
                return PTR_ERR(rzn1_adc->regs);

        clk = devm_clk_get_enabled(dev, "pclk");
        if (IS_ERR(clk))
                return dev_err_probe(dev, PTR_ERR(clk), "Failed to get pclk\n");

        clk = devm_clk_get_enabled(dev, "adc");
        if (IS_ERR(clk))
                return dev_err_probe(dev, PTR_ERR(clk), "Failed to get adc clk\n");

        ret = rzn1_adc_core_get_regulators(rzn1_adc, &rzn1_adc->adc1_vref_mV,
                                           "adc1-avdd", "adc1-vref");
        if (ret)
                return ret;

        ret = rzn1_adc_core_get_regulators(rzn1_adc, &rzn1_adc->adc2_vref_mV,
                                           "adc2-avdd", "adc2-vref");
        if (ret)
                return ret;

        platform_set_drvdata(pdev, rzn1_adc);

        indio_dev->name = "rzn1-adc";
        indio_dev->info = &rzn1_adc_info;
        indio_dev->modes = INDIO_DIRECT_MODE;
        ret = rzn1_adc_set_iio_dev_channels(rzn1_adc, indio_dev);
        if (ret)
                return ret;

        pm_runtime_set_autosuspend_delay(dev, 500);
        pm_runtime_use_autosuspend(dev);
        ret = devm_pm_runtime_enable(dev);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to enable runtime PM\n");

        return devm_iio_device_register(dev, indio_dev);
}

static int rzn1_adc_pm_runtime_suspend(struct device *dev)
{
        struct rzn1_adc *rzn1_adc = dev_get_drvdata(dev);

        return rzn1_adc_power(rzn1_adc, false);
}

static int rzn1_adc_pm_runtime_resume(struct device *dev)
{
        struct rzn1_adc *rzn1_adc = dev_get_drvdata(dev);

        return rzn1_adc_power(rzn1_adc, true);
}

static DEFINE_RUNTIME_DEV_PM_OPS(rzn1_adc_pm_ops,
                                 rzn1_adc_pm_runtime_suspend,
                                 rzn1_adc_pm_runtime_resume,
                                 NULL);

static const struct of_device_id rzn1_adc_of_match[] = {
        { .compatible = "renesas,rzn1-adc" },
        { }
};
MODULE_DEVICE_TABLE(of, rzn1_adc_of_match);

static struct platform_driver rzn1_adc_driver = {
        .probe = rzn1_adc_probe,
        .driver = {
                .name = "rzn1-adc",
                .of_match_table = rzn1_adc_of_match,
                .pm = pm_ptr(&rzn1_adc_pm_ops),
        },
};
module_platform_driver(rzn1_adc_driver);

MODULE_AUTHOR("Herve Codina <herve.codina@bootlin.com>");
MODULE_DESCRIPTION("Renesas RZ/N1 ADC Driver");
MODULE_LICENSE("GPL");