// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part the core part STM32 DFSDM driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author(s): Arnaud Pouliquen <arnaud.pouliquen@st.com> for STMicroelectronics.
 */

#include <linux/clk.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/slab.h>

#include "stm32-dfsdm.h"

struct stm32_dfsdm_dev_data {
        unsigned int num_filters;
        unsigned int num_channels;
        const struct regmap_config *regmap_cfg;
};

#define STM32H7_DFSDM_NUM_FILTERS       4
#define STM32H7_DFSDM_NUM_CHANNELS      8
#define STM32MP1_DFSDM_NUM_FILTERS      6
#define STM32MP1_DFSDM_NUM_CHANNELS     8

static bool stm32_dfsdm_volatile_reg(struct device *dev, unsigned int reg)
{
        if (reg < DFSDM_FILTER_BASE_ADR)
                return false;

        /*
         * Mask is done on register to avoid to list registers of all
         * filter instances.
         */
        switch (reg & DFSDM_FILTER_REG_MASK) {
        case DFSDM_CR1(0) & DFSDM_FILTER_REG_MASK:
        case DFSDM_ISR(0) & DFSDM_FILTER_REG_MASK:
        case DFSDM_JDATAR(0) & DFSDM_FILTER_REG_MASK:
        case DFSDM_RDATAR(0) & DFSDM_FILTER_REG_MASK:
                return true;
        }

        return false;
}

static const struct regmap_config stm32h7_dfsdm_regmap_cfg = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = sizeof(u32),
        .max_register = 0x2B8,
        .volatile_reg = stm32_dfsdm_volatile_reg,
        .fast_io = true,
};

static const struct stm32_dfsdm_dev_data stm32h7_dfsdm_data = {
        .num_filters = STM32H7_DFSDM_NUM_FILTERS,
        .num_channels = STM32H7_DFSDM_NUM_CHANNELS,
        .regmap_cfg = &stm32h7_dfsdm_regmap_cfg,
};

static const struct regmap_config stm32mp1_dfsdm_regmap_cfg = {
        .reg_bits = 32,
        .val_bits = 32,
        .reg_stride = sizeof(u32),
        .max_register = 0x7fc,
        .volatile_reg = stm32_dfsdm_volatile_reg,
        .fast_io = true,
};

static const struct stm32_dfsdm_dev_data stm32mp1_dfsdm_data = {
        .num_filters = STM32MP1_DFSDM_NUM_FILTERS,
        .num_channels = STM32MP1_DFSDM_NUM_CHANNELS,
        .regmap_cfg = &stm32mp1_dfsdm_regmap_cfg,
};

struct dfsdm_priv {
        struct platform_device *pdev; /* platform device */

        struct stm32_dfsdm dfsdm; /* common data exported for all instances */

        unsigned int spi_clk_out_div; /* SPI clkout divider value */
        atomic_t n_active_ch;   /* number of current active channels */

        struct clk *clk; /* DFSDM clock */
        struct clk *aclk; /* audio clock */
};

static inline struct dfsdm_priv *to_stm32_dfsdm_priv(struct stm32_dfsdm *dfsdm)
{
        return container_of(dfsdm, struct dfsdm_priv, dfsdm);
}

static int stm32_dfsdm_clk_prepare_enable(struct stm32_dfsdm *dfsdm)
{
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        int ret;

        ret = clk_prepare_enable(priv->clk);
        if (ret || !priv->aclk)
                return ret;

        ret = clk_prepare_enable(priv->aclk);
        if (ret)
                clk_disable_unprepare(priv->clk);

        return ret;
}

static void stm32_dfsdm_clk_disable_unprepare(struct stm32_dfsdm *dfsdm)
{
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);

        if (priv->aclk)
                clk_disable_unprepare(priv->aclk);
        clk_disable_unprepare(priv->clk);
}

/**
 * stm32_dfsdm_start_dfsdm - start global dfsdm interface.
 *
 * Enable interface if n_active_ch is not null.
 * @dfsdm: Handle used to retrieve dfsdm context.
 */
int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
{
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        struct device *dev = &priv->pdev->dev;
        unsigned int clk_div = priv->spi_clk_out_div, clk_src;
        int ret;

        if (atomic_inc_return(&priv->n_active_ch) == 1) {
                ret = pm_runtime_get_sync(dev);
                if (ret < 0) {
                        pm_runtime_put_noidle(dev);
                        goto error_ret;
                }

                /* select clock source, e.g. 0 for "dfsdm" or 1 for "audio" */
                clk_src = priv->aclk ? 1 : 0;
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_CKOUTSRC_MASK,
                                         DFSDM_CHCFGR1_CKOUTSRC(clk_src));
                if (ret < 0)
                        goto pm_put;

                /* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_CKOUTDIV_MASK,
                                         DFSDM_CHCFGR1_CKOUTDIV(clk_div));
                if (ret < 0)
                        goto pm_put;

                /* Global enable of DFSDM interface */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_DFSDMEN_MASK,
                                         DFSDM_CHCFGR1_DFSDMEN(1));
                if (ret < 0)
                        goto pm_put;
        }

        dev_dbg(dev, "%s: n_active_ch %d\n", __func__,
                atomic_read(&priv->n_active_ch));

        return 0;

pm_put:
        pm_runtime_put_sync(dev);
error_ret:
        atomic_dec(&priv->n_active_ch);

        return ret;
}
EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm);

/**
 * stm32_dfsdm_stop_dfsdm - stop global DFSDM interface.
 *
 * Disable interface if n_active_ch is null
 * @dfsdm: Handle used to retrieve dfsdm context.
 */
int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
{
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        int ret;

        if (atomic_dec_and_test(&priv->n_active_ch)) {
                /* Global disable of DFSDM interface */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_DFSDMEN_MASK,
                                         DFSDM_CHCFGR1_DFSDMEN(0));
                if (ret < 0)
                        return ret;

                /* Stop SPI CLKOUT */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_CKOUTDIV_MASK,
                                         DFSDM_CHCFGR1_CKOUTDIV(0));
                if (ret < 0)
                        return ret;

                pm_runtime_put_sync(&priv->pdev->dev);
        }
        dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__,
                atomic_read(&priv->n_active_ch));

        return 0;
}
EXPORT_SYMBOL_GPL(stm32_dfsdm_stop_dfsdm);

static int stm32_dfsdm_parse_of(struct platform_device *pdev,
                                struct dfsdm_priv *priv)
{
        struct device_node *node = pdev->dev.of_node;
        struct resource *res;
        unsigned long clk_freq, divider;
        unsigned int spi_freq, rem;
        int ret;

        if (!node)
                return -EINVAL;

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res) {
                dev_err(&pdev->dev, "Failed to get memory resource\n");
                return -ENODEV;
        }
        priv->dfsdm.phys_base = res->start;
        priv->dfsdm.base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(priv->dfsdm.base))
                return PTR_ERR(priv->dfsdm.base);

        /*
         * "dfsdm" clock is mandatory for DFSDM peripheral clocking.
         * "dfsdm" or "audio" clocks can be used as source clock for
         * the SPI clock out signal and internal processing, depending
         * on use case.
         */
        priv->clk = devm_clk_get(&pdev->dev, "dfsdm");
        if (IS_ERR(priv->clk)) {
                ret = PTR_ERR(priv->clk);
                if (ret != -EPROBE_DEFER)
                        dev_err(&pdev->dev, "Failed to get clock (%d)\n", ret);
                return ret;
        }

        priv->aclk = devm_clk_get(&pdev->dev, "audio");
        if (IS_ERR(priv->aclk))
                priv->aclk = NULL;

        if (priv->aclk)
                clk_freq = clk_get_rate(priv->aclk);
        else
                clk_freq = clk_get_rate(priv->clk);

        /* SPI clock out frequency */
        ret = of_property_read_u32(pdev->dev.of_node, "spi-max-frequency",
                                   &spi_freq);
        if (ret < 0) {
                /* No SPI master mode */
                return 0;
        }

        divider = div_u64_rem(clk_freq, spi_freq, &rem);
        /* Round up divider when ckout isn't precise, not to exceed spi_freq */
        if (rem)
                divider++;

        /* programmable divider is in range of [2:256] */
        if (divider < 2 || divider > 256) {
                dev_err(&pdev->dev, "spi-max-frequency not achievable\n");
                return -EINVAL;
        }

        /* SPI clock output divider is: divider = CKOUTDIV + 1 */
        priv->spi_clk_out_div = divider - 1;
        priv->dfsdm.spi_master_freq = clk_freq / (priv->spi_clk_out_div + 1);

        if (rem) {
                dev_warn(&pdev->dev, "SPI clock not accurate\n");
                dev_warn(&pdev->dev, "%ld = %d * %d + %d\n",
                         clk_freq, spi_freq, priv->spi_clk_out_div + 1, rem);
        }

        return 0;
};

static const struct of_device_id stm32_dfsdm_of_match[] = {
        {
                .compatible = "st,stm32h7-dfsdm",
                .data = &stm32h7_dfsdm_data,
        },
        {
                .compatible = "st,stm32mp1-dfsdm",
                .data = &stm32mp1_dfsdm_data,
        },
        {}
};
MODULE_DEVICE_TABLE(of, stm32_dfsdm_of_match);

static int stm32_dfsdm_probe(struct platform_device *pdev)
{
        struct dfsdm_priv *priv;
        const struct stm32_dfsdm_dev_data *dev_data;
        struct stm32_dfsdm *dfsdm;
        int ret;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->pdev = pdev;

        dev_data = of_device_get_match_data(&pdev->dev);

        dfsdm = &priv->dfsdm;
        dfsdm->fl_list = devm_kcalloc(&pdev->dev, dev_data->num_filters,
                                      sizeof(*dfsdm->fl_list), GFP_KERNEL);
        if (!dfsdm->fl_list)
                return -ENOMEM;

        dfsdm->num_fls = dev_data->num_filters;
        dfsdm->ch_list = devm_kcalloc(&pdev->dev, dev_data->num_channels,
                                      sizeof(*dfsdm->ch_list),
                                      GFP_KERNEL);
        if (!dfsdm->ch_list)
                return -ENOMEM;
        dfsdm->num_chs = dev_data->num_channels;

        ret = stm32_dfsdm_parse_of(pdev, priv);
        if (ret < 0)
                return ret;

        dfsdm->regmap = devm_regmap_init_mmio_clk(&pdev->dev, "dfsdm",
                                                  dfsdm->base,
                                                  dev_data->regmap_cfg);
        if (IS_ERR(dfsdm->regmap)) {
                ret = PTR_ERR(dfsdm->regmap);
                dev_err(&pdev->dev, "%s: Failed to allocate regmap: %d\n",
                        __func__, ret);
                return ret;
        }

        platform_set_drvdata(pdev, dfsdm);

        ret = stm32_dfsdm_clk_prepare_enable(dfsdm);
        if (ret) {
                dev_err(&pdev->dev, "Failed to start clock\n");
                return ret;
        }

        pm_runtime_get_noresume(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);
        pm_runtime_enable(&pdev->dev);

        ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
        if (ret)
                goto pm_put;

        pm_runtime_put(&pdev->dev);

        return 0;

pm_put:
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
        stm32_dfsdm_clk_disable_unprepare(dfsdm);

        return ret;
}

static int stm32_dfsdm_core_remove(struct platform_device *pdev)
{
        struct stm32_dfsdm *dfsdm = platform_get_drvdata(pdev);

        pm_runtime_get_sync(&pdev->dev);
        of_platform_depopulate(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
        pm_runtime_set_suspended(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
        stm32_dfsdm_clk_disable_unprepare(dfsdm);

        return 0;
}

static int __maybe_unused stm32_dfsdm_core_suspend(struct device *dev)
{
        struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        int ret;

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

        /* Balance devm_regmap_init_mmio_clk() clk_prepare() */
        clk_unprepare(priv->clk);

        return pinctrl_pm_select_sleep_state(dev);
}

static int __maybe_unused stm32_dfsdm_core_resume(struct device *dev)
{
        struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
        struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        int ret;

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

        ret = clk_prepare(priv->clk);
        if (ret)
                return ret;

        return pm_runtime_force_resume(dev);
}

static int __maybe_unused stm32_dfsdm_core_runtime_suspend(struct device *dev)
{
        struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);

        stm32_dfsdm_clk_disable_unprepare(dfsdm);

        return 0;
}

static int __maybe_unused stm32_dfsdm_core_runtime_resume(struct device *dev)
{
        struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);

        return stm32_dfsdm_clk_prepare_enable(dfsdm);
}

static const struct dev_pm_ops stm32_dfsdm_core_pm_ops = {
        SET_SYSTEM_SLEEP_PM_OPS(stm32_dfsdm_core_suspend,
                                stm32_dfsdm_core_resume)
        SET_RUNTIME_PM_OPS(stm32_dfsdm_core_runtime_suspend,
                           stm32_dfsdm_core_runtime_resume,
                           NULL)
};

static struct platform_driver stm32_dfsdm_driver = {
        .probe = stm32_dfsdm_probe,
        .remove = stm32_dfsdm_core_remove,
        .driver = {
                .name = "stm32-dfsdm",
                .of_match_table = stm32_dfsdm_of_match,
                .pm = &stm32_dfsdm_core_pm_ops,
        },
};

module_platform_driver(stm32_dfsdm_driver);

MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 dfsdm driver");
MODULE_LICENSE("GPL v2");