// SPDX-License-Identifier: (GPL-2.0 OR MIT)
//
// Copyright (c) 2018 BayLibre, SAS.
// Author: Jerome Brunet <jbrunet@baylibre.com>

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <sound/soc.h>

#include "axg-tdm-formatter.h"

struct axg_tdm_formatter {
        struct list_head list;
        struct axg_tdm_stream *stream;
        const struct axg_tdm_formatter_driver *drv;
        struct clk *pclk;
        struct clk *sclk;
        struct clk *lrclk;
        struct clk *sclk_sel;
        struct clk *lrclk_sel;
        struct reset_control *reset;
        bool enabled;
        struct regmap *map;
};

int axg_tdm_formatter_set_channel_masks(struct regmap *map,
                                        struct axg_tdm_stream *ts,
                                        unsigned int offset)
{
        unsigned int ch = ts->channels;
        u32 val[AXG_TDM_NUM_LANES];
        int i, j, k;

        /*
         * We need to mimick the slot distribution used by the HW to keep the
         * channel placement consistent regardless of the number of channel
         * in the stream. This is why the odd algorithm below is used.
         */
        memset(val, 0, sizeof(*val) * AXG_TDM_NUM_LANES);

        /*
         * Distribute the channels of the stream over the available slots
         * of each TDM lane. We need to go over the 32 slots ...
         */
        for (i = 0; (i < 32) && ch; i += 2) {
                /* ... of all the lanes ... */
                for (j = 0; j < AXG_TDM_NUM_LANES; j++) {
                        /* ... then distribute the channels in pairs */
                        for (k = 0; k < 2; k++) {
                                if ((BIT(i + k) & ts->mask[j]) && ch) {
                                        val[j] |= BIT(i + k);
                                        ch -= 1;
                                }
                        }
                }
        }

        /*
         * If we still have channel left at the end of the process, it means
         * the stream has more channels than we can accommodate and we should
         * have caught this earlier.
         */
        if (WARN_ON(ch != 0)) {
                pr_err("channel mask error\n");
                return -EINVAL;
        }

        for (i = 0; i < AXG_TDM_NUM_LANES; i++) {
                regmap_write(map, offset, val[i]);
                offset += regmap_get_reg_stride(map);
        }

        return 0;
}
EXPORT_SYMBOL_GPL(axg_tdm_formatter_set_channel_masks);

static int axg_tdm_formatter_enable(struct axg_tdm_formatter *formatter)
{
        struct axg_tdm_stream *ts = formatter->stream;
        bool invert;
        int ret;

        /* Do nothing if the formatter is already enabled */
        if (formatter->enabled)
                return 0;

        /*
         * On the g12a (and possibly other SoCs), when a stream using
         * multiple lanes is restarted, it will sometimes not start
         * from the first lane, but randomly from another used one.
         * The result is an unexpected and random channel shift.
         *
         * The hypothesis is that an HW counter is not properly reset
         * and the formatter simply starts on the lane it stopped
         * before. Unfortunately, there does not seems to be a way to
         * reset this through the registers of the block.
         *
         * However, the g12a has indenpendent reset lines for each audio
         * devices. Using this reset before each start solves the issue.
         */
        ret = reset_control_reset(formatter->reset);
        if (ret)
                return ret;

        /*
         * If sclk is inverted, it means the bit should latched on the
         * rising edge which is what our HW expects. If not, we need to
         * invert it before the formatter.
         */
        invert = axg_tdm_sclk_invert(ts->iface->fmt);
        ret = clk_set_phase(formatter->sclk, invert ? 0 : 180);
        if (ret)
                return ret;

        /* Setup the stream parameter in the formatter */
        ret = formatter->drv->ops->prepare(formatter->map,
                                           formatter->drv->quirks,
                                           formatter->stream);
        if (ret)
                return ret;

        /* Enable the signal clocks feeding the formatter */
        ret = clk_prepare_enable(formatter->sclk);
        if (ret)
                return ret;

        ret = clk_prepare_enable(formatter->lrclk);
        if (ret) {
                clk_disable_unprepare(formatter->sclk);
                return ret;
        }

        /* Finally, actually enable the formatter */
        formatter->drv->ops->enable(formatter->map);
        formatter->enabled = true;

        return 0;
}

static void axg_tdm_formatter_disable(struct axg_tdm_formatter *formatter)
{
        /* Do nothing if the formatter is already disabled */
        if (!formatter->enabled)
                return;

        formatter->drv->ops->disable(formatter->map);
        clk_disable_unprepare(formatter->lrclk);
        clk_disable_unprepare(formatter->sclk);
        formatter->enabled = false;
}

static int axg_tdm_formatter_attach(struct axg_tdm_formatter *formatter)
{
        struct axg_tdm_stream *ts = formatter->stream;
        int ret = 0;

        mutex_lock(&ts->lock);

        /* Catch up if the stream is already running when we attach */
        if (ts->ready) {
                ret = axg_tdm_formatter_enable(formatter);
                if (ret) {
                        pr_err("failed to enable formatter\n");
                        goto out;
                }
        }

        list_add_tail(&formatter->list, &ts->formatter_list);
out:
        mutex_unlock(&ts->lock);
        return ret;
}

static void axg_tdm_formatter_dettach(struct axg_tdm_formatter *formatter)
{
        struct axg_tdm_stream *ts = formatter->stream;

        mutex_lock(&ts->lock);
        list_del(&formatter->list);
        mutex_unlock(&ts->lock);

        axg_tdm_formatter_disable(formatter);
}

static int axg_tdm_formatter_power_up(struct axg_tdm_formatter *formatter,
                                      struct snd_soc_dapm_widget *w)
{
        struct axg_tdm_stream *ts = formatter->drv->ops->get_stream(w);
        int ret;

        /*
         * If we don't get a stream at this stage, it would mean that the
         * widget is powering up but is not attached to any backend DAI.
         * It should not happen, ever !
         */
        if (WARN_ON(!ts))
                return -ENODEV;

        /* Clock our device */
        ret = clk_prepare_enable(formatter->pclk);
        if (ret)
                return ret;

        /* Reparent the bit clock to the TDM interface */
        ret = clk_set_parent(formatter->sclk_sel, ts->iface->sclk);
        if (ret)
                goto disable_pclk;

        /* Reparent the sample clock to the TDM interface */
        ret = clk_set_parent(formatter->lrclk_sel, ts->iface->lrclk);
        if (ret)
                goto disable_pclk;

        formatter->stream = ts;
        ret = axg_tdm_formatter_attach(formatter);
        if (ret)
                goto disable_pclk;

        return 0;

disable_pclk:
        clk_disable_unprepare(formatter->pclk);
        return ret;
}

static void axg_tdm_formatter_power_down(struct axg_tdm_formatter *formatter)
{
        axg_tdm_formatter_dettach(formatter);
        clk_disable_unprepare(formatter->pclk);
        formatter->stream = NULL;
}

int axg_tdm_formatter_event(struct snd_soc_dapm_widget *w,
                            struct snd_kcontrol *control,
                            int event)
{
        struct snd_soc_component *c = snd_soc_dapm_to_component(w->dapm);
        struct axg_tdm_formatter *formatter = snd_soc_component_get_drvdata(c);
        int ret = 0;

        switch (event) {
        case SND_SOC_DAPM_PRE_PMU:
                ret = axg_tdm_formatter_power_up(formatter, w);
                break;

        case SND_SOC_DAPM_PRE_PMD:
                axg_tdm_formatter_power_down(formatter);
                break;

        default:
                dev_err(c->dev, "Unexpected event %d\n", event);
                return -EINVAL;
        }

        return ret;
}
EXPORT_SYMBOL_GPL(axg_tdm_formatter_event);

int axg_tdm_formatter_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        const struct axg_tdm_formatter_driver *drv;
        struct axg_tdm_formatter *formatter;
        void __iomem *regs;

        drv = of_device_get_match_data(dev);
        if (!drv) {
                dev_err(dev, "failed to match device\n");
                return -ENODEV;
        }

        formatter = devm_kzalloc(dev, sizeof(*formatter), GFP_KERNEL);
        if (!formatter)
                return -ENOMEM;
        platform_set_drvdata(pdev, formatter);
        formatter->drv = drv;

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

        formatter->map = devm_regmap_init_mmio(dev, regs, drv->regmap_cfg);
        if (IS_ERR(formatter->map)) {
                dev_err(dev, "failed to init regmap: %ld\n",
                        PTR_ERR(formatter->map));
                return PTR_ERR(formatter->map);
        }

        /* Peripharal clock */
        formatter->pclk = devm_clk_get(dev, "pclk");
        if (IS_ERR(formatter->pclk))
                return dev_err_probe(dev, PTR_ERR(formatter->pclk), "failed to get pclk\n");

        /* Formatter bit clock */
        formatter->sclk = devm_clk_get(dev, "sclk");
        if (IS_ERR(formatter->sclk))
                return dev_err_probe(dev, PTR_ERR(formatter->sclk), "failed to get sclk\n");

        /* Formatter sample clock */
        formatter->lrclk = devm_clk_get(dev, "lrclk");
        if (IS_ERR(formatter->lrclk))
                return dev_err_probe(dev, PTR_ERR(formatter->lrclk), "failed to get lrclk\n");

        /* Formatter bit clock input multiplexer */
        formatter->sclk_sel = devm_clk_get(dev, "sclk_sel");
        if (IS_ERR(formatter->sclk_sel))
                return dev_err_probe(dev, PTR_ERR(formatter->sclk_sel), "failed to get sclk_sel\n");

        /* Formatter sample clock input multiplexer */
        formatter->lrclk_sel = devm_clk_get(dev, "lrclk_sel");
        if (IS_ERR(formatter->lrclk_sel))
                return dev_err_probe(dev, PTR_ERR(formatter->lrclk_sel),
                                     "failed to get lrclk_sel\n");

        /* Formatter dedicated reset line */
        formatter->reset = devm_reset_control_get_optional_exclusive(dev, NULL);
        if (IS_ERR(formatter->reset))
                return dev_err_probe(dev, PTR_ERR(formatter->reset), "failed to get reset\n");

        return devm_snd_soc_register_component(dev, drv->component_drv,
                                               NULL, 0);
}
EXPORT_SYMBOL_GPL(axg_tdm_formatter_probe);

int axg_tdm_stream_start(struct axg_tdm_stream *ts)
{
        struct axg_tdm_formatter *formatter;
        int ret = 0;

        mutex_lock(&ts->lock);
        ts->ready = true;

        /* Start all the formatters attached to the stream */
        list_for_each_entry(formatter, &ts->formatter_list, list) {
                ret = axg_tdm_formatter_enable(formatter);
                if (ret) {
                        pr_err("failed to start tdm stream\n");
                        goto out;
                }
        }

out:
        mutex_unlock(&ts->lock);
        return ret;
}
EXPORT_SYMBOL_GPL(axg_tdm_stream_start);

void axg_tdm_stream_stop(struct axg_tdm_stream *ts)
{
        struct axg_tdm_formatter *formatter;

        mutex_lock(&ts->lock);
        ts->ready = false;

        /* Stop all the formatters attached to the stream */
        list_for_each_entry(formatter, &ts->formatter_list, list) {
                axg_tdm_formatter_disable(formatter);
        }

        mutex_unlock(&ts->lock);
}
EXPORT_SYMBOL_GPL(axg_tdm_stream_stop);

struct axg_tdm_stream *axg_tdm_stream_alloc(struct axg_tdm_iface *iface)
{
        struct axg_tdm_stream *ts;

        ts = kzalloc_obj(*ts);
        if (ts) {
                INIT_LIST_HEAD(&ts->formatter_list);
                mutex_init(&ts->lock);
                ts->iface = iface;
        }

        return ts;
}
EXPORT_SYMBOL_GPL(axg_tdm_stream_alloc);

void axg_tdm_stream_free(struct axg_tdm_stream *ts)
{
        /*
         * If the list is not empty, it would mean that one of the formatter
         * widget is still powered and attached to the interface while we
         * are removing the TDM DAI. It should not be possible
         */
        WARN_ON(!list_empty(&ts->formatter_list));
        mutex_destroy(&ts->lock);
        kfree(ts);
}
EXPORT_SYMBOL_GPL(axg_tdm_stream_free);

int axg_tdm_stream_set_cont_clocks(struct axg_tdm_stream *ts,
                                   unsigned int fmt)
{
        int ret = 0;

        if (fmt & SND_SOC_DAIFMT_CONT) {
                /* Clock are already enabled - skipping */
                if (ts->clk_enabled)
                        return 0;

                ret = clk_prepare_enable(ts->iface->mclk);
                if (ret)
                        return ret;

                ret = clk_prepare_enable(ts->iface->sclk);
                if (ret)
                        goto err_sclk;

                ret = clk_prepare_enable(ts->iface->lrclk);
                if (ret)
                        goto err_lrclk;

                ts->clk_enabled = true;
                return 0;
        }

        /* Clocks are already disabled - skipping */
        if (!ts->clk_enabled)
                return 0;

        clk_disable_unprepare(ts->iface->lrclk);
err_lrclk:
        clk_disable_unprepare(ts->iface->sclk);
err_sclk:
        clk_disable_unprepare(ts->iface->mclk);
        ts->clk_enabled = false;
        return ret;
}
EXPORT_SYMBOL_GPL(axg_tdm_stream_set_cont_clocks);

MODULE_DESCRIPTION("Amlogic AXG TDM formatter driver");
MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
MODULE_LICENSE("GPL v2");