// SPDX-License-Identifier: GPL-2.0-only
/*
 *  Copyright (C) 2014 Linaro Ltd
 *
 * Author: Ulf Hansson <ulf.hansson@linaro.org>
 *
 *  Simple MMC power sequence management
 */
#include <linux/clk.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/gpio/consumer.h>
#include <linux/delay.h>
#include <linux/property.h>
#include <linux/of.h>
#include <linux/reset.h>

#include <linux/mmc/host.h>

#include "pwrseq.h"

struct mmc_pwrseq_simple {
        struct mmc_pwrseq pwrseq;
        bool clk_enabled;
        u32 post_power_on_delay_ms;
        u32 power_off_delay_us;
        struct clk *ext_clk;
        struct gpio_descs *reset_gpios;
        struct reset_control *reset_ctrl;
};

#define to_pwrseq_simple(p) container_of(p, struct mmc_pwrseq_simple, pwrseq)

static void mmc_pwrseq_simple_set_gpios_value(struct mmc_pwrseq_simple *pwrseq,
                                              int value)
{
        struct gpio_descs *reset_gpios = pwrseq->reset_gpios;

        if (!IS_ERR(reset_gpios)) {
                unsigned long *values;
                int nvalues = reset_gpios->ndescs;

                values = bitmap_alloc(nvalues, GFP_KERNEL);
                if (!values)
                        return;

                if (value)
                        bitmap_fill(values, nvalues);
                else
                        bitmap_zero(values, nvalues);

                gpiod_multi_set_value_cansleep(reset_gpios, values);

                bitmap_free(values);
        }
}

static void mmc_pwrseq_simple_pre_power_on(struct mmc_host *host)
{
        struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);

        if (!IS_ERR(pwrseq->ext_clk) && !pwrseq->clk_enabled) {
                clk_prepare_enable(pwrseq->ext_clk);
                pwrseq->clk_enabled = true;
        }

        if (pwrseq->reset_ctrl) {
                reset_control_deassert(pwrseq->reset_ctrl);
                reset_control_assert(pwrseq->reset_ctrl);
        } else
                mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);
}

static void mmc_pwrseq_simple_post_power_on(struct mmc_host *host)
{
        struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);

        if (pwrseq->reset_ctrl)
                reset_control_deassert(pwrseq->reset_ctrl);
        else
                mmc_pwrseq_simple_set_gpios_value(pwrseq, 0);

        if (pwrseq->post_power_on_delay_ms)
                msleep(pwrseq->post_power_on_delay_ms);
}

static void mmc_pwrseq_simple_power_off(struct mmc_host *host)
{
        struct mmc_pwrseq_simple *pwrseq = to_pwrseq_simple(host->pwrseq);

        if (pwrseq->reset_ctrl)
                reset_control_assert(pwrseq->reset_ctrl);
        else
                mmc_pwrseq_simple_set_gpios_value(pwrseq, 1);

        if (pwrseq->power_off_delay_us)
                usleep_range(pwrseq->power_off_delay_us,
                        2 * pwrseq->power_off_delay_us);

        if (!IS_ERR(pwrseq->ext_clk) && pwrseq->clk_enabled) {
                clk_disable_unprepare(pwrseq->ext_clk);
                pwrseq->clk_enabled = false;
        }
}

static const struct mmc_pwrseq_ops mmc_pwrseq_simple_ops = {
        .pre_power_on = mmc_pwrseq_simple_pre_power_on,
        .post_power_on = mmc_pwrseq_simple_post_power_on,
        .power_off = mmc_pwrseq_simple_power_off,
};

static const struct of_device_id mmc_pwrseq_simple_of_match[] = {
        { .compatible = "mmc-pwrseq-simple",},
        {/* sentinel */},
};
MODULE_DEVICE_TABLE(of, mmc_pwrseq_simple_of_match);

static int mmc_pwrseq_simple_probe(struct platform_device *pdev)
{
        struct mmc_pwrseq_simple *pwrseq;
        struct device *dev = &pdev->dev;
        int ngpio;

        pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
        if (!pwrseq)
                return -ENOMEM;

        pwrseq->ext_clk = devm_clk_get(dev, "ext_clock");
        if (IS_ERR(pwrseq->ext_clk) && PTR_ERR(pwrseq->ext_clk) != -ENOENT)
                return dev_err_probe(dev, PTR_ERR(pwrseq->ext_clk), "external clock not ready\n");

        ngpio = of_count_phandle_with_args(dev->of_node, "reset-gpios", "#gpio-cells");
        if (ngpio == 1) {
                pwrseq->reset_ctrl = devm_reset_control_get_optional_shared(dev, NULL);
                if (IS_ERR(pwrseq->reset_ctrl))
                        return dev_err_probe(dev, PTR_ERR(pwrseq->reset_ctrl),
                                             "reset control not ready\n");
        }

        /*
         * Fallback to GPIO based reset control in case of multiple reset lines
         * are specified or the platform doesn't have support for RESET at all.
         */
        if (!pwrseq->reset_ctrl) {
                pwrseq->reset_gpios = devm_gpiod_get_array(dev, "reset", GPIOD_OUT_HIGH);
                if (IS_ERR(pwrseq->reset_gpios) &&
                    PTR_ERR(pwrseq->reset_gpios) != -ENOENT &&
                    PTR_ERR(pwrseq->reset_gpios) != -ENOSYS) {
                        return dev_err_probe(dev, PTR_ERR(pwrseq->reset_gpios),
                                             "reset GPIOs not ready\n");
                }
        }

        device_property_read_u32(dev, "post-power-on-delay-ms",
                                 &pwrseq->post_power_on_delay_ms);
        device_property_read_u32(dev, "power-off-delay-us",
                                 &pwrseq->power_off_delay_us);

        pwrseq->pwrseq.dev = dev;
        pwrseq->pwrseq.ops = &mmc_pwrseq_simple_ops;
        pwrseq->pwrseq.owner = THIS_MODULE;
        platform_set_drvdata(pdev, pwrseq);

        return mmc_pwrseq_register(&pwrseq->pwrseq);
}

static void mmc_pwrseq_simple_remove(struct platform_device *pdev)
{
        struct mmc_pwrseq_simple *pwrseq = platform_get_drvdata(pdev);

        mmc_pwrseq_unregister(&pwrseq->pwrseq);
}

static struct platform_driver mmc_pwrseq_simple_driver = {
        .probe = mmc_pwrseq_simple_probe,
        .remove = mmc_pwrseq_simple_remove,
        .driver = {
                .name = "pwrseq_simple",
                .of_match_table = mmc_pwrseq_simple_of_match,
        },
};

module_platform_driver(mmc_pwrseq_simple_driver);
MODULE_DESCRIPTION("Simple power sequence management for MMC");
MODULE_LICENSE("GPL v2");