// SPDX-License-Identifier: GPL-2.0

#include <linux/bitfield.h>
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>

#include "cpufreq-dt.h"

struct airoha_cpufreq_priv {
        int opp_token;
        struct dev_pm_domain_list *pd_list;
        struct platform_device *cpufreq_dt;
};

static struct platform_device *cpufreq_pdev;

/* NOP function to disable OPP from setting clock */
static int airoha_cpufreq_config_clks_nop(struct device *dev,
                                          struct opp_table *opp_table,
                                          struct dev_pm_opp *opp,
                                          void *data, bool scaling_down)
{
        return 0;
}

static const char * const airoha_cpufreq_clk_names[] = { "cpu", NULL };
static const char * const airoha_cpufreq_pd_names[] = { "perf" };

static int airoha_cpufreq_probe(struct platform_device *pdev)
{
        const struct dev_pm_domain_attach_data attach_data = {
                .pd_names = airoha_cpufreq_pd_names,
                .num_pd_names = ARRAY_SIZE(airoha_cpufreq_pd_names),
                .pd_flags = PD_FLAG_DEV_LINK_ON | PD_FLAG_REQUIRED_OPP,
        };
        struct dev_pm_opp_config config = {
                .clk_names = airoha_cpufreq_clk_names,
                .config_clks = airoha_cpufreq_config_clks_nop,
        };
        struct platform_device *cpufreq_dt;
        struct airoha_cpufreq_priv *priv;
        struct device *dev = &pdev->dev;
        struct device *cpu_dev;
        int ret;

        /* CPUs refer to the same OPP table */
        cpu_dev = get_cpu_device(0);
        if (!cpu_dev)
                return -ENODEV;

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

        /* Set OPP table conf with NOP config_clks */
        priv->opp_token = dev_pm_opp_set_config(cpu_dev, &config);
        if (priv->opp_token < 0)
                return dev_err_probe(dev, priv->opp_token, "Failed to set OPP config\n");

        /* Attach PM for OPP */
        ret = dev_pm_domain_attach_list(cpu_dev, &attach_data,
                                        &priv->pd_list);
        if (ret)
                goto clear_opp_config;

        cpufreq_dt = platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
        ret = PTR_ERR_OR_ZERO(cpufreq_dt);
        if (ret) {
                dev_err(dev, "failed to create cpufreq-dt device: %d\n", ret);
                goto detach_pm;
        }

        priv->cpufreq_dt = cpufreq_dt;
        platform_set_drvdata(pdev, priv);

        return 0;

detach_pm:
        dev_pm_domain_detach_list(priv->pd_list);
clear_opp_config:
        dev_pm_opp_clear_config(priv->opp_token);

        return ret;
}

static void airoha_cpufreq_remove(struct platform_device *pdev)
{
        struct airoha_cpufreq_priv *priv = platform_get_drvdata(pdev);

        platform_device_unregister(priv->cpufreq_dt);

        dev_pm_domain_detach_list(priv->pd_list);

        dev_pm_opp_clear_config(priv->opp_token);
}

static struct platform_driver airoha_cpufreq_driver = {
        .probe = airoha_cpufreq_probe,
        .remove = airoha_cpufreq_remove,
        .driver = {
                .name = "airoha-cpufreq",
        },
};

static const struct of_device_id airoha_cpufreq_match_list[] __initconst = {
        { .compatible = "airoha,an7583" },
        { .compatible = "airoha,en7581" },
        {},
};
MODULE_DEVICE_TABLE(of, airoha_cpufreq_match_list);

static int __init airoha_cpufreq_init(void)
{
        struct device_node *np = of_find_node_by_path("/");
        const struct of_device_id *match;
        int ret;

        if (!np)
                return -ENODEV;

        match = of_match_node(airoha_cpufreq_match_list, np);
        of_node_put(np);
        if (!match)
                return -ENODEV;

        ret = platform_driver_register(&airoha_cpufreq_driver);
        if (unlikely(ret < 0))
                return ret;

        cpufreq_pdev = platform_device_register_data(NULL, "airoha-cpufreq",
                                                     -1, match, sizeof(*match));
        ret = PTR_ERR_OR_ZERO(cpufreq_pdev);
        if (ret)
                platform_driver_unregister(&airoha_cpufreq_driver);

        return ret;
}
module_init(airoha_cpufreq_init);

static void __exit airoha_cpufreq_exit(void)
{
        platform_device_unregister(cpufreq_pdev);
        platform_driver_unregister(&airoha_cpufreq_driver);
}
module_exit(airoha_cpufreq_exit);

MODULE_AUTHOR("Christian Marangi <ansuelsmth@gmail.com>");
MODULE_DESCRIPTION("CPUfreq driver for Airoha SoCs");
MODULE_LICENSE("GPL");