// 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,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");