// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2024 Linaro Ltd.
 * Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
 */

#include <linux/clk.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of_graph.h>
#include <linux/pci-pwrctrl.h>
#include <linux/platform_device.h>
#include <linux/pwrseq/consumer.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

struct slot_pwrctrl {
        struct pci_pwrctrl pwrctrl;
        struct regulator_bulk_data *supplies;
        int num_supplies;
        struct clk *clk;
        struct pwrseq_desc *pwrseq;
};

static int slot_pwrctrl_power_on(struct pci_pwrctrl *pwrctrl)
{
        struct slot_pwrctrl *slot = container_of(pwrctrl,
                                                struct slot_pwrctrl, pwrctrl);
        int ret;

        if (slot->pwrseq) {
                pwrseq_power_on(slot->pwrseq);
                return 0;
        }

        ret = regulator_bulk_enable(slot->num_supplies, slot->supplies);
        if (ret < 0) {
                dev_err(slot->pwrctrl.dev, "Failed to enable slot regulators\n");
                return ret;
        }

        return clk_prepare_enable(slot->clk);
}

static int slot_pwrctrl_power_off(struct pci_pwrctrl *pwrctrl)
{
        struct slot_pwrctrl *slot = container_of(pwrctrl,
                                                struct slot_pwrctrl, pwrctrl);

        if (slot->pwrseq) {
                pwrseq_power_off(slot->pwrseq);
                return 0;
        }

        regulator_bulk_disable(slot->num_supplies, slot->supplies);
        clk_disable_unprepare(slot->clk);

        return 0;
}

static void devm_slot_pwrctrl_release(void *data)
{
        struct slot_pwrctrl *slot = data;

        regulator_bulk_free(slot->num_supplies, slot->supplies);
}

static int slot_pwrctrl_probe(struct platform_device *pdev)
{
        struct slot_pwrctrl *slot;
        struct device *dev = &pdev->dev;
        int ret;

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

        if (of_graph_is_present(dev_of_node(dev))) {
                slot->pwrseq = devm_pwrseq_get(dev, "pcie");
                if (IS_ERR(slot->pwrseq))
                        return dev_err_probe(dev, PTR_ERR(slot->pwrseq),
                                     "Failed to get the power sequencer\n");

                goto skip_resources;
        }

        ret = of_regulator_bulk_get_all(dev, dev_of_node(dev),
                                        &slot->supplies);
        if (ret < 0) {
                dev_err_probe(dev, ret, "Failed to get slot regulators\n");
                return ret;
        }

        slot->num_supplies = ret;

        slot->clk = devm_clk_get_optional(dev, NULL);
        if (IS_ERR(slot->clk)) {
                return dev_err_probe(dev, PTR_ERR(slot->clk),
                                     "Failed to enable slot clock\n");
        }

skip_resources:
        slot->pwrctrl.power_on = slot_pwrctrl_power_on;
        slot->pwrctrl.power_off = slot_pwrctrl_power_off;

        ret = devm_add_action_or_reset(dev, devm_slot_pwrctrl_release, slot);
        if (ret)
                return ret;

        pci_pwrctrl_init(&slot->pwrctrl, dev);

        ret = devm_pci_pwrctrl_device_set_ready(dev, &slot->pwrctrl);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to register pwrctrl driver\n");

        return 0;
}

static const struct of_device_id slot_pwrctrl_of_match[] = {
        {
                .compatible = "pciclass,0604",
        },
        { }
};
MODULE_DEVICE_TABLE(of, slot_pwrctrl_of_match);

static struct platform_driver slot_pwrctrl_driver = {
        .driver = {
                .name = "pci-pwrctrl-slot",
                .of_match_table = slot_pwrctrl_of_match,
        },
        .probe = slot_pwrctrl_probe,
};
module_platform_driver(slot_pwrctrl_driver);

MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
MODULE_DESCRIPTION("Generic PCI Power Control driver for PCI Slots");
MODULE_LICENSE("GPL");