// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018 Spreadtrum Communications Inc.
 * Copyright (C) 2018 Linaro Ltd.
 */

#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm.h>
#include <linux/regmap.h>
#include <linux/syscore_ops.h>

#define SC27XX_PWR_PD_HW        0xc2c
#define SC27XX_PWR_OFF_EN       BIT(0)
#define SC27XX_SLP_CTRL         0xdf0
#define SC27XX_LDO_XTL_EN       BIT(3)

static struct regmap *regmap;

/*
 * On Spreadtrum platform, we need power off system through external SC27xx
 * series PMICs, and it is one similar SPI bus mapped by regmap to access PMIC,
 * which is not fast io access.
 *
 * So before stopping other cores, we need release other cores' resource by
 * taking cpus down to avoid racing regmap or spi mutex lock when poweroff
 * system through PMIC.
 */
static void sc27xx_poweroff_shutdown(void *data)
{
#ifdef CONFIG_HOTPLUG_CPU
        int cpu;

        for_each_online_cpu(cpu) {
                if (cpu != smp_processor_id())
                        remove_cpu(cpu);
        }
#endif
}

static const struct syscore_ops poweroff_syscore_ops = {
        .shutdown = sc27xx_poweroff_shutdown,
};

static struct syscore poweroff_syscore = {
        .ops = &poweroff_syscore_ops,
};

static void sc27xx_poweroff_do_poweroff(void)
{
        /* Disable the external subsys connection's power firstly */
        regmap_write(regmap, SC27XX_SLP_CTRL, SC27XX_LDO_XTL_EN);

        regmap_write(regmap, SC27XX_PWR_PD_HW, SC27XX_PWR_OFF_EN);
}

static int sc27xx_poweroff_probe(struct platform_device *pdev)
{
        if (regmap)
                return -EINVAL;

        regmap = dev_get_regmap(pdev->dev.parent, NULL);
        if (!regmap)
                return -ENODEV;

        pm_power_off = sc27xx_poweroff_do_poweroff;
        register_syscore(&poweroff_syscore);
        return 0;
}

static const struct platform_device_id sc27xx_poweroff_id_table[] = {
        { "sc2731-poweroff" },
        { }
};
MODULE_DEVICE_TABLE(platform, sc27xx_poweroff_id_table);

static struct platform_driver sc27xx_poweroff_driver = {
        .probe = sc27xx_poweroff_probe,
        .driver = {
                .name = "sc27xx-poweroff",
        },
        .id_table = sc27xx_poweroff_id_table,
};
module_platform_driver(sc27xx_poweroff_driver);

MODULE_DESCRIPTION("Power off driver for SC27XX PMIC Device");
MODULE_AUTHOR("Baolin Wang <baolin.wang@unisoc.com>");
MODULE_LICENSE("GPL v2");