// SPDX-License-Identifier: GPL-2.0
/*
 * Power-source driver for Bay Trail Crystal Cove PMIC
 *
 * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
 *
 * Based on intel_crystalcove_pwrsrc.c from Android kernel sources, which is:
 * Copyright (C) 2013 Intel Corporation
 */

#include <linux/array_size.h>
#include <linux/bits.h>
#include <linux/debugfs.h>
#include <linux/interrupt.h>
#include <linux/mfd/intel_soc_pmic.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/property.h>
#include <linux/regmap.h>

#define CRYSTALCOVE_PWRSRC_IRQ          0x03
#define CRYSTALCOVE_SPWRSRC_REG         0x1E
#define CRYSTALCOVE_SPWRSRC_USB         BIT(0)
#define CRYSTALCOVE_SPWRSRC_DC          BIT(1)
#define CRYSTALCOVE_SPWRSRC_BATTERY     BIT(2)
#define CRYSTALCOVE_RESETSRC0_REG       0x20
#define CRYSTALCOVE_RESETSRC1_REG       0x21
#define CRYSTALCOVE_WAKESRC_REG         0x22

struct crc_pwrsrc_data {
        struct regmap *regmap;
        struct dentry *debug_dentry;
        struct power_supply *psy;
        unsigned int resetsrc0;
        unsigned int resetsrc1;
        unsigned int wakesrc;
};

static const char * const pwrsrc_pwrsrc_info[] = {
        /* bit 0 */ "USB",
        /* bit 1 */ "DC in",
        /* bit 2 */ "Battery",
        NULL,
};

static const char * const pwrsrc_resetsrc0_info[] = {
        /* bit 0 */ "SOC reporting a thermal event",
        /* bit 1 */ "critical PMIC temperature",
        /* bit 2 */ "critical system temperature",
        /* bit 3 */ "critical battery temperature",
        /* bit 4 */ "VSYS under voltage",
        /* bit 5 */ "VSYS over voltage",
        /* bit 6 */ "battery removal",
        NULL,
};

static const char * const pwrsrc_resetsrc1_info[] = {
        /* bit 0 */ "VCRIT threshold",
        /* bit 1 */ "BATID reporting battery removal",
        /* bit 2 */ "user pressing the power button",
        NULL,
};

static const char * const pwrsrc_wakesrc_info[] = {
        /* bit 0 */ "user pressing the power button",
        /* bit 1 */ "a battery insertion",
        /* bit 2 */ "a USB charger insertion",
        /* bit 3 */ "an adapter insertion",
        NULL,
};

static void crc_pwrsrc_log(struct seq_file *seq, const char *prefix,
                           const char * const *info, unsigned int reg_val)
{
        int i;

        for (i = 0; info[i]; i++) {
                if (reg_val & BIT(i))
                        seq_printf(seq, "%s by %s\n", prefix, info[i]);
        }
}

static int pwrsrc_show(struct seq_file *seq, void *unused)
{
        struct crc_pwrsrc_data *data = seq->private;
        unsigned int reg_val;
        int ret;

        ret = regmap_read(data->regmap, CRYSTALCOVE_SPWRSRC_REG, &reg_val);
        if (ret)
                return ret;

        crc_pwrsrc_log(seq, "System powered", pwrsrc_pwrsrc_info, reg_val);
        return 0;
}

static int resetsrc_show(struct seq_file *seq, void *unused)
{
        struct crc_pwrsrc_data *data = seq->private;

        crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc0_info, data->resetsrc0);
        crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc1_info, data->resetsrc1);
        return 0;
}

static int wakesrc_show(struct seq_file *seq, void *unused)
{
        struct crc_pwrsrc_data *data = seq->private;

        crc_pwrsrc_log(seq, "Last wake caused", pwrsrc_wakesrc_info, data->wakesrc);
        return 0;
}

DEFINE_SHOW_ATTRIBUTE(pwrsrc);
DEFINE_SHOW_ATTRIBUTE(resetsrc);
DEFINE_SHOW_ATTRIBUTE(wakesrc);

static int crc_pwrsrc_read_and_clear(struct crc_pwrsrc_data *data,
                                     unsigned int reg, unsigned int *val)
{
        int ret;

        ret = regmap_read(data->regmap, reg, val);
        if (ret)
                return ret;

        return regmap_write(data->regmap, reg, *val);
}

static irqreturn_t crc_pwrsrc_irq_handler(int irq, void *_data)
{
        struct crc_pwrsrc_data *data = _data;
        unsigned int irq_mask;

        if (regmap_read(data->regmap, CRYSTALCOVE_PWRSRC_IRQ, &irq_mask))
                return IRQ_NONE;

        regmap_write(data->regmap, CRYSTALCOVE_PWRSRC_IRQ, irq_mask);

        power_supply_changed(data->psy);
        return IRQ_HANDLED;
}

static int crc_pwrsrc_psy_get_property(struct power_supply *psy,
                                       enum power_supply_property psp,
                                       union power_supply_propval *val)
{
        struct crc_pwrsrc_data *data = power_supply_get_drvdata(psy);
        unsigned int pwrsrc;
        int ret;

        if (psp != POWER_SUPPLY_PROP_ONLINE)
                return -EINVAL;

        ret = regmap_read(data->regmap, CRYSTALCOVE_SPWRSRC_REG, &pwrsrc);
        if (ret)
                return ret;

        val->intval = !!(pwrsrc & (CRYSTALCOVE_SPWRSRC_USB |
                                   CRYSTALCOVE_SPWRSRC_DC));
        return 0;
}

static const enum power_supply_property crc_pwrsrc_psy_props[] = {
        POWER_SUPPLY_PROP_ONLINE,
};

static const struct power_supply_desc crc_pwrsrc_psy_desc = {
        .name = "crystal_cove_pwrsrc",
        .type = POWER_SUPPLY_TYPE_MAINS,
        .properties = crc_pwrsrc_psy_props,
        .num_properties = ARRAY_SIZE(crc_pwrsrc_psy_props),
        .get_property = crc_pwrsrc_psy_get_property,
};

static int crc_pwrsrc_probe(struct platform_device *pdev)
{
        struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
        struct device *dev = &pdev->dev;
        struct crc_pwrsrc_data *data;
        int irq, ret;

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

        data->regmap = pmic->regmap;

        /*
         * Read + clear resetsrc0/1 and wakesrc now, so that they get
         * cleared even if the debugfs interface is never used.
         *
         * Properly clearing the wakesrc is important, leaving bit 0 of it
         * set turns reboot into poweroff on some tablets.
         */
        ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC0_REG, &data->resetsrc0);
        if (ret)
                return ret;

        ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC1_REG, &data->resetsrc1);
        if (ret)
                return ret;

        ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_WAKESRC_REG, &data->wakesrc);
        if (ret)
                return ret;

        if (device_property_read_bool(dev->parent, "linux,register-pwrsrc-power_supply")) {
                struct power_supply_config psy_cfg = { .drv_data = data };

                irq = platform_get_irq(pdev, 0);
                if (irq < 0)
                        return irq;

                data->psy = devm_power_supply_register(dev, &crc_pwrsrc_psy_desc, &psy_cfg);
                if (IS_ERR(data->psy))
                        return dev_err_probe(dev, PTR_ERR(data->psy), "registering power-supply\n");

                ret = devm_request_threaded_irq(dev, irq, NULL,
                                                crc_pwrsrc_irq_handler,
                                                IRQF_ONESHOT, KBUILD_MODNAME, data);
                if (ret)
                        return dev_err_probe(dev, ret, "requesting IRQ\n");
        }

        data->debug_dentry = debugfs_create_dir(KBUILD_MODNAME, NULL);
        debugfs_create_file("pwrsrc", 0444, data->debug_dentry, data, &pwrsrc_fops);
        debugfs_create_file("resetsrc", 0444, data->debug_dentry, data, &resetsrc_fops);
        debugfs_create_file("wakesrc", 0444, data->debug_dentry, data, &wakesrc_fops);

        platform_set_drvdata(pdev, data);
        return 0;
}

static void crc_pwrsrc_remove(struct platform_device *pdev)
{
        struct crc_pwrsrc_data *data = platform_get_drvdata(pdev);

        debugfs_remove_recursive(data->debug_dentry);
}

static struct platform_driver crc_pwrsrc_driver = {
        .probe = crc_pwrsrc_probe,
        .remove = crc_pwrsrc_remove,
        .driver = {
                .name = "crystal_cove_pwrsrc",
        },
};
module_platform_driver(crc_pwrsrc_driver);

MODULE_ALIAS("platform:crystal_cove_pwrsrc");
MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
MODULE_DESCRIPTION("Power-source driver for Bay Trail Crystal Cove PMIC");
MODULE_LICENSE("GPL");