// SPDX-License-Identifier: GPL-2.0
// Battery charger driver for TI's tps65217
//
// Copyright (C) 2015 Collabora Ltd.
// Author: Enric Balletbo i Serra <enric.balletbo@collabora.com>

/*
 * Battery charger driver for TI's tps65217
 */
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/power_supply.h>

#include <linux/mfd/core.h>
#include <linux/mfd/tps65217.h>

#define CHARGER_STATUS_PRESENT  (TPS65217_STATUS_ACPWR | TPS65217_STATUS_USBPWR)
#define NUM_CHARGER_IRQS        2
#define POLL_INTERVAL           (HZ * 2)

struct tps65217_charger {
        struct tps65217 *tps;
        struct device *dev;
        struct power_supply *psy;

        int     online;
        int     prev_online;

        struct task_struct      *poll_task;
};

static enum power_supply_property tps65217_charger_props[] = {
        POWER_SUPPLY_PROP_ONLINE,
};

static int tps65217_config_charger(struct tps65217_charger *charger)
{
        int ret;

        /*
         * tps65217 rev. G, p. 31 (see p. 32 for NTC schematic)
         *
         * The device can be configured to support a 100k NTC (B = 3960) by
         * setting the NTC_TYPE bit in register CHGCONFIG1 to 1. However it
         * is not recommended to do so. In sleep mode, the charger continues
         * charging the battery, but all register values are reset to default
         * values. Therefore, the charger would get the wrong temperature
         * information. If 100k NTC setting is required, please contact the
         * factory.
         *
         * ATTENTION, conflicting information, from p. 46
         *
         * NTC TYPE (for battery temperature measurement)
         *   0 – 100k (curve 1, B = 3960)
         *   1 – 10k  (curve 2, B = 3480) (default on reset)
         *
         */
        ret = tps65217_clear_bits(charger->tps, TPS65217_REG_CHGCONFIG1,
                                  TPS65217_CHGCONFIG1_NTC_TYPE,
                                  TPS65217_PROTECT_NONE);
        if (ret) {
                dev_err(charger->dev,
                        "failed to set 100k NTC setting: %d\n", ret);
                return ret;
        }

        return 0;
}

static int tps65217_enable_charging(struct tps65217_charger *charger)
{
        int ret;

        /* charger already enabled */
        if (charger->online)
                return 0;

        dev_dbg(charger->dev, "%s: enable charging\n", __func__);
        ret = tps65217_set_bits(charger->tps, TPS65217_REG_CHGCONFIG1,
                                TPS65217_CHGCONFIG1_CHG_EN,
                                TPS65217_CHGCONFIG1_CHG_EN,
                                TPS65217_PROTECT_NONE);
        if (ret) {
                dev_err(charger->dev,
                        "%s: Error in writing CHG_EN in reg 0x%x: %d\n",
                        __func__, TPS65217_REG_CHGCONFIG1, ret);
                return ret;
        }

        charger->online = 1;

        return 0;
}

static int tps65217_charger_get_property(struct power_supply *psy,
                                         enum power_supply_property psp,
                                         union power_supply_propval *val)
{
        struct tps65217_charger *charger = power_supply_get_drvdata(psy);

        if (psp == POWER_SUPPLY_PROP_ONLINE) {
                val->intval = charger->online;
                return 0;
        }
        return -EINVAL;
}

static irqreturn_t tps65217_charger_irq(int irq, void *dev)
{
        int ret, val;
        struct tps65217_charger *charger = dev;

        charger->prev_online = charger->online;

        ret = tps65217_reg_read(charger->tps, TPS65217_REG_STATUS, &val);
        if (ret < 0) {
                dev_err(charger->dev, "%s: Error in reading reg 0x%x\n",
                        __func__, TPS65217_REG_STATUS);
                return IRQ_HANDLED;
        }

        dev_dbg(charger->dev, "%s: 0x%x\n", __func__, val);

        /* check for charger status bit */
        if (val & CHARGER_STATUS_PRESENT) {
                ret = tps65217_enable_charging(charger);
                if (ret) {
                        dev_err(charger->dev,
                                "failed to enable charger: %d\n", ret);
                        return IRQ_HANDLED;
                }
        } else {
                charger->online = 0;
        }

        if (charger->prev_online != charger->online)
                power_supply_changed(charger->psy);

        ret = tps65217_reg_read(charger->tps, TPS65217_REG_CHGCONFIG0, &val);
        if (ret < 0) {
                dev_err(charger->dev, "%s: Error in reading reg 0x%x\n",
                        __func__, TPS65217_REG_CHGCONFIG0);
                return IRQ_HANDLED;
        }

        if (val & TPS65217_CHGCONFIG0_ACTIVE)
                dev_dbg(charger->dev, "%s: charger is charging\n", __func__);
        else
                dev_dbg(charger->dev,
                        "%s: charger is NOT charging\n", __func__);

        return IRQ_HANDLED;
}

static int tps65217_charger_poll_task(void *data)
{
        set_freezable();

        while (!kthread_should_stop()) {
                schedule_timeout_interruptible(POLL_INTERVAL);
                try_to_freeze();
                tps65217_charger_irq(-1, data);
        }
        return 0;
}

static const struct power_supply_desc tps65217_charger_desc = {
        .name                   = "tps65217-charger",
        .type                   = POWER_SUPPLY_TYPE_MAINS,
        .get_property           = tps65217_charger_get_property,
        .properties             = tps65217_charger_props,
        .num_properties         = ARRAY_SIZE(tps65217_charger_props),
};

static int tps65217_charger_probe(struct platform_device *pdev)
{
        struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
        struct tps65217_charger *charger;
        struct power_supply_config cfg = {};
        struct task_struct *poll_task;
        int irq[NUM_CHARGER_IRQS];
        int ret;
        int i;

        charger = devm_kzalloc(&pdev->dev, sizeof(*charger), GFP_KERNEL);
        if (!charger)
                return -ENOMEM;

        platform_set_drvdata(pdev, charger);
        charger->tps = tps;
        charger->dev = &pdev->dev;

        cfg.fwnode = dev_fwnode(&pdev->dev);
        cfg.drv_data = charger;

        charger->psy = devm_power_supply_register(&pdev->dev,
                                                  &tps65217_charger_desc,
                                                  &cfg);
        if (IS_ERR(charger->psy)) {
                dev_err(&pdev->dev, "failed: power supply register\n");
                return PTR_ERR(charger->psy);
        }

        irq[0] = platform_get_irq_byname(pdev, "USB");
        irq[1] = platform_get_irq_byname(pdev, "AC");

        ret = tps65217_config_charger(charger);
        if (ret < 0) {
                dev_err(charger->dev, "charger config failed, err %d\n", ret);
                return ret;
        }

        /* Create a polling thread if an interrupt is invalid */
        if (irq[0] < 0 || irq[1] < 0) {
                poll_task = kthread_run(tps65217_charger_poll_task,
                                        charger, "ktps65217charger");
                if (IS_ERR(poll_task)) {
                        ret = PTR_ERR(poll_task);
                        dev_err(charger->dev,
                                "Unable to run kthread err %d\n", ret);
                        return ret;
                }

                charger->poll_task = poll_task;
                return 0;
        }

        /* Create IRQ threads for charger interrupts */
        for (i = 0; i < NUM_CHARGER_IRQS; i++) {
                ret = devm_request_threaded_irq(&pdev->dev, irq[i], NULL,
                                                tps65217_charger_irq,
                                                IRQF_SHARED, "tps65217-charger",
                                                charger);
                if (ret) {
                        dev_err(charger->dev,
                                "Unable to register irq %d err %d\n", irq[i],
                                ret);
                        return ret;
                }

                /* Check current state */
                tps65217_charger_irq(-1, charger);
        }

        return 0;
}

static void tps65217_charger_remove(struct platform_device *pdev)
{
        struct tps65217_charger *charger = platform_get_drvdata(pdev);

        if (charger->poll_task)
                kthread_stop(charger->poll_task);
}

static const struct of_device_id tps65217_charger_match_table[] = {
        { .compatible = "ti,tps65217-charger", },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, tps65217_charger_match_table);

static struct platform_driver tps65217_charger_driver = {
        .probe  = tps65217_charger_probe,
        .remove = tps65217_charger_remove,
        .driver = {
                .name   = "tps65217-charger",
                .of_match_table = of_match_ptr(tps65217_charger_match_table),
        },

};
module_platform_driver(tps65217_charger_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Enric Balletbo Serra <enric.balletbo@collabora.com>");
MODULE_DESCRIPTION("TPS65217 battery charger driver");