// SPDX-License-Identifier: GPL-2.0+
/*
 *  Driver for Analog Devices (Linear Technology) LT3651 charger IC.
 *  Copyright (C) 2017, Topic Embedded Products
 */

#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/of.h>

struct lt3651_charger {
        struct power_supply *charger;
        struct power_supply_desc charger_desc;
        struct gpio_desc *acpr_gpio;
        struct gpio_desc *fault_gpio;
        struct gpio_desc *chrg_gpio;
};

static irqreturn_t lt3651_charger_irq(int irq, void *devid)
{
        struct power_supply *charger = devid;

        power_supply_changed(charger);

        return IRQ_HANDLED;
}

static inline struct lt3651_charger *psy_to_lt3651_charger(
        struct power_supply *psy)
{
        return power_supply_get_drvdata(psy);
}

static int lt3651_charger_get_property(struct power_supply *psy,
                enum power_supply_property psp, union power_supply_propval *val)
{
        struct lt3651_charger *lt3651_charger = psy_to_lt3651_charger(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                if (!lt3651_charger->chrg_gpio) {
                        val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
                        break;
                }
                if (gpiod_get_value(lt3651_charger->chrg_gpio))
                        val->intval = POWER_SUPPLY_STATUS_CHARGING;
                else
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                break;
        case POWER_SUPPLY_PROP_ONLINE:
                val->intval = gpiod_get_value(lt3651_charger->acpr_gpio);
                break;
        case POWER_SUPPLY_PROP_HEALTH:
                if (!lt3651_charger->fault_gpio) {
                        val->intval = POWER_SUPPLY_HEALTH_UNKNOWN;
                        break;
                }
                if (!gpiod_get_value(lt3651_charger->fault_gpio)) {
                        val->intval = POWER_SUPPLY_HEALTH_GOOD;
                        break;
                }
                /*
                 * If the fault pin is active, the chrg pin explains the type
                 * of failure.
                 */
                if (!lt3651_charger->chrg_gpio) {
                        val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
                        break;
                }
                val->intval = gpiod_get_value(lt3651_charger->chrg_gpio) ?
                                POWER_SUPPLY_HEALTH_OVERHEAT :
                                POWER_SUPPLY_HEALTH_DEAD;
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static enum power_supply_property lt3651_charger_properties[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_HEALTH,
};

static int lt3651_charger_probe(struct platform_device *pdev)
{
        struct power_supply_config psy_cfg = {};
        struct lt3651_charger *lt3651_charger;
        struct power_supply_desc *charger_desc;
        int ret;

        lt3651_charger = devm_kzalloc(&pdev->dev, sizeof(*lt3651_charger),
                                        GFP_KERNEL);
        if (!lt3651_charger)
                return -ENOMEM;

        lt3651_charger->acpr_gpio = devm_gpiod_get(&pdev->dev,
                                        "lltc,acpr", GPIOD_IN);
        if (IS_ERR(lt3651_charger->acpr_gpio)) {
                ret = PTR_ERR(lt3651_charger->acpr_gpio);
                dev_err(&pdev->dev, "Failed to acquire acpr GPIO: %d\n", ret);
                return ret;
        }
        lt3651_charger->fault_gpio = devm_gpiod_get_optional(&pdev->dev,
                                        "lltc,fault", GPIOD_IN);
        if (IS_ERR(lt3651_charger->fault_gpio)) {
                ret = PTR_ERR(lt3651_charger->fault_gpio);
                dev_err(&pdev->dev, "Failed to acquire fault GPIO: %d\n", ret);
                return ret;
        }
        lt3651_charger->chrg_gpio = devm_gpiod_get_optional(&pdev->dev,
                                        "lltc,chrg", GPIOD_IN);
        if (IS_ERR(lt3651_charger->chrg_gpio)) {
                ret = PTR_ERR(lt3651_charger->chrg_gpio);
                dev_err(&pdev->dev, "Failed to acquire chrg GPIO: %d\n", ret);
                return ret;
        }

        charger_desc = &lt3651_charger->charger_desc;
        charger_desc->name = pdev->dev.of_node->name;
        charger_desc->type = POWER_SUPPLY_TYPE_MAINS;
        charger_desc->properties = lt3651_charger_properties;
        charger_desc->num_properties = ARRAY_SIZE(lt3651_charger_properties);
        charger_desc->get_property = lt3651_charger_get_property;
        psy_cfg.fwnode = dev_fwnode(&pdev->dev);
        psy_cfg.drv_data = lt3651_charger;

        lt3651_charger->charger = devm_power_supply_register(&pdev->dev,
                                                      charger_desc, &psy_cfg);
        if (IS_ERR(lt3651_charger->charger)) {
                ret = PTR_ERR(lt3651_charger->charger);
                dev_err(&pdev->dev, "Failed to register power supply: %d\n",
                        ret);
                return ret;
        }

        /*
         * Acquire IRQs for the GPIO pins if possible. If the system does not
         * support IRQs on these pins, userspace will have to poll the sysfs
         * files manually.
         */
        if (lt3651_charger->acpr_gpio) {
                ret = gpiod_to_irq(lt3651_charger->acpr_gpio);
                if (ret >= 0)
                        ret = devm_request_any_context_irq(&pdev->dev, ret,
                                lt3651_charger_irq,
                                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                                dev_name(&pdev->dev), lt3651_charger->charger);
                if (ret < 0)
                        dev_warn(&pdev->dev, "Failed to request acpr irq\n");
        }
        if (lt3651_charger->fault_gpio) {
                ret = gpiod_to_irq(lt3651_charger->fault_gpio);
                if (ret >= 0)
                        ret = devm_request_any_context_irq(&pdev->dev, ret,
                                lt3651_charger_irq,
                                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                                dev_name(&pdev->dev), lt3651_charger->charger);
                if (ret < 0)
                        dev_warn(&pdev->dev, "Failed to request fault irq\n");
        }
        if (lt3651_charger->chrg_gpio) {
                ret = gpiod_to_irq(lt3651_charger->chrg_gpio);
                if (ret >= 0)
                        ret = devm_request_any_context_irq(&pdev->dev, ret,
                                lt3651_charger_irq,
                                IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
                                dev_name(&pdev->dev), lt3651_charger->charger);
                if (ret < 0)
                        dev_warn(&pdev->dev, "Failed to request chrg irq\n");
        }

        platform_set_drvdata(pdev, lt3651_charger);

        return 0;
}

static const struct of_device_id lt3651_charger_match[] = {
        { .compatible = "lltc,ltc3651-charger" }, /* DEPRECATED */
        { .compatible = "lltc,lt3651-charger" },
        { }
};
MODULE_DEVICE_TABLE(of, lt3651_charger_match);

static struct platform_driver lt3651_charger_driver = {
        .probe = lt3651_charger_probe,
        .driver = {
                .name = "lt3651-charger",
                .of_match_table = lt3651_charger_match,
        },
};

module_platform_driver(lt3651_charger_driver);

MODULE_AUTHOR("Mike Looijmans <mike.looijmans@topic.nl>");
MODULE_DESCRIPTION("Driver for LT3651 charger");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:lt3651-charger");