// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2012, Code Aurora Forum. All rights reserved.
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/gpio/consumer.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pm_qos.h>
#include <linux/irq.h>
#include <media/rc-core.h>

#define GPIO_IR_DEVICE_NAME     "gpio_ir_recv"

struct gpio_rc_dev {
        struct rc_dev *rcdev;
        struct gpio_desc *gpiod;
        int irq;
        struct device *pmdev;
        struct pm_qos_request qos;
};

static irqreturn_t gpio_ir_recv_irq(int irq, void *dev_id)
{
        int val;
        struct gpio_rc_dev *gpio_dev = dev_id;
        struct device *pmdev = gpio_dev->pmdev;

        /*
         * For some cpuidle systems, not all:
         * Respond to interrupt taking more latency when cpu in idle.
         * Invoke asynchronous pm runtime get from interrupt context,
         * this may introduce a millisecond delay to call resume callback,
         * where to disable cpuilde.
         *
         * Two issues lead to fail to decode first frame, one is latency to
         * respond to interrupt, another is delay introduced by async api.
         */
        if (pmdev)
                pm_runtime_get(pmdev);

        val = gpiod_get_value(gpio_dev->gpiod);
        if (val >= 0)
                ir_raw_event_store_edge(gpio_dev->rcdev, val == 1);

        if (pmdev) {
                pm_runtime_mark_last_busy(pmdev);
                pm_runtime_put_autosuspend(pmdev);
        }

        return IRQ_HANDLED;
}

static int gpio_ir_recv_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        struct gpio_rc_dev *gpio_dev;
        struct rc_dev *rcdev;
        u32 period = 0;
        int rc;

        if (!np)
                return -ENODEV;

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

        gpio_dev->gpiod = devm_gpiod_get(dev, NULL, GPIOD_IN);
        if (IS_ERR(gpio_dev->gpiod)) {
                rc = PTR_ERR(gpio_dev->gpiod);
                /* Just try again if this happens */
                if (rc != -EPROBE_DEFER)
                        dev_err(dev, "error getting gpio (%d)\n", rc);
                return rc;
        }
        gpio_dev->irq = gpiod_to_irq(gpio_dev->gpiod);
        if (gpio_dev->irq < 0)
                return gpio_dev->irq;

        rcdev = devm_rc_allocate_device(dev, RC_DRIVER_IR_RAW);
        if (!rcdev)
                return -ENOMEM;

        rcdev->priv = gpio_dev;
        rcdev->device_name = GPIO_IR_DEVICE_NAME;
        rcdev->input_phys = GPIO_IR_DEVICE_NAME "/input0";
        rcdev->input_id.bustype = BUS_HOST;
        rcdev->input_id.vendor = 0x0001;
        rcdev->input_id.product = 0x0001;
        rcdev->input_id.version = 0x0100;
        rcdev->dev.parent = dev;
        rcdev->driver_name = KBUILD_MODNAME;
        rcdev->min_timeout = 1;
        rcdev->timeout = IR_DEFAULT_TIMEOUT;
        rcdev->max_timeout = 10 * IR_DEFAULT_TIMEOUT;
        rcdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
        rcdev->map_name = of_get_property(np, "linux,rc-map-name", NULL);
        if (!rcdev->map_name)
                rcdev->map_name = RC_MAP_EMPTY;

        gpio_dev->rcdev = rcdev;

        rc = devm_rc_register_device(dev, rcdev);
        if (rc < 0) {
                dev_err(dev, "failed to register rc device (%d)\n", rc);
                return rc;
        }

        of_property_read_u32(np, "linux,autosuspend-period", &period);
        if (period) {
                gpio_dev->pmdev = dev;
                pm_runtime_set_autosuspend_delay(dev, period);
                pm_runtime_use_autosuspend(dev);
                pm_runtime_set_suspended(dev);
                pm_runtime_enable(dev);
        }

        platform_set_drvdata(pdev, gpio_dev);

        return devm_request_irq(dev, gpio_dev->irq, gpio_ir_recv_irq,
                                IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
                                "gpio-ir-recv-irq", gpio_dev);
}

#ifdef CONFIG_PM
static int gpio_ir_recv_suspend(struct device *dev)
{
        struct gpio_rc_dev *gpio_dev = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                enable_irq_wake(gpio_dev->irq);
        else
                disable_irq(gpio_dev->irq);

        return 0;
}

static int gpio_ir_recv_resume(struct device *dev)
{
        struct gpio_rc_dev *gpio_dev = dev_get_drvdata(dev);

        if (device_may_wakeup(dev))
                disable_irq_wake(gpio_dev->irq);
        else
                enable_irq(gpio_dev->irq);

        return 0;
}

static int gpio_ir_recv_runtime_suspend(struct device *dev)
{
        struct gpio_rc_dev *gpio_dev = dev_get_drvdata(dev);

        cpu_latency_qos_remove_request(&gpio_dev->qos);

        return 0;
}

static int gpio_ir_recv_runtime_resume(struct device *dev)
{
        struct gpio_rc_dev *gpio_dev = dev_get_drvdata(dev);

        cpu_latency_qos_add_request(&gpio_dev->qos, 0);

        return 0;
}

static const struct dev_pm_ops gpio_ir_recv_pm_ops = {
        .suspend        = gpio_ir_recv_suspend,
        .resume         = gpio_ir_recv_resume,
        .runtime_suspend = gpio_ir_recv_runtime_suspend,
        .runtime_resume  = gpio_ir_recv_runtime_resume,
};
#endif

static const struct of_device_id gpio_ir_recv_of_match[] = {
        { .compatible = "gpio-ir-receiver", },
        { },
};
MODULE_DEVICE_TABLE(of, gpio_ir_recv_of_match);

static struct platform_driver gpio_ir_recv_driver = {
        .probe  = gpio_ir_recv_probe,
        .driver = {
                .name   = KBUILD_MODNAME,
                .of_match_table = of_match_ptr(gpio_ir_recv_of_match),
#ifdef CONFIG_PM
                .pm     = &gpio_ir_recv_pm_ops,
#endif
        },
};
module_platform_driver(gpio_ir_recv_driver);

MODULE_DESCRIPTION("GPIO IR Receiver driver");
MODULE_LICENSE("GPL v2");