#include <linux/module.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/gpio/driver.h>
#include <linux/slab.h>
#include <linux/regmap.h>

static struct gpio_chip *g_gpio_virtual;
static int g_gpio_val = 0;

static int gpio_virtual_direction_output(struct gpio_chip *gc, unsigned offset, int val)
{
    printk("set pin %d as output %s\r\n", offset, val ? "high" : "low");
    return 0;
}

static int gpio_virtual_direction_input(struct gpio_chip *gc, unsigned offset)
{
    printk("set pin %d as input\r\n", offset);
    return 0;
}

static int gpio_virtual_get_value(struct gpio_chip *gc, unsigned offset)
{
    int val = (g_gpio_val & (1 << offset)) ? 1 : 0;
    printk("get pin %d value %d\r\n", offset, val);
    return val;
}

static void gpio_virtual_set_value(struct gpio_chip *gc, unsigned offset, int val)
{
    if (val) {
        g_gpio_val |= (1 << offset);
    } else {
        g_gpio_val &= ~(1 << offset);
    }
    printk("set pin %d value %d\r\n", offset, val);
}

static int gpio_virtual_probe(struct platform_device *pdev)
{
    int ret;
    uint32_t val;

    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
    g_gpio_virtual = devm_kzalloc(&pdev->dev, sizeof(*g_gpio_virtual), GFP_KERNEL);

    g_gpio_virtual->label = pdev->name;
    g_gpio_virtual->direction_output = gpio_virtual_direction_output;
    g_gpio_virtual->direction_input = gpio_virtual_direction_input;
    g_gpio_virtual->get = gpio_virtual_get_value;
    g_gpio_virtual->set = gpio_virtual_set_value;

    g_gpio_virtual->parent = &pdev->dev;
    g_gpio_virtual->owner = THIS_MODULE;

    g_gpio_virtual->base = -1;
    ret = of_property_read_u32(pdev->dev.of_node, "ngpios", &val);
    g_gpio_virtual->ngpio = val;

    ret = devm_gpiochip_add_data(&pdev->dev, g_gpio_virtual, NULL);
    return 0;
}

static int gpio_virtual_remove(struct platform_device *pdev)
{
    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
    return 0;
}

static const struct of_device_id gpio_virtual_of_match[] = {
    { .compatible = "jzh,gpio-virtual", },
    {  },
};

static struct platform_driver gpio_virtual_driver = {
    .probe = gpio_virtual_probe,
    .remove = gpio_virtual_remove,
    .driver = {
        .name = "gpio-virtual",
        .of_match_table = of_match_ptr(gpio_virtual_of_match),
    },
};

static int __init gpio_virtual_init(void)
{
    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
    return platform_driver_register(&gpio_virtual_driver);
}

static void __exit gpio_virtual_exit(void)
{
    printk("%s %s %d\r\n", __FILE__, __FUNCTION__, __LINE__);
    platform_driver_unregister(&gpio_virtual_driver);
}

module_init(gpio_virtual_init);
module_exit(gpio_virtual_exit);
MODULE_DESCRIPTION("Virtual GPIO Driver");
MODULE_AUTHOR("jzhgonha@163.com");
MODULE_LICENSE("GPL");