网友说Linux驱动讲不彻底，原来这才是Linux驱动

#define GITCHAT_BASE 0x0001
#define GITCHAT_INTERRUPT 2

int gitchat_send()
{
    writel(GITCHAT_BASE + REG, 1);
    ...
}

int gitchat_init()
{
    request_init(GITCHAT_INTERRUPT, ...);
    ...
}

static struct resource gitchat_resource[] = {
    {
            .start = ...,
            .end = ...,
            .flags = IORESOURCE_MEM
    }...
};

static struct platform_device gitchat_device = {
    .name = "gitchat";
    .id = 0;
    .num_resources = ARRAY_SIZE(gitchat_resource);
    .resource = gitchat_resource,
};

static struct platform_device *ip0x_device __initdata = {
    &gitchat_device,
    ...
};

static ini __init ip0x_init(void)
{
    platform_add_devices(ip0x_device, ARRAY_SIZE(ip0x_device));
}

static int gitchat_probe(struct platform_device *pdev)
{
    ...
    db->addr_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    db->data_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
    db->irq_res  = platform_get_resource(pdev, IORESOURCE_IRQ, 2);
    ...
}

static int platform_match(struct device *dev, struct device_driver *drv)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct platform_driver *pdrv = to_platform_driver(drv);

        /* When driver_override is set, only bind to the matching driver */
        if (pdev->driver_override) 
                return !strcmp(pdev->driver_override, drv->name);

        /* Attempt an OF style match first */
        if (of_driver_match_device(dev, drv))
                return 1;

        /* Then try ACPI style match */
        if (acpi_driver_match_device(dev, drv))
                return 1;

        /* Then try to match against the id table */
        if (pdrv->id_table)
                return platform_match_id(pdrv->id_table, pdev) != NULL;

        /* fall-back to driver name match */
        return (strcmp(pdev->name, drv->name) == 0);
}

static struct resource gitchat_resource[] = {
    {
        .start = 0x20100000 ,
        .end = 0x20100000 +1,
        .flags = IORESOURCE_MEM 
        …
        .start = IRQ_PF IRQ_PF 15 ,
        .end = IRQ_PF IRQ_PF 15 ,
        .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE
    }
};

static struct platform_device gitchat_device = {
    .name name ="gitchat",
    .id = 0,
    .num_resources num_resources = ARRAY_SIZE(gitchat_resource),
    .resource = gitchat_resource,
};

static struct platform_device *ip0x_devices[] __initdata ={
    &gitchat_device,
};

static int __init ip0x_init(void)
{
    platform_add_devices(ip0x_devices, ARRAY_SIZE(ip0x_devices)); 
}

eth:eth@ 4,c00000 {
    compatible ="csdn, gitchat";
    reg =<
        4 0x00c00000 0x2
        4 0x00c00002 0x2
    >;
    interrupt-parent =<&gpio 2>;
    interrupts=<14 IRQ_TYPE_LEVEL_LOW>;
    …
};

struct device_node *of_find_node_by_phandle(phandle handle);
struct device_node *of_get_parent(const struct device_node_ *node);
of_get_child_count()
of_property_read_u32_array()
of_property_read_u64()
of_property_read_string()
of_property_read_string_array()
of_property_read_bool()

/*
 * DTS file for demo platform for Dec20,2017 CSDN/Gitchat course
 *
 * Copyright (c) 2017 xxx <xxx@gmail.com>
 *
 * Licensed under GPLv2.
 */

/ {
    compatible = "csdn,gitchat";
    #address-cells = <1>;
    #size-cells = <1>;
    interrupt-parent = <&intc>;

    aliases {
        serial0 = &uart0;
    };

    cpus {
        #address-cells = <1>;
        #size-cells = <0>;

        cpu@0 {
            compatible = "arm,cortex-a9";
            device_type = "cpu";
            reg = <0x0>;
        };
        cpu@1 {
            compatible = "arm,cortex-a9";
            device_type = "cpu";
            reg = <0x1>;
        };
    };

    axi@40000000 {
        compatible = "simple-bus";
        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0x40000000 0x40000000 0x80000000>;

        l2-cache-controller@80040000 {
            compatible = "arm,pl310-cache";
            reg = <0x80040000 0x1000>;
            interrupts = <59>;
            arm,tag-latency = <1 1 1>;
            arm,data-latency = <1 1 1>;
            arm,filter-ranges = <0 0x40000000>;
        };

        intc: interrupt-controller@80020000 {
            #interrupt-cells = <1>;
            interrupt-controller;
            compatible = "csdn,gitchat";
            reg = <0x80020000 0x1000>;
        };

        peri-iobg@b0000000 {
            compatible = "simple-bus";
            #address-cells = <1>;
            #size-cells = <1>;
            ranges = <0x0 0xb0000000 0x180000>;

            ethernet@10000 {
                compatible = "davicom,dm9000";
                reg = <0x10000 0x2 0x10004 0x2>;
                interrupts = <7>;
                davicom,no-eeprom;
            };

            timer@20000 {
                compatible = "csdn,gitchat-tick";
                reg = <0x20000 0x1000>;
                interrupts = <0>;
                clocks = <&clks 11>;
            };

            clks: clock-controller@30000 {
                compatible = "csdn,gitchat-clkc";
                reg = <0x30000 0x1000>;
                #clock-cells = <1>;
            };

            gpio0: goio@40000 {
                #gpio-cells = <2>;
                #interrupt-cells = <2>;
                compatible = "csdn,gitchat-gpio";
                reg = <0x40000 0x200>;
                interrupts = <43>;
                gpio-controller;
                interrupt-controller;
            };

            uart0: uart@50000 {
                cell-index = <0>;
                compatible = "csdn,gitchat-uart";
                reg = <0x50000 0x1000>;
                interrupts = <17>;
                status = "disabled";
            };

            spi0: spi@d0000 {
                cell-index = <0>;
                compatible = "csdn,gitchat-spi";
                reg = <0xd0000 0x10000>;
                interrupts = <15>;
                #address-cells = <1>;
                #size-cells = <0>;
                status = "okay";
            };

            i2c0: i2c@e0000 {
                cell-index = <0>;
                compatible = "csdn,gitchat-i2c";
                reg = <0xe0000 0x10000>;
                interrupts = <24>;
                #address-cells = <1>;
                #size-cells = <0>;
                status = "okay";
            };
        };
    };
};
/dts-v1/;

/include/ "csdn-gitchat.dtsi"

/ {
    model = "Csdn Gitchat EVB Board";
    compatible = "csdn,gitchat-evb", "csdn,gitchat";

    memory {
        device_type = "memory";
        reg = <0x00000000 0x20000000>;
    };

    chosen {
        bootargs = "console=ttyS0,115200 root=/dev/mtdblock5 rw rootfstype=ubifs";
    };

    axi@40000000 {
        peri-iobg@b0000000 {
            spi@d0000 {
                status = "disabled";
            };
            i2c@e0000 {
                pixcir_ts@5c {
                    compatible = "pixcir,pixcir_tangoc";
                    reg = <0x5c>;
                    interrupt-parent = <&gpio0>;
                    interrupts = <17 0>;
                    attb-gpio = <&gpio0 22 0>;
                    touchscreen-size-x = <1024>;
                    touchscreen-size-y = <600>;
                };
            };
        };
    };

};

&uart0 {
    status = "okay";
};