174 struct platform_driver {
175 int (*probe)(struct platform_device *);
176 int (*remove)(struct platform_device *);
177 void (*shutdown)(struct platform_device *);
178 int (*suspend)(struct platform_device *, pm_message_t state);
179 int (*resume)(struct platform_device *);
180 struct device_driver driver;
181 const struct platform_device_id *id_table;
182 bool prevent_deferred_probe;
183 };
259 struct device_driver {
260 const char *name;
261 struct bus_type *bus;
262
263 struct module *owner;
264 const char *mod_name; /* used for built-in modules */
265
266 bool suppress_bind_attrs; /* disables bind/unbind via sysfs */
267 enum probe_type probe_type;
268
269 const struct of_device_id *of_match_table; //device tree通过这个去匹配
270 const struct acpi_device_id *acpi_match_table;
271
272 int (*probe) (struct device *dev);
273 int (*remove) (struct device *dev);
274 void (*shutdown) (struct device *dev);
275 int (*suspend) (struct device *dev, pm_message_t state);
276 int (*resume) (struct device *dev);
277 const struct attribute_group **groups;
278
279 const struct dev_pm_ops *pm;
280
281 struct driver_private *p;
282 };
22 struct platform_device {
23 const char *name;
24 int id;
25 bool id_auto;
26 struct device dev;
27 u32 num_resources;
28 struct resource *resource;
29
30 const struct platform_device_id *id_entry;
31 char *driver_override; /* Driver name to force a match */
32
33 /* MFD cell pointer */
34 struct mfd_cell *mfd_cell;
35
36 /* arch specific additions */
37 struct pdev_archdata archdata;
38 };
以上是头文件的结构体定义
129 static const struct of_device_id dw_spi_mmio_of_match[] = {
130 { .compatible = "snps,dw-apb-ssi", },
131 { /* end of table */}
132 };
133 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
134
135 static struct platform_driver dw_spi_mmio_driver = {
136 .probe = dw_spi_mmio_probe,
137 .remove = dw_spi_mmio_remove,
138 .driver = {
139 .name = DRIVER_NAME,
140 .of_match_table = dw_spi_mmio_of_match,
141 },
142 };
143 module_platform_driver(dw_spi_mmio_driver);
144
145 MODULE_AUTHOR("Jean-Hugues Deschenes <[email protected]>");
146 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
147 MODULE_LICENSE("GPL v2");
以前的写法 ：
struct platform_device s3c_device_usb = {
.name = "s3c2410-ohci", //s3c6410-usb
.id = -1,
.num_resources = ARRAY_SIZE(s3c_usb_resource),
.resource = s3c_usb_resource,
.dev = {
.dma_mask = &s3c_device_usb_dmamask,
.coherent_dma_mask = 0xffffffffUL
}
};
有了platform_device就可以调用函数platform_add_devices向系统中添加该设备了。系统中的设备资源都可以采用这种方式列举在一起，然后成一个指针数组，如：
static struct platform_device *smdk6410_devices[] __initdata = {
......
&s3c_device_usbgadget,
&s3c_device_usb, //jeff add.
......
}
static struct platform_driver ohci_hcd_s3c2410_driver = {
.probe = ohci_hcd_s3c2410_drv_probe,
.remove = ohci_hcd_s3c2410_drv_remove,
.shutdown = usb_hcd_platform_shutdown,
/*.suspend = ohci_hcd_s3c2410_drv_suspend, */
/*.resume = ohci_hcd_s3c2410_drv_resume, */
.driver = {
.owner = THIS_MODULE,
.name = "s3c2410-ohci",
},
};
（1）在内核初始化时kernel_init()->do_basic_setup()->driver_init()->platform_bus_init()初始化platform_bus(虚拟总线)；
（2）设备注册的时候platform_device_register()->platform_device_add()->(pdev->dev.bus = &platform_bus_type)把设备挂在虚拟的platform bus下；
（3）驱动注册的时候platform_driver_register()->driver_register()->bus_add_driver()->driver_attach()->bus_for_each_dev()，对每个挂在虚拟的 platform bus的设备作__driver_attach()->driver_probe_device()，判断drv->bus->match()是否存在并且是否执行成功，此时通过指针执行platform_match， 比较strncmp(pdev->name, drv->name, BUS_ID_SIZE)，如果相符就调用really_probe（实际就是执行的相应设备的platform_driver->probe(platform_device)， 注意platform_drv_probe的_dev参数是由bus_for_each_dev的next_device获得）开始真正的探测加载，如果probe成功则绑定该设备到该驱动。
当进入probe函数后，需要获取设备的资源信息，根据参数type所指定类型，例如IORESOURCE_MEM，来分别获取指定的资源。
struct resource * platform_get_resource(struct platform_device *dev, unsigned int type, unsigned int num);当然，也可以固定资源类型，如获取资源中的中断号：struct int platform_get_irq(struct platform_device *dev, unsigned int num);
probe函数一般完成硬件设备使能，struct resource的获取以及虚拟地址的动态映射和具体类型设备的注册（因为平台设备只是一种虚拟的设备类型);remove函数完成硬件设备的关闭，struct resource以及虚拟地址的动态映射的释放和具体类型设备的注销。只要和内核本身运行依赖性不大的外围设备 ( 换句话说只要不在内核运行所需的一个最小系统之内的设备 ), 相对独立的拥有各自独自的资源 (addresses and IRQs) ，都可以用platform_driver 实现。如：lcd,usb,uart 等，都可以用platfrom_driver 写，而timer,irq等最小系统之内的设备则最好不用platfrom_driver 机制，实际上内核实现也是这样的。
http://blog.csdn.net/zhandoushi1982/article/details/5130207
http://blog.csdn.net/lichengtongxiazai/article/details/38941997 ＤＴ书写规范
http://www.right.com.cn/forum/thread-146260-1-1.html ＤＴ（２）
时间： 2024-08-03 04:31:03