2010/11/17 Dave Hylands <[email protected]>:
> Hi lalith,
>
> On Tue, Nov 16, 2010 at 12:19 AM, laliteshwar yadav <[email protected]>
> wrote:
>> how probe function works?
>>
>> how is it getting called?
>>
>> after registering the device driver who is the first function to call it..
>
> There are 2 things required for the probe function to be called: a
> device and a driver.
>
> Normally, the architecture portion of the kernel registers devices for
> all of the device that it has.
> Then when you register a driver, it will detect if a device with a
> matching name has been registered. If it finds a match, it will call
> the probe routine.
>
> I normally work with linux in an embedded environment (ARM and MIPS),
> not programming for linux under x86, so its possible that things
> happen a little differently in that environment.
>
Dave gave the good explanation.
In linux world, codes show everything.
codes:
/* Structure for a device driver */
static struct platform_driver gfar_driver = {
.probe = gfar_probe,
.remove = gfar_remove,
.driver = {
.name = "fsl-gianfar",
},
};
1987 static int __init gfar_init(void)
1988 {
1989 int err = gfar_mdio_init();
1990
1991 if (err)
1992 return err;
1993
1994 err = platform_driver_register(&gfar_driver);
1995
1996 if (err)
1997 gfar_mdio_exit();
1998
1999 return err;
2000 }
443 int platform_driver_register(struct platform_driver *drv)
444 {
445 drv->driver.bus = &platform_bus_type;
446 if (drv->probe)
447 drv->driver.probe = platform_drv_probe;
448 if (drv->remove)
449 drv->driver.remove = platform_drv_remove;
450 if (drv->shutdown)
451 drv->driver.shutdown = platform_drv_shutdown;
452 if (drv->suspend)
453 drv->driver.suspend = platform_drv_suspend;
454 if (drv->resume)
455 drv->driver.resume = platform_drv_resume;
456 return driver_register(&drv->driver);
457 }
217 int driver_register(struct device_driver *drv)
218 {
219 int ret;
220
221 if ((drv->bus->probe && drv->probe) ||
222 (drv->bus->remove && drv->remove) ||
223 (drv->bus->shutdown && drv->shutdown))
224 printk(KERN_WARNING "Driver '%s' needs updating -
please use "
225 "bus_type methods\n", drv->name);
226 ret = bus_add_driver(drv);
227 if (ret)
228 return ret;
229 ret = driver_add_groups(drv, drv->groups);
230 if (ret)
231 bus_remove_driver(drv);
232 return ret;
233 }
> --
> Dave Hylands
> Shuswap, BC, Canada
> http://www.DaveHylands.com/
>
> --
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>
--
Best Regards
Lin
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