diff options
| -rw-r--r-- | Documentation/sparc/sbus_drivers.txt | 95 |
1 files changed, 65 insertions, 30 deletions
diff --git a/Documentation/sparc/sbus_drivers.txt b/Documentation/sparc/sbus_drivers.txt index 876195dc2aef..4b9351624f13 100644 --- a/Documentation/sparc/sbus_drivers.txt +++ b/Documentation/sparc/sbus_drivers.txt @@ -25,42 +25,84 @@ the bits necessary to run your device. The most commonly used members of this structure, and their typical usage, will be detailed below. - Here is how probing is performed by an SBUS driver -under Linux: + Here is a piece of skeleton code for perofming a device +probe in an SBUS driverunder Linux: - static void init_one_mydevice(struct sbus_dev *sdev) + static int __devinit mydevice_probe_one(struct sbus_dev *sdev) { + struct mysdevice *mp = kzalloc(sizeof(*mp), GFP_KERNEL); + + if (!mp) + return -ENODEV; + + ... + dev_set_drvdata(&sdev->ofdev.dev, mp); + return 0; ... } - static int mydevice_match(struct sbus_dev *sdev) + static int __devinit mydevice_probe(struct of_device *dev, + const struct of_device_id *match) { - if (some_criteria(sdev)) - return 1; - return 0; + struct sbus_dev *sdev = to_sbus_device(&dev->dev); + + return mydevice_probe_one(sdev); } - static void mydevice_probe(void) + static int __devexit mydevice_remove(struct of_device *dev) { - struct sbus_bus *sbus; - struct sbus_dev *sdev; + struct sbus_dev *sdev = to_sbus_device(&dev->dev); + struct mydevice *mp = dev_get_drvdata(&dev->dev); - for_each_sbus(sbus) { - for_each_sbusdev(sdev, sbus) { - if (mydevice_match(sdev)) - init_one_mydevice(sdev); - } - } + return mydevice_remove_one(sdev, mp); } - All this does is walk through all SBUS devices in the -system, checks each to see if it is of the type which -your driver is written for, and if so it calls the init -routine to attach the device and prepare to drive it. + static struct of_device_id mydevice_match[] = { + { + .name = "mydevice", + }, + {}, + }; + + MODULE_DEVICE_TABLE(of, mydevice_match); - "init_one_mydevice" might do things like allocate software -state structures, map in I/O registers, place the hardware -into an initialized state, etc. + static struct of_platform_driver mydevice_driver = { + .name = "mydevice", + .match_table = mydevice_match, + .probe = mydevice_probe, + .remove = __devexit_p(mydevice_remove), + }; + + static int __init mydevice_init(void) + { + return of_register_driver(&mydevice_driver, &sbus_bus_type); + } + + static void __exit mydevice_exit(void) + { + of_unregister_driver(&mydevice_driver); + } + + module_init(mydevice_init); + module_exit(mydevice_exit); + + The mydevice_match table is a series of entries which +describes what SBUS devices your driver is meant for. In the +simplest case you specify a string for the 'name' field. Every +SBUS device with a 'name' property matching your string will +be passed one-by-one to your .probe method. + + You should store away your device private state structure +pointer in the drvdata area so that you can retrieve it later on +in your .remove method. + + Any memory allocated, registers mapped, IRQs registered, +etc. must be undone by your .remove method so that all resources +of your device are relased by the time it returns. + + You should _NOT_ use the for_each_sbus(), for_each_sbusdev(), +and for_all_sbusdev() interfaces. They are deprecated, will be +removed, and no new driver should reference them ever. Mapping and Accessing I/O Registers @@ -263,10 +305,3 @@ discussed above and plus it handles both PCI and SBUS boards. Lance driver abuses consistent mappings for data transfer. It is a nifty trick which we do not particularly recommend... Just check it out and know that it's legal. - - Bad examples, do NOT use - - drivers/video/cgsix.c - This one uses result of sbus_ioremap as if it is an address. -This does NOT work on sparc64 and therefore is broken. We will -convert it at a later date. |