diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/driver-model/device.txt | 8 | ||||
| -rw-r--r-- | Documentation/driver-model/driver.txt | 51 |
2 files changed, 33 insertions, 26 deletions
diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt index 58cc5dc..a05ec50 100644 --- a/Documentation/driver-model/device.txt +++ b/Documentation/driver-model/device.txt @@ -76,6 +76,14 @@ driver_data: Driver-specific data. platform_data: Platform data specific to the device. + Example: for devices on custom boards, as typical of embedded + and SOC based hardware, Linux often uses platform_data to point + to board-specific structures describing devices and how they + are wired. That can include what ports are available, chip + variants, which GPIO pins act in what additional roles, and so + on. This shrinks the "Board Support Packages" (BSPs) and + minimizes board-specific #ifdefs in drivers. + current_state: Current power state of the device. saved_state: Pointer to saved state of the device. This is usable by diff --git a/Documentation/driver-model/driver.txt b/Documentation/driver-model/driver.txt index 6031a68..fabaca1 100644 --- a/Documentation/driver-model/driver.txt +++ b/Documentation/driver-model/driver.txt @@ -5,21 +5,17 @@ struct device_driver { char * name; struct bus_type * bus; - rwlock_t lock; - atomic_t refcount; - - list_t bus_list; + struct completion unloaded; + struct kobject kobj; list_t devices; - struct driver_dir_entry dir; + struct module *owner; int (*probe) (struct device * dev); int (*remove) (struct device * dev); int (*suspend) (struct device * dev, pm_message_t state, u32 level); int (*resume) (struct device * dev, u32 level); - - void (*release) (struct device_driver * drv); }; @@ -51,7 +47,6 @@ being converted completely to the new model. static struct device_driver eepro100_driver = { .name = "eepro100", .bus = &pci_bus_type, - .devclass = ðernet_devclass, /* when it's implemented */ .probe = eepro100_probe, .remove = eepro100_remove, @@ -85,7 +80,6 @@ static struct pci_driver eepro100_driver = { .driver = { .name = "eepro100", .bus = &pci_bus_type, - .devclass = ðernet_devclass, /* when it's implemented */ .probe = eepro100_probe, .remove = eepro100_remove, .suspend = eepro100_suspend, @@ -166,27 +160,32 @@ Callbacks int (*probe) (struct device * dev); -probe is called to verify the existence of a certain type of -hardware. This is called during the driver binding process, after the -bus has verified that the device ID of a device matches one of the -device IDs supported by the driver. - -This callback only verifies that there actually is supported hardware -present. It may allocate a driver-specific structure, but it should -not do any initialization of the hardware itself. The device-specific -structure may be stored in the device's driver_data field. - - int (*init) (struct device * dev); - -init is called during the binding stage. It is called after probe has -successfully returned and the device has been registered with its -class. It is responsible for initializing the hardware. +The probe() entry is called in task context, with the bus's rwsem locked +and the driver partially bound to the device. Drivers commonly use +container_of() to convert "dev" to a bus-specific type, both in probe() +and other routines. That type often provides device resource data, such +as pci_dev.resource[] or platform_device.resources, which is used in +addition to dev->platform_data to initialize the driver. + +This callback holds the driver-specific logic to bind the driver to a +given device. That includes verifying that the device is present, that +it's a version the driver can handle, that driver data structures can +be allocated and initialized, and that any hardware can be initialized. +Drivers often store a pointer to their state with dev_set_drvdata(). +When the driver has successfully bound itself to that device, then probe() +returns zero and the driver model code will finish its part of binding +the driver to that device. + +A driver's probe() may return a negative errno value to indicate that +the driver did not bind to this device, in which case it should have +released all reasources it allocated. int (*remove) (struct device * dev); -remove is called to dissociate a driver with a device. This may be +remove is called to unbind a driver from a device. This may be called if a device is physically removed from the system, if the -driver module is being unloaded, or during a reboot sequence. +driver module is being unloaded, during a reboot sequence, or +in other cases. It is up to the driver to determine if the device is present or not. It should free any resources allocated specifically for the |