diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/driver-model/platform.txt | 40 | ||||
| -rw-r--r-- | Documentation/firmware_class/README | 2 | ||||
| -rw-r--r-- | Documentation/firmware_class/firmware_sample_driver.c | 2 | ||||
| -rw-r--r-- | Documentation/firmware_class/firmware_sample_firmware_class.c | 4 |
4 files changed, 44 insertions, 4 deletions
diff --git a/Documentation/driver-model/platform.txt b/Documentation/driver-model/platform.txt index 19c4a6e1367..2a97320ee17 100644 --- a/Documentation/driver-model/platform.txt +++ b/Documentation/driver-model/platform.txt @@ -96,6 +96,46 @@ System setup also associates those clocks with the device, so that that calls to clk_get(&pdev->dev, clock_name) return them as needed. +Legacy Drivers: Device Probing +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Some drivers are not fully converted to the driver model, because they take +on a non-driver role: the driver registers its platform device, rather than +leaving that for system infrastructure. Such drivers can't be hotplugged +or coldplugged, since those mechanisms require device creation to be in a +different system component than the driver. + +The only "good" reason for this is to handle older system designs which, like +original IBM PCs, rely on error-prone "probe-the-hardware" models for hardware +configuration. Newer systems have largely abandoned that model, in favor of +bus-level support for dynamic configuration (PCI, USB), or device tables +provided by the boot firmware (e.g. PNPACPI on x86). There are too many +conflicting options about what might be where, and even educated guesses by +an operating system will be wrong often enough to make trouble. + +This style of driver is discouraged. If you're updating such a driver, +please try to move the device enumeration to a more appropriate location, +outside the driver. This will usually be cleanup, since such drivers +tend to already have "normal" modes, such as ones using device nodes that +were created by PNP or by platform device setup. + +None the less, there are some APIs to support such legacy drivers. Avoid +using these calls except with such hotplug-deficient drivers. + + struct platform_device *platform_device_alloc( + char *name, unsigned id); + +You can use platform_device_alloc() to dynamically allocate a device, which +you will then initialize with resources and platform_device_register(). +A better solution is usually: + + struct platform_device *platform_device_register_simple( + char *name, unsigned id, + struct resource *res, unsigned nres); + +You can use platform_device_register_simple() as a one-step call to allocate +and register a device. + + Device Naming and Driver Binding ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The platform_device.dev.bus_id is the canonical name for the devices. diff --git a/Documentation/firmware_class/README b/Documentation/firmware_class/README index e9cc8bb26f7..c3480aa66ba 100644 --- a/Documentation/firmware_class/README +++ b/Documentation/firmware_class/README @@ -1,7 +1,7 @@ request_firmware() hotplug interface: ------------------------------------ - Copyright (C) 2003 Manuel Estrada Sainz <ranty@debian.org> + Copyright (C) 2003 Manuel Estrada Sainz Why: --- diff --git a/Documentation/firmware_class/firmware_sample_driver.c b/Documentation/firmware_class/firmware_sample_driver.c index 87feccdb5c9..6865cbe075e 100644 --- a/Documentation/firmware_class/firmware_sample_driver.c +++ b/Documentation/firmware_class/firmware_sample_driver.c @@ -1,7 +1,7 @@ /* * firmware_sample_driver.c - * - * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org> + * Copyright (c) 2003 Manuel Estrada Sainz * * Sample code on how to use request_firmware() from drivers. * diff --git a/Documentation/firmware_class/firmware_sample_firmware_class.c b/Documentation/firmware_class/firmware_sample_firmware_class.c index 9e1b0e4051c..4994f1f28f8 100644 --- a/Documentation/firmware_class/firmware_sample_firmware_class.c +++ b/Documentation/firmware_class/firmware_sample_firmware_class.c @@ -1,7 +1,7 @@ /* * firmware_sample_firmware_class.c - * - * Copyright (c) 2003 Manuel Estrada Sainz <ranty@debian.org> + * Copyright (c) 2003 Manuel Estrada Sainz * * NOTE: This is just a probe of concept, if you think that your driver would * be well served by this mechanism please contact me first. @@ -19,7 +19,7 @@ #include <linux/firmware.h> -MODULE_AUTHOR("Manuel Estrada Sainz <ranty@debian.org>"); +MODULE_AUTHOR("Manuel Estrada Sainz"); MODULE_DESCRIPTION("Hackish sample for using firmware class directly"); MODULE_LICENSE("GPL"); |