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Diffstat (limited to 'doc/driver-model/README.txt')
| -rw-r--r-- | doc/driver-model/README.txt | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt index 7a24552560..1b5ccec4b2 100644 --- a/doc/driver-model/README.txt +++ b/doc/driver-model/README.txt @@ -606,19 +606,24 @@ methods actually defined. 1. Bind stage -A device and its driver are bound using one of these two methods: +U-Boot discovers devices using one of these two methods: - - Scan the U_BOOT_DEVICE() definitions. U-Boot It looks up the -name specified by each, to find the appropriate driver. It then calls -device_bind() to create a new device and bind' it to its driver. This will -call the device's bind() method. + - Scan the U_BOOT_DEVICE() definitions. U-Boot looks up the name specified +by each, to find the appropriate U_BOOT_DRIVER() definition. In this case, +there is no path by which driver_data may be provided, but the U_BOOT_DEVICE() +may provide platdata. - Scan through the device tree definitions. U-Boot looks at top-level nodes in the the device tree. It looks at the compatible string in each node -and uses the of_match part of the U_BOOT_DRIVER() structure to find the -right driver for each node. It then calls device_bind() to bind the -newly-created device to its driver (thereby creating a device structure). -This will also call the device's bind() method. +and uses the of_match table of the U_BOOT_DRIVER() structure to find the +right driver for each node. In this case, the of_match table may provide a +driver_data value, but platdata cannot be provided until later. + +For each device that is discovered, U-Boot then calls device_bind() to create a +new device, initializes various core fields of the device object such as name, +uclass & driver, initializes any optional fields of the device object that are +applicable such as of_offset, driver_data & platdata, and finally calls the +driver's bind() method if one is defined. At this point all the devices are known, and bound to their drivers. There is a 'struct udevice' allocated for all devices. However, nothing has been |