You should see something like this:
<...U-Boot banner...>
- Running 29 driver model tests
+ Running 53 driver model tests
Test: dm_test_autobind
Test: dm_test_autoprobe
+ Test: dm_test_bus_child_post_bind
+ Test: dm_test_bus_child_post_bind_uclass
+ Test: dm_test_bus_child_pre_probe_uclass
Test: dm_test_bus_children
- Device 'd-test': seq 3 is in use by 'b-test'
- Device 'c-test@0': seq 0 is in use by 'a-test'
- Device 'c-test@1': seq 1 is in use by 'd-test'
+ Device 'c-test@0': seq 0 is in use by 'd-test'
+ Device 'c-test@1': seq 1 is in use by 'f-test'
Test: dm_test_bus_children_funcs
Test: dm_test_bus_children_iterators
Test: dm_test_bus_parent_data
+ Test: dm_test_bus_parent_data_uclass
Test: dm_test_bus_parent_ops
+ Test: dm_test_bus_parent_platdata
+ Test: dm_test_bus_parent_platdata_uclass
Test: dm_test_children
+ Test: dm_test_device_get_uclass_id
+ Test: dm_test_eth
+ Using eth@10002000 device
+ Using eth@10003000 device
+ Using eth@10004000 device
+ Test: dm_test_eth_alias
+ Using eth@10002000 device
+ Using eth@10004000 device
+ Using eth@10002000 device
+ Using eth@10003000 device
+ Test: dm_test_eth_prime
+ Using eth@10003000 device
+ Using eth@10002000 device
+ Test: dm_test_eth_rotate
+
+ Error: eth@10004000 address not set.
+
+ Error: eth@10004000 address not set.
+ Using eth@10002000 device
+
+ Error: eth@10004000 address not set.
+
+ Error: eth@10004000 address not set.
+ Using eth@10004000 device
Test: dm_test_fdt
- Device 'd-test': seq 3 is in use by 'b-test'
Test: dm_test_fdt_offset
Test: dm_test_fdt_pre_reloc
Test: dm_test_fdt_uclass_seq
- Device 'd-test': seq 3 is in use by 'b-test'
- Device 'a-test': seq 0 is in use by 'd-test'
Test: dm_test_gpio
extra-gpios: get_value: error: gpio b5 not reserved
Test: dm_test_gpio_anon
Test: dm_test_gpio_copy
Test: dm_test_gpio_leak
extra-gpios: get_value: error: gpio b5 not reserved
+ Test: dm_test_gpio_phandles
Test: dm_test_gpio_requestf
+ Test: dm_test_i2c_bytewise
+ Test: dm_test_i2c_find
+ Test: dm_test_i2c_offset
+ Test: dm_test_i2c_offset_len
+ Test: dm_test_i2c_probe_empty
+ Test: dm_test_i2c_read_write
+ Test: dm_test_i2c_speed
Test: dm_test_leak
Test: dm_test_lifecycle
+ Test: dm_test_net_retry
+ Using eth@10004000 device
+ Using eth@10002000 device
+ Using eth@10004000 device
Test: dm_test_operations
Test: dm_test_ordering
+ Test: dm_test_pci_base
+ Test: dm_test_pci_swapcase
Test: dm_test_platdata
Test: dm_test_pre_reloc
Test: dm_test_remove
Test: dm_test_spi_find
Invalid chip select 0:0 (err=-19)
SF: Failed to get idcodes
- Device 'name-emul': seq 0 is in use by 'name-emul'
SF: Detected M25P16 with page size 256 Bytes, erase size 64 KiB, total 2 MiB
Test: dm_test_spi_flash
2097152 bytes written in 0 ms
SF: Detected M25P16 with page size 256 Bytes, erase size 64 KiB, total 2 MiB
Test: dm_test_uclass
Test: dm_test_uclass_before_ready
+ Test: dm_test_usb_base
+ Test: dm_test_usb_flash
+ USB-1: scanning bus 1 for devices... 2 USB Device(s) found
Failures: 0
Platform Data
-------------
+*** Note: platform data is the old way of doing things. It is
+*** basically a C structure which is passed to drivers to tell them about
+*** platform-specific settings like the address of its registers, bus
+*** speed, etc. Device tree is now the preferred way of handling this.
+*** Unless you have a good reason not to use device tree (the main one
+*** being you need serial support in SPL and don't have enough SRAM for
+*** the cut-down device tree and libfdt libraries) you should stay away
+*** from platform data.
+
Platform data is like Linux platform data, if you are familiar with that.
It provides the board-specific information to start up a device.
-----------
While platdata is useful, a more flexible way of providing device data is
-by using device tree. With device tree we replace the above code with the
-following device tree fragment:
+by using device tree. In U-Boot you should use this where possible. Avoid
+sending patches which make use of the U_BOOT_DEVICE() macro unless strictly
+necessary.
+
+With device tree we replace the above code with the following device tree
+fragment:
red-square {
compatible = "demo-shape";
in your ofdata_to_platdata (or probe) method to allocate the required memory,
and you should free it in the remove method.
+The driver model tree is intended to mirror that of the device tree. The
+root driver is at device tree offset 0 (the root node, '/'), and its
+children are the children of the root node.
+
Declaring Uclasses
------------------
U-Boot numbers devices from 0 in many situations, such as in the command
line for I2C and SPI buses, and the device names for serial ports (serial0,
serial1, ...). Driver model supports this numbering and permits devices
-to be locating by their 'sequence'. This numbering unique identifies a
+to be locating by their 'sequence'. This numbering uniquely identifies a
device in its uclass, so no two devices within a particular uclass can have
the same sequence number.
Sequence numbers start from 0 but gaps are permitted. For example, a board
-may have I2C buses 0, 1, 4, 5 but no 2 or 3. The choice of how devices are
+may have I2C buses 1, 4, 5 but no 0, 2 or 3. The choice of how devices are
numbered is up to a particular board, and may be set by the SoC in some
cases. While it might be tempting to automatically renumber the devices
where there are gaps in the sequence, this can lead to confusion and is
device will be automatically allocated the next available sequence number.
To specify the sequence number in the device tree an alias is typically
-used.
+used. Make sure that the uclass has the DM_UC_FLAG_SEQ_ALIAS flag set.
aliases {
serial2 = "/serial@22230000";
("/serial@22230000") will be given sequence number 2. Any command or driver
which requests serial device 2 will obtain this device.
-Some devices represent buses where the devices on the bus are numbered or
-addressed. For example, SPI typically numbers its slaves from 0, and I2C
-uses a 7-bit address. In these cases the 'reg' property of the subnode is
-used, for example:
-
-{
- aliases {
- spi2 = "/spi@22300000";
- };
-
- spi@22300000 {
- #address-cells = <1>;
- #size-cells = <1>;
- spi-flash@0 {
- reg = <0>;
- ...
- }
- eeprom@1 {
- reg = <1>;
- };
- };
-
-In this case we have a SPI bus with two slaves at 0 and 1. The SPI bus
-itself is numbered 2. So we might access the SPI flash with:
+More commonly you can use node references, which expand to the full path:
- sf probe 2:0
-
-and the eeprom with
-
- sspi 2:1 32 ef
-
-These commands simply need to look up the 2nd device in the SPI uclass to
-find the right SPI bus. Then, they look at the children of that bus for the
-right sequence number (0 or 1 in this case).
+aliases {
+ serial2 = &serial_2;
+};
+...
+serial_2: serial@22230000 {
+...
+};
-Typically the alias method is used for top-level nodes and the 'reg' method
-is used only for buses.
+The alias resolves to the same string in this case, but this version is
+easier to read.
Device sequence numbers are resolved when a device is probed. Before then
the sequence number is only a request which may or may not be honoured,
the bus provides some sort of transport or translation that makes it
possible to talk to the devices on the bus.
-Driver model provides a few useful features to help with implementing
-buses. Firstly, a bus can request that its children store some 'parent
-data' which can be used to keep track of child state. Secondly, the bus can
-define methods which are called when a child is probed or removed. This is
-similar to the methods the uclass driver provides.
+Driver model provides some useful features to help with implementing buses.
+Firstly, a bus can request that its children store some 'parent data' which
+can be used to keep track of child state. Secondly, the bus can define
+methods which are called when a child is probed or removed. This is similar
+to the methods the uclass driver provides. Thirdly, per-child platform data
+can be provided to specify things like the child's address on the bus. This
+persists across child probe()/remove() cycles.
+
+For consistency and ease of implementation, the bus uclass can specify the
+per-child platform data, so that it can be the same for all children of buses
+in that uclass. There are also uclass methods which can be called when
+children are bound and probed.
Here an explanation of how a bus fits with a uclass may be useful. Consider
a USB bus with several devices attached to it, each from a different (made
The bus device wants to store this address and some other information such
as the bus speed for each device.
-To achieve this, the bus device can use dev->parent_priv in each of its
-three children. This can be auto-allocated if the bus driver has a non-zero
-value for per_child_auto_alloc_size. If not, then the bus device can
-allocate the space itself before the child device is probed.
+To achieve this, the bus device can use dev->parent_platdata in each of its
+three children. This can be auto-allocated if the bus driver (or bus uclass)
+has a non-zero value for per_child_platdata_auto_alloc_size. If not, then
+the bus device or uclass can allocate the space itself before the child
+device is probed.
Also the bus driver can define the child_pre_probe() and child_post_remove()
methods to allow it to do some processing before the child is activated or
after it is deactivated.
+Similarly the bus uclass can define the child_post_bind() method to obtain
+the per-child platform data from the device tree and set it up for the child.
+The bus uclass can also provide a child_pre_probe() method. Very often it is
+the bus uclass that controls these features, since it avoids each driver
+having to do the same processing. Of course the driver can still tweak and
+override these activities.
+
Note that the information that controls this behaviour is in the bus's
driver, not the child's. In fact it is possible that child has no knowledge
that it is connected to a bus. The same child device may even be used on two
The uclass for the device can also contain data private to that uclass.
But note that each device on the bus may be a memeber of a different
uclass, and this data has nothing to do with the child data for each child
-on the bus.
+on the bus. It is the bus' uclass that controls the child with respect to
+the bus.
Driver Lifecycle
projects / karo-tx-uboot.git / blobdiff