Commit Graph

55 Commits

Author SHA1 Message Date
Simon Glass
c57f806bf2 dm: core: Add a way to find a device by its driver
Some SoCs have a single clock device. Provide a way to find it given its
driver name. This is handled by the linker so will fail if the name is not
found, avoiding strange errors when names change and do not match. It is
also faster than a string comparison.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-07-25 20:46:43 -06:00
Simon Glass
9fa2819009 dm: core: Expand platdata for of-platdata devices
Devices which use of-platdata have their own platdata. However, in many
cases the driver will have its own auto-alloced platdata, for use with the
device tree. The ofdata_to_platdata() method converts the device tree
settings to platdata.

With of-platdata we would not normally allocate the platdata since it is
provided by the U_BOOT_DEVICE() declaration. However this is inconvenient
since the of-platdata struct is closely tied to the device tree properties.
It is unlikely to exactly match the platdata needed by the driver.

In fact a useful approach is to declare platdata in the driver like this:

struct r3288_mmc_platdata {
	struct dtd_rockchip_rk3288_dw_mshc of_platdata;
	/* the 'normal' fields go here */
};

In this case we have dt_platadata available, but the normal fields are not
present, since ofdata_to_platdata() is never called. In fact driver model
doesn't allocate any space for the 'normal' fields, since it sees that there
is already platform data attached to the device.

To make this easier, adjust driver model to allocate the full size of the
struct (i.e. platdata_auto_alloc_size from the driver) and copy in the
of-platdata. This means that when the driver's bind() method is called,
the of-platdata will be present, followed by zero bytes for the empty
'normal field' portion.

A new DM_FLAG_OF_PLATDATA flag is available that indicates that the platdata
came from of-platdata. When the allocation/copy happens, the
DM_FLAG_ALLOC_PDATA flag will be set as well. The dtoc tool is updated to
output the platdata_size field, since U-Boot has no other way of knowing
the size of the of-platdata struct.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-07-14 20:40:24 -06:00
Simon Glass
fd1c2d9b6a dm: core: Rename DM_NAME_ALLOCED to DM_FLAG_NAME_ALLOCED
This is a flag. Adjust the name to be consistent with the other flags.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-07-14 20:40:24 -06:00
Vignesh R
7c61686255 dm: core: implement dev_map_physmem()
This API helps to map physical register addresss pace of device to
virtual address space easily. Its just a wrapper around map_physmem()
with MAP_NOCACHE flag.

Signed-off-by: Vignesh R <vigneshr@ti.com>
Suggested-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Jagan Teki <jteki@openedev.com>
2016-07-09 20:16:08 +05:30
Mugunthan V N
73443b9e4c drivers: core: device: add support to check dt compatible for a device/machine
Provide an api to check whether the given device or machine is
compatible with the given compat string which helps in making
decisions in drivers based on device or machine compatible.

Idea taken from Linux.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
2016-05-24 11:42:02 -05:00
Simon Glass
a2040facd2 dm: core: Allow device names to be freed automatically
Some devices have a name that is stored in allocated memory. At present
there is no mechanism to free this memory when the device is unbound.

Add a device flag to track whether a name is allocated and a function to
add the flag. Free the memory when the device is unbound.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-05-17 09:54:43 -06:00
Stefan Roese
28027521be dm: core: Add dev_get_addr_ptr() to return a pointer to the reg address
On some platforms (e.g. x86), the return value of dev_get_addr() can't
be assigned to a pointer type variable directly. As there might be a
difference between the size of fdt_addr_t and the pointer type. On
x86 for example, "fdt_addr_t" is 64bit but "void *" only 32bit. So
assigning the register base directly in dev_get_addr() results in this
compilation warning:
  warning: cast to pointer from integer of different size

This patch introduces the new function dev_get_addr_ptr() that
returns a pointer to the 'reg' address that can be used by drivers
in this case.

Signed-off-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2016-04-25 07:30:16 +02:00
Stephen Warren
43c4d44e33 fdt: implement dev_get_addr_name()
This function parses the reg property based on an index found in the
reg-names property. This is required for bindings that are written
using reg-names rather than hard-coding indices in reg.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Acked-by: Simon Glass <sjg@chromium.org>
2016-04-15 08:14:37 -06:00
Mugunthan V N
69b41388ba dm: core: Add a new api to get indexed device address
Add new api to get device address based on index.

Signed-off-by: Mugunthan V N <mugunthanvnm@ti.com>
Acked-by: Jagan Teki <jteki@openedev.com>
[Rebased on master]
Signed-off-by: Jagan Teki <jteki@openedev.com>
2016-01-13 18:54:22 +05:30
Stefan Roese
66eaea6cd1 dm: core: Add option to configure an offset for the address translation
Some platforms need to ability to configure an offset to the standard
addresses extracted from the device-tree. This patch allows this by
adding a function to DM to configure this offset (if needed).

Signed-off-by: Stefan Roese <sr@denx.de>
Acked-by: Simon Glass <sjg@chromium.org>
Cc: Simon Glass <sjg@chromium.org>
Fixed space before tab:
Signed-off-by: Simon Glass <sjg@chromium.org>
2016-01-12 10:19:09 -07:00
Simon Glass
7aeac5bc8c dm: core: Add safe device iteration macros
Add iteration macros which support unbinding a device within the loop.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-11-19 20:27:51 -07:00
Simon Glass
8d1f3a9daf dm: core: Tidy up comments in device.h
Correct a few nits found in a recent review. Expand the comments in
dev_get_driver_data() to make it clearer.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-10-23 09:42:28 -06:00
Simon Glass
99b81a4d86 dm: core: Remove a comment about dropping per_child_auto_alloc_size
This has proven useful and we no-longer intend to remove it. Drop the
comment.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-10-23 09:42:28 -06:00
Simon Glass
93c7fe4a0c dm: core: Tidy up devres comments
Adjust the devres comments to be consistent with the rest of the file, and
add one for the struct udevice member. Also rename the 'p' parameter to
'ptr' to avoid single-character names.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-10-23 09:42:28 -06:00
Simon Glass
fb04c9d7b8 dm: core: Fix device flag whitespace
Line up the flag values in the code for easier readability.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-10-23 09:42:28 -06:00
Simon Glass
9a79f6e6d5 dm: core: Adjust device.h header file order
Move a few functions around so that the ordering is consistent.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-10-23 09:42:28 -06:00
Simon Glass
bcbe3d1579 dm: Rename dev_get_parentdata() to dev_get_parent_priv()
The current name is inconsistent with other driver model data access
functions. Rename it and fix up all users.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
2015-10-23 09:42:28 -06:00
Bin Meng
1e0f226362 dm: pci: Add an inline API to test if a device is on a PCI bus
Introduce device_is_on_pci_bus() which can be utilized by driver
to test if a device is on a PCI bus.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-09-16 19:53:52 -06:00
Masahiro Yamada
0f9258228e of: clean up OF_CONTROL ifdef conditionals
We have flipped CONFIG_SPL_DISABLE_OF_CONTROL.  We have cleansing
devices, $(SPL_) and CONFIG_IS_ENABLED(), so we are ready to clear
away the ugly logic in include/fdtdec.h:

 #ifdef CONFIG_OF_CONTROL
 # if defined(CONFIG_SPL_BUILD) && !defined(SPL_OF_CONTROL)
 #  define OF_CONTROL 0
 # else
 #  define OF_CONTROL 1
 # endif
 #else
 # define OF_CONTROL 0
 #endif

Now CONFIG_IS_ENABLED(OF_CONTROL) is the substitute.  It refers to
CONFIG_OF_CONTROL for U-boot proper and CONFIG_SPL_OF_CONTROL for
SPL.

Also, we no longer have to cancel CONFIG_OF_CONTROL in
include/config_uncmd_spl.h and scripts/Makefile.spl.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
2015-08-18 13:46:05 -04:00
Simon Glass
f5c67ea036 dm: core: Add a way to set a device name
Some devices are bound entirely by probing and do not have the benefit of
a device tree to give them a name. This is very common with PCI and USB. In
most cases this is fine, but we should add an official way to set a device
name. This should be called in the device's bind() method.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2015-08-06 07:44:29 -06:00
Masahiro Yamada
e2282d7076 devres: make Devres optional with CONFIG_DEVRES
Currently, Devres requires additional 16 byte for each allocation,
which is not so insignificant in some cases.

Add CONFIG_DEVRES to make this framework optional.
If the option is disabled, devres functions fall back to
non-managed variants.  For example, devres_alloc() to kzalloc(),
devm_kmalloc() to kmalloc(), etc.

Because devres_head is also surrounded by an ifdef conditional,
there is no memory overhead when CONFIG_DEVRES is disabled.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Suggested-by: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
2015-08-06 07:44:29 -06:00
Masahiro Yamada
2b07f6859a devres: add devm_kmalloc() and friends (managed memory allocators)
devm_kmalloc() is identical to kmalloc() except that the memory
allocated with it is managed and will be automatically released
when the device is removed/unbound.

Likewise for the other variants.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-08-06 07:44:29 -06:00
Masahiro Yamada
608f26c51b devres: introduce Devres (Managed Device Resource) framework
In U-Boot's driver model, memory is basically allocated and freed
in the core framework.  So, low level drivers generally only have
to specify the size of needed memory with .priv_auto_alloc_size,
.platdata_auto_alloc_size, etc.  Nevertheless, some drivers still
need to allocate/free memory on their own in case they cannot
statically know the necessary memory size.  So, I believe it is
reasonable enough to port Devres into U-boot.

Devres, which originates in Linux, manages device resources for each
device and automatically releases them on driver detach.  With devres,
device resources are guaranteed to be freed whether initialization
fails half-way or the device gets detached.

The basic idea is totally the same to that of Linux, but I tweaked
it a bit so that it fits in U-Boot's driver model.

In U-Boot, drivers are activated in two steps: binding and probing.
Binding puts a driver and a device together.  It is just data
manipulation on the system memory, so nothing has happened on the
hardware device at this moment.  When the device is really used, it
is probed.  Probing initializes the real hardware device to make it
really ready for use.

So, the resources acquired during the probing process must be freed
when the device is removed.  Likewise, what has been allocated in
binding should be released when the device is unbound.  The struct
devres has a member "probe" to remember when the resource was
allocated.

CONFIG_DEBUG_DEVRES is also supported for easier debugging.
If enabled, debug messages are printed each time a resource is
allocated/freed.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-08-06 07:44:29 -06:00
Masahiro Yamada
aed1a4dd88 dm: add DM_FLAG_BOUND flag
Currently, we only have DM_FLAG_ACTIVATED to indicate the device
status, but we still cannot know in which stage is in progress,
binding or probing.

This commit introduces a new flag, DM_FLAG_BOUND, which is set when
the device is really bound, and cleared when it is unbound.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>
2015-08-06 07:44:29 -06:00
Simon Glass
3f416f336e dm: Add a return value comment to device_get_child()
At present this function does not specify its return value. Fix it.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2015-08-05 08:42:42 -06:00
Simon Glass
132f9bfc9e dm: core: Correct device_get_child_by_of_offset() parameter
This parameter is named 'seq' but should be named 'of_offset'.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:23 -06:00
Simon Glass
2693047acd dm: core: Add a function to find any device from device tree
In some rare cases it is useful to be able to locate a device given a device
tree node offset. An example is when you have an alias that points to a node
and you want to find the associated device. The device may be SPI, MMC or
something else, but you don't need to know the uclass to find it.

Add a function to do a global search for a device, given its device tree
offset.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:22 -06:00
Przemyslaw Marczak
f9c370dcdf dm: core: device: add function: dev_get_uclass_name()
This commit extends the driver model device's API by function:
- dev_get_uclass_name()

And this function returns the device's uclass driver name if:
- given dev pointer, is non_NULL
otherwise, the NULL pointer is returned.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
2015-04-22 11:03:15 -06:00
Przemyslaw Marczak
cc73d37b7f dm: core: device: add function: dev_get_driver_ops()
This commit extends the driver model device's API by function:
- dev_get_driver_ops()

And this function returns the device's driver's operations if given:
- dev pointer, is non-NULL
- dev->driver->ops pointer, is non-NULL
in other case the, the NULL pointer is returned.

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
2015-04-22 11:03:15 -06:00
Przemyslaw Marczak
5eaed88028 dm: core: Extend struct udevice by '.uclass_platdata' field.
This commit adds 'uclass_platdata' field to 'struct udevice', which
can be automatically allocated at bind. The allocation size is defined
in 'struct uclass_driver' as 'per_device_platdata_auto_alloc_size'.

New device's flag is added: DM_FLAG_ALLOC_UCLASS_PDATA, which is used
for memory freeing at device unbind method.

As for other udevice's fields, a complementary function is added:
- dev_get_uclass_platdata()

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
Acked-by: Simon Glass <sjg@chromium.org>
2015-04-22 11:03:14 -06:00
Simon Glass
c5785673bc dm: core: Add device children and sibling functions
Add some utility functions to check for children and for the last sibling in
a device's parent.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
2015-04-18 11:11:19 -06:00
Simon Glass
39de843352 dm: core: Rename driver data function to dev_get_driver_data()
The existing get_get_of_data() function provides access to both the driver's
compatible string and its driver data. However only the latter is actually
useful. Update the interface to reflect this and fix up existing users.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
2015-04-18 11:11:19 -06:00
Simon Glass
3479253dad dm: core: Convert driver_bind() to use const
The driver is not modified by driver model, so update driver_bind() to
recognise that.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
2015-04-18 11:11:19 -06:00
Simon Glass
2c03c4633b dm: core: Support allocating driver-private data for DMA
Some driver want to put DMA buffers in their private data. Add a flag
to tell driver model to align driver-private data to a cache boundary so
that DMA will work correctly in this case.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Marek Vasut <marex@denx.de>
2015-04-18 11:11:19 -06:00
Simon Glass
e564f054af dm: core: Add dev_get_uclass_priv() to access uclass private data
Add a convenience function to access the private data that a uclass stores
for each of its devices. Convert over most existing uses for consistency
and to provide an example for others.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-04-16 19:27:42 -06:00
Peng Fan
c9cac3f841 dm: introduce dev_get_addr interface
Abstracting dev_get_addr can improve drivers that want to
get device's address.

Signed-off-by: Peng Fan <Peng.Fan@freescale.com>
Acked-by: Igor Grinberg <grinberg@compulab.co.il>
Acked-by: Simon Glass <sjg@chromium.org>
2015-02-12 15:17:29 -07:00
Simon Glass
b367053102 dm: core: Add a function to get a device's uclass ID
This is useful to check which uclass a device is in.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2015-01-29 17:09:55 -07:00
Simon Glass
0118ce7957 dm: core: Add a post_bind method for parents
Allow parent drivers to be called when a new child is bound to them. This
allows a bus to set up information it needs for that child.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2015-01-29 17:09:55 -07:00
Simon Glass
cdc133bde9 dm: core: Allow parents to have platform data for their children
For buses it is common for parents to need to know the address of the child
on the bus, the bus speed to use for that child, and other information. This
can be provided in platform data attached to each child.

Add driver model support for this, including auto-allocation which can be
requested using a new property to specify the size of the data.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
2015-01-29 17:09:54 -07:00
Simon Glass
479728cb0c dm: core: Add functions to find parent and OF data
Add dev_get_parent() as a convenience to obtain the parent of a device.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>
Acked-by: Heiko Schocher <hs@denx.de>
2014-11-22 10:16:47 +01:00
Simon Glass
2ef249b442 dm: core: Allow access to the device's driver_id data
When the device is created from a device tree node, it matches a compatible
string. Allow access to that string and the associated data.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>
Acked-by: Heiko Schocher <hs@denx.de>
2014-11-22 10:16:45 +01:00
Simon Glass
547cea19b8 dm: core: Add a clarifying comment on struct udevice's seq member
The sequence number is unique within the uclass, so state this clearly.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
2014-10-22 10:36:46 -06:00
Simon Glass
accd4b19b3 dm: core: Allow parents to pass data to children during probe
Buses sometimes want to pass data to their children when they are probed.
For example, a SPI bus may want to tell the slave device about the chip
select it is connected to.

Add a new function to permit the parent data to be supplied to the child.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
2014-10-22 10:36:46 -06:00
Simon Glass
a8981d4f80 dm: core: Add functions for iterating through device children
Buses need to iterate through their children in some situations. Add a few
functions to make this easy.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
2014-10-22 10:36:45 -06:00
Masahiro Yamada
f887cb6d86 dm: add of_match_ptr() macro
The driver model supports two ways for passing device parameters;
Device Tree and platform_data (board file).
Each driver should generally support both of them because some
popular IPs are used on various platforms.

Assume the following scenario:
  - The driver Foo is used on SoC Bar and SoC Baz
  - The SoC Bar uses Device Tree control (CONFIG_OF_CONTROL=y)
  - The SoC Baz does not support Device Tree; uses a board file

In this situation, the device driver Foo should work with/without
the device tree control.  The driver should have .of_match and
.ofdata_to_platdata members for SoC Bar, while they are meaningless
for SoC Baz; therefore those device-tree control code should go
inside #ifdef CONFIG_OF_CONTROL.

The driver code will be like this:

  #ifdef CONFIG_OF_CONTROL
  static const struct udevice_id foo_of_match = {
          { .compatible = "foo_driver" },
          {},
  }

  static int foo_ofdata_to_platdata(struct udevice *dev)
  {
          ...
  }
  #endif

  U_BOOT_DRIVER(foo_driver) = {
          ...
          .of_match = of_match_ptr(foo_of_match),
          .ofdata_to_platdata = of_match_ptr(foo_ofdata_to_platdata),
          ...
  }

This idea has been borrowed from Linux.
(In Linux, this macro is defined in include/linux/of.h)

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
2014-10-22 10:32:17 -06:00
Simon Glass
a327dee0f4 dm: Add child_pre_probe() and child_post_remove() methods
Some devices (particularly bus devices) must track their children, knowing
when a new child is added so that it can be set up for communication on the
bus.

Add a child_pre_probe() method to provide this feature, and a corresponding
child_post_remove() method.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-07-23 14:08:37 +01:00
Simon Glass
e59f458de6 dm: Introduce per-child data for devices
Some device types can have child devices and want to store information
about them. For example a USB flash stick attached to a USB host
controller would likely use this space. The controller can hold
information about the USB state of each of its children.

The data is stored attached to the child device in the 'parent_priv'
member. It can be auto-allocated by dm when the child is probed. To
do this, add a per_child_auto_alloc_size value to the parent driver.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-07-23 14:08:37 +01:00
Simon Glass
997c87bb0b dm: Add functions to access a device's children
Devices can have childen that can be addressed by a simple index, the
sequence number or a device tree offset. Add functions to access a child
in each of these ways.

The index is typically used as a fallback when the sequence number is not
available. For example we may use a serial UART with sequence number 0 as
the console, but if no UART has sequence number 0, then we can fall back
to just using the first UART (index 0).

The device tree offset function is useful for buses, where they want to
locate one of their children. The device tree can be scanned to find the
offset of each child, and that offset can then find the device.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-07-23 14:08:37 +01:00
Simon Glass
0040b94429 dm: Tidy up some header file comments
Fix up the style of a few comments and add/clarify a few others.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-07-23 14:07:26 +01:00
Simon Glass
5a66a8ff86 dm: Introduce device sequence numbering
In U-Boot it is pretty common to number devices from 0 and access them
on the command line using this numbering. While it may come to pass that
we will move away from this numbering, the possibility seems remote at
present.

Given that devices within a uclass will have an implied numbering, it
makes sense to build this into driver model as a core feature. The cost
is fairly small in terms of code and data space.

With each uclass having numbered devices we can ask for SPI port 0 or
serial port 1 and receive a single device.

Devices typically request a sequence number using aliases in the device
tree. These are resolved when the device is probed, to deal with conflicts.
Sequence numbers need not be sequential and holes are permitted.

At present there is no support for sequence numbers using static platform
data. It could easily be added to 'struct driver_info' if needed, but it
seems better to add features as we find a use for them, and the use of -1
to mean 'no sequence' makes the default value somewhat painful.

Signed-off-by: Simon Glass <sjg@chromium.org>
2014-07-23 14:07:25 +01:00