Commit graph

10 commits

Author SHA1 Message Date
Masahiro Yamada
e151a1c288 syscon: add Linux-compatible syscon API
The syscon implementation in U-Boot is different from that in Linux.
Thus, DT files imported from Linux do not work for U-Boot.

In U-Boot driver model, each node is bound to a dedicated driver
that is the most compatible to it.  This design gets along with the
concept of DT, and the syscon in Linux originally worked like that.

However, Linux commit bdb0066df96e ("mfd: syscon: Decouple syscon
interface from platform devices") changed the behavior because it is
useful to let a device bind to another driver, but still work as a
syscon provider.

That change had happened before U-Boot initially supported the syscon
driver by commit 6f98b7504f ("dm: Add support for generic system
controllers (syscon)").  So, the U-Boot's syscon works differently
from the beginning.  I'd say this is mis-implementation given that
DT is not oriented to a particular project, but Linux is the canon
of DT in practice.

The problem typically arises in the combination of "syscon" and
"simple-mfd" compatibles.

In Linux, they are orthogonal, i.e., the order between "syscon" and
"simple-mfd" does not matter at all.

Assume the following compatible.

   compatible = "foo,bar-syscon", "syscon", "simple-mfd";

In U-Boot, this device node is bound to the syscon driver
(driver/core/syscon-uclass.c) since the "syscon" is found to be the
most compatible.  Then, syscon_get_regmap() succeeds.

However,

   compatible = "foo,bar-syscon", "simple-mfd", "syscon";

does not work because this node is bound to the simple-bus driver
(drivers/core/simple-bus.c) in favor of "simple-mfd" compatible.
The compatible string "syscon" is just dismissed.

Moreover,

   compatible = "foo,bar-syscon", "syscon";

works like the first case because the syscon driver populates the
child devices.  This is wrong because populating children is the job
of "simple-mfd" (or "simple-bus").

This commit ports syscon_node_to_regmap() from Linux.  This API
does not require the given node to be bound to a driver in any way.

Reported-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-05-07 15:49:52 -04:00
Masahiro Yamada
d35812368a regmap: change regmap_init_mem() to take ofnode instead udevice
Currently, regmap_init_mem() takes a udevice. This requires the node
has already been associated with a device. It prevents syscon/regmap
from behaving like those in Linux.

Change the first argumenet to take a device node.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2018-05-07 15:49:51 -04:00
Tom Rini
83d290c56f SPDX: Convert all of our single license tags to Linux Kernel style
When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini <trini@konsulko.com>
2018-05-07 09:34:12 -04:00
Simon Glass
745fb9c25e dm: core: Avoid calling dm_scan_fdt_dev() with of-platdata
We cannot call dm_scan_fdt_dev() with of-platdata since there is no device
tree. Fix this with an #if check.

Fixes: 3be9a37 (dm: syscon: scan sub-nodes of the syscon node)
Signed-off-by: Simon Glass <sjg@chromium.org>
2017-08-17 16:44:16 +09:00
Paul Burton
8291bc8747 dm: syscon: Provide a generic syscon driver
Provide a trivial syscon driver matching the generic "syscon" compatible
string, allowing for simple system controllers to be used without a
custom driver just as in Linux.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
2016-09-21 15:04:32 +02:00
Simon Glass
04ecf36ba6 dm: syscon: Add support for of-platdata
Provide a new function which can cope with obtaining information from
of-platdata instead of the device tree.

Signed-off-by: Simon Glass <sjg@chromium.org>
2016-07-14 20:40:24 -06:00
Simon Glass
532f2435cf syscon: Avoid returning a device on failure
If the device cannot be probed, syscon_get_by_driver_data() will still
return a useful value in its devp parameter. Ensure that it returns NULL
instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2016-03-17 10:27:24 +08:00
Simon Glass
ac94b7bcbe dm: syscon: Allow finding devices by driver data
We have a way to find a regmap by its syscon driver data value. Add the same
for syscon itself.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
2016-01-24 12:07:19 +08:00
Simon Glass
9f4629be8a dm: core: Add device checking to syscon_get_regmap()
This function can only handle a syscon device. It is possible that someone
will make a mistake, so add a check for this.

Also we should return -ENODEV when a device cannot be found, so update the
syscon_get_regmap_by_driver_data() to follow this convention.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:33 -06:00
Simon Glass
5725128507 dm: Add support for generic system controllers (syscon)
Many SoCs have a number of system controllers which are dealt with as a
group by a single driver. It is a pain to have to add lots of compatible
strings and/or separate drivers for each. Instead we can identify the
controllers by a number and request the address of the one we want.

Add a simple implementation of this which can be used by SoC driver code.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:24 -06:00