Hi Paul,
On 27 July 2016 at 08:26, Paul Burton paul.burton@imgtec.com wrote:
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
Changes in v2:
- New patch
drivers/core/syscon-uclass.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/core/syscon-uclass.c b/drivers/core/syscon-uclass.c index 01bd968..2148469 100644 --- a/drivers/core/syscon-uclass.c +++ b/drivers/core/syscon-uclass.c @@ -95,3 +95,14 @@ UCLASS_DRIVER(syscon) = { .per_device_auto_alloc_size = sizeof(struct syscon_uc_info), .pre_probe = syscon_pre_probe, };
+static const struct udevice_id generic_syscon_ids[] = {
{ .compatible = "syscon" },{ }+};
+U_BOOT_DRIVER(generic_syscon) = {
.name = "syscon",.id = UCLASS_SYSCON,.of_match = generic_syscon_ids,+};
2.9.0
This would work if driver model checked compatible strings in priority order. But it does not.
lists_bind_fdt() checks every driver to see if it is compatible. So your driver may be picked in preference to a more specific one.
I've been aware of this limitation but it hasn't come up until now.
I suppose the solution is to flip things around so that we:
1. Pick a node 2. Look at each compatible string in turn, starting from the first (most specific) 3. Search for a driver for that string
Do you want to take a look?
Regards, Simon