From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
The reset framework only supports device-tree. There are some platforms
however, which need to use it even in legacy, board-file based mode.
An example of such architecture is the DaVinci family of SoCs which
supports both device tree and legacy boot modes and we don't want to
introduce any regressions.
We're currently working on converting the platform from its hand-crafted
clock API to using the common clock framework. Part of the overhaul will
be representing the chip's power sleep controller's reset lines using
the reset framework.
This changeset extends the core reset code with a new field in the
reset controller struct which contains an array of lookup entries. Each
entry contains the device name and an additional, optional identifier
string.
Drivers can register a set of reset lines using this lookup table and
concerned devices can access them using the regular reset_control API.
This new function is only called as a fallback in case the of_node
field is NULL and doesn't change anything for current users.
Tested with a dummy reset driver with several lookup entries.
An example lookup table can look like this:
static const struct reset_lookup foobar_reset_lookup[] = {
[FOO_RESET] = { .dev = "foo", .id = "foo_id" },
[BAR_RESET] = { .dev = "bar", .id = NULL },
{ }
};
where FOO_RESET and BAR_RESET will correspond with the id parameters
of reset callbacks.
Cc: Sekhar Nori <nsekhar@xxxxxx>
Cc: Kevin Hilman <khilman@xxxxxxxxxxxx>
Cc: David Lechner <david@xxxxxxxxxxxxxx>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
---
v1 -> v2:
- renamed the new function to __reset_control_get_from_lookup()
- added a missing break; when a matching entry is found
- rearranged the code in __reset_control_get() - we can no longer get to the
return at the bottom, so remove it and return from
__reset_control_get_from_lookup() if __of_reset_control_get() fails
- return -ENOENT from reset_contol_get() if we can't find a matching entry,
prevously returned -EINVAL referred to the fact that we passed a device
without the of_node which is no longer an error condition
- add a comment about needing a sentinel in the lookup table
drivers/reset/core.c | 40 +++++++++++++++++++++++++++++++++++++++-
include/linux/reset-controller.h | 14 ++++++++++++++
2 files changed, 53 insertions(+), 1 deletion(-)
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index da4292e9de97..b104a0c5c511 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -493,6 +493,44 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
}
EXPORT_SYMBOL_GPL(__of_reset_control_get);
+static struct reset_control *
+__reset_control_get_from_lookup(struct device *dev, const char *id,
+ bool shared, bool optional)
+{
+ struct reset_controller_dev *rcdev;
+ const char *dev_id = dev_name(dev);
+ struct reset_control *rstc = NULL;
+ const struct reset_lookup *lookup;
+ int index;
+
+ mutex_lock(&reset_list_mutex);
+
+ list_for_each_entry(rcdev, &reset_controller_list, list) {
+ if (!rcdev->lookup)
+ continue;
+
+ lookup = rcdev->lookup;
+ for (index = 0; lookup->dev; index++, lookup++) {> + if (strcmp(dev_id, lookup->dev))
+ continue;
+
+ if ((!id && !lookup->id) ||
+ (id && lookup->id && !strcmp(id, lookup->id))) {
+ rstc = __reset_control_get_internal(rcdev,
+ index, shared);
+ break;
+ }
+ }
+ }