2018-02-23 12:39 GMT+01:00 Bartosz Golaszewski <b...@bgdev.pl>:
> From: Bartosz Golaszewski <bgolaszew...@baylibre.com>
>
> 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 reset lookup
> entry structure. It contains data allowing the reset core to associate
> reset lines with devices by comparing the dev_id and con_id strings.
>
> It also provides a function allowing drivers to register lookup entries
> with the framework.
>
> The new lookup 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 registration from a driver can be found below:
>
> static struct reset_control_lookup foobar_reset_lookup[] = {
> RESET_LOOKUP("foo.0", "foo", 15),
> RESET_LOOKUP("bar.0", NULL, 5),
> };
>
> foobar_probe()
> {
> ...
>
> reset_controller_add_lookup(&rcdev, foobar_reset_lookup,
> ARRAY_SIZE(foobar_reset_lookup));
>
> ...
> }
>
> Cc: Sekhar Nori <nsek...@ti.com>
> Cc: Kevin Hilman <khil...@baylibre.com>
> Cc: David Lechner <da...@lechnology.com>
> Signed-off-by: Bartosz Golaszewski <bgolaszew...@baylibre.com>
> ---
> 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
>
> v2 -> v3:
> - added the reset id number field to the lookup struct so that we don't need
> to rely on the array index
>
> v3 -> v4:
> - separated the driver and lookup table registration logic by adding a
> function meant to be called by machine-specific code that adds a lookup
> table to the internal list
> - the correct reset controller is now found by first finding the lookup
> table associated with it, then finding the actual reset controller by
> the associated device
>
> v4 -> v5:
> - since the first user of this will be the davinci clk driver and it
> already registers clock lookup from within the driver code - allow
> drivers to register lookups with the assumption that the code can be
> extended to make it possible to register entries from machine code as
> well
> - simplify the code - only expose a single lookup structure and a simply
> registration function
> - add the RESET_LOOKUP macro for brevity
>
> drivers/reset/core.c | 65
> +++++++++++++++++++++++++++++++++++++++-
> include/linux/reset-controller.h | 28 +++++++++++++++++
> 2 files changed, 92 insertions(+), 1 deletion(-)
Also: I decided not to go the phy way of allocating memory dynamically
for lookup entries - I believe this is overkill and makes the code
more complicated with all the error checking required.
Instead, the lookup entries structs should be provided by the caller.
Bart
