2018-02-17 3:01 GMT+01:00 David Lechner <da...@lechnology.com>: > On 02/13/2018 12:39 PM, Bartosz Golaszewski wrote: >> >> 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 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 <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 >> >> 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; >> + } >> + } >> + } > > > > This method of determining the index is not very useful. In the case of the > DSP > reset on OMAP-L138, the index *must* be the LPSC module domain number, which > is > 15. This would require us to create 15 dummy entries in the rcdev->lookup > array > so that we get the correct index in order to get the correct reset control. > > I think it would be better to just store the index in struct reset_lookup. > > Another option would be to require the length of lookup to be > rcdev->nr_resets > instead of using a sentinel.
Indeed. Please take a look at v3. Thanks, Bartosz