Messages in this thread | | | Subject | Re: [PATCH] reset: add support for non-DT systems | From | David Lechner <> | Date | Tue, 13 Feb 2018 11:17:56 -0600 |
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On 02/13/2018 09:25 AM, Bartosz Golaszewski wrote: > From: Bartosz Golaszewski <bgolaszewski@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 <nsekhar@ti.com> > Cc: Kevin Hilman <khilman@baylibre.com> > Cc: David Lechner <david@lechnology.com> > Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> > ---
Looks good to me. I just made a few very minor comments. I will try to use this in PSC driver later today.
> drivers/reset/core.c | 43 ++++++++++++++++++++++++++++++++++++++-- > include/linux/reset-controller.h | 13 ++++++++++++ > 2 files changed, 54 insertions(+), 2 deletions(-) > > diff --git a/drivers/reset/core.c b/drivers/reset/core.c > index da4292e9de97..ba7011c6e06f 100644 > --- a/drivers/reset/core.c > +++ b/drivers/reset/core.c > @@ -493,12 +493,51 @@ 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_lookup(struct device *dev, const char *id,
Based on the name of the function, I expected this to return struct reset_lookup. Perhaps __reset_control_lookup() or __reset_control_match_lookup() would be a slightly better name?
> + 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); > + } > + } > + } > + > + mutex_unlock(&reset_list_mutex); > + > + if (!rstc) > + return optional ? NULL : ERR_PTR(-ENOENT); > + > + return rstc; > +} > + > struct reset_control *__reset_control_get(struct device *dev, const char *id, > int index, bool shared, bool optional) > { > if (dev->of_node) > - return __of_reset_control_get(dev->of_node, id, index, shared, > - optional); > + return __of_reset_control_get(dev->of_node, id, > + index, shared, optional);
I don't understand why this line is changed. It is just being rearranged?
> + else > + return __reset_control_get_lookup(dev, id, shared, optional); > > return optional ? NULL : ERR_PTR(-EINVAL); > } > diff --git a/include/linux/reset-controller.h b/include/linux/reset-controller.h > index adb88f8cefbc..0c081336e08b 100644 > --- a/include/linux/reset-controller.h > +++ b/include/linux/reset-controller.h > @@ -22,6 +22,17 @@ struct reset_control_ops { > int (*status)(struct reset_controller_dev *rcdev, unsigned long id); > }; > > +/** > + * struct reset_lookup - a single entry in a reset lookup table > + * > + * @dev: name of the device associated with this reset > + * @id: additional reset identifier (if the device uses multiple reset lines) > + */ > +struct reset_lookup { > + const char *dev; > + const char *id; > +}; > + > struct module; > struct device_node; > struct of_phandle_args; > @@ -34,6 +45,7 @@ struct of_phandle_args; > * @list: internal list of reset controller devices > * @reset_control_head: head of internal list of requested reset controls > * @of_node: corresponding device tree node as phandle target > + * @lookup: array of lookup entries associated with this request controller
Might be nice to mention that this array must end with an empty struct (i.e. lookup->dev == NULL)
> * @of_reset_n_cells: number of cells in reset line specifiers > * @of_xlate: translation function to translate from specifier as found in the > * device tree to id as given to the reset control ops > @@ -45,6 +57,7 @@ struct reset_controller_dev { > struct list_head list; > struct list_head reset_control_head; > struct device_node *of_node; > + const struct reset_lookup *lookup; > int of_reset_n_cells; > int (*of_xlate)(struct reset_controller_dev *rcdev, > const struct of_phandle_args *reset_spec); >
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