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reset: Add reset_control_get_count()

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Currently the reset core has internal support for counting the number of
resets for a device described in DT.  Generalize this to devices using
lookup resets, and export it for public use.

This will be used by generic drivers that need to be sure a device is
controlled by a single, dedicated reset line (e.g. vfio-platform).

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
[p.zabel@pengutronix.de: fixed a typo in reset_control_get_count comment]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
This commit is contained in:
Geert Uytterhoeven 2018-11-13 13:47:44 +01:00 committed by Philipp Zabel
parent 12c62b9d6c
commit eaf91db0ab
2 changed files with 48 additions and 0 deletions
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41
drivers/reset/core.c
View File

@ -795,3 +795,44 @@ devm_reset_control_array_get(struct device *dev, bool shared, bool optional)
return rstc;
}
EXPORT_SYMBOL_GPL(devm_reset_control_array_get);
static int reset_control_get_count_from_lookup(struct device *dev)
{
const struct reset_control_lookup *lookup;
const char *dev_id = dev_name(dev);
int count = 0;
if (!dev)
return -EINVAL;
mutex_lock(&reset_lookup_mutex);
list_for_each_entry(lookup, &reset_lookup_list, list) {
if (!strcmp(lookup->dev_id, dev_id))
count++;
}
mutex_unlock(&reset_lookup_mutex);
if (count == 0)
count = -ENOENT;
return count;
}
/**
* reset_control_get_count - Count number of resets available with a device
*
* @dev: device for which to return the number of resets
*
* Returns positive reset count on success, or error number on failure and
* on count being zero.
*/
int reset_control_get_count(struct device *dev)
{
if (dev->of_node)
return of_reset_control_get_count(dev->of_node);
return reset_control_get_count_from_lookup(dev);
}
EXPORT_SYMBOL_GPL(reset_control_get_count);

7
include/linux/reset.h
View File

@ -32,6 +32,8 @@ struct reset_control *devm_reset_control_array_get(struct device *dev,
struct reset_control *of_reset_control_array_get(struct device_node *np,
bool shared, bool optional);
int reset_control_get_count(struct device *dev);
#else
static inline int reset_control_reset(struct reset_control *rstc)
@ -97,6 +99,11 @@ of_reset_control_array_get(struct device_node *np, bool shared, bool optional)
return optional ? NULL : ERR_PTR(-ENOTSUPP);
}
static inline int reset_control_get_count(struct device *dev)
{
return -ENOENT;
}
#endif /* CONFIG_RESET_CONTROLLER */
static inline int __must_check device_reset(struct device *dev)