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@xxxxxxxxx> --- See https://lore.kernel.org/lkml/1539003437.11512.20.camel@xxxxxxxxxxxxxx/ for the rationale to ensure a single, dedicated reset line. drivers/reset/core.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/reset.h | 7 +++++++ 2 files changed, 48 insertions(+) diff --git a/drivers/reset/core.c b/drivers/reset/core.c index 654e20ff2d5da9d4..c32b755ec373c338 100644 --- a/drivers/reset/core.c +++ b/drivers/reset/core.c @@ -859,3 +859,44 @@ 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; +} + +/** + * of_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); diff --git a/include/linux/reset.h b/include/linux/reset.h index f0b094130686bf32..2698b36bd1eb3e0c 100644 --- a/include/linux/reset.h +++ b/include/linux/reset.h @@ -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) -- 2.17.1
