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-rw-r--r--drivers/reset/core.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/drivers/reset/core.c b/drivers/reset/core.c
index c8fb4426b218..1d21c6f7d56c 100644
--- a/drivers/reset/core.c
+++ b/drivers/reset/core.c
@@ -280,9 +280,6 @@ int reset_control_assert(struct reset_control *rstc)
if (reset_control_is_array(rstc))
return reset_control_array_assert(rstc_to_array(rstc));
- if (!rstc->rcdev->ops->assert)
- return -ENOTSUPP;
-
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
return -EINVAL;
@@ -292,6 +289,21 @@ int reset_control_assert(struct reset_control *rstc)
if (atomic_dec_return(&rstc->deassert_count) != 0)
return 0;
+
+ /*
+ * Shared reset controls allow the reset line to be in any state
+ * after this call, so doing nothing is a valid option.
+ */
+ if (!rstc->rcdev->ops->assert)
+ return 0;
+ } else {
+ /*
+ * If the reset controller does not implement .assert(), there
+ * is no way to guarantee that the reset line is asserted after
+ * this call.
+ */
+ if (!rstc->rcdev->ops->assert)
+ return -ENOTSUPP;
}
return rstc->rcdev->ops->assert(rstc->rcdev, rstc->id);
@@ -321,9 +333,6 @@ int reset_control_deassert(struct reset_control *rstc)
if (reset_control_is_array(rstc))
return reset_control_array_deassert(rstc_to_array(rstc));
- if (!rstc->rcdev->ops->deassert)
- return -ENOTSUPP;
-
if (rstc->shared) {
if (WARN_ON(atomic_read(&rstc->triggered_count) != 0))
return -EINVAL;
@@ -332,6 +341,16 @@ int reset_control_deassert(struct reset_control *rstc)
return 0;
}
+ /*
+ * If the reset controller does not implement .deassert(), we assume
+ * that it handles self-deasserting reset lines via .reset(). In that
+ * case, the reset lines are deasserted by default. If that is not the
+ * case, the reset controller driver should implement .deassert() and
+ * return -ENOTSUPP.
+ */
+ if (!rstc->rcdev->ops->deassert)
+ return 0;
+
return rstc->rcdev->ops->deassert(rstc->rcdev, rstc->id);
}
EXPORT_SYMBOL_GPL(reset_control_deassert);