diff options
Diffstat (limited to 'drivers/gpio/gpiolib-shared.c')
| -rw-r--r-- | drivers/gpio/gpiolib-shared.c | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c index 076d8642675c..17343fdc9758 100644 --- a/drivers/gpio/gpiolib-shared.c +++ b/drivers/gpio/gpiolib-shared.c @@ -41,6 +41,7 @@ struct gpio_shared_ref { struct lock_class_key lock_key; struct auxiliary_device adev; struct gpiod_lookup_table *lookup; + bool is_reset_gpio; }; /* Represents a single GPIO pin. */ @@ -112,7 +113,8 @@ static int gpio_shared_setup_reset_proxy(struct gpio_shared_entry *entry, struct gpio_shared_ref *ref; list_for_each_entry(ref, &entry->refs, list) { - if (!ref->fwnode && ref->con_id && strcmp(ref->con_id, "reset") == 0) + if (ref->is_reset_gpio) + /* Already set-up. */ return 0; } @@ -120,6 +122,8 @@ static int gpio_shared_setup_reset_proxy(struct gpio_shared_entry *entry, if (!ref) return -ENOMEM; + ref->is_reset_gpio = true; + list_add_tail(&ref->list, &entry->refs); pr_debug("Created a secondary shared GPIO reference for potential reset-gpio device for GPIO %u at %s\n", @@ -714,12 +718,38 @@ static void __init gpio_shared_teardown(void) } } +static bool gpio_shared_entry_is_really_shared(struct gpio_shared_entry *entry) +{ + size_t num_nodes = list_count_nodes(&entry->refs); + struct gpio_shared_ref *ref; + + if (num_nodes <= 1) + return false; + + if (num_nodes > 2) + return true; + + /* Exactly two references: */ + list_for_each_entry(ref, &entry->refs, list) { + /* + * Corner-case: the second reference comes from the potential + * reset-gpio instance. However, this pin is not really shared + * as it would have three references in this case. Avoid + * creating unnecessary proxies. + */ + if (ref->is_reset_gpio) + return false; + } + + return true; +} + static void gpio_shared_free_exclusive(void) { struct gpio_shared_entry *entry, *epos; list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) { - if (list_count_nodes(&entry->refs) > 1) + if (gpio_shared_entry_is_really_shared(entry)) continue; gpio_shared_drop_ref(list_first_entry(&entry->refs, |