diff options
| -rw-r--r-- | drivers/gpio/gpiolib-shared.c | 81 |
1 files changed, 80 insertions, 1 deletions
diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c index 3803b5c938f9..cc8646f563d2 100644 --- a/drivers/gpio/gpiolib-shared.c +++ b/drivers/gpio/gpiolib-shared.c @@ -253,6 +253,84 @@ static int gpio_shared_make_adev(struct gpio_device *gdev, return 0; } +#if IS_ENABLED(CONFIG_RESET_GPIO) +/* + * Special case: reset-gpio is an auxiliary device that's created dynamically + * and put in between the GPIO controller and consumers of shared GPIOs + * referred to by the "reset-gpios" property. + * + * If the supposed consumer of a shared GPIO didn't match any of the mappings + * we created when scanning the firmware nodes, it's still possible that it's + * the reset-gpio device which didn't exist at the time of the scan. + * + * This function verifies it an return true if it's the case. + */ +static bool gpio_shared_dev_is_reset_gpio(struct device *consumer, + struct gpio_shared_entry *entry, + struct gpio_shared_ref *ref) +{ + struct fwnode_handle *reset_fwnode = dev_fwnode(consumer); + struct fwnode_reference_args ref_args, aux_args; + struct device *parent = consumer->parent; + bool match; + int ret; + + /* The reset-gpio device must have a parent AND a firmware node. */ + if (!parent || !reset_fwnode) + return false; + + /* + * FIXME: use device_is_compatible() once the reset-gpio drivers gains + * a compatible string which it currently does not have. + */ + if (!strstarts(dev_name(consumer), "reset.gpio.")) + return false; + + /* + * Parent of the reset-gpio auxiliary device is the GPIO chip whose + * fwnode we stored in the entry structure. + */ + if (!device_match_fwnode(parent, entry->fwnode)) + return false; + + /* + * The device associated with the shared reference's firmware node is + * the consumer of the reset control exposed by the reset-gpio device. + * It must have a "reset-gpios" property that's referencing the entry's + * firmware node. + * + * The reference args must agree between the real consumer and the + * auxiliary reset-gpio device. + */ + ret = fwnode_property_get_reference_args(ref->fwnode, "reset-gpios", + NULL, 2, 0, &ref_args); + if (ret) + return false; + + ret = fwnode_property_get_reference_args(reset_fwnode, "reset-gpios", + NULL, 2, 0, &aux_args); + if (ret) { + fwnode_handle_put(ref_args.fwnode); + return false; + } + + match = ((ref_args.fwnode == entry->fwnode) && + (aux_args.fwnode == entry->fwnode) && + (ref_args.args[0] == aux_args.args[0])); + + fwnode_handle_put(ref_args.fwnode); + fwnode_handle_put(aux_args.fwnode); + return match; +} +#else +static bool gpio_shared_dev_is_reset_gpio(struct device *consumer, + struct gpio_shared_entry *entry, + struct gpio_shared_ref *ref) +{ + return false; +} +#endif /* CONFIG_RESET_GPIO */ + int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags) { const char *dev_id = dev_name(consumer); @@ -268,7 +346,8 @@ int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags) list_for_each_entry(entry, &gpio_shared_list, list) { list_for_each_entry(ref, &entry->refs, list) { - if (!device_match_fwnode(consumer, ref->fwnode)) + if (!device_match_fwnode(consumer, ref->fwnode) && + !gpio_shared_dev_is_reset_gpio(consumer, entry, ref)) continue; /* We've already done that on a previous request. */ |