diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 70 |
1 files changed, 61 insertions, 9 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index cd8800ba5825..476fcc897d90 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -37,6 +37,7 @@ #include "gpiolib-acpi.h" #include "gpiolib-cdev.h" #include "gpiolib-of.h" +#include "gpiolib-shared.h" #include "gpiolib-swnode.h" #include "gpiolib-sysfs.h" #include "gpiolib.h" @@ -1200,6 +1201,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (ret) goto err_remove_irqchip_mask; + ret = gpio_device_setup_shared(gdev); + if (ret) + goto err_remove_irqchip; + /* * By first adding the chardev, and then adding the device, * we get a device node entry in sysfs under @@ -1211,10 +1216,13 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, if (gpiolib_initialized) { ret = gpiochip_setup_dev(gdev); if (ret) - goto err_remove_irqchip; + goto err_teardown_shared; } + return 0; +err_teardown_shared: + gpio_device_teardown_shared(gdev); err_remove_irqchip: gpiochip_irqchip_remove(gc); err_remove_irqchip_mask: @@ -1283,6 +1291,7 @@ void gpiochip_remove(struct gpio_chip *gc) /* Numb the device, cancelling all outstanding operations */ rcu_assign_pointer(gdev->chip, NULL); synchronize_srcu(&gdev->srcu); + gpio_device_teardown_shared(gdev); gpiochip_irqchip_remove(gc); acpi_gpiochip_remove(gc); of_gpiochip_remove(gc); @@ -3982,6 +3991,26 @@ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name) EXPORT_SYMBOL_GPL(gpiod_set_consumer_name); /** + * gpiod_is_shared() - check if this GPIO can be shared by multiple consumers + * @desc: GPIO to inspect + * + * Returns: + * True if this GPIO can be shared by multiple consumers at once. False if it's + * a regular, exclusive GPIO. + * + * Note: + * This function returning true does not mean that this GPIO is currently being + * shared. It means the GPIO core has registered the fact that the firmware + * configuration indicates that it can be shared by multiple consumers and is + * in charge of arbitrating the access. + */ +bool gpiod_is_shared(const struct gpio_desc *desc) +{ + return test_bit(GPIOD_FLAG_SHARED_PROXY, &desc->flags); +} +EXPORT_SYMBOL_GPL(gpiod_is_shared); + +/** * gpiod_to_irq() - return the IRQ corresponding to a GPIO * @desc: gpio whose IRQ will be returned (already requested) * @@ -4652,11 +4681,29 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer, scoped_guard(srcu, &gpio_devices_srcu) { desc = gpiod_fwnode_lookup(fwnode, consumer, con_id, idx, &flags, &lookupflags); + if (!IS_ERR_OR_NULL(desc) && + test_bit(GPIOD_FLAG_SHARED, &desc->flags)) { + /* + * We're dealing with a GPIO shared by multiple + * consumers. This is the moment to add the machine + * lookup table for the proxy device as previously + * we only knew the consumer's fwnode. + */ + ret = gpio_shared_add_proxy_lookup(consumer, lookupflags); + if (ret) + return ERR_PTR(ret); + + /* Trigger platform lookup for shared GPIO proxy. */ + desc = ERR_PTR(-ENOENT); + /* Trigger it even for fwnode-only gpiod_get(). */ + platform_lookup_allowed = true; + } + if (gpiod_not_found(desc) && platform_lookup_allowed) { /* * Either we are not using DT or ACPI, or their lookup - * did not return a result. In that case, use platform - * lookup as a fallback. + * did not return a result or this is a shared GPIO. In + * that case, use platform lookup as a fallback. */ dev_dbg(consumer, "using lookup tables for GPIO lookup\n"); @@ -4679,14 +4726,19 @@ struct gpio_desc *gpiod_find_and_request(struct device *consumer, return ERR_PTR(ret); /* - * This happens when there are several consumers for - * the same GPIO line: we just return here without - * further initialization. It is a bit of a hack. - * This is necessary to support fixed regulators. + * This happens when there are several consumers for the same + * GPIO line: we just return here without further + * initialization. It's a hack introduced long ago to support + * fixed regulators. We now have a better solution with + * automated scanning where affected platforms just need to + * select the provided Kconfig option. * - * FIXME: Make this more sane and safe. + * FIXME: Remove the GPIOD_FLAGS_BIT_NONEXCLUSIVE flag after + * making sure all platforms use the new mechanism. */ - dev_info(consumer, "nonexclusive access to GPIO for %s\n", name); + dev_info(consumer, + "nonexclusive access to GPIO for %s, consider updating your code to using gpio-shared-proxy\n", + name); return desc; } |