From: Bartosz Golaszewski <[email protected]> As the final step in adding official support for shared GPIOs, enable the previously added elements in core GPIO subsystem code. Set-up shared GPIOs when adding a GPIO chip, tear it down on removal and check if a GPIO descriptor looked up during the firmware-node stage is shared and fall-back to machine lookup in this case.
Signed-off-by: Bartosz Golaszewski <[email protected]> --- drivers/gpio/gpiolib.c | 50 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 41 insertions(+), 9 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9952e412da505c12ceddfefd9cfd778aad3bd5e6..1e4c991797126d0d91233bbe7c3ae3831bf77d6c 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); @@ -4652,11 +4661,29 @@ 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 +4706,19 @@ 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; } -- 2.48.1
