[PATCH v4 10/16] gpio: devres: Add devm_gpiod_get_parent_array
From: Matti Vaittinen <hidden>
Date: 2019-11-16 19:00:12
Also in:
linux-clk, linux-doc, linux-gpio, linux-leds, linux-rtc, lkml
Subsystem:
documentation, driver core, kobjects, debugfs and sysfs, gpio subsystem, the rest · Maintainers:
Jonathan Corbet, Greg Kroah-Hartman, "Rafael J. Wysocki", Danilo Krummrich, Linus Walleij, Bartosz Golaszewski, Linus Torvalds
Bunch of MFD sub-devices which are instantiated by MFD do not have own device-tree nodes but have (for example) the GPIO consumer information in parent device's DT node. Add resource managed devm_gpiod_get_array() for such devices so that they can get the consumer information from parent DT while still binding the GPIO reservation life-time to this sub-device life time. If devm_gpiod_get_array is used as such - then unloading and then re-loading the child device fails as the GPIOs reserved during first load are not freed when driver for sub-device is unload (if parent stays there). Signed-off-by: Matti Vaittinen <redacted> --- .../driver-api/driver-model/devres.rst | 1 + drivers/gpio/gpiolib-devres.c | 65 ++++++++++++++----- include/linux/gpio/consumer.h | 5 ++ 3 files changed, 56 insertions(+), 15 deletions(-)
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index a100bef54952..1b8302ba405b 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst@@ -270,6 +270,7 @@ GPIO devm_gpiod_get_index() devm_gpiod_get_index_optional() devm_gpiod_get_optional() + devm_gpiod_get_parent_array() devm_gpiod_put() devm_gpiod_unhinge() devm_gpiochip_add_data()
diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
index 98e3c20d9730..584fa6edfd20 100644
--- a/drivers/gpio/gpiolib-devres.c
+++ b/drivers/gpio/gpiolib-devres.c@@ -270,19 +270,11 @@ struct gpio_desc *__must_check devm_gpiod_get_index_optional(struct device *dev, } EXPORT_SYMBOL_GPL(devm_gpiod_get_index_optional); -/** - * devm_gpiod_get_array - Resource-managed gpiod_get_array() - * @dev: GPIO consumer - * @con_id: function within the GPIO consumer - * @flags: optional GPIO initialization flags - * - * Managed gpiod_get_array(). GPIO descriptors returned from this function are - * automatically disposed on driver detach. See gpiod_get_array() for detailed - * information about behavior and return values. - */ -struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev, - const char *con_id, - enum gpiod_flags flags) +static struct gpio_descs *__must_check +__devm_gpiod_get_array(struct device *gpiodev, + struct device *managed, + const char *con_id, + enum gpiod_flags flags) { struct gpio_descs **dr; struct gpio_descs *descs;
@@ -292,19 +284,62 @@ struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev, if (!dr) return ERR_PTR(-ENOMEM); - descs = gpiod_get_array(dev, con_id, flags); + descs = gpiod_get_array(gpiodev, con_id, flags); if (IS_ERR(descs)) { devres_free(dr); return descs; } *dr = descs; - devres_add(dev, dr); + if (managed) + devres_add(managed, dr); + else + devres_add(gpiodev, dr); return descs; } + +/** + * devm_gpiod_get_array - Resource-managed gpiod_get_array() + * @dev: GPIO consumer + * @con_id: function within the GPIO consumer + * @flags: optional GPIO initialization flags + * + * Managed gpiod_get_array(). GPIO descriptors returned from this function are + * automatically disposed on driver detach. See gpiod_get_array() for detailed + * information about behavior and return values. + */ +struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev, + const char *con_id, + enum gpiod_flags flags) +{ + return __devm_gpiod_get_array(dev, NULL, con_id, flags); +} EXPORT_SYMBOL_GPL(devm_gpiod_get_array); +/** + * devm_gpiod_get_parent_array - Resource-managed gpiod_get_array for subdevices + * @dev: Managed device whose parent is the GPIO consumer + * @con_id: function within the GPIO consumer + * @flags: optional GPIO initialization flags + * + * Managed gpiod_get_array() for subdevices. This function is intended to be + * used by MFD sub-devices whose GPIO bindings are in parent (MFD) device but + * whose GPIO reservation should last only for the dub-device life time. + * Returns EINVAL if no parent device is found. Rest of the behaviour and + * return values are as documented for gpiod_get_array() + */ +struct gpio_descs *__must_check +devm_gpiod_get_parent_array(struct device *dev, + const char *con_id, + enum gpiod_flags flags) +{ + if (!dev | !dev->parent) + return ERR_PTR(-EINVAL); + return __devm_gpiod_get_array(dev->parent, dev, con_id, flags); +} +EXPORT_SYMBOL_GPL(devm_gpiod_get_parent_array); + /** * devm_gpiod_get_array_optional - Resource-managed gpiod_get_array_optional() * @dev: GPIO consumer
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index b70af921c614..01a82b1c6828 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h@@ -103,6 +103,11 @@ struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev, struct gpio_descs *__must_check devm_gpiod_get_array_optional(struct device *dev, const char *con_id, enum gpiod_flags flags); +struct gpio_descs *__must_check +devm_gpiod_get_parent_array(struct device *dev, + const char *con_id, + enum gpiod_flags flags); + void devm_gpiod_put(struct device *dev, struct gpio_desc *desc); void devm_gpiod_unhinge(struct device *dev, struct gpio_desc *desc); void devm_gpiod_put_array(struct device *dev, struct gpio_descs *descs);
--
2.21.0
--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND
~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]