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 <matti.vaittinen@xxxxxxxxxxxxxxxxx>
---
.../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 =]
