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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-04-03 23:23:37 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-04-03 23:23:37 +0200
commit97badf873ab60e841243b66133ff9eff2a46ef29 (patch)
tree3504372747c1610d89f5e3909667603beaf1a335 /drivers/base/core.c
parent9017f25254e474f2cc05df489e4f83b972d3d6fd (diff)
device property: Make it possible to use secondary firmware nodes
Add a secondary pointer to struct fwnode_handle so as to make it possible for a device to have two firmware nodes associated with it at the same time, for example, an ACPI node and a node with a set of properties provided by platform initialization code. In the future that will allow device property lookup to fall back from the primary firmware node to the secondary one if the given property is not present there to make it easier to provide defaults for device properties used by device drivers. Introduce two helper routines, set_primary_fwnode() and set_secondary_fwnode() allowing callers to add a primary/secondary firmware node to the given device in such a way that (1) If there's only one firmware node for that device, it will be pointed to by the device's firmware node pointer. (2) If both the primary and secondary firmware nodes are present, the primary one will be pointed to by the device's firmware node pointer, while the secondary one will be pointed to by the primary node's secondary pointer. (3) If one of these nodes is removed (by calling one of the new nelpers with NULL as the second argument), the other one will be preserved. Make ACPI use set_primary_fwnode() for attaching its firmware nodes to devices. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/core.c')
-rw-r--r--drivers/base/core.c51
1 files changed, 51 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 07304a3b9ee2..c7e2a9a70865 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -12,6 +12,7 @@
#include <linux/device.h>
#include <linux/err.h>
+#include <linux/fwnode.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
@@ -2133,3 +2134,53 @@ define_dev_printk_level(dev_notice, KERN_NOTICE);
define_dev_printk_level(_dev_info, KERN_INFO);
#endif
+
+static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
+{
+ return fwnode && !IS_ERR(fwnode->secondary);
+}
+
+/**
+ * set_primary_fwnode - Change the primary firmware node of a given device.
+ * @dev: Device to handle.
+ * @fwnode: New primary firmware node of the device.
+ *
+ * Set the device's firmware node pointer to @fwnode, but if a secondary
+ * firmware node of the device is present, preserve it.
+ */
+void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
+{
+ if (fwnode) {
+ struct fwnode_handle *fn = dev->fwnode;
+
+ if (fwnode_is_primary(fn))
+ fn = fn->secondary;
+
+ fwnode->secondary = fn;
+ dev->fwnode = fwnode;
+ } else {
+ dev->fwnode = fwnode_is_primary(dev->fwnode) ?
+ dev->fwnode->secondary : NULL;
+ }
+}
+EXPORT_SYMBOL_GPL(set_primary_fwnode);
+
+/**
+ * set_secondary_fwnode - Change the secondary firmware node of a given device.
+ * @dev: Device to handle.
+ * @fwnode: New secondary firmware node of the device.
+ *
+ * If a primary firmware node of the device is present, set its secondary
+ * pointer to @fwnode. Otherwise, set the device's firmware node pointer to
+ * @fwnode.
+ */
+void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
+{
+ if (fwnode)
+ fwnode->secondary = ERR_PTR(-ENODEV);
+
+ if (fwnode_is_primary(dev->fwnode))
+ dev->fwnode->secondary = fwnode;
+ else
+ dev->fwnode = fwnode;
+}

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