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authorAndres Salomon <dilinger@queued.net>2011-02-17 19:07:35 -0800
committerSamuel Ortiz <sameo@linux.intel.com>2011-03-23 10:41:58 +0100
commita9bbba996302344b1fac7773cf8198f6fee35ac1 (patch)
tree8cd804a7169232bf4a14a575e8b41092fe4e0fdf /drivers/mfd
parent1e29af62f2b285bd18685da93c3ce8c33ca2d1db (diff)
mfd: add platform_device sharing support for mfd
This adds functions to enable platform_device sharing for mfd clients. Each platform driver (mfd client) that wants to share an mfd_cell's platform_device uses the mfd_shared_platform_driver_{un,}register() functions instead of platform_driver_{un,}register(). Along with registering the platform driver, these also register a new platform device with the same characteristics as the original cell, but a different name. Given an mfd_cell with the name "foo", drivers that want to share access to its resources can call mfd_shared_platform_driver_register with platform drivers named (for example) "bar" and "baz". This will register two platform devices and drivers named "bar" and "baz" that share the same cell as the platform device "foo". The drivers can then call "foo" cell's enable hooks (or mfd_shared_cell_enable) to enable resources, and obtain platform resources as they normally would. This deals with platform handling only; mfd driver-specific details, hardware handling, refcounting, etc are all dealt with separately. Signed-off-by: Andres Salomon <dilinger@queued.net> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/mfd-core.c61
1 files changed, 61 insertions, 0 deletions
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index ca789f88230..bb2264cc410 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -184,5 +184,66 @@ void mfd_remove_devices(struct device *parent)
}
EXPORT_SYMBOL(mfd_remove_devices);
+static int add_shared_platform_device(const char *cell, const char *name)
+{
+ struct mfd_cell cell_entry;
+ struct device *dev;
+ struct platform_device *pdev;
+ int err;
+
+ /* check if we've already registered a device (don't fail if we have) */
+ if (bus_find_device_by_name(&platform_bus_type, NULL, name))
+ return 0;
+
+ /* fetch the parent cell's device (should already be registered!) */
+ dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
+ if (!dev) {
+ printk(KERN_ERR "failed to find device for cell %s\n", cell);
+ return -ENODEV;
+ }
+ pdev = to_platform_device(dev);
+ memcpy(&cell_entry, mfd_get_cell(pdev), sizeof(cell_entry));
+
+ WARN_ON(!cell_entry.enable);
+
+ cell_entry.name = name;
+ err = mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0);
+ if (err)
+ dev_err(dev, "MFD add devices failed: %d\n", err);
+ return err;
+}
+
+int mfd_shared_platform_driver_register(struct platform_driver *drv,
+ const char *cellname)
+{
+ int err;
+
+ err = add_shared_platform_device(cellname, drv->driver.name);
+ if (err)
+ printk(KERN_ERR "failed to add platform device %s\n",
+ drv->driver.name);
+
+ err = platform_driver_register(drv);
+ if (err)
+ printk(KERN_ERR "failed to add platform driver %s\n",
+ drv->driver.name);
+
+ return err;
+}
+EXPORT_SYMBOL(mfd_shared_platform_driver_register);
+
+void mfd_shared_platform_driver_unregister(struct platform_driver *drv)
+{
+ struct device *dev;
+
+ dev = bus_find_device_by_name(&platform_bus_type, NULL,
+ drv->driver.name);
+ if (dev)
+ platform_device_unregister(to_platform_device(dev));
+
+ platform_driver_unregister(drv);
+}
+EXPORT_SYMBOL(mfd_shared_platform_driver_unregister);
+
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");