mfd-core: Unconditionally add mfd_cell to every platform_device

Previously, one would set the mfd_cell's platform_data/data_size to point
to the current mfd_cell in order to pass that information along to drivers.

This causes the current mfd_cell to always be available to drivers.  It
also adds a wrapper function for fetching the mfd cell from a platform
device, similar to what originally existed for mfd devices.

Drivers who previously used platform_data for other purposes can still
use it; the difference is that mfd_get_data() must be used to
access it (and the pdata structure is no longer allocated in
mfd_add_devices).

Note that mfd_get_data is intentionally vague (in name) about where
the data is stored; variable name changes can come later without having
to touch brazillions of drivers.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 24 insertions, 8 deletions

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index d83ad0f141af..21a39dc64ea0 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -39,12 +39,9 @@ static int mfd_add_device(struct device *parent, int id,
         pdev->dev.parent = parent;
         platform_set_drvdata(pdev, cell->driver_data);
 
-        if (cell->data_size) {
-                ret = platform_device_add_data(pdev,
-                                        cell->platform_data, cell->data_size);
-                if (ret)
-                        goto fail_res;
-        }
+        ret = platform_device_add_data(pdev, cell, sizeof(*cell));
+        if (ret)
+                goto fail_res;
 
         for (r = 0; r < cell->num_resources; r++) {
                 res[r].name = cell->resources[r].name;
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index 1fd7c4467e5a..aefc378f8dc9 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -33,9 +33,10 @@ struct mfd_cell {
         /* driver-specific data for MFD-aware "cell" drivers */
         void                    *driver_data;
 
-        /* platform_data can be used to either pass data to "generic"
-           driver or as a hook to mfd_cell for the "cell" drivers */
+        /* platform_data can be used to pass data to "generic" drivers */
         void                    *platform_data;
+
+        /* unused */
         size_t                  data_size;
 
         /*
@@ -55,6 +56,24 @@ struct mfd_cell {
         bool                    pm_runtime_no_callbacks;
 };
 
+/*
+ * Given a platform device that's been created by mfd_add_devices(), fetch
+ * the mfd_cell that created it.
+ */
+static inline const struct mfd_cell *mfd_get_cell(struct platform_device *pdev)
+{
+        return pdev->dev.platform_data;
+}
+
+/*
+ * Given a platform device that's been created by mfd_add_devices(), fetch
+ * the .platform_data entry from the mfd_cell that created it.
+ */
+static inline void *mfd_get_data(struct platform_device *pdev)
+{
+        return mfd_get_cell(pdev)->platform_data;
+}
+
 extern int mfd_add_devices(struct device *parent, int id,
                            const struct mfd_cell *cells, int n_devs,
                            struct resource *mem_base,