Some drivers will need to create regmaps differently based on whether they
are a child of an MFD or a standalone device. An example of this would be
if a regmap were directly memory-mapped or an external bus. In the
memory-mapped case a call to devm_regmap_init_mmio would return the correct
regmap. In the case of an MFD, the regmap would need to be requested from
the parent device.

This addition allows the driver to correctly reason about these scenarios.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---
 drivers/mfd/mfd-core.c   |  5 +++++
 include/linux/mfd/core.h | 10 ++++++++++
 2 files changed, 15 insertions(+)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 684a011a6396..905f508a31b4 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c

@@ -33,6 +33,11 @@ static struct device_type mfd_dev_type = {
 	.name	= "mfd_device",
 };
 
+int device_is_mfd(struct platform_device *pdev)
+{
+	return (!strcmp(pdev->dev.type->name, mfd_dev_type.name));
+}
+