[PATCH v5 net-next 07/13] net: dsa: felix: add support for MFD configurations

The architecture around the VSC7512 differs from existing felix drivers. In
order to add support for all the chip's features (pinctrl, MDIO, gpio) the
device had to be laid out as a multi-function device (MFD).

One difference between an MFD and a standard platform device is that the
regmaps are allocated to the parent device before the child devices are
probed. As such, there is no need for felix to initialize new regmaps in
these configurations, they can simply be requested from the parent device.

Add support for MFD configurations by performing this request from the
parent device.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---

v5
    * No changes

v4
    * New patch

---
 drivers/net/dsa/ocelot/felix.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/dsa/ocelot/felix.c b/drivers/net/dsa/ocelot/felix.c
index 462a1a683996..d3ff6e8a82e9 100644
--- a/drivers/net/dsa/ocelot/felix.c
+++ b/drivers/net/dsa/ocelot/felix.c

@@ -1315,6 +1315,13 @@ static struct regmap *felix_request_regmap_by_name(struct felix *felix,
 	struct resource res;
 	int i;
 
+	/* In an MFD configuration, regmaps are registered directly to the
+	 * parent device before the child devices are probed, so there is no
+	 * need to initialize a new one.
+	 */
+	if (!felix->info->resources)
+		return dev_get_regmap(ocelot->dev->parent, resource_name);
+
 	for (i = 0; i < felix->info->num_resources; i++) {
 		if (strcmp(resource_name, felix->info->resources[i].name))
 			continue;

-- 
2.25.1