[RFC v7 net-next 08/13] phy: ocelot-serdes: add ability to be used in mfd configuration

[Colin Foster <colin.foster@in-advantage.com>]

When ocelot-serdes is used in an MFD configuration, it might need to get
regmaps from an mfd instead of syscon. Add this ability to be used in
either configuration.

Signed-off-by: Colin Foster <colin.foster@in-advantage.com>
---
 drivers/phy/mscc/phy-ocelot-serdes.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/phy/mscc/phy-ocelot-serdes.c b/drivers/phy/mscc/phy-ocelot-serdes.c
index 76f596365176..ae1284e356e7 100644
--- a/drivers/phy/mscc/phy-ocelot-serdes.c
+++ b/drivers/phy/mscc/phy-ocelot-serdes.c
@@ -15,6 +15,7 @@
 #include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/regmap.h>
+#include <soc/mscc/ocelot.h>
 #include <soc/mscc/ocelot_hsio.h>
 #include <dt-bindings/phy/phy-ocelot-serdes.h>
 
@@ -492,8 +493,10 @@ static int serdes_phy_create(struct serdes_ctrl *ctrl, u8 idx, struct phy **phy)
 
 static int serdes_probe(struct platform_device *pdev)
 {
+	struct device *dev = &pdev->dev;
 	struct phy_provider *provider;
 	struct serdes_ctrl *ctrl;
+	struct resource *res;
 	unsigned int i;
 	int ret;
 
@@ -502,7 +505,15 @@ static int serdes_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	ctrl->dev = &pdev->dev;
+
 	ctrl->regs = syscon_node_to_regmap(pdev->dev.parent->of_node);
+	if (IS_ERR(ctrl->regs)) {
+		/* Fall back to using IORESOURCE_REG, if possible */
+		res = platform_get_resource(pdev, IORESOURCE_REG, 0);
+		if (!res)
+			ctrl->regs = ocelot_get_regmap_from_resource(dev, res);
+	}
+
 	if (IS_ERR(ctrl->regs))
 		return PTR_ERR(ctrl->regs);
 
-- 
2.25.1