[net-next PATCH v12 07/13] net: mdio: regmap: add support for multiple valid addr

[Christian Marangi <ansuelsmth@gmail.com>]

Add support for multiple valid addr for mdio regmap. This can be done by
defining the new valid_addr_mask value in the mdio regmap config.

In such case, the PHY address is appended to the regmap regnum right
after the first 16 bit of the PHY register used for the read/write
operation.

The passed regmap will then extract the address from the passed regnum
and execute the needed operations accordingly.

Notice that if valid_addr_mask, the unique valid_addr in config is
ignored.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/mdio/mdio-regmap.c   | 14 +++++++++++++-
 include/linux/mdio/mdio-regmap.h |  9 +++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/mdio-regmap.c b/drivers/net/mdio/mdio-regmap.c
index 810ba0a736f0..8bfcd9e415c8 100644
--- a/drivers/net/mdio/mdio-regmap.c
+++ b/drivers/net/mdio/mdio-regmap.c
@@ -20,6 +20,7 @@
 struct mdio_regmap_priv {
 	struct regmap *regmap;
 	u32 valid_addr_mask;
+	bool append_addr;
 };
 
 static int mdio_regmap_read_c22(struct mii_bus *bus, int addr, int regnum)
@@ -31,6 +32,9 @@ static int mdio_regmap_read_c22(struct mii_bus *bus, int addr, int regnum)
 	if (!(ctx->valid_addr_mask & BIT(addr)))
 		return -ENODEV;
 
+	if (ctx->append_addr)
+		regnum |= FIELD_PREP(MDIO_REGMAP_PHY_ADDR, addr);
+
 	ret = regmap_read(ctx->regmap, regnum, &val);
 	if (ret < 0)
 		return ret;
@@ -46,6 +50,9 @@ static int mdio_regmap_write_c22(struct mii_bus *bus, int addr, int regnum,
 	if (!(ctx->valid_addr_mask & BIT(addr)))
 		return -ENODEV;
 
+	if (ctx->append_addr)
+		regnum |= FIELD_PREP(MDIO_REGMAP_PHY_ADDR, addr);
+
 	return regmap_write(ctx->regmap, regnum, val);
 }
 
@@ -65,7 +72,12 @@ struct mii_bus *devm_mdio_regmap_register(struct device *dev,
 
 	mr = mii->priv;
 	mr->regmap = config->regmap;
-	mr->valid_addr_mask = BIT(config->valid_addr);
+	if (config->valid_addr_mask) {
+		mr->valid_addr_mask = config->valid_addr_mask;
+		mr->append_addr = true;
+	} else {
+		mr->valid_addr_mask = BIT(config->valid_addr);
+	}
 
 	mii->name = DRV_NAME;
 	strscpy(mii->id, config->name, MII_BUS_ID_SIZE);
diff --git a/include/linux/mdio/mdio-regmap.h b/include/linux/mdio/mdio-regmap.h
index 679d9069846b..8c7061e39ccb 100644
--- a/include/linux/mdio/mdio-regmap.h
+++ b/include/linux/mdio/mdio-regmap.h
@@ -12,11 +12,20 @@
 struct device;
 struct regmap;
 
+/* If a non empty valid_addr_mask is passed, PHY address and
+ * read/write register are encoded in the regmap register
+ * by placing the register in the first 16 bits and the PHY address
+ * right after.
+ */
+#define MDIO_REGMAP_PHY_ADDR		GENMASK(20, 16)
+#define MDIO_REGMAP_PHY_REG		GENMASK(15, 0)
+
 struct mdio_regmap_config {
 	struct device *parent;
 	struct regmap *regmap;
 	char name[MII_BUS_ID_SIZE];
 	u8 valid_addr;
+	u32 valid_addr_mask;
 	bool autoscan;
 };
 
-- 
2.48.1