net: dsa: microchip: Add KSZ8463 switch support to KSZ DSA driver

KSZ8463 switch is a 3-port switch based from KSZ8863.  Its major
difference from other KSZ SPI switches is its register access is not a
simple continual 8-bit transfer with automatic address increase but uses
a byte-enable mechanism specifying 8-bit, 16-bit, or 32-bit access.  Its
registers are also defined in 16-bit format because it shares a design
with a MAC controller using 16-bit access.  As a result some common
register accesses need to be re-arranged.

This patch adds the basic structure for using KSZ8463.  It cannot use the
same regmap table for other KSZ switches as it interprets the 16-bit
value as little-endian and its SPI commands are different.

KSZ8463 uses a byte-enable mechanism to specify 8-bit, 16-bit, and 32-bit
access.  The register is first shifted right by 2 then left by 4.  Extra
4 bits are added.  If the access is 8-bit one of the 4 bits is set.  If
the access is 16-bit two of the 4 bits are set.  If the access is 32-bit
all 4 bits are set.  The SPI command for read or write is then added.

Because of this register transformation separate SPI read and write
functions are provided for KSZ8463.

KSZ8463's internal PHYs use standard PHY register definitions so there is
no need to remap things.  However, the hardware has a bug that the high
word and low word of the PHY id are swapped.  In addition the port
registers are arranged differently so KSZ8463 has its own mapping for
port registers and PHY registers.  Therefore the PORT_CTRL_ADDR macro is
replaced with the get_port_addr helper function.

Signed-off-by: Tristram Ha <tristram.ha@microchip.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://patch.msgid.link/20250725001753.6330-3-Tristram.Ha@microchip.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 35 insertions, 2 deletions

diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index a08417df2ca4..a1eb39771bb9 100644
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -222,6 +222,7 @@ struct ksz_device {
 
 /* List of supported models */
 enum ksz_model {
+	KSZ8463,
 	KSZ8563,
 	KSZ8567,
 	KSZ8795,
@@ -484,6 +485,11 @@ static inline struct regmap *ksz_regmap_32(struct ksz_device *dev)
 	return dev->regmap[KSZ_REGMAP_32];
 }
 
+static inline bool ksz_is_ksz8463(struct ksz_device *dev)
+{
+	return dev->chip_id == KSZ8463_CHIP_ID;
+}
+
 static inline int ksz_read8(struct ksz_device *dev, u32 reg, u8 *val)
 {
 	unsigned int value;
@@ -709,12 +715,13 @@ static inline bool ksz_is_8895_family(struct ksz_device *dev)
 static inline bool is_ksz8(struct ksz_device *dev)
 {
 	return ksz_is_ksz87xx(dev) || ksz_is_ksz88x3(dev) ||
-	       ksz_is_8895_family(dev);
+	       ksz_is_8895_family(dev) || ksz_is_ksz8463(dev);
 }
 
 static inline bool is_ksz88xx(struct ksz_device *dev)
 {
-	return ksz_is_ksz88x3(dev) || ksz_is_8895_family(dev);
+	return ksz_is_ksz88x3(dev) || ksz_is_8895_family(dev) ||
+	       ksz_is_ksz8463(dev);
 }
 
 static inline bool is_ksz9477(struct ksz_device *dev)
@@ -761,6 +768,7 @@ static inline bool ksz_is_sgmii_port(struct ksz_device *dev, int port)
 #define REG_CHIP_ID0			0x00
 
 #define SW_FAMILY_ID_M			GENMASK(15, 8)
+#define KSZ84_FAMILY_ID			0x84
 #define KSZ87_FAMILY_ID			0x87
 #define KSZ88_FAMILY_ID			0x88
 #define KSZ8895_FAMILY_ID		0x95
@@ -939,4 +947,29 @@ static inline bool ksz_is_sgmii_port(struct ksz_device *dev, int port)
 		[KSZ_REGMAP_32] = KSZ_REGMAP_ENTRY(32, swp, (regbits), (regpad), (regalign)), \
 	}
 
+#define KSZ8463_REGMAP_ENTRY(width, regbits, regpad, regalign)		\
+	{								\
+		.name = #width,						\
+		.val_bits = (width),					\
+		.reg_stride = (width / 8),				\
+		.reg_bits = (regbits) + (regalign),			\
+		.pad_bits = (regpad),					\
+		.read = ksz8463_spi_read,				\
+		.write = ksz8463_spi_write,				\
+		.max_register = BIT(regbits) - 1,			\
+		.cache_type = REGCACHE_NONE,				\
+		.zero_flag_mask = 1,					\
+		.use_single_read = 1,					\
+		.use_single_write = 1,					\
+		.lock = ksz_regmap_lock,				\
+		.unlock = ksz_regmap_unlock,				\
+	}
+
+#define KSZ8463_REGMAP_TABLE(ksz, regbits, regpad, regalign)		\
+	static const struct regmap_config ksz##_regmap_config[] = {	\
+		[KSZ_REGMAP_8] = KSZ8463_REGMAP_ENTRY(8, (regbits), (regpad), (regalign)), \
+		[KSZ_REGMAP_16] = KSZ8463_REGMAP_ENTRY(16, (regbits), (regpad), (regalign)), \
+		[KSZ_REGMAP_32] = KSZ8463_REGMAP_ENTRY(32, (regbits), (regpad), (regalign)), \
+	}
+
 #endif