Merge branch 'dsa-LAN9303'

Juergen Borleis says:

====================
net: dsa: add SMSC/Microchip LAN9303 three port ethernet switch driver

The LAN9303 is a three port 10/100 ethernet switch with integrated phys
for the two external ethernet ports. The third port is an RMII/MII
interface to a host master network interface (e.g. fixed link).

While the LAN9303 device itself supports offload packet processing, this
driver does not make use of it yet. This driver just configures the device
to provide two separate network interfaces (which is the default state of
a DSA device).

Please note: the "MDIO managed mode" driver part isn't tested yet. I have
used and tested the "I2C managed mode" only.

Changes in v6:

- fix support to use the driver as a module (core, i2c and mdio)
- license info added in all parts of the driver (for module support)

Changes in v5:

- add missing include file to 'net/dsa/tag_lan9303.c'

Changes in v4:

- rebased on net-next, 'net/dsa/tag_lan9303.c' adapted to changed API

Changes in v3:

- 'ds_to_lan9303()' removed
- special PHY reg MII_LAN911X_SPECIAL_CONTROL_STATUS mapping removed
- compatible strings for I2C and MDIO are now different
- MDIO-managed-mode devicetree binding added (still compile time tested only)

Changes in v2:

- code moved to 'drivers/net/dsa'
- timeouts in completion wait loops
- macros instead of various magic numbers
- development code removed
- devicetree property names changed
- devicetree example adapted
- tried to avoid to mix 'switching' and 'forwarding'...

Comments are welcome.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/dsa/lan9303.txt

+SMSC/MicroChip LAN9303 three port ethernet switch
+-------------------------------------------------
+
+Required properties:
+
+- compatible: should be
+  - "smsc,lan9303-i2c" for I2C managed mode
+    or
+  - "smsc,lan9303-mdio" for mdio managed mode
+
+Optional properties:
+
+- reset-gpios: GPIO to be used to reset the whole device
+- reset-duration: reset duration in milliseconds, defaults to 200 ms
+
+Subnodes:
+
+The integrated switch subnode should be specified according to the binding
+described in dsa/dsa.txt. The CPU port of this switch is always port 0.
+
+Note: always use 'reg = <0/1/2>;' for the three DSA ports, even if the device is
+configured to use 1/2/3 instead. This hardware configuration will be
+auto-detected and mapped accordingly.
+
+Example:
+
+I2C managed mode:
+
+	master: masterdevice@X {
+		status = "okay";
+
+		fixed-link { /* RMII fixed link to LAN9303 */
+			speed = <100>;
+			full-duplex;
+		};
+	};
+
+	switch: switch@a {
+		compatible = "smsc,lan9303-i2c";
+		reg = <0xa>;
+		status = "okay";
+		reset-gpios = <&gpio7 6 GPIO_ACTIVE_LOW>;
+		reset-duration = <200>;
+
+		ports {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			port@0 { /* RMII fixed link to master */
+				reg = <0>;
+				label = "cpu";
+				ethernet = <&master>;
+			};
+
+			port@1 { /* external port 1 */
+				reg = <1>;
+				label = "lan1;
+			};
+
+			port@2 { /* external port 2 */
+				reg = <2>;
+				label = "lan2";
+			};
+		};
+	};
+
+MDIO managed mode:
+
+	master: masterdevice@X {
+		status = "okay";
+		phy-handle = <&switch>;
+
+		mdio {
+			#address-cells = <1>;
+			#size-cells = <0>;
+
+			switch: switch-phy@0 {
+				compatible = "smsc,lan9303-mdio";
+				reg = <0>;
+				reset-gpios = <&gpio7 6 GPIO_ACTIVE_LOW>;
+				reset-duration = <100>;
+
+				ports {
+					#address-cells = <1>;
+					#size-cells = <0>;
+
+					port@0 {
+						reg = <0>;
+						label = "cpu";
+						ethernet = <&master>;
+					};
+
+					port@1 { /* external port 1 */
+						reg = <1>;
+						label = "lan1;
+					};
+
+					port@2 { /* external port 2 */
+						reg = <2>;
+						label = "lan2";
+					};
+				};
+			};
+		};
+	};

drivers/net/dsa/Kconfig

@@ -50,4 +50,28 @@ config NET_DSA_MT7530
 	  This enables support for the Mediatek MT7530 Ethernet switch
 	  chip.
 
+config NET_DSA_SMSC_LAN9303
+	tristate
+	select NET_DSA_TAG_LAN9303
+	---help---
+	  This enables support for the SMSC/Microchip LAN9303 3 port ethernet
+	  switch chips.
+
+config NET_DSA_SMSC_LAN9303_I2C
+	tristate "SMSC/Microchip LAN9303 3-ports 10/100 ethernet switch in I2C managed mode"
+	depends on NET_DSA
+	select NET_DSA_SMSC_LAN9303
+	select REGMAP_I2C
+	---help---
+	  Enable access functions if the SMSC/Microchip LAN9303 is configured
+	  for I2C managed mode.
+
+config NET_DSA_SMSC_LAN9303_MDIO
+	tristate "SMSC/Microchip LAN9303 3-ports 10/100 ethernet switch in MDIO managed mode"
+	depends on NET_DSA
+	select NET_DSA_SMSC_LAN9303
+	---help---
+	  Enable access functions if the SMSC/Microchip LAN9303 is configured
+	  for MDIO managed mode.
+
 endmenu

drivers/net/dsa/Makefile

@@ -3,6 +3,9 @@ obj-$(CONFIG_NET_DSA_BCM_SF2)	+= bcm-sf2.o
 bcm-sf2-objs			:= bcm_sf2.o bcm_sf2_cfp.o
 obj-$(CONFIG_NET_DSA_QCA8K)	+= qca8k.o
 obj-$(CONFIG_NET_DSA_MT7530)	+= mt7530.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303) += lan9303-core.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_I2C) += lan9303_i2c.o
+obj-$(CONFIG_NET_DSA_SMSC_LAN9303_MDIO) += lan9303_mdio.o
 obj-y				+= b53/
 obj-y				+= mv88e6xxx/
 obj-$(CONFIG_NET_DSA_LOOP)	+= dsa_loop.o dsa_loop_bdinfo.o

drivers/net/dsa/lan9303-core.c

+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regmap.h>
+#include <linux/mutex.h>
+#include <linux/mii.h>
+
+#include "lan9303.h"
+
+#define LAN9303_CHIP_REV 0x14
+# define LAN9303_CHIP_ID 0x9303
+#define LAN9303_IRQ_CFG 0x15
+# define LAN9303_IRQ_CFG_IRQ_ENABLE BIT(8)
+# define LAN9303_IRQ_CFG_IRQ_POL BIT(4)
+# define LAN9303_IRQ_CFG_IRQ_TYPE BIT(0)
+#define LAN9303_INT_STS 0x16
+# define LAN9303_INT_STS_PHY_INT2 BIT(27)
+# define LAN9303_INT_STS_PHY_INT1 BIT(26)
+#define LAN9303_INT_EN 0x17
+# define LAN9303_INT_EN_PHY_INT2_EN BIT(27)
+# define LAN9303_INT_EN_PHY_INT1_EN BIT(26)
+#define LAN9303_HW_CFG 0x1D
+# define LAN9303_HW_CFG_READY BIT(27)
+# define LAN9303_HW_CFG_AMDX_EN_PORT2 BIT(26)
+# define LAN9303_HW_CFG_AMDX_EN_PORT1 BIT(25)
+#define LAN9303_PMI_DATA 0x29
+#define LAN9303_PMI_ACCESS 0x2A
+# define LAN9303_PMI_ACCESS_PHY_ADDR(x) (((x) & 0x1f) << 11)
+# define LAN9303_PMI_ACCESS_MIIRINDA(x) (((x) & 0x1f) << 6)
+# define LAN9303_PMI_ACCESS_MII_BUSY BIT(0)
+# define LAN9303_PMI_ACCESS_MII_WRITE BIT(1)
+#define LAN9303_MANUAL_FC_1 0x68
+#define LAN9303_MANUAL_FC_2 0x69
+#define LAN9303_MANUAL_FC_0 0x6a
+#define LAN9303_SWITCH_CSR_DATA 0x6b
+#define LAN9303_SWITCH_CSR_CMD 0x6c
+#define LAN9303_SWITCH_CSR_CMD_BUSY BIT(31)
+#define LAN9303_SWITCH_CSR_CMD_RW BIT(30)
+#define LAN9303_SWITCH_CSR_CMD_LANES (BIT(19) | BIT(18) | BIT(17) | BIT(16))
+#define LAN9303_VIRT_PHY_BASE 0x70
+#define LAN9303_VIRT_SPECIAL_CTRL 0x77
+
+#define LAN9303_SW_DEV_ID 0x0000
+#define LAN9303_SW_RESET 0x0001
+#define LAN9303_SW_RESET_RESET BIT(0)
+#define LAN9303_SW_IMR 0x0004
+#define LAN9303_SW_IPR 0x0005
+#define LAN9303_MAC_VER_ID_0 0x0400
+#define LAN9303_MAC_RX_CFG_0 0x0401
+# define LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES BIT(1)
+# define LAN9303_MAC_RX_CFG_X_RX_ENABLE BIT(0)
+#define LAN9303_MAC_RX_UNDSZE_CNT_0 0x0410
+#define LAN9303_MAC_RX_64_CNT_0 0x0411
+#define LAN9303_MAC_RX_127_CNT_0 0x0412
+#define LAN9303_MAC_RX_255_CNT_0 0x413
+#define LAN9303_MAC_RX_511_CNT_0 0x0414
+#define LAN9303_MAC_RX_1023_CNT_0 0x0415
+#define LAN9303_MAC_RX_MAX_CNT_0 0x0416
+#define LAN9303_MAC_RX_OVRSZE_CNT_0 0x0417
+#define LAN9303_MAC_RX_PKTOK_CNT_0 0x0418
+#define LAN9303_MAC_RX_CRCERR_CNT_0 0x0419
+#define LAN9303_MAC_RX_MULCST_CNT_0 0x041a
+#define LAN9303_MAC_RX_BRDCST_CNT_0 0x041b
+#define LAN9303_MAC_RX_PAUSE_CNT_0 0x041c
+#define LAN9303_MAC_RX_FRAG_CNT_0 0x041d
+#define LAN9303_MAC_RX_JABB_CNT_0 0x041e
+#define LAN9303_MAC_RX_ALIGN_CNT_0 0x041f
+#define LAN9303_MAC_RX_PKTLEN_CNT_0 0x0420
+#define LAN9303_MAC_RX_GOODPKTLEN_CNT_0 0x0421
+#define LAN9303_MAC_RX_SYMBL_CNT_0 0x0422
+#define LAN9303_MAC_RX_CTLFRM_CNT_0 0x0423
+
+#define LAN9303_MAC_TX_CFG_0 0x0440
+# define LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT (21 << 2)
+# define LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE BIT(1)
+# define LAN9303_MAC_TX_CFG_X_TX_ENABLE BIT(0)
+#define LAN9303_MAC_TX_DEFER_CNT_0 0x0451
+#define LAN9303_MAC_TX_PAUSE_CNT_0 0x0452
+#define LAN9303_MAC_TX_PKTOK_CNT_0 0x0453
+#define LAN9303_MAC_TX_64_CNT_0 0x0454
+#define LAN9303_MAC_TX_127_CNT_0 0x0455
+#define LAN9303_MAC_TX_255_CNT_0 0x0456
+#define LAN9303_MAC_TX_511_CNT_0 0x0457
+#define LAN9303_MAC_TX_1023_CNT_0 0x0458
+#define LAN9303_MAC_TX_MAX_CNT_0 0x0459
+#define LAN9303_MAC_TX_UNDSZE_CNT_0 0x045a
+#define LAN9303_MAC_TX_PKTLEN_CNT_0 0x045c
+#define LAN9303_MAC_TX_BRDCST_CNT_0 0x045d
+#define LAN9303_MAC_TX_MULCST_CNT_0 0x045e
+#define LAN9303_MAC_TX_LATECOL_0 0x045f
+#define LAN9303_MAC_TX_EXCOL_CNT_0 0x0460
+#define LAN9303_MAC_TX_SNGLECOL_CNT_0 0x0461
+#define LAN9303_MAC_TX_MULTICOL_CNT_0 0x0462
+#define LAN9303_MAC_TX_TOTALCOL_CNT_0 0x0463
+
+#define LAN9303_MAC_VER_ID_1 0x0800
+#define LAN9303_MAC_RX_CFG_1 0x0801
+#define LAN9303_MAC_TX_CFG_1 0x0840
+#define LAN9303_MAC_VER_ID_2 0x0c00
+#define LAN9303_MAC_RX_CFG_2 0x0c01
+#define LAN9303_MAC_TX_CFG_2 0x0c40
+#define LAN9303_SWE_ALR_CMD 0x1800
+#define LAN9303_SWE_VLAN_CMD 0x180b
+# define LAN9303_SWE_VLAN_CMD_RNW BIT(5)
+# define LAN9303_SWE_VLAN_CMD_PVIDNVLAN BIT(4)
+#define LAN9303_SWE_VLAN_WR_DATA 0x180c
+#define LAN9303_SWE_VLAN_RD_DATA 0x180e
+# define LAN9303_SWE_VLAN_MEMBER_PORT2 BIT(17)
+# define LAN9303_SWE_VLAN_UNTAG_PORT2 BIT(16)
+# define LAN9303_SWE_VLAN_MEMBER_PORT1 BIT(15)
+# define LAN9303_SWE_VLAN_UNTAG_PORT1 BIT(14)
+# define LAN9303_SWE_VLAN_MEMBER_PORT0 BIT(13)
+# define LAN9303_SWE_VLAN_UNTAG_PORT0 BIT(12)
+#define LAN9303_SWE_VLAN_CMD_STS 0x1810
+#define LAN9303_SWE_GLB_INGRESS_CFG 0x1840
+#define LAN9303_SWE_PORT_STATE 0x1843
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT2 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT2 BIT(5)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT2 BIT(4)
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT1 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT1 BIT(3)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT1 BIT(2)
+# define LAN9303_SWE_PORT_STATE_FORWARDING_PORT0 (0)
+# define LAN9303_SWE_PORT_STATE_LEARNING_PORT0 BIT(1)
+# define LAN9303_SWE_PORT_STATE_BLOCKING_PORT0 BIT(0)
+#define LAN9303_SWE_PORT_MIRROR 0x1846
+# define LAN9303_SWE_PORT_MIRROR_SNIFF_ALL BIT(8)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT2 BIT(7)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT1 BIT(6)
+# define LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT0 BIT(5)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT2 BIT(4)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT1 BIT(3)
+# define LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT0 BIT(2)
+# define LAN9303_SWE_PORT_MIRROR_ENABLE_RX_MIRRORING BIT(1)
+# define LAN9303_SWE_PORT_MIRROR_ENABLE_TX_MIRRORING BIT(0)
+#define LAN9303_SWE_INGRESS_PORT_TYPE 0x1847
+#define LAN9303_BM_CFG 0x1c00
+#define LAN9303_BM_EGRSS_PORT_TYPE 0x1c0c
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT2 (BIT(17) | BIT(16))
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT1 (BIT(9) | BIT(8))
+# define LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT0 (BIT(1) | BIT(0))
+
+#define LAN9303_PORT_0_OFFSET 0x400
+#define LAN9303_PORT_1_OFFSET 0x800
+#define LAN9303_PORT_2_OFFSET 0xc00
+
+/* the built-in PHYs are of type LAN911X */
+#define MII_LAN911X_SPECIAL_MODES 0x12
+#define MII_LAN911X_SPECIAL_CONTROL_STATUS 0x1f
+
+static const struct regmap_range lan9303_valid_regs[] = {
+	regmap_reg_range(0x14, 0x17), /* misc, interrupt */
+	regmap_reg_range(0x19, 0x19), /* endian test */
+	regmap_reg_range(0x1d, 0x1d), /* hardware config */
+	regmap_reg_range(0x23, 0x24), /* general purpose timer */
+	regmap_reg_range(0x27, 0x27), /* counter */
+	regmap_reg_range(0x29, 0x2a), /* PMI index regs */
+	regmap_reg_range(0x68, 0x6a), /* flow control */
+	regmap_reg_range(0x6b, 0x6c), /* switch fabric indirect regs */
+	regmap_reg_range(0x6d, 0x6f), /* misc */
+	regmap_reg_range(0x70, 0x77), /* virtual phy */
+	regmap_reg_range(0x78, 0x7a), /* GPIO */
+	regmap_reg_range(0x7c, 0x7e), /* MAC & reset */
+	regmap_reg_range(0x80, 0xb7), /* switch fabric direct regs (wr only) */
+};
+
+static const struct regmap_range lan9303_reserved_ranges[] = {
+	regmap_reg_range(0x00, 0x13),
+	regmap_reg_range(0x18, 0x18),
+	regmap_reg_range(0x1a, 0x1c),
+	regmap_reg_range(0x1e, 0x22),
+	regmap_reg_range(0x25, 0x26),
+	regmap_reg_range(0x28, 0x28),
+	regmap_reg_range(0x2b, 0x67),
+	regmap_reg_range(0x7b, 0x7b),
+	regmap_reg_range(0x7f, 0x7f),
+	regmap_reg_range(0xb8, 0xff),
+};
+
+const struct regmap_access_table lan9303_register_set = {
+	.yes_ranges = lan9303_valid_regs,
+	.n_yes_ranges = ARRAY_SIZE(lan9303_valid_regs),
+	.no_ranges = lan9303_reserved_ranges,
+	.n_no_ranges = ARRAY_SIZE(lan9303_reserved_ranges),
+};
+EXPORT_SYMBOL(lan9303_register_set);
+
+static int lan9303_read(struct regmap *regmap, unsigned int offset, u32 *reg)
+{
+	int ret, i;
+
+	/* we can lose arbitration for the I2C case, because the device
+	 * tries to detect and read an external EEPROM after reset and acts as
+	 * a master on the shared I2C bus itself. This conflicts with our
+	 * attempts to access the device as a slave at the same moment.
+	 */
+	for (i = 0; i < 5; i++) {
+		ret = regmap_read(regmap, offset, reg);
+		if (!ret)
+			return 0;
+		if (ret != -EAGAIN)
+			break;
+		msleep(500);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_virt_phy_reg_read(struct lan9303 *chip, int regnum)
+{
+	int ret;
+	u32 val;
+
+	if (regnum > MII_EXPANSION)
+		return -EINVAL;
+
+	ret = lan9303_read(chip->regmap, LAN9303_VIRT_PHY_BASE + regnum, &val);
+	if (ret)
+		return ret;
+
+	return val & 0xffff;
+}
+
+static int lan9303_virt_phy_reg_write(struct lan9303 *chip, int regnum, u16 val)
+{
+	if (regnum > MII_EXPANSION)
+		return -EINVAL;
+
+	return regmap_write(chip->regmap, LAN9303_VIRT_PHY_BASE + regnum, val);
+}
+
+static int lan9303_port_phy_reg_wait_for_completion(struct lan9303 *chip)
+{
+	int ret, i;
+	u32 reg;
+
+	for (i = 0; i < 25; i++) {
+		ret = lan9303_read(chip->regmap, LAN9303_PMI_ACCESS, &reg);
+		if (ret) {
+			dev_err(chip->dev,
+				"Failed to read pmi access status: %d\n", ret);
+			return ret;
+		}
+		if (!(reg & LAN9303_PMI_ACCESS_MII_BUSY))
+			return 0;
+		msleep(1);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_port_phy_reg_read(struct lan9303 *chip, int addr, int regnum)
+{
+	int ret;
+	u32 val;
+
+	val = LAN9303_PMI_ACCESS_PHY_ADDR(addr);
+	val |= LAN9303_PMI_ACCESS_MIIRINDA(regnum);
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* start the MII read cycle */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_ACCESS, val);
+	if (ret)
+		goto on_error;
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* read the result of this operation */
+	ret = lan9303_read(chip->regmap, LAN9303_PMI_DATA, &val);
+	if (ret)
+		goto on_error;
+
+	mutex_unlock(&chip->indirect_mutex);
+
+	return val & 0xffff;
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_phy_reg_write(struct lan9303 *chip, int addr, int regnum,
+				 unsigned int val)
+{
+	int ret;
+	u32 reg;
+
+	reg = LAN9303_PMI_ACCESS_PHY_ADDR(addr);
+	reg |= LAN9303_PMI_ACCESS_MIIRINDA(regnum);
+	reg |= LAN9303_PMI_ACCESS_MII_WRITE;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_port_phy_reg_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* write the data first... */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_DATA, val);
+	if (ret)
+		goto on_error;
+
+	/* ...then start the MII write cycle */
+	ret = regmap_write(chip->regmap, LAN9303_PMI_ACCESS, reg);
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_switch_wait_for_completion(struct lan9303 *chip)
+{
+	int ret, i;
+	u32 reg;
+
+	for (i = 0; i < 25; i++) {
+		ret = lan9303_read(chip->regmap, LAN9303_SWITCH_CSR_CMD, &reg);
+		if (ret) {
+			dev_err(chip->dev,
+				"Failed to read csr command status: %d\n", ret);
+			return ret;
+		}
+		if (!(reg & LAN9303_SWITCH_CSR_CMD_BUSY))
+			return 0;
+		msleep(1);
+	}
+
+	return -EIO;
+}
+
+static int lan9303_write_switch_reg(struct lan9303 *chip, u16 regnum, u32 val)
+{
+	u32 reg;
+	int ret;
+
+	reg = regnum;
+	reg |= LAN9303_SWITCH_CSR_CMD_LANES;
+	reg |= LAN9303_SWITCH_CSR_CMD_BUSY;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_DATA, val);
+	if (ret) {
+		dev_err(chip->dev, "Failed to write csr data reg: %d\n", ret);
+		goto on_error;
+	}
+
+	/* trigger write */
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_CMD, reg);
+	if (ret)
+		dev_err(chip->dev, "Failed to write csr command reg: %d\n",
+			ret);
+
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_read_switch_reg(struct lan9303 *chip, u16 regnum, u32 *val)
+{
+	u32 reg;
+	int ret;
+
+	reg = regnum;
+	reg |= LAN9303_SWITCH_CSR_CMD_LANES;
+	reg |= LAN9303_SWITCH_CSR_CMD_RW;
+	reg |= LAN9303_SWITCH_CSR_CMD_BUSY;
+
+	mutex_lock(&chip->indirect_mutex);
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	/* trigger read */
+	ret = regmap_write(chip->regmap, LAN9303_SWITCH_CSR_CMD, reg);
+	if (ret) {
+		dev_err(chip->dev, "Failed to write csr command reg: %d\n",
+			ret);
+		goto on_error;
+	}
+
+	ret = lan9303_switch_wait_for_completion(chip);
+	if (ret)
+		goto on_error;
+
+	ret = lan9303_read(chip->regmap, LAN9303_SWITCH_CSR_DATA, val);
+	if (ret)
+		dev_err(chip->dev, "Failed to read csr data reg: %d\n", ret);
+on_error:
+	mutex_unlock(&chip->indirect_mutex);
+	return ret;
+}
+
+static int lan9303_detect_phy_setup(struct lan9303 *chip)
+{
+	int reg;
+
+	/* depending on the 'phy_addr_sel_strap' setting, the three phys are
+	 * using IDs 0-1-2 or IDs 1-2-3. We cannot read back the
+	 * 'phy_addr_sel_strap' setting directly, so we need a test, which
+	 * configuration is active:
+	 * Special reg 18 of phy 3 reads as 0x0000, if 'phy_addr_sel_strap' is 0
+	 * and the IDs are 0-1-2, else it contains something different from
+	 * 0x0000, which means 'phy_addr_sel_strap' is 1 and the IDs are 1-2-3.
+	 */
+	reg = lan9303_port_phy_reg_read(chip, 3, MII_LAN911X_SPECIAL_MODES);
+	if (reg < 0) {
+		dev_err(chip->dev, "Failed to detect phy config: %d\n", reg);
+		return reg;
+	}
+
+	if (reg != 0)
+		chip->phy_addr_sel_strap = 1;
+	else
+		chip->phy_addr_sel_strap = 0;
+
+	dev_dbg(chip->dev, "Phy setup '%s' detected\n",
+		chip->phy_addr_sel_strap ? "1-2-3" : "0-1-2");
+
+	return 0;
+}
+
+#define LAN9303_MAC_RX_CFG_OFFS (LAN9303_MAC_RX_CFG_0 - LAN9303_PORT_0_OFFSET)
+#define LAN9303_MAC_TX_CFG_OFFS (LAN9303_MAC_TX_CFG_0 - LAN9303_PORT_0_OFFSET)
+
+static int lan9303_disable_packet_processing(struct lan9303 *chip,
+					     unsigned int port)
+{
+	int ret;
+
+	/* disable RX, but keep register reset default values else */
+	ret = lan9303_write_switch_reg(chip, LAN9303_MAC_RX_CFG_OFFS + port,
+				       LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES);
+	if (ret)
+		return ret;
+
+	/* disable TX, but keep register reset default values else */
+	return lan9303_write_switch_reg(chip, LAN9303_MAC_TX_CFG_OFFS + port,
+				LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT |
+				LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE);
+}
+
+static int lan9303_enable_packet_processing(struct lan9303 *chip,
+					    unsigned int port)
+{
+	int ret;
+
+	/* enable RX and keep register reset default values else */
+	ret = lan9303_write_switch_reg(chip, LAN9303_MAC_RX_CFG_OFFS + port,
+				       LAN9303_MAC_RX_CFG_X_REJECT_MAC_TYPES |
+				       LAN9303_MAC_RX_CFG_X_RX_ENABLE);
+	if (ret)
+		return ret;
+
+	/* enable TX and keep register reset default values else */
+	return lan9303_write_switch_reg(chip, LAN9303_MAC_TX_CFG_OFFS + port,
+				LAN9303_MAC_TX_CFG_X_TX_IFG_CONFIG_DEFAULT |
+				LAN9303_MAC_TX_CFG_X_TX_PAD_ENABLE |
+				LAN9303_MAC_TX_CFG_X_TX_ENABLE);
+}
+
+/* We want a special working switch:
+ * - do not forward packets between port 1 and 2
+ * - forward everything from port 1 to port 0
+ * - forward everything from port 2 to port 0
+ * - forward special tagged packets from port 0 to port 1 *or* port 2
+ */
+static int lan9303_separate_ports(struct lan9303 *chip)
+{
+	int ret;
+
+	ret = lan9303_write_switch_reg(chip, LAN9303_SWE_PORT_MIRROR,
+				LAN9303_SWE_PORT_MIRROR_SNIFFER_PORT0 |
+				LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT1 |
+				LAN9303_SWE_PORT_MIRROR_MIRRORED_PORT2 |
+				LAN9303_SWE_PORT_MIRROR_ENABLE_RX_MIRRORING |
+				LAN9303_SWE_PORT_MIRROR_SNIFF_ALL);
+	if (ret)
+		return ret;
+
+	/* enable defining the destination port via special VLAN tagging
+	 * for port 0
+	 */
+	ret = lan9303_write_switch_reg(chip, LAN9303_SWE_INGRESS_PORT_TYPE,
+				       0x03);
+	if (ret)
+		return ret;
+
+	/* tag incoming packets at port 1 and 2 on their way to port 0 to be
+	 * able to discover their source port
+	 */
+	ret = lan9303_write_switch_reg(chip, LAN9303_BM_EGRSS_PORT_TYPE,
+			LAN9303_BM_EGRSS_PORT_TYPE_SPECIAL_TAG_PORT0);
+	if (ret)
+		return ret;
+
+	/* prevent port 1 and 2 from forwarding packets by their own */
+	return lan9303_write_switch_reg(chip, LAN9303_SWE_PORT_STATE,
+				LAN9303_SWE_PORT_STATE_FORWARDING_PORT0 |
+				LAN9303_SWE_PORT_STATE_BLOCKING_PORT1 |
+				LAN9303_SWE_PORT_STATE_BLOCKING_PORT2);
+}
+
+static int lan9303_handle_reset(struct lan9303 *chip)
+{
+	if (!chip->reset_gpio)
+		return 0;
+
+	if (chip->reset_duration != 0)
+		msleep(chip->reset_duration);
+
+	/* release (deassert) reset and activate the device */
+	gpiod_set_value_cansleep(chip->reset_gpio, 0);
+
+	return 0;
+}
+
+/* stop processing packets for all ports */
+static int lan9303_disable_processing(struct lan9303 *chip)
+{
+	int ret;
+
+	ret = lan9303_disable_packet_processing(chip, LAN9303_PORT_0_OFFSET);
+	if (ret)
+		return ret;
+	ret = lan9303_disable_packet_processing(chip, LAN9303_PORT_1_OFFSET);
+	if (ret)
+		return ret;
+	return lan9303_disable_packet_processing(chip, LAN9303_PORT_2_OFFSET);
+}
+
+static int lan9303_check_device(struct lan9303 *chip)
+{
+	int ret;
+	u32 reg;
+
+	ret = lan9303_read(chip->regmap, LAN9303_CHIP_REV, &reg);
+	if (ret) {
+		dev_err(chip->dev, "failed to read chip revision register: %d\n",
+			ret);
+		if (!chip->reset_gpio) {
+			dev_dbg(chip->dev,
+				"hint: maybe failed due to missing reset GPIO\n");
+		}
+		return ret;
+	}
+
+	if ((reg >> 16) != LAN9303_CHIP_ID) {
+		dev_err(chip->dev, "expecting LAN9303 chip, but found: %X\n",
+			reg >> 16);
+		return ret;
+	}
+
+	/* The default state of the LAN9303 device is to forward packets between
+	 * all ports (if not configured differently by an external EEPROM).
+	 * The initial state of a DSA device must be forwarding packets only
+	 * between the external and the internal ports and no forwarding
+	 * between the external ports. In preparation we stop packet handling
+	 * at all for now until the LAN9303 device is re-programmed accordingly.
+	 */
+	ret = lan9303_disable_processing(chip);
+	if (ret)
+		dev_warn(chip->dev, "failed to disable switching %d\n", ret);
+
+	dev_info(chip->dev, "Found LAN9303 rev. %u\n", reg & 0xffff);
+
+	ret = lan9303_detect_phy_setup(chip);
+	if (ret) {
+		dev_err(chip->dev,
+			"failed to discover phy bootstrap setup: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+/* ---------------------------- DSA -----------------------------------*/
+
+static enum dsa_tag_protocol lan9303_get_tag_protocol(struct dsa_switch *ds)
+{
+	return DSA_TAG_PROTO_LAN9303;
+}
+
+static int lan9303_setup(struct dsa_switch *ds)
+{
+	struct lan9303 *chip = ds->priv;
+	int ret;
+
+	/* Make sure that port 0 is the cpu port */
+	if (!dsa_is_cpu_port(ds, 0)) {
+		dev_err(chip->dev, "port 0 is not the CPU port\n");
+		return -EINVAL;
+	}
+
+	ret = lan9303_separate_ports(chip);
+	if (ret)
+		dev_err(chip->dev, "failed to separate ports %d\n", ret);
+
+	ret = lan9303_enable_packet_processing(chip, LAN9303_PORT_0_OFFSET);
+	if (ret)
+		dev_err(chip->dev, "failed to re-enable switching %d\n", ret);
+
+	return 0;
+}
+
+struct lan9303_mib_desc {
+	unsigned int offset; /* offset of first MAC */
+	const char *name;
+};
+
+static const struct lan9303_mib_desc lan9303_mib[] = {
+	{ .offset = LAN9303_MAC_RX_BRDCST_CNT_0, .name = "RxBroad", },
+	{ .offset = LAN9303_MAC_RX_PAUSE_CNT_0, .name = "RxPause", },
+	{ .offset = LAN9303_MAC_RX_MULCST_CNT_0, .name = "RxMulti", },
+	{ .offset = LAN9303_MAC_RX_PKTOK_CNT_0, .name = "RxOk", },
+	{ .offset = LAN9303_MAC_RX_CRCERR_CNT_0, .name = "RxCrcErr", },
+	{ .offset = LAN9303_MAC_RX_ALIGN_CNT_0, .name = "RxAlignErr", },
+	{ .offset = LAN9303_MAC_RX_JABB_CNT_0, .name = "RxJabber", },
+	{ .offset = LAN9303_MAC_RX_FRAG_CNT_0, .name = "RxFragment", },
+	{ .offset = LAN9303_MAC_RX_64_CNT_0, .name = "Rx64Byte", },
+	{ .offset = LAN9303_MAC_RX_127_CNT_0, .name = "Rx128Byte", },
+	{ .offset = LAN9303_MAC_RX_255_CNT_0, .name = "Rx256Byte", },
+	{ .offset = LAN9303_MAC_RX_511_CNT_0, .name = "Rx512Byte", },
+	{ .offset = LAN9303_MAC_RX_1023_CNT_0, .name = "Rx1024Byte", },
+	{ .offset = LAN9303_MAC_RX_MAX_CNT_0, .name = "RxMaxByte", },
+	{ .offset = LAN9303_MAC_RX_PKTLEN_CNT_0, .name = "RxByteCnt", },
+	{ .offset = LAN9303_MAC_RX_SYMBL_CNT_0, .name = "RxSymbolCnt", },
+	{ .offset = LAN9303_MAC_RX_CTLFRM_CNT_0, .name = "RxCfs", },
+	{ .offset = LAN9303_MAC_RX_OVRSZE_CNT_0, .name = "RxOverFlow", },
+	{ .offset = LAN9303_MAC_TX_UNDSZE_CNT_0, .name = "TxShort", },
+	{ .offset = LAN9303_MAC_TX_BRDCST_CNT_0, .name = "TxBroad", },
+	{ .offset = LAN9303_MAC_TX_PAUSE_CNT_0, .name = "TxPause", },
+	{ .offset = LAN9303_MAC_TX_MULCST_CNT_0, .name = "TxMulti", },
+	{ .offset = LAN9303_MAC_RX_UNDSZE_CNT_0, .name = "TxUnderRun", },
+	{ .offset = LAN9303_MAC_TX_64_CNT_0, .name = "Tx64Byte", },
+	{ .offset = LAN9303_MAC_TX_127_CNT_0, .name = "Tx128Byte", },
+	{ .offset = LAN9303_MAC_TX_255_CNT_0, .name = "Tx256Byte", },
+	{ .offset = LAN9303_MAC_TX_511_CNT_0, .name = "Tx512Byte", },
+	{ .offset = LAN9303_MAC_TX_1023_CNT_0, .name = "Tx1024Byte", },
+	{ .offset = LAN9303_MAC_TX_MAX_CNT_0, .name = "TxMaxByte", },
+	{ .offset = LAN9303_MAC_TX_PKTLEN_CNT_0, .name = "TxByteCnt", },
+	{ .offset = LAN9303_MAC_TX_PKTOK_CNT_0, .name = "TxOk", },
+	{ .offset = LAN9303_MAC_TX_TOTALCOL_CNT_0, .name = "TxCollision", },
+	{ .offset = LAN9303_MAC_TX_MULTICOL_CNT_0, .name = "TxMultiCol", },
+	{ .offset = LAN9303_MAC_TX_SNGLECOL_CNT_0, .name = "TxSingleCol", },
+	{ .offset = LAN9303_MAC_TX_EXCOL_CNT_0, .name = "TxExcCol", },
+	{ .offset = LAN9303_MAC_TX_DEFER_CNT_0, .name = "TxDefer", },
+	{ .offset = LAN9303_MAC_TX_LATECOL_0, .name = "TxLateCol", },
+};
+
+static void lan9303_get_strings(struct dsa_switch *ds, int port, uint8_t *data)
+{
+	unsigned int u;
+
+	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++) {
+		strncpy(data + u * ETH_GSTRING_LEN, lan9303_mib[u].name,
+			ETH_GSTRING_LEN);
+	}
+}
+
+static void lan9303_get_ethtool_stats(struct dsa_switch *ds, int port,
+				      uint64_t *data)
+{
+	struct lan9303 *chip = ds->priv;
+	u32 reg;
+	unsigned int u, poff;
+	int ret;
+
+	poff = port * 0x400;
+
+	for (u = 0; u < ARRAY_SIZE(lan9303_mib); u++) {
+		ret = lan9303_read_switch_reg(chip,
+					      lan9303_mib[u].offset + poff,
+					      &reg);
+		if (ret)
+			dev_warn(chip->dev, "Reading status reg %u failed\n",
+				 lan9303_mib[u].offset + poff);
+		data[u] = reg;
+	}
+}
+
+static int lan9303_get_sset_count(struct dsa_switch *ds)
+{
+	return ARRAY_SIZE(lan9303_mib);
+}
+
+static int lan9303_phy_read(struct dsa_switch *ds, int phy, int regnum)
+{
+	struct lan9303 *chip = ds->priv;
+	int phy_base = chip->phy_addr_sel_strap;
+
+	if (phy == phy_base)
+		return lan9303_virt_phy_reg_read(chip, regnum);
+	if (phy > phy_base + 2)
+		return -ENODEV;
+
+	return lan9303_port_phy_reg_read(chip, phy, regnum);
+}
+
+static int lan9303_phy_write(struct dsa_switch *ds, int phy, int regnum,
+			     u16 val)
+{
+	struct lan9303 *chip = ds->priv;
+	int phy_base = chip->phy_addr_sel_strap;
+
+	if (phy == phy_base)
+		return lan9303_virt_phy_reg_write(chip, regnum, val);
+	if (phy > phy_base + 2)
+		return -ENODEV;
+
+	return lan9303_phy_reg_write(chip, phy, regnum, val);
+}
+
+static int lan9303_port_enable(struct dsa_switch *ds, int port,
+			       struct phy_device *phy)
+{
+	struct lan9303 *chip = ds->priv;
+
+	/* enable internal packet processing */
+	switch (port) {
+	case 1:
+		return lan9303_enable_packet_processing(chip,
+							LAN9303_PORT_1_OFFSET);
+	case 2:
+		return lan9303_enable_packet_processing(chip,
+							LAN9303_PORT_2_OFFSET);
+	default:
+		dev_dbg(chip->dev,
+			"Error: request to power up invalid port %d\n", port);
+	}
+
+	return -ENODEV;
+}
+
+static void lan9303_port_disable(struct dsa_switch *ds, int port,
+				 struct phy_device *phy)
+{
+	struct lan9303 *chip = ds->priv;
+
+	/* disable internal packet processing */
+	switch (port) {
+	case 1:
+		lan9303_disable_packet_processing(chip, LAN9303_PORT_1_OFFSET);
+		lan9303_phy_reg_write(chip, chip->phy_addr_sel_strap + 1,
+				      MII_BMCR, BMCR_PDOWN);
+		break;
+	case 2:
+		lan9303_disable_packet_processing(chip, LAN9303_PORT_2_OFFSET);
+		lan9303_phy_reg_write(chip, chip->phy_addr_sel_strap + 2,
+				      MII_BMCR, BMCR_PDOWN);
+		break;
+	default:
+		dev_dbg(chip->dev,
+			"Error: request to power down invalid port %d\n", port);
+	}
+}
+
+static struct dsa_switch_ops lan9303_switch_ops = {
+	.get_tag_protocol = lan9303_get_tag_protocol,
+	.setup = lan9303_setup,
+	.get_strings = lan9303_get_strings,
+	.phy_read = lan9303_phy_read,
+	.phy_write = lan9303_phy_write,
+	.get_ethtool_stats = lan9303_get_ethtool_stats,
+	.get_sset_count = lan9303_get_sset_count,
+	.port_enable = lan9303_port_enable,
+	.port_disable = lan9303_port_disable,
+};
+
+static int lan9303_register_switch(struct lan9303 *chip)
+{
+	chip->ds = dsa_switch_alloc(chip->dev, DSA_MAX_PORTS);
+	if (!chip->ds)
+		return -ENOMEM;
+
+	chip->ds->priv = chip;
+	chip->ds->ops = &lan9303_switch_ops;
+	chip->ds->phys_mii_mask = chip->phy_addr_sel_strap ? 0xe : 0x7;
+
+	return dsa_register_switch(chip->ds, chip->dev);
+}
+
+static void lan9303_probe_reset_gpio(struct lan9303 *chip,
+				     struct device_node *np)
+{
+	chip->reset_gpio = devm_gpiod_get_optional(chip->dev, "reset",
+						   GPIOD_OUT_LOW);
+
+	if (!chip->reset_gpio) {
+		dev_dbg(chip->dev, "No reset GPIO defined\n");
+		return;
+	}
+
+	chip->reset_duration = 200;
+
+	if (np) {
+		of_property_read_u32(np, "reset-duration",
+				     &chip->reset_duration);
+	} else {
+		dev_dbg(chip->dev, "reset duration defaults to 200 ms\n");
+	}
+
+	/* A sane reset duration should not be longer than 1s */
+	if (chip->reset_duration > 1000)
+		chip->reset_duration = 1000;
+}
+
+int lan9303_probe(struct lan9303 *chip, struct device_node *np)
+{
+	int ret;
+
+	mutex_init(&chip->indirect_mutex);
+
+	lan9303_probe_reset_gpio(chip, np);
+
+	ret = lan9303_handle_reset(chip);
+	if (ret)
+		return ret;
+
+	ret = lan9303_check_device(chip);
+	if (ret)
+		return ret;
+
+	ret = lan9303_register_switch(chip);
+	if (ret) {
+		dev_dbg(chip->dev, "Failed to register switch: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(lan9303_probe);
+
+int lan9303_remove(struct lan9303 *chip)
+{
+	int rc;
+
+	rc = lan9303_disable_processing(chip);
+	if (rc != 0)
+		dev_warn(chip->dev, "shutting down failed\n");
+
+	dsa_unregister_switch(chip->ds);
+
+	/* assert reset to the whole device to prevent it from doing anything */
+	gpiod_set_value_cansleep(chip->reset_gpio, 1);
+	gpiod_unexport(chip->reset_gpio);
+
+	return 0;
+}
+EXPORT_SYMBOL(lan9303_remove);
+
+MODULE_AUTHOR("Juergen Borleis <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("Core driver for SMSC/Microchip LAN9303 three port ethernet switch");
+MODULE_LICENSE("GPL v2");

drivers/net/dsa/lan9303.h

+#include <linux/regmap.h>
+#include <linux/device.h>
+#include <net/dsa.h>
+
+struct lan9303 {
+	struct device *dev;
+	struct regmap *regmap;
+	struct regmap_irq_chip_data *irq_data;
+	struct gpio_desc *reset_gpio;
+	u32 reset_duration; /* in [ms] */
+	bool phy_addr_sel_strap;
+	struct dsa_switch *ds;
+	struct mutex indirect_mutex; /* protect indexed register access */
+};
+
+extern const struct regmap_access_table lan9303_register_set;
+
+int lan9303_probe(struct lan9303 *chip, struct device_node *np);
+int lan9303_remove(struct lan9303 *chip);

drivers/net/dsa/lan9303_i2c.c

+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <kernel@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/of.h>
+
+#include "lan9303.h"
+
+struct lan9303_i2c {
+	struct i2c_client *device;
+	struct lan9303 chip;
+};
+
+static const struct regmap_config lan9303_i2c_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 32,
+	.reg_stride = 1,
+	.can_multi_write = true,
+	.max_register = 0x0ff, /* address bits 0..1 are not used */
+	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
+
+	.volatile_table = &lan9303_register_set,
+	.wr_table = &lan9303_register_set,
+	.rd_table = &lan9303_register_set,
+
+	.cache_type = REGCACHE_NONE,
+};
+
+static int lan9303_i2c_probe(struct i2c_client *client,
+			     const struct i2c_device_id *id)
+{
+	struct lan9303_i2c *sw_dev;
+	int ret;
+
+	sw_dev = devm_kzalloc(&client->dev, sizeof(struct lan9303_i2c),
+			      GFP_KERNEL);
+	if (!sw_dev)
+		return -ENOMEM;
+
+	sw_dev->chip.regmap = devm_regmap_init_i2c(client,
+						&lan9303_i2c_regmap_config);
+	if (IS_ERR(sw_dev->chip.regmap)) {
+		ret = PTR_ERR(sw_dev->chip.regmap);
+		dev_err(&client->dev, "Failed to allocate register map: %d\n",
+			ret);
+		return ret;
+	}
+
+	/* link forward and backward */
+	sw_dev->device = client;
+	i2c_set_clientdata(client, sw_dev);
+	sw_dev->chip.dev = &client->dev;
+
+	ret = lan9303_probe(&sw_dev->chip, client->dev.of_node);
+	if (ret != 0)
+		return ret;
+
+	dev_info(&client->dev, "LAN9303 I2C driver loaded successfully\n");
+
+	return 0;
+}
+
+static int lan9303_i2c_remove(struct i2c_client *client)
+{
+	struct lan9303_i2c *sw_dev;
+
+	sw_dev = i2c_get_clientdata(client);
+	if (!sw_dev)
+		return -ENODEV;
+
+	return lan9303_remove(&sw_dev->chip);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static const struct i2c_device_id lan9303_i2c_id[] = {
+	{ "lan9303", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, lan9303_i2c_id);
+
+static const struct of_device_id lan9303_i2c_of_match[] = {
+	{ .compatible = "smsc,lan9303-i2c", },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, lan9303_i2c_of_match);
+
+static struct i2c_driver lan9303_i2c_driver = {
+	.driver = {
+		.name = "LAN9303_I2C",
+		.of_match_table = of_match_ptr(lan9303_i2c_of_match),
+	},
+	.probe = lan9303_i2c_probe,
+	.remove = lan9303_i2c_remove,
+	.id_table = lan9303_i2c_id,
+};
+module_i2c_driver(lan9303_i2c_driver);
+
+MODULE_AUTHOR("Juergen Borleis <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("Driver for SMSC/Microchip LAN9303 three port ethernet switch in I2C managed mode");
+MODULE_LICENSE("GPL v2");

drivers/net/dsa/lan9303_mdio.c

+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <kernel@pengutronix.de>
+ *
+ * Partially based on a patch from
+ * Copyright (c) 2014 Stefan Roese <sr@denx.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mdio.h>
+#include <linux/phy.h>
+#include <linux/of.h>
+
+#include "lan9303.h"
+
+/* Generate phy-addr and -reg from the input address */
+#define PHY_ADDR(x) ((((x) >> 6) + 0x10) & 0x1f)
+#define PHY_REG(x) (((x) >> 1) & 0x1f)
+
+struct lan9303_mdio {
+	struct mdio_device *device;
+	struct lan9303 chip;
+};
+
+static void lan9303_mdio_real_write(struct mdio_device *mdio, int reg, u16 val)
+{
+	mdio->bus->write(mdio->bus, PHY_ADDR(reg), PHY_REG(reg), val);
+}
+
+static int lan9303_mdio_write(void *ctx, uint32_t reg, uint32_t val)
+{
+	struct lan9303_mdio *sw_dev = (struct lan9303_mdio *)ctx;
+
+	mutex_lock(&sw_dev->device->bus->mdio_lock);
+	lan9303_mdio_real_write(sw_dev->device, reg, val & 0xffff);
+	lan9303_mdio_real_write(sw_dev->device, reg + 2, (val >> 16) & 0xffff);
+	mutex_unlock(&sw_dev->device->bus->mdio_lock);
+
+	return 0;
+}
+
+static u16 lan9303_mdio_real_read(struct mdio_device *mdio, int reg)
+{
+	return mdio->bus->read(mdio->bus, PHY_ADDR(reg), PHY_REG(reg));
+}
+
+static int lan9303_mdio_read(void *ctx, uint32_t reg, uint32_t *val)
+{
+	struct lan9303_mdio *sw_dev = (struct lan9303_mdio *)ctx;
+
+	mutex_lock(&sw_dev->device->bus->mdio_lock);
+	*val = lan9303_mdio_real_read(sw_dev->device, reg);
+	*val |= (lan9303_mdio_real_read(sw_dev->device, reg + 2) << 16);
+	mutex_unlock(&sw_dev->device->bus->mdio_lock);
+
+	return 0;
+}
+
+static const struct regmap_config lan9303_mdio_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 32,
+	.reg_stride = 1,
+	.can_multi_write = true,
+	.max_register = 0x0ff, /* address bits 0..1 are not used */
+	.reg_format_endian = REGMAP_ENDIAN_LITTLE,
+
+	.volatile_table = &lan9303_register_set,
+	.wr_table = &lan9303_register_set,
+	.rd_table = &lan9303_register_set,
+
+	.reg_read = lan9303_mdio_read,
+	.reg_write = lan9303_mdio_write,
+
+	.cache_type = REGCACHE_NONE,
+};
+
+static int lan9303_mdio_probe(struct mdio_device *mdiodev)
+{
+	struct lan9303_mdio *sw_dev;
+	int ret;
+
+	sw_dev = devm_kzalloc(&mdiodev->dev, sizeof(struct lan9303_mdio),
+			      GFP_KERNEL);
+	if (!sw_dev)
+		return -ENOMEM;
+
+	sw_dev->chip.regmap = devm_regmap_init(&mdiodev->dev, NULL, sw_dev,
+						&lan9303_mdio_regmap_config);
+	if (IS_ERR(sw_dev->chip.regmap)) {
+		ret = PTR_ERR(sw_dev->chip.regmap);
+		dev_err(&mdiodev->dev, "regmap init failed: %d\n", ret);
+		return ret;
+	}
+
+	/* link forward and backward */
+	sw_dev->device = mdiodev;
+	dev_set_drvdata(&mdiodev->dev, sw_dev);
+	sw_dev->chip.dev = &mdiodev->dev;
+
+	ret = lan9303_probe(&sw_dev->chip, mdiodev->dev.of_node);
+	if (ret != 0)
+		return ret;
+
+	dev_info(&mdiodev->dev, "LAN9303 MDIO driver loaded successfully\n");
+
+	return 0;
+}
+
+static void lan9303_mdio_remove(struct mdio_device *mdiodev)
+{
+	struct lan9303_mdio *sw_dev = dev_get_drvdata(&mdiodev->dev);
+
+	if (!sw_dev)
+		return;
+
+	lan9303_remove(&sw_dev->chip);
+}
+
+/*-------------------------------------------------------------------------*/
+
+static const struct of_device_id lan9303_mdio_of_match[] = {
+	{ .compatible = "smsc,lan9303-mdio" },
+	{ /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, lan9303_mdio_of_match);
+
+static struct mdio_driver lan9303_mdio_driver = {
+	.mdiodrv.driver = {
+		.name = "LAN9303_MDIO",
+		.of_match_table = of_match_ptr(lan9303_mdio_of_match),
+	},
+	.probe  = lan9303_mdio_probe,
+	.remove = lan9303_mdio_remove,
+};
+mdio_module_driver(lan9303_mdio_driver);
+
+MODULE_AUTHOR("Stefan Roese <sr@denx.de>, Juergen Borleis <kernel@pengutronix.de>");
+MODULE_DESCRIPTION("Driver for SMSC/Microchip LAN9303 three port ethernet switch in MDIO managed mode");
+MODULE_LICENSE("GPL v2");

include/net/dsa.h

@@ -33,6 +33,7 @@ enum dsa_tag_protocol {
 	DSA_TAG_PROTO_BRCM,
 	DSA_TAG_PROTO_QCA,
 	DSA_TAG_PROTO_MTK,
+	DSA_TAG_PROTO_LAN9303,
 	DSA_TAG_LAST,		/* MUST BE LAST */
 };
 

net/dsa/Kconfig

@@ -33,4 +33,8 @@ config NET_DSA_TAG_QCA
 
 config NET_DSA_TAG_MTK
 	bool
+
+config NET_DSA_TAG_LAN9303
+	bool
+
 endif

net/dsa/Makefile

@@ -9,3 +9,4 @@ dsa_core-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
 dsa_core-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
 dsa_core-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
 dsa_core-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+dsa_core-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o

net/dsa/dsa.c

@@ -57,6 +57,9 @@ const struct dsa_device_ops *dsa_device_ops[DSA_TAG_LAST] = {
 #endif
 #ifdef CONFIG_NET_DSA_TAG_MTK
 	[DSA_TAG_PROTO_MTK] = &mtk_netdev_ops,
+#endif
+#ifdef CONFIG_NET_DSA_TAG_LAN9303
+	[DSA_TAG_PROTO_LAN9303] = &lan9303_netdev_ops,
 #endif
 	[DSA_TAG_PROTO_NONE] = &none_ops,
 };

net/dsa/dsa_priv.h

@@ -93,4 +93,7 @@ extern const struct dsa_device_ops qca_netdev_ops;
 /* tag_mtk.c */
 extern const struct dsa_device_ops mtk_netdev_ops;
 
+/* tag_lan9303.c */
+extern const struct dsa_device_ops lan9303_netdev_ops;
+
 #endif

net/dsa/tag_lan9303.c

+/*
+ * Copyright (C) 2017 Pengutronix, Juergen Borleis <jbe@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+#include <linux/etherdevice.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <net/dsa.h>
+#include "dsa_priv.h"
+
+/* To define the outgoing port and to discover the incoming port a regular
+ * VLAN tag is used by the LAN9303. But its VID meaning is 'special':
+ *
+ *       Dest MAC       Src MAC        TAG    Type
+ * ...| 1 2 3 4 5 6 | 1 2 3 4 5 6 | 1 2 3 4 | 1 2 |...
+ *                                |<------->|
+ * TAG:
+ *    |<------------->|
+ *    |  1  2 | 3  4  |
+ *      TPID    VID
+ *     0x8100
+ *
+ * VID bit 3 indicates a request for an ALR lookup.
+ *
+ * If VID bit 3 is zero, then bits 0 and 1 specify the destination port
+ * (0, 1, 2) or broadcast (3) or the source port (1, 2).
+ *
+ * VID bit 4 is used to specify if the STP port state should be overridden.
+ * Required when no forwarding between the external ports should happen.
+ */
+
+#define LAN9303_TAG_LEN 4
+#define LAN9303_MAX_PORTS 3
+
+static struct sk_buff *lan9303_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct dsa_slave_priv *p = netdev_priv(dev);
+	u16 *lan9303_tag;
+
+	/* insert a special VLAN tag between the MAC addresses
+	 * and the current ethertype field.
+	 */
+	if (skb_cow_head(skb, LAN9303_TAG_LEN) < 0) {
+		dev_dbg(&dev->dev,
+			"Cannot make room for the special tag. Dropping packet\n");
+		goto out_free;
+	}
+
+	/* provide 'LAN9303_TAG_LEN' bytes additional space */
+	skb_push(skb, LAN9303_TAG_LEN);
+
+	/* make room between MACs and Ether-Type */
+	memmove(skb->data, skb->data + LAN9303_TAG_LEN, 2 * ETH_ALEN);
+
+	lan9303_tag = (u16 *)(skb->data + 2 * ETH_ALEN);
+	lan9303_tag[0] = htons(ETH_P_8021Q);
+	lan9303_tag[1] = htons(p->dp->index | BIT(4));
+
+	return skb;
+out_free:
+	kfree_skb(skb);
+	return NULL;
+}
+
+static struct sk_buff *lan9303_rcv(struct sk_buff *skb, struct net_device *dev,
+			struct packet_type *pt, struct net_device *orig_dev)
+{
+	u16 *lan9303_tag;
+	struct dsa_switch_tree *dst = dev->dsa_ptr;
+	struct dsa_switch *ds;
+	unsigned int source_port;
+
+	if (unlikely(!dst)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet, due to missing switch tree device\n");
+		return NULL;
+	}
+
+	ds = dst->ds[0];
+
+	if (unlikely(!ds)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet, due to missing DSA switch device\n");
+		return NULL;
+	}
+
+	if (unlikely(!pskb_may_pull(skb, LAN9303_TAG_LEN))) {
+		dev_warn_ratelimited(&dev->dev,
+				     "Dropping packet, cannot pull\n");
+		return NULL;
+	}
+
+	/* '->data' points into the middle of our special VLAN tag information:
+	 *
+	 * ~ MAC src   | 0x81 | 0x00 | 0xyy | 0xzz | ether type
+	 *                           ^
+	 *                        ->data
+	 */
+	lan9303_tag = (u16 *)(skb->data - 2);
+
+	if (lan9303_tag[0] != htons(ETH_P_8021Q)) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid VLAN marker\n");
+		return NULL;
+	}
+
+	source_port = ntohs(lan9303_tag[1]) & 0x3;
+
+	if (source_port >= LAN9303_MAX_PORTS) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid source port\n");
+		return NULL;
+	}
+
+	if (!ds->ports[source_port].netdev) {
+		dev_warn_ratelimited(&dev->dev, "Dropping packet due to invalid netdev or device\n");
+		return NULL;
+	}
+
+	/* remove the special VLAN tag between the MAC addresses
+	 * and the current ethertype field.
+	 */
+	skb_pull_rcsum(skb, 2 + 2);
+	memmove(skb->data - ETH_HLEN, skb->data - (ETH_HLEN + LAN9303_TAG_LEN),
+		2 * ETH_ALEN);
+
+	/* forward the packet to the dedicated interface */
+	skb->dev = ds->ports[source_port].netdev;
+
+	return skb;
+}
+
+const struct dsa_device_ops lan9303_netdev_ops = {
+	.xmit = lan9303_xmit,
+	.rcv = lan9303_rcv,
+};