Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 518 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-diolan-u2c.c b/drivers/i2c/busses/i2c-diolan-u2c.c
new file mode 100644
index 000000000..b48b78889
--- /dev/null
+++ b/drivers/i2c/busses/i2c-diolan-u2c.c
@@ -0,0 +1,518 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for the Diolan u2c-12 USB-I2C adapter
+ *
+ * Copyright (c) 2010-2011 Ericsson AB
+ *
+ * Derived from:
+ *  i2c-tiny-usb.c
+ *  Copyright (C) 2006-2007 Till Harbaum (Till@Harbaum.org)
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/usb.h>
+#include <linux/i2c.h>
+
+#define DRIVER_NAME		"i2c-diolan-u2c"
+
+#define USB_VENDOR_ID_DIOLAN		0x0abf
+#define USB_DEVICE_ID_DIOLAN_U2C	0x3370
+
+
+/* commands via USB, must match command ids in the firmware */
+#define CMD_I2C_READ		0x01
+#define CMD_I2C_WRITE		0x02
+#define CMD_I2C_SCAN		0x03	/* Returns list of detected devices */
+#define CMD_I2C_RELEASE_SDA	0x04
+#define CMD_I2C_RELEASE_SCL	0x05
+#define CMD_I2C_DROP_SDA	0x06
+#define CMD_I2C_DROP_SCL	0x07
+#define CMD_I2C_READ_SDA	0x08
+#define CMD_I2C_READ_SCL	0x09
+#define CMD_GET_FW_VERSION	0x0a
+#define CMD_GET_SERIAL		0x0b
+#define CMD_I2C_START		0x0c
+#define CMD_I2C_STOP		0x0d
+#define CMD_I2C_REPEATED_START	0x0e
+#define CMD_I2C_PUT_BYTE	0x0f
+#define CMD_I2C_GET_BYTE	0x10
+#define CMD_I2C_PUT_ACK		0x11
+#define CMD_I2C_GET_ACK		0x12
+#define CMD_I2C_PUT_BYTE_ACK	0x13
+#define CMD_I2C_GET_BYTE_ACK	0x14
+#define CMD_I2C_SET_SPEED	0x1b
+#define CMD_I2C_GET_SPEED	0x1c
+#define CMD_I2C_SET_CLK_SYNC	0x24
+#define CMD_I2C_GET_CLK_SYNC	0x25
+#define CMD_I2C_SET_CLK_SYNC_TO	0x26
+#define CMD_I2C_GET_CLK_SYNC_TO	0x27
+
+#define RESP_OK			0x00
+#define RESP_FAILED		0x01
+#define RESP_BAD_MEMADDR	0x04
+#define RESP_DATA_ERR		0x05
+#define RESP_NOT_IMPLEMENTED	0x06
+#define RESP_NACK		0x07
+#define RESP_TIMEOUT		0x09
+
+#define U2C_I2C_SPEED_FAST	0	/* 400 kHz */
+#define U2C_I2C_SPEED_STD	1	/* 100 kHz */
+#define U2C_I2C_SPEED_2KHZ	242	/* 2 kHz, minimum speed */
+#define U2C_I2C_SPEED(f)	((DIV_ROUND_UP(1000000, (f)) - 10) / 2 + 1)
+
+#define U2C_I2C_FREQ(s)		(1000000 / (2 * (s - 1) + 10))
+
+#define DIOLAN_USB_TIMEOUT	100	/* in ms */
+#define DIOLAN_SYNC_TIMEOUT	20	/* in ms */
+
+#define DIOLAN_OUTBUF_LEN	128
+#define DIOLAN_FLUSH_LEN	(DIOLAN_OUTBUF_LEN - 4)
+#define DIOLAN_INBUF_LEN	256	/* Maximum supported receive length */
+
+/* Structure to hold all of our device specific stuff */
+struct i2c_diolan_u2c {
+	u8 obuffer[DIOLAN_OUTBUF_LEN];	/* output buffer */
+	u8 ibuffer[DIOLAN_INBUF_LEN];	/* input buffer */
+	int ep_in, ep_out;              /* Endpoints    */
+	struct usb_device *usb_dev;	/* the usb device for this device */
+	struct usb_interface *interface;/* the interface for this device */
+	struct i2c_adapter adapter;	/* i2c related things */
+	int olen;			/* Output buffer length */
+	int ocount;			/* Number of enqueued messages */
+};
+
+static uint frequency = I2C_MAX_STANDARD_MODE_FREQ;	/* I2C clock frequency in Hz */
+
+module_param(frequency, uint, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(frequency, "I2C clock frequency in hertz");
+
+/* usb layer */
+
+/* Send command to device, and get response. */
+static int diolan_usb_transfer(struct i2c_diolan_u2c *dev)
+{
+	int ret = 0;
+	int actual;
+	int i;
+
+	if (!dev->olen || !dev->ocount)
+		return -EINVAL;
+
+	ret = usb_bulk_msg(dev->usb_dev,
+			   usb_sndbulkpipe(dev->usb_dev, dev->ep_out),
+			   dev->obuffer, dev->olen, &actual,
+			   DIOLAN_USB_TIMEOUT);
+	if (!ret) {
+		for (i = 0; i < dev->ocount; i++) {
+			int tmpret;
+
+			tmpret = usb_bulk_msg(dev->usb_dev,
+					      usb_rcvbulkpipe(dev->usb_dev,
+							      dev->ep_in),
+					      dev->ibuffer,
+					      sizeof(dev->ibuffer), &actual,
+					      DIOLAN_USB_TIMEOUT);
+			/*
+			 * Stop command processing if a previous command
+			 * returned an error.
+			 * Note that we still need to retrieve all messages.
+			 */
+			if (ret < 0)
+				continue;
+			ret = tmpret;
+			if (ret == 0 && actual > 0) {
+				switch (dev->ibuffer[actual - 1]) {
+				case RESP_NACK:
+					/*
+					 * Return ENXIO if NACK was received as
+					 * response to the address phase,
+					 * EIO otherwise
+					 */
+					ret = i == 1 ? -ENXIO : -EIO;
+					break;
+				case RESP_TIMEOUT:
+					ret = -ETIMEDOUT;
+					break;
+				case RESP_OK:
+					/* strip off return code */
+					ret = actual - 1;
+					break;
+				default:
+					ret = -EIO;
+					break;
+				}
+			}
+		}
+	}
+	dev->olen = 0;
+	dev->ocount = 0;
+	return ret;
+}
+
+static int diolan_write_cmd(struct i2c_diolan_u2c *dev, bool flush)
+{
+	if (flush || dev->olen >= DIOLAN_FLUSH_LEN)
+		return diolan_usb_transfer(dev);
+	return 0;
+}
+
+/* Send command (no data) */
+static int diolan_usb_cmd(struct i2c_diolan_u2c *dev, u8 command, bool flush)
+{
+	dev->obuffer[dev->olen++] = command;
+	dev->ocount++;
+	return diolan_write_cmd(dev, flush);
+}
+
+/* Send command with one byte of data */
+static int diolan_usb_cmd_data(struct i2c_diolan_u2c *dev, u8 command, u8 data,
+			       bool flush)
+{
+	dev->obuffer[dev->olen++] = command;
+	dev->obuffer[dev->olen++] = data;
+	dev->ocount++;
+	return diolan_write_cmd(dev, flush);
+}
+
+/* Send command with two bytes of data */
+static int diolan_usb_cmd_data2(struct i2c_diolan_u2c *dev, u8 command, u8 d1,
+				u8 d2, bool flush)
+{
+	dev->obuffer[dev->olen++] = command;
+	dev->obuffer[dev->olen++] = d1;
+	dev->obuffer[dev->olen++] = d2;
+	dev->ocount++;
+	return diolan_write_cmd(dev, flush);
+}
+
+/*
+ * Flush input queue.
+ * If we don't do this at startup and the controller has queued up
+ * messages which were not retrieved, it will stop responding
+ * at some point.
+ */
+static void diolan_flush_input(struct i2c_diolan_u2c *dev)
+{
+	int i;
+
+	for (i = 0; i < 10; i++) {
+		int actual = 0;
+		int ret;
+
+		ret = usb_bulk_msg(dev->usb_dev,
+				   usb_rcvbulkpipe(dev->usb_dev, dev->ep_in),
+				   dev->ibuffer, sizeof(dev->ibuffer), &actual,
+				   DIOLAN_USB_TIMEOUT);
+		if (ret < 0 || actual == 0)
+			break;
+	}
+	if (i == 10)
+		dev_err(&dev->interface->dev, "Failed to flush input buffer\n");
+}
+
+static int diolan_i2c_start(struct i2c_diolan_u2c *dev)
+{
+	return diolan_usb_cmd(dev, CMD_I2C_START, false);
+}
+
+static int diolan_i2c_repeated_start(struct i2c_diolan_u2c *dev)
+{
+	return diolan_usb_cmd(dev, CMD_I2C_REPEATED_START, false);
+}
+
+static int diolan_i2c_stop(struct i2c_diolan_u2c *dev)
+{
+	return diolan_usb_cmd(dev, CMD_I2C_STOP, true);
+}
+
+static int diolan_i2c_get_byte_ack(struct i2c_diolan_u2c *dev, bool ack,
+				   u8 *byte)
+{
+	int ret;
+
+	ret = diolan_usb_cmd_data(dev, CMD_I2C_GET_BYTE_ACK, ack, true);
+	if (ret > 0)
+		*byte = dev->ibuffer[0];
+	else if (ret == 0)
+		ret = -EIO;
+
+	return ret;
+}
+
+static int diolan_i2c_put_byte_ack(struct i2c_diolan_u2c *dev, u8 byte)
+{
+	return diolan_usb_cmd_data(dev, CMD_I2C_PUT_BYTE_ACK, byte, false);
+}
+
+static int diolan_set_speed(struct i2c_diolan_u2c *dev, u8 speed)
+{
+	return diolan_usb_cmd_data(dev, CMD_I2C_SET_SPEED, speed, true);
+}
+
+/* Enable or disable clock synchronization (stretching) */
+static int diolan_set_clock_synch(struct i2c_diolan_u2c *dev, bool enable)
+{
+	return diolan_usb_cmd_data(dev, CMD_I2C_SET_CLK_SYNC, enable, true);
+}
+
+/* Set clock synchronization timeout in ms */
+static int diolan_set_clock_synch_timeout(struct i2c_diolan_u2c *dev, int ms)
+{
+	int to_val = ms * 10;
+
+	return diolan_usb_cmd_data2(dev, CMD_I2C_SET_CLK_SYNC_TO,
+				    to_val & 0xff, (to_val >> 8) & 0xff, true);
+}
+
+static void diolan_fw_version(struct i2c_diolan_u2c *dev)
+{
+	int ret;
+
+	ret = diolan_usb_cmd(dev, CMD_GET_FW_VERSION, true);
+	if (ret >= 2)
+		dev_info(&dev->interface->dev,
+			 "Diolan U2C firmware version %u.%u\n",
+			 (unsigned int)dev->ibuffer[0],
+			 (unsigned int)dev->ibuffer[1]);
+}
+
+static void diolan_get_serial(struct i2c_diolan_u2c *dev)
+{
+	int ret;
+	u32 serial;
+
+	ret = diolan_usb_cmd(dev, CMD_GET_SERIAL, true);
+	if (ret >= 4) {
+		serial = le32_to_cpu(*(u32 *)dev->ibuffer);
+		dev_info(&dev->interface->dev,
+			 "Diolan U2C serial number %u\n", serial);
+	}
+}
+
+static int diolan_init(struct i2c_diolan_u2c *dev)
+{
+	int speed, ret;
+
+	if (frequency >= 2 * I2C_MAX_STANDARD_MODE_FREQ) {
+		speed = U2C_I2C_SPEED_FAST;
+		frequency = I2C_MAX_FAST_MODE_FREQ;
+	} else if (frequency >= I2C_MAX_STANDARD_MODE_FREQ || frequency == 0) {
+		speed = U2C_I2C_SPEED_STD;
+		frequency = I2C_MAX_STANDARD_MODE_FREQ;
+	} else {
+		speed = U2C_I2C_SPEED(frequency);
+		if (speed > U2C_I2C_SPEED_2KHZ)
+			speed = U2C_I2C_SPEED_2KHZ;
+		frequency = U2C_I2C_FREQ(speed);
+	}
+
+	dev_info(&dev->interface->dev,
+		 "Diolan U2C at USB bus %03d address %03d speed %d Hz\n",
+		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum, frequency);
+
+	diolan_flush_input(dev);
+	diolan_fw_version(dev);
+	diolan_get_serial(dev);
+
+	/* Set I2C speed */
+	ret = diolan_set_speed(dev, speed);
+	if (ret < 0)
+		return ret;
+
+	/* Configure I2C clock synchronization */
+	ret = diolan_set_clock_synch(dev, speed != U2C_I2C_SPEED_FAST);
+	if (ret < 0)
+		return ret;
+
+	if (speed != U2C_I2C_SPEED_FAST)
+		ret = diolan_set_clock_synch_timeout(dev, DIOLAN_SYNC_TIMEOUT);
+
+	return ret;
+}
+
+/* i2c layer */
+
+static int diolan_usb_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
+			   int num)
+{
+	struct i2c_diolan_u2c *dev = i2c_get_adapdata(adapter);
+	struct i2c_msg *pmsg;
+	int i, j;
+	int ret, sret;
+
+	ret = diolan_i2c_start(dev);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < num; i++) {
+		pmsg = &msgs[i];
+		if (i) {
+			ret = diolan_i2c_repeated_start(dev);
+			if (ret < 0)
+				goto abort;
+		}
+		ret = diolan_i2c_put_byte_ack(dev,
+					      i2c_8bit_addr_from_msg(pmsg));
+		if (ret < 0)
+			goto abort;
+		if (pmsg->flags & I2C_M_RD) {
+			for (j = 0; j < pmsg->len; j++) {
+				u8 byte;
+				bool ack = j < pmsg->len - 1;
+
+				/*
+				 * Don't send NACK if this is the first byte
+				 * of a SMBUS_BLOCK message.
+				 */
+				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN))
+					ack = true;
+
+				ret = diolan_i2c_get_byte_ack(dev, ack, &byte);
+				if (ret < 0)
+					goto abort;
+				/*
+				 * Adjust count if first received byte is length
+				 */
+				if (j == 0 && (pmsg->flags & I2C_M_RECV_LEN)) {
+					if (byte == 0
+					    || byte > I2C_SMBUS_BLOCK_MAX) {
+						ret = -EPROTO;
+						goto abort;
+					}
+					pmsg->len += byte;
+				}
+				pmsg->buf[j] = byte;
+			}
+		} else {
+			for (j = 0; j < pmsg->len; j++) {
+				ret = diolan_i2c_put_byte_ack(dev,
+							      pmsg->buf[j]);
+				if (ret < 0)
+					goto abort;
+			}
+		}
+	}
+	ret = num;
+abort:
+	sret = diolan_i2c_stop(dev);
+	if (sret < 0 && ret >= 0)
+		ret = sret;
+	return ret;
+}
+
+/*
+ * Return list of supported functionality.
+ */
+static u32 diolan_usb_func(struct i2c_adapter *a)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+	       I2C_FUNC_SMBUS_READ_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL;
+}
+
+static const struct i2c_algorithm diolan_usb_algorithm = {
+	.master_xfer = diolan_usb_xfer,
+	.functionality = diolan_usb_func,
+};
+
+/* device layer */
+
+static const struct usb_device_id diolan_u2c_table[] = {
+	{ USB_DEVICE(USB_VENDOR_ID_DIOLAN, USB_DEVICE_ID_DIOLAN_U2C) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(usb, diolan_u2c_table);
+
+static void diolan_u2c_free(struct i2c_diolan_u2c *dev)
+{
+	usb_put_dev(dev->usb_dev);
+	kfree(dev);
+}
+
+static int diolan_u2c_probe(struct usb_interface *interface,
+			    const struct usb_device_id *id)
+{
+	struct usb_host_interface *hostif = interface->cur_altsetting;
+	struct i2c_diolan_u2c *dev;
+	int ret;
+
+	if (hostif->desc.bInterfaceNumber != 0
+	    || hostif->desc.bNumEndpoints < 2)
+		return -ENODEV;
+
+	/* allocate memory for our device state and initialize it */
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (dev == NULL) {
+		ret = -ENOMEM;
+		goto error;
+	}
+	dev->ep_out = hostif->endpoint[0].desc.bEndpointAddress;
+	dev->ep_in = hostif->endpoint[1].desc.bEndpointAddress;
+
+	dev->usb_dev = usb_get_dev(interface_to_usbdev(interface));
+	dev->interface = interface;
+
+	/* save our data pointer in this interface device */
+	usb_set_intfdata(interface, dev);
+
+	/* setup i2c adapter description */
+	dev->adapter.owner = THIS_MODULE;
+	dev->adapter.class = I2C_CLASS_HWMON;
+	dev->adapter.algo = &diolan_usb_algorithm;
+	i2c_set_adapdata(&dev->adapter, dev);
+	snprintf(dev->adapter.name, sizeof(dev->adapter.name),
+		 DRIVER_NAME " at bus %03d device %03d",
+		 dev->usb_dev->bus->busnum, dev->usb_dev->devnum);
+
+	dev->adapter.dev.parent = &dev->interface->dev;
+
+	/* initialize diolan i2c interface */
+	ret = diolan_init(dev);
+	if (ret < 0) {
+		dev_err(&interface->dev, "failed to initialize adapter\n");
+		goto error_free;
+	}
+
+	/* and finally attach to i2c layer */
+	ret = i2c_add_adapter(&dev->adapter);
+	if (ret < 0)
+		goto error_free;
+
+	dev_dbg(&interface->dev, "connected " DRIVER_NAME "\n");
+
+	return 0;
+
+error_free:
+	usb_set_intfdata(interface, NULL);
+	diolan_u2c_free(dev);
+error:
+	return ret;
+}
+
+static void diolan_u2c_disconnect(struct usb_interface *interface)
+{
+	struct i2c_diolan_u2c *dev = usb_get_intfdata(interface);
+
+	i2c_del_adapter(&dev->adapter);
+	usb_set_intfdata(interface, NULL);
+	diolan_u2c_free(dev);
+
+	dev_dbg(&interface->dev, "disconnected\n");
+}
+
+static struct usb_driver diolan_u2c_driver = {
+	.name = DRIVER_NAME,
+	.probe = diolan_u2c_probe,
+	.disconnect = diolan_u2c_disconnect,
+	.id_table = diolan_u2c_table,
+};
+
+module_usb_driver(diolan_u2c_driver);
+
+MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
+MODULE_DESCRIPTION(DRIVER_NAME " driver");
+MODULE_LICENSE("GPL");