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, 565 insertions, 0 deletions

diff --git a/drivers/w1/masters/ds2482.c b/drivers/w1/masters/ds2482.c
new file mode 100644
index 000000000..62c44616d
--- /dev/null
+++ b/drivers/w1/masters/ds2482.c
@@ -0,0 +1,565 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ds2482.c - provides i2c to w1-master bridge(s)
+ * Copyright (C) 2005  Ben Gardner <bgardner@wabtec.com>
+ *
+ * The DS2482 is a sensor chip made by Dallas Semiconductor (Maxim).
+ * It is a I2C to 1-wire bridge.
+ * There are two variations: -100 and -800, which have 1 or 8 1-wire ports.
+ * The complete datasheet can be obtained from MAXIM's website at:
+ *   http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4382
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/delay.h>
+#include <asm/delay.h>
+
+#include <linux/w1.h>
+
+/*
+ * Allow the active pullup to be disabled, default is enabled.
+ *
+ * Note from the DS2482 datasheet:
+ * The APU bit controls whether an active pullup (controlled slew-rate
+ * transistor) or a passive pullup (Rwpu resistor) will be used to drive
+ * a 1-Wire line from low to high. When APU = 0, active pullup is disabled
+ * (resistor mode). Active Pullup should always be selected unless there is
+ * only a single slave on the 1-Wire line.
+ */
+static int ds2482_active_pullup = 1;
+module_param_named(active_pullup, ds2482_active_pullup, int, 0644);
+MODULE_PARM_DESC(active_pullup, "Active pullup (apply to all buses): " \
+				"0-disable, 1-enable (default)");
+
+/* extra configurations - e.g. 1WS */
+static int extra_config;
+module_param(extra_config, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(extra_config, "Extra Configuration settings 1=APU,2=PPM,3=SPU,8=1WS");
+
+/*
+ * The DS2482 registers - there are 3 registers that are addressed by a read
+ * pointer. The read pointer is set by the last command executed.
+ *
+ * To read the data, issue a register read for any address
+ */
+#define DS2482_CMD_RESET		0xF0	/* No param */
+#define DS2482_CMD_SET_READ_PTR		0xE1	/* Param: DS2482_PTR_CODE_xxx */
+#define DS2482_CMD_CHANNEL_SELECT	0xC3	/* Param: Channel byte - DS2482-800 only */
+#define DS2482_CMD_WRITE_CONFIG		0xD2	/* Param: Config byte */
+#define DS2482_CMD_1WIRE_RESET		0xB4	/* Param: None */
+#define DS2482_CMD_1WIRE_SINGLE_BIT	0x87	/* Param: Bit byte (bit7) */
+#define DS2482_CMD_1WIRE_WRITE_BYTE	0xA5	/* Param: Data byte */
+#define DS2482_CMD_1WIRE_READ_BYTE	0x96	/* Param: None */
+/* Note to read the byte, Set the ReadPtr to Data then read (any addr) */
+#define DS2482_CMD_1WIRE_TRIPLET	0x78	/* Param: Dir byte (bit7) */
+
+/* Values for DS2482_CMD_SET_READ_PTR */
+#define DS2482_PTR_CODE_STATUS		0xF0
+#define DS2482_PTR_CODE_DATA		0xE1
+#define DS2482_PTR_CODE_CHANNEL		0xD2	/* DS2482-800 only */
+#define DS2482_PTR_CODE_CONFIG		0xC3
+
+/*
+ * Configure Register bit definitions
+ * The top 4 bits always read 0.
+ * To write, the top nibble must be the 1's compl. of the low nibble.
+ */
+#define DS2482_REG_CFG_1WS		0x08	/* 1-wire speed */
+#define DS2482_REG_CFG_SPU		0x04	/* strong pull-up */
+#define DS2482_REG_CFG_PPM		0x02	/* presence pulse masking */
+#define DS2482_REG_CFG_APU		0x01	/* active pull-up */
+
+
+/*
+ * Write and verify codes for the CHANNEL_SELECT command (DS2482-800 only).
+ * To set the channel, write the value at the index of the channel.
+ * Read and compare against the corresponding value to verify the change.
+ */
+static const u8 ds2482_chan_wr[8] =
+	{ 0xF0, 0xE1, 0xD2, 0xC3, 0xB4, 0xA5, 0x96, 0x87 };
+static const u8 ds2482_chan_rd[8] =
+	{ 0xB8, 0xB1, 0xAA, 0xA3, 0x9C, 0x95, 0x8E, 0x87 };
+
+
+/*
+ * Status Register bit definitions (read only)
+ */
+#define DS2482_REG_STS_DIR		0x80
+#define DS2482_REG_STS_TSB		0x40
+#define DS2482_REG_STS_SBR		0x20
+#define DS2482_REG_STS_RST		0x10
+#define DS2482_REG_STS_LL		0x08
+#define DS2482_REG_STS_SD		0x04
+#define DS2482_REG_STS_PPD		0x02
+#define DS2482_REG_STS_1WB		0x01
+
+/*
+ * Client data (each client gets its own)
+ */
+
+struct ds2482_data;
+
+struct ds2482_w1_chan {
+	struct ds2482_data	*pdev;
+	u8			channel;
+	struct w1_bus_master	w1_bm;
+};
+
+struct ds2482_data {
+	struct i2c_client	*client;
+	struct mutex		access_lock;
+
+	/* 1-wire interface(s) */
+	int			w1_count;	/* 1 or 8 */
+	struct ds2482_w1_chan	w1_ch[8];
+
+	/* per-device values */
+	u8			channel;
+	u8			read_prt;	/* see DS2482_PTR_CODE_xxx */
+	u8			reg_config;
+};
+
+
+/**
+ * ds2482_calculate_config - Helper to calculate values for configuration register
+ * @conf: the raw config value
+ * Return: the value w/ complements that can be written to register
+ */
+static inline u8 ds2482_calculate_config(u8 conf)
+{
+	conf |= extra_config;
+
+	if (ds2482_active_pullup)
+		conf |= DS2482_REG_CFG_APU;
+
+	return conf | ((~conf & 0x0f) << 4);
+}
+
+
+/**
+ * ds2482_select_register - Sets the read pointer.
+ * @pdev:		The ds2482 client pointer
+ * @read_ptr:	see DS2482_PTR_CODE_xxx above
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_select_register(struct ds2482_data *pdev, u8 read_ptr)
+{
+	if (pdev->read_prt != read_ptr) {
+		if (i2c_smbus_write_byte_data(pdev->client,
+					      DS2482_CMD_SET_READ_PTR,
+					      read_ptr) < 0)
+			return -1;
+
+		pdev->read_prt = read_ptr;
+	}
+	return 0;
+}
+
+/**
+ * ds2482_send_cmd - Sends a command without a parameter
+ * @pdev:	The ds2482 client pointer
+ * @cmd:	DS2482_CMD_RESET,
+ *		DS2482_CMD_1WIRE_RESET,
+ *		DS2482_CMD_1WIRE_READ_BYTE
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_send_cmd(struct ds2482_data *pdev, u8 cmd)
+{
+	if (i2c_smbus_write_byte(pdev->client, cmd) < 0)
+		return -1;
+
+	pdev->read_prt = DS2482_PTR_CODE_STATUS;
+	return 0;
+}
+
+/**
+ * ds2482_send_cmd_data - Sends a command with a parameter
+ * @pdev:	The ds2482 client pointer
+ * @cmd:	DS2482_CMD_WRITE_CONFIG,
+ *		DS2482_CMD_1WIRE_SINGLE_BIT,
+ *		DS2482_CMD_1WIRE_WRITE_BYTE,
+ *		DS2482_CMD_1WIRE_TRIPLET
+ * @byte:	The data to send
+ * Return: -1 on failure, 0 on success
+ */
+static inline int ds2482_send_cmd_data(struct ds2482_data *pdev,
+				       u8 cmd, u8 byte)
+{
+	if (i2c_smbus_write_byte_data(pdev->client, cmd, byte) < 0)
+		return -1;
+
+	/* all cmds leave in STATUS, except CONFIG */
+	pdev->read_prt = (cmd != DS2482_CMD_WRITE_CONFIG) ?
+			 DS2482_PTR_CODE_STATUS : DS2482_PTR_CODE_CONFIG;
+	return 0;
+}
+
+
+/*
+ * 1-Wire interface code
+ */
+
+#define DS2482_WAIT_IDLE_TIMEOUT	100
+
+/**
+ * ds2482_wait_1wire_idle - Waits until the 1-wire interface is idle (not busy)
+ *
+ * @pdev: Pointer to the device structure
+ * Return: the last value read from status or -1 (failure)
+ */
+static int ds2482_wait_1wire_idle(struct ds2482_data *pdev)
+{
+	int temp = -1;
+	int retries = 0;
+
+	if (!ds2482_select_register(pdev, DS2482_PTR_CODE_STATUS)) {
+		do {
+			temp = i2c_smbus_read_byte(pdev->client);
+		} while ((temp >= 0) && (temp & DS2482_REG_STS_1WB) &&
+			 (++retries < DS2482_WAIT_IDLE_TIMEOUT));
+	}
+
+	if (retries >= DS2482_WAIT_IDLE_TIMEOUT)
+		pr_err("%s: timeout on channel %d\n",
+		       __func__, pdev->channel);
+
+	return temp;
+}
+
+/**
+ * ds2482_set_channel - Selects a w1 channel.
+ * The 1-wire interface must be idle before calling this function.
+ *
+ * @pdev:		The ds2482 client pointer
+ * @channel:		0-7
+ * Return:		-1 (failure) or 0 (success)
+ */
+static int ds2482_set_channel(struct ds2482_data *pdev, u8 channel)
+{
+	if (i2c_smbus_write_byte_data(pdev->client, DS2482_CMD_CHANNEL_SELECT,
+				      ds2482_chan_wr[channel]) < 0)
+		return -1;
+
+	pdev->read_prt = DS2482_PTR_CODE_CHANNEL;
+	pdev->channel = -1;
+	if (i2c_smbus_read_byte(pdev->client) == ds2482_chan_rd[channel]) {
+		pdev->channel = channel;
+		return 0;
+	}
+	return -1;
+}
+
+
+/**
+ * ds2482_w1_touch_bit - Performs the touch-bit function, which writes a 0 or 1 and reads the level.
+ *
+ * @data:	The ds2482 channel pointer
+ * @bit:	The level to write: 0 or non-zero
+ * Return:	The level read: 0 or 1
+ */
+static u8 ds2482_w1_touch_bit(void *data, u8 bit)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int status = -1;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the touch command, wait until 1WB == 0, return the status */
+	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_SINGLE_BIT,
+				  bit ? 0xFF : 0))
+		status = ds2482_wait_1wire_idle(pdev);
+
+	mutex_unlock(&pdev->access_lock);
+
+	return (status & DS2482_REG_STS_SBR) ? 1 : 0;
+}
+
+/**
+ * ds2482_w1_triplet - Performs the triplet function, which reads two bits and writes a bit.
+ * The bit written is determined by the two reads:
+ *   00 => dbit, 01 => 0, 10 => 1
+ *
+ * @data:	The ds2482 channel pointer
+ * @dbit:	The direction to choose if both branches are valid
+ * Return:	b0=read1 b1=read2 b3=bit written
+ */
+static u8 ds2482_w1_triplet(void *data, u8 dbit)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int status = (3 << 5);
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the triplet command, wait until 1WB == 0, return the status */
+	if (!ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_TRIPLET,
+				  dbit ? 0xFF : 0))
+		status = ds2482_wait_1wire_idle(pdev);
+
+	mutex_unlock(&pdev->access_lock);
+
+	/* Decode the status */
+	return (status >> 5);
+}
+
+/**
+ * ds2482_w1_write_byte - Performs the write byte function.
+ *
+ * @data:	The ds2482 channel pointer
+ * @byte:	The value to write
+ */
+static void ds2482_w1_write_byte(void *data, u8 byte)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the write byte command */
+	ds2482_send_cmd_data(pdev, DS2482_CMD_1WIRE_WRITE_BYTE, byte);
+
+	mutex_unlock(&pdev->access_lock);
+}
+
+/**
+ * ds2482_w1_read_byte - Performs the read byte function.
+ *
+ * @data:	The ds2482 channel pointer
+ * Return:	The value read
+ */
+static u8 ds2482_w1_read_byte(void *data)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int result;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the read byte command */
+	ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_READ_BYTE);
+
+	/* Wait until 1WB == 0 */
+	ds2482_wait_1wire_idle(pdev);
+
+	/* Select the data register */
+	ds2482_select_register(pdev, DS2482_PTR_CODE_DATA);
+
+	/* Read the data byte */
+	result = i2c_smbus_read_byte(pdev->client);
+
+	mutex_unlock(&pdev->access_lock);
+
+	return result;
+}
+
+
+/**
+ * ds2482_w1_reset_bus - Sends a reset on the 1-wire interface
+ *
+ * @data:	The ds2482 channel pointer
+ * Return:	0=Device present, 1=No device present or error
+ */
+static u8 ds2482_w1_reset_bus(void *data)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	int err;
+	u8 retval = 1;
+
+	mutex_lock(&pdev->access_lock);
+
+	/* Select the channel */
+	ds2482_wait_1wire_idle(pdev);
+	if (pdev->w1_count > 1)
+		ds2482_set_channel(pdev, pchan->channel);
+
+	/* Send the reset command */
+	err = ds2482_send_cmd(pdev, DS2482_CMD_1WIRE_RESET);
+	if (err >= 0) {
+		/* Wait until the reset is complete */
+		err = ds2482_wait_1wire_idle(pdev);
+		retval = !(err & DS2482_REG_STS_PPD);
+
+		/* If the chip did reset since detect, re-config it */
+		if (err & DS2482_REG_STS_RST)
+			ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
+					     ds2482_calculate_config(0x00));
+	}
+
+	mutex_unlock(&pdev->access_lock);
+
+	return retval;
+}
+
+static u8 ds2482_w1_set_pullup(void *data, int delay)
+{
+	struct ds2482_w1_chan *pchan = data;
+	struct ds2482_data    *pdev = pchan->pdev;
+	u8 retval = 1;
+
+	/* if delay is non-zero activate the pullup,
+	 * the strong pullup will be automatically deactivated
+	 * by the master, so do not explicitly deactive it
+	 */
+	if (delay) {
+		/* both waits are crucial, otherwise devices might not be
+		 * powered long enough, causing e.g. a w1_therm sensor to
+		 * provide wrong conversion results
+		 */
+		ds2482_wait_1wire_idle(pdev);
+		/* note: it seems like both SPU and APU have to be set! */
+		retval = ds2482_send_cmd_data(pdev, DS2482_CMD_WRITE_CONFIG,
+			ds2482_calculate_config(DS2482_REG_CFG_SPU |
+						DS2482_REG_CFG_APU));
+		ds2482_wait_1wire_idle(pdev);
+	}
+
+	return retval;
+}
+
+
+static int ds2482_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ds2482_data *data;
+	int err = -ENODEV;
+	int temp1;
+	int idx;
+
+	if (!i2c_check_functionality(client->adapter,
+				     I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
+				     I2C_FUNC_SMBUS_BYTE))
+		return -ENODEV;
+
+	if (!(data = kzalloc(sizeof(struct ds2482_data), GFP_KERNEL))) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	data->client = client;
+	i2c_set_clientdata(client, data);
+
+	/* Reset the device (sets the read_ptr to status) */
+	if (ds2482_send_cmd(data, DS2482_CMD_RESET) < 0) {
+		dev_warn(&client->dev, "DS2482 reset failed.\n");
+		goto exit_free;
+	}
+
+	/* Sleep at least 525ns to allow the reset to complete */
+	ndelay(525);
+
+	/* Read the status byte - only reset bit and line should be set */
+	temp1 = i2c_smbus_read_byte(client);
+	if (temp1 != (DS2482_REG_STS_LL | DS2482_REG_STS_RST)) {
+		dev_warn(&client->dev, "DS2482 reset status "
+			 "0x%02X - not a DS2482\n", temp1);
+		goto exit_free;
+	}
+
+	/* Detect the 8-port version */
+	data->w1_count = 1;
+	if (ds2482_set_channel(data, 7) == 0)
+		data->w1_count = 8;
+
+	/* Set all config items to 0 (off) */
+	ds2482_send_cmd_data(data, DS2482_CMD_WRITE_CONFIG,
+		ds2482_calculate_config(0x00));
+
+	mutex_init(&data->access_lock);
+
+	/* Register 1-wire interface(s) */
+	for (idx = 0; idx < data->w1_count; idx++) {
+		data->w1_ch[idx].pdev = data;
+		data->w1_ch[idx].channel = idx;
+
+		/* Populate all the w1 bus master stuff */
+		data->w1_ch[idx].w1_bm.data       = &data->w1_ch[idx];
+		data->w1_ch[idx].w1_bm.read_byte  = ds2482_w1_read_byte;
+		data->w1_ch[idx].w1_bm.write_byte = ds2482_w1_write_byte;
+		data->w1_ch[idx].w1_bm.touch_bit  = ds2482_w1_touch_bit;
+		data->w1_ch[idx].w1_bm.triplet    = ds2482_w1_triplet;
+		data->w1_ch[idx].w1_bm.reset_bus  = ds2482_w1_reset_bus;
+		data->w1_ch[idx].w1_bm.set_pullup = ds2482_w1_set_pullup;
+
+		err = w1_add_master_device(&data->w1_ch[idx].w1_bm);
+		if (err) {
+			data->w1_ch[idx].pdev = NULL;
+			goto exit_w1_remove;
+		}
+	}
+
+	return 0;
+
+exit_w1_remove:
+	for (idx = 0; idx < data->w1_count; idx++) {
+		if (data->w1_ch[idx].pdev != NULL)
+			w1_remove_master_device(&data->w1_ch[idx].w1_bm);
+	}
+exit_free:
+	kfree(data);
+exit:
+	return err;
+}
+
+static void ds2482_remove(struct i2c_client *client)
+{
+	struct ds2482_data   *data = i2c_get_clientdata(client);
+	int idx;
+
+	/* Unregister the 1-wire bridge(s) */
+	for (idx = 0; idx < data->w1_count; idx++) {
+		if (data->w1_ch[idx].pdev != NULL)
+			w1_remove_master_device(&data->w1_ch[idx].w1_bm);
+	}
+
+	/* Free the memory */
+	kfree(data);
+}
+
+/*
+ * Driver data (common to all clients)
+ */
+static const struct i2c_device_id ds2482_id[] = {
+	{ "ds2482", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ds2482_id);
+
+static struct i2c_driver ds2482_driver = {
+	.driver = {
+		.name	= "ds2482",
+	},
+	.probe		= ds2482_probe,
+	.remove		= ds2482_remove,
+	.id_table	= ds2482_id,
+};
+module_i2c_driver(ds2482_driver);
+
+MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
+MODULE_DESCRIPTION("DS2482 driver");
+
+MODULE_LICENSE("GPL");