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, 490 insertions, 0 deletions

diff --git a/drivers/hwmon/ltc4245.c b/drivers/hwmon/ltc4245.c
new file mode 100644
index 000000000..5088d28b3
--- /dev/null
+++ b/drivers/hwmon/ltc4245.c
@@ -0,0 +1,490 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller
+ *
+ * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu>
+ *
+ * This driver is based on the ds1621 and ina209 drivers.
+ *
+ * Datasheet:
+ * http://www.linear.com/pc/downloadDocument.do?navId=H0,C1,C1003,C1006,C1140,P19392,D13517
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/jiffies.h>
+#include <linux/platform_data/ltc4245.h>
+
+/* Here are names of the chip's registers (a.k.a. commands) */
+enum ltc4245_cmd {
+	LTC4245_STATUS			= 0x00, /* readonly */
+	LTC4245_ALERT			= 0x01,
+	LTC4245_CONTROL			= 0x02,
+	LTC4245_ON			= 0x03,
+	LTC4245_FAULT1			= 0x04,
+	LTC4245_FAULT2			= 0x05,
+	LTC4245_GPIO			= 0x06,
+	LTC4245_ADCADR			= 0x07,
+
+	LTC4245_12VIN			= 0x10,
+	LTC4245_12VSENSE		= 0x11,
+	LTC4245_12VOUT			= 0x12,
+	LTC4245_5VIN			= 0x13,
+	LTC4245_5VSENSE			= 0x14,
+	LTC4245_5VOUT			= 0x15,
+	LTC4245_3VIN			= 0x16,
+	LTC4245_3VSENSE			= 0x17,
+	LTC4245_3VOUT			= 0x18,
+	LTC4245_VEEIN			= 0x19,
+	LTC4245_VEESENSE		= 0x1a,
+	LTC4245_VEEOUT			= 0x1b,
+	LTC4245_GPIOADC			= 0x1c,
+};
+
+struct ltc4245_data {
+	struct i2c_client *client;
+
+	struct mutex update_lock;
+	bool valid;
+	unsigned long last_updated; /* in jiffies */
+
+	/* Control registers */
+	u8 cregs[0x08];
+
+	/* Voltage registers */
+	u8 vregs[0x0d];
+
+	/* GPIO ADC registers */
+	bool use_extra_gpios;
+	int gpios[3];
+};
+
+/*
+ * Update the readings from the GPIO pins. If the driver has been configured to
+ * sample all GPIO's as analog voltages, a round-robin sampling method is used.
+ * Otherwise, only the configured GPIO pin is sampled.
+ *
+ * LOCKING: must hold data->update_lock
+ */
+static void ltc4245_update_gpios(struct device *dev)
+{
+	struct ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	u8 gpio_curr, gpio_next, gpio_reg;
+	int i;
+
+	/* no extra gpio support, we're basically done */
+	if (!data->use_extra_gpios) {
+		data->gpios[0] = data->vregs[LTC4245_GPIOADC - 0x10];
+		return;
+	}
+
+	/*
+	 * If the last reading was too long ago, then we mark all old GPIO
+	 * readings as stale by setting them to -EAGAIN
+	 */
+	if (time_after(jiffies, data->last_updated + 5 * HZ)) {
+		for (i = 0; i < ARRAY_SIZE(data->gpios); i++)
+			data->gpios[i] = -EAGAIN;
+	}
+
+	/*
+	 * Get the current GPIO pin
+	 *
+	 * The datasheet calls these GPIO[1-3], but we'll calculate the zero
+	 * based array index instead, and call them GPIO[0-2]. This is much
+	 * easier to think about.
+	 */
+	gpio_curr = (data->cregs[LTC4245_GPIO] & 0xc0) >> 6;
+	if (gpio_curr > 0)
+		gpio_curr -= 1;
+
+	/* Read the GPIO voltage from the GPIOADC register */
+	data->gpios[gpio_curr] = data->vregs[LTC4245_GPIOADC - 0x10];
+
+	/* Find the next GPIO pin to read */
+	gpio_next = (gpio_curr + 1) % ARRAY_SIZE(data->gpios);
+
+	/*
+	 * Calculate the correct setting for the GPIO register so it will
+	 * sample the next GPIO pin
+	 */
+	gpio_reg = (data->cregs[LTC4245_GPIO] & 0x3f) | ((gpio_next + 1) << 6);
+
+	/* Update the GPIO register */
+	i2c_smbus_write_byte_data(client, LTC4245_GPIO, gpio_reg);
+
+	/* Update saved data */
+	data->cregs[LTC4245_GPIO] = gpio_reg;
+}
+
+static struct ltc4245_data *ltc4245_update_device(struct device *dev)
+{
+	struct ltc4245_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	s32 val;
+	int i;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+
+		/* Read control registers -- 0x00 to 0x07 */
+		for (i = 0; i < ARRAY_SIZE(data->cregs); i++) {
+			val = i2c_smbus_read_byte_data(client, i);
+			if (unlikely(val < 0))
+				data->cregs[i] = 0;
+			else
+				data->cregs[i] = val;
+		}
+
+		/* Read voltage registers -- 0x10 to 0x1c */
+		for (i = 0; i < ARRAY_SIZE(data->vregs); i++) {
+			val = i2c_smbus_read_byte_data(client, i+0x10);
+			if (unlikely(val < 0))
+				data->vregs[i] = 0;
+			else
+				data->vregs[i] = val;
+		}
+
+		/* Update GPIO readings */
+		ltc4245_update_gpios(dev);
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+/* Return the voltage from the given register in millivolts */
+static int ltc4245_get_voltage(struct device *dev, u8 reg)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+	const u8 regval = data->vregs[reg - 0x10];
+	u32 voltage = 0;
+
+	switch (reg) {
+	case LTC4245_12VIN:
+	case LTC4245_12VOUT:
+		voltage = regval * 55;
+		break;
+	case LTC4245_5VIN:
+	case LTC4245_5VOUT:
+		voltage = regval * 22;
+		break;
+	case LTC4245_3VIN:
+	case LTC4245_3VOUT:
+		voltage = regval * 15;
+		break;
+	case LTC4245_VEEIN:
+	case LTC4245_VEEOUT:
+		voltage = regval * -55;
+		break;
+	case LTC4245_GPIOADC:
+		voltage = regval * 10;
+		break;
+	default:
+		/* If we get here, the developer messed up */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	return voltage;
+}
+
+/* Return the current in the given sense register in milliAmperes */
+static unsigned int ltc4245_get_current(struct device *dev, u8 reg)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+	const u8 regval = data->vregs[reg - 0x10];
+	unsigned int voltage;
+	unsigned int curr;
+
+	/*
+	 * The strange looking conversions that follow are fixed-point
+	 * math, since we cannot do floating point in the kernel.
+	 *
+	 * Step 1: convert sense register to microVolts
+	 * Step 2: convert voltage to milliAmperes
+	 *
+	 * If you play around with the V=IR equation, you come up with
+	 * the following: X uV / Y mOhm == Z mA
+	 *
+	 * With the resistors that are fractions of a milliOhm, we multiply
+	 * the voltage and resistance by 10, to shift the decimal point.
+	 * Now we can use the normal division operator again.
+	 */
+
+	switch (reg) {
+	case LTC4245_12VSENSE:
+		voltage = regval * 250; /* voltage in uV */
+		curr = voltage / 50; /* sense resistor 50 mOhm */
+		break;
+	case LTC4245_5VSENSE:
+		voltage = regval * 125; /* voltage in uV */
+		curr = (voltage * 10) / 35; /* sense resistor 3.5 mOhm */
+		break;
+	case LTC4245_3VSENSE:
+		voltage = regval * 125; /* voltage in uV */
+		curr = (voltage * 10) / 25; /* sense resistor 2.5 mOhm */
+		break;
+	case LTC4245_VEESENSE:
+		voltage = regval * 250; /* voltage in uV */
+		curr = voltage / 100; /* sense resistor 100 mOhm */
+		break;
+	default:
+		/* If we get here, the developer messed up */
+		WARN_ON_ONCE(1);
+		curr = 0;
+		break;
+	}
+
+	return curr;
+}
+
+/* Map from voltage channel index to voltage register */
+
+static const s8 ltc4245_in_regs[] = {
+	LTC4245_12VIN, LTC4245_5VIN, LTC4245_3VIN, LTC4245_VEEIN,
+	LTC4245_12VOUT, LTC4245_5VOUT, LTC4245_3VOUT, LTC4245_VEEOUT,
+};
+
+/* Map from current channel index to current register */
+
+static const s8 ltc4245_curr_regs[] = {
+	LTC4245_12VSENSE, LTC4245_5VSENSE, LTC4245_3VSENSE, LTC4245_VEESENSE,
+};
+
+static int ltc4245_read_curr(struct device *dev, u32 attr, int channel,
+			     long *val)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+
+	switch (attr) {
+	case hwmon_curr_input:
+		*val = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+		return 0;
+	case hwmon_curr_max_alarm:
+		*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel + 4));
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read_in(struct device *dev, u32 attr, int channel, long *val)
+{
+	struct ltc4245_data *data = ltc4245_update_device(dev);
+
+	switch (attr) {
+	case hwmon_in_input:
+		if (channel < 8) {
+			*val = ltc4245_get_voltage(dev,
+						ltc4245_in_regs[channel]);
+		} else {
+			int regval = data->gpios[channel - 8];
+
+			if (regval < 0)
+				return regval;
+			*val = regval * 10;
+		}
+		return 0;
+	case hwmon_in_min_alarm:
+		if (channel < 4)
+			*val = !!(data->cregs[LTC4245_FAULT1] & BIT(channel));
+		else
+			*val = !!(data->cregs[LTC4245_FAULT2] &
+				  BIT(channel - 4));
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read_power(struct device *dev, u32 attr, int channel,
+			      long *val)
+{
+	unsigned long curr;
+	long voltage;
+
+	switch (attr) {
+	case hwmon_power_input:
+		(void)ltc4245_update_device(dev);
+		curr = ltc4245_get_current(dev, ltc4245_curr_regs[channel]);
+		voltage = ltc4245_get_voltage(dev, ltc4245_in_regs[channel]);
+		*val = abs(curr * voltage);
+		return 0;
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static int ltc4245_read(struct device *dev, enum hwmon_sensor_types type,
+			u32 attr, int channel, long *val)
+{
+
+	switch (type) {
+	case hwmon_curr:
+		return ltc4245_read_curr(dev, attr, channel, val);
+	case hwmon_power:
+		return ltc4245_read_power(dev, attr, channel, val);
+	case hwmon_in:
+		return ltc4245_read_in(dev, attr, channel - 1, val);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+static umode_t ltc4245_is_visible(const void *_data,
+				  enum hwmon_sensor_types type,
+				  u32 attr, int channel)
+{
+	const struct ltc4245_data *data = _data;
+
+	switch (type) {
+	case hwmon_in:
+		if (channel == 0)
+			return 0;
+		switch (attr) {
+		case hwmon_in_input:
+			if (channel > 9 && !data->use_extra_gpios)
+				return 0;
+			return 0444;
+		case hwmon_in_min_alarm:
+			if (channel > 8)
+				return 0;
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_curr:
+		switch (attr) {
+		case hwmon_curr_input:
+		case hwmon_curr_max_alarm:
+			return 0444;
+		default:
+			return 0;
+		}
+	case hwmon_power:
+		switch (attr) {
+		case hwmon_power_input:
+			return 0444;
+		default:
+			return 0;
+		}
+	default:
+		return 0;
+	}
+}
+
+static const struct hwmon_channel_info *ltc4245_info[] = {
+	HWMON_CHANNEL_INFO(in,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT | HWMON_I_MIN_ALARM,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT,
+			   HWMON_I_INPUT),
+	HWMON_CHANNEL_INFO(curr,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM,
+			   HWMON_C_INPUT | HWMON_C_MAX_ALARM),
+	HWMON_CHANNEL_INFO(power,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT,
+			   HWMON_P_INPUT),
+	NULL
+};
+
+static const struct hwmon_ops ltc4245_hwmon_ops = {
+	.is_visible = ltc4245_is_visible,
+	.read = ltc4245_read,
+};
+
+static const struct hwmon_chip_info ltc4245_chip_info = {
+	.ops = &ltc4245_hwmon_ops,
+	.info = ltc4245_info,
+};
+
+static bool ltc4245_use_extra_gpios(struct i2c_client *client)
+{
+	struct ltc4245_platform_data *pdata = dev_get_platdata(&client->dev);
+	struct device_node *np = client->dev.of_node;
+
+	/* prefer platform data */
+	if (pdata)
+		return pdata->use_extra_gpios;
+
+	/* fallback on OF */
+	if (of_find_property(np, "ltc4245,use-extra-gpios", NULL))
+		return true;
+
+	return false;
+}
+
+static int ltc4245_probe(struct i2c_client *client)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	struct ltc4245_data *data;
+	struct device *hwmon_dev;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->update_lock);
+	data->use_extra_gpios = ltc4245_use_extra_gpios(client);
+
+	/* Initialize the LTC4245 chip */
+	i2c_smbus_write_byte_data(client, LTC4245_FAULT1, 0x00);
+	i2c_smbus_write_byte_data(client, LTC4245_FAULT2, 0x00);
+
+	hwmon_dev = devm_hwmon_device_register_with_info(&client->dev,
+							 client->name, data,
+							 &ltc4245_chip_info,
+							 NULL);
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id ltc4245_id[] = {
+	{ "ltc4245", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ltc4245_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc4245_driver = {
+	.driver = {
+		.name	= "ltc4245",
+	},
+	.probe_new	= ltc4245_probe,
+	.id_table	= ltc4245_id,
+};
+
+module_i2c_driver(ltc4245_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("LTC4245 driver");
+MODULE_LICENSE("GPL");