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, 514 insertions, 0 deletions

diff --git a/drivers/hwmon/max6620.c b/drivers/hwmon/max6620.c
new file mode 100644
index 000000000..202b64381
--- /dev/null
+++ b/drivers/hwmon/max6620.c
@@ -0,0 +1,514 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for Maxim MAX6620
+ *
+ * Originally from L. Grunenberg.
+ * (C) 2012 by L. Grunenberg <contact@lgrunenberg.de>
+ *
+ * Copyright (c) 2021 Dell Inc. or its subsidiaries. All Rights Reserved.
+ *
+ * based on code written by :
+ * 2007 by Hans J. Koch <hjk@hansjkoch.de>
+ * John Morris <john.morris@spirentcom.com>
+ * Copyright (c) 2003 Spirent Communications
+ * and Claus Gindhart <claus.gindhart@kontron.com>
+ *
+ * This module has only been tested with the MAX6620 chip.
+ *
+ * The datasheet was last seen at:
+ *
+ *        http://pdfserv.maxim-ic.com/en/ds/MAX6620.pdf
+ *
+ */
+
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+/*
+ * MAX 6620 registers
+ */
+
+#define MAX6620_REG_CONFIG	0x00
+#define MAX6620_REG_FAULT	0x01
+#define MAX6620_REG_CONF_FAN0	0x02
+#define MAX6620_REG_CONF_FAN1	0x03
+#define MAX6620_REG_CONF_FAN2	0x04
+#define MAX6620_REG_CONF_FAN3	0x05
+#define MAX6620_REG_DYN_FAN0	0x06
+#define MAX6620_REG_DYN_FAN1	0x07
+#define MAX6620_REG_DYN_FAN2	0x08
+#define MAX6620_REG_DYN_FAN3	0x09
+#define MAX6620_REG_TACH0	0x10
+#define MAX6620_REG_TACH1	0x12
+#define MAX6620_REG_TACH2	0x14
+#define MAX6620_REG_TACH3	0x16
+#define MAX6620_REG_VOLT0	0x18
+#define MAX6620_REG_VOLT1	0x1A
+#define MAX6620_REG_VOLT2	0x1C
+#define MAX6620_REG_VOLT3	0x1E
+#define MAX6620_REG_TAR0	0x20
+#define MAX6620_REG_TAR1	0x22
+#define MAX6620_REG_TAR2	0x24
+#define MAX6620_REG_TAR3	0x26
+#define MAX6620_REG_DAC0	0x28
+#define MAX6620_REG_DAC1	0x2A
+#define MAX6620_REG_DAC2	0x2C
+#define MAX6620_REG_DAC3	0x2E
+
+/*
+ * Config register bits
+ */
+
+#define MAX6620_CFG_RUN		BIT(7)
+#define MAX6620_CFG_POR		BIT(6)
+#define MAX6620_CFG_TIMEOUT	BIT(5)
+#define MAX6620_CFG_FULLFAN	BIT(4)
+#define MAX6620_CFG_OSC		BIT(3)
+#define MAX6620_CFG_WD_MASK	(BIT(2) | BIT(1))
+#define MAX6620_CFG_WD_2	BIT(1)
+#define MAX6620_CFG_WD_6	BIT(2)
+#define MAX6620_CFG_WD10	(BIT(2) | BIT(1))
+#define MAX6620_CFG_WD		BIT(0)
+
+/*
+ * Failure status register bits
+ */
+
+#define MAX6620_FAIL_TACH0	BIT(4)
+#define MAX6620_FAIL_TACH1	BIT(5)
+#define MAX6620_FAIL_TACH2	BIT(6)
+#define MAX6620_FAIL_TACH3	BIT(7)
+#define MAX6620_FAIL_MASK0	BIT(0)
+#define MAX6620_FAIL_MASK1	BIT(1)
+#define MAX6620_FAIL_MASK2	BIT(2)
+#define MAX6620_FAIL_MASK3	BIT(3)
+
+#define MAX6620_CLOCK_FREQ	8192 /* Clock frequency in Hz */
+#define MAX6620_PULSE_PER_REV	2 /* Tachometer pulses per revolution */
+
+/* Minimum and maximum values of the FAN-RPM */
+#define FAN_RPM_MIN	240
+#define FAN_RPM_MAX	30000
+
+static const u8 config_reg[] = {
+	MAX6620_REG_CONF_FAN0,
+	MAX6620_REG_CONF_FAN1,
+	MAX6620_REG_CONF_FAN2,
+	MAX6620_REG_CONF_FAN3,
+};
+
+static const u8 dyn_reg[] = {
+	MAX6620_REG_DYN_FAN0,
+	MAX6620_REG_DYN_FAN1,
+	MAX6620_REG_DYN_FAN2,
+	MAX6620_REG_DYN_FAN3,
+};
+
+static const u8 tach_reg[] = {
+	MAX6620_REG_TACH0,
+	MAX6620_REG_TACH1,
+	MAX6620_REG_TACH2,
+	MAX6620_REG_TACH3,
+};
+
+static const u8 target_reg[] = {
+	MAX6620_REG_TAR0,
+	MAX6620_REG_TAR1,
+	MAX6620_REG_TAR2,
+	MAX6620_REG_TAR3,
+};
+
+/*
+ * Client data (each client gets its own)
+ */
+
+struct max6620_data {
+	struct i2c_client *client;
+	struct mutex update_lock;
+	bool valid; /* false until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* register values */
+	u8 fancfg[4];
+	u8 fandyn[4];
+	u8 fault;
+	u16 tach[4];
+	u16 target[4];
+};
+
+static u8 max6620_fan_div_from_reg(u8 val)
+{
+	return BIT((val & 0xE0) >> 5);
+}
+
+static u16 max6620_fan_rpm_to_tach(u8 div, int rpm)
+{
+	return (60 * div * MAX6620_CLOCK_FREQ) / (rpm * MAX6620_PULSE_PER_REV);
+}
+
+static int max6620_fan_tach_to_rpm(u8 div, u16 tach)
+{
+	return (60 * div * MAX6620_CLOCK_FREQ) / (tach * MAX6620_PULSE_PER_REV);
+}
+
+static int max6620_update_device(struct device *dev)
+{
+	struct max6620_data *data = dev_get_drvdata(dev);
+	struct i2c_client *client = data->client;
+	int i;
+	int ret = 0;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		for (i = 0; i < 4; i++) {
+			ret = i2c_smbus_read_byte_data(client, config_reg[i]);
+			if (ret < 0)
+				goto error;
+			data->fancfg[i] = ret;
+
+			ret = i2c_smbus_read_byte_data(client, dyn_reg[i]);
+			if (ret < 0)
+				goto error;
+			data->fandyn[i] = ret;
+
+			ret = i2c_smbus_read_byte_data(client, tach_reg[i]);
+			if (ret < 0)
+				goto error;
+			data->tach[i] = (ret << 3) & 0x7f8;
+			ret = i2c_smbus_read_byte_data(client, tach_reg[i] + 1);
+			if (ret < 0)
+				goto error;
+			data->tach[i] |= (ret >> 5) & 0x7;
+
+			ret = i2c_smbus_read_byte_data(client, target_reg[i]);
+			if (ret < 0)
+				goto error;
+			data->target[i] = (ret << 3) & 0x7f8;
+			ret = i2c_smbus_read_byte_data(client, target_reg[i] + 1);
+			if (ret < 0)
+				goto error;
+			data->target[i] |= (ret >> 5) & 0x7;
+		}
+
+		/*
+		 * Alarms are cleared on read in case the condition that
+		 * caused the alarm is removed. Keep the value latched here
+		 * for providing the register through different alarm files.
+		 */
+		ret = i2c_smbus_read_byte_data(client, MAX6620_REG_FAULT);
+		if (ret < 0)
+			goto error;
+		data->fault |= (ret >> 4) & (ret & 0x0F);
+
+		data->last_updated = jiffies;
+		data->valid = true;
+	}
+
+error:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static umode_t
+max6620_is_visible(const void *data, enum hwmon_sensor_types type, u32 attr,
+		   int channel)
+{
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_alarm:
+		case hwmon_fan_input:
+			return 0444;
+		case hwmon_fan_div:
+		case hwmon_fan_target:
+			return 0644;
+		default:
+			break;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int
+max6620_read(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+	     int channel, long *val)
+{
+	struct max6620_data *data;
+	struct i2c_client *client;
+	int ret;
+	u8 div;
+	u8 val1;
+	u8 val2;
+
+	ret = max6620_update_device(dev);
+	if (ret < 0)
+		return ret;
+	data = dev_get_drvdata(dev);
+	client = data->client;
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_alarm:
+			mutex_lock(&data->update_lock);
+			*val = !!(data->fault & BIT(channel));
+
+			/* Setting TACH count to re-enable fan fault detection */
+			if (*val == 1) {
+				val1 = (data->target[channel] >> 3) & 0xff;
+				val2 = (data->target[channel] << 5) & 0xe0;
+				ret = i2c_smbus_write_byte_data(client,
+								target_reg[channel], val1);
+				if (ret < 0) {
+					mutex_unlock(&data->update_lock);
+					return ret;
+				}
+				ret = i2c_smbus_write_byte_data(client,
+								target_reg[channel] + 1, val2);
+				if (ret < 0) {
+					mutex_unlock(&data->update_lock);
+					return ret;
+				}
+
+				data->fault &= ~BIT(channel);
+			}
+			mutex_unlock(&data->update_lock);
+
+			break;
+		case hwmon_fan_div:
+			*val = max6620_fan_div_from_reg(data->fandyn[channel]);
+			break;
+		case hwmon_fan_input:
+			if (data->tach[channel] == 0) {
+				*val = 0;
+			} else {
+				div = max6620_fan_div_from_reg(data->fandyn[channel]);
+				*val = max6620_fan_tach_to_rpm(div, data->tach[channel]);
+			}
+			break;
+		case hwmon_fan_target:
+			if (data->target[channel] == 0) {
+				*val = 0;
+			} else {
+				div = max6620_fan_div_from_reg(data->fandyn[channel]);
+				*val = max6620_fan_tach_to_rpm(div, data->target[channel]);
+			}
+			break;
+		default:
+			return -EOPNOTSUPP;
+		}
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+static int
+max6620_write(struct device *dev, enum hwmon_sensor_types type, u32 attr,
+	      int channel, long val)
+{
+	struct max6620_data *data;
+	struct i2c_client *client;
+	int ret;
+	u8 div;
+	u16 tach;
+	u8 val1;
+	u8 val2;
+
+	ret = max6620_update_device(dev);
+	if (ret < 0)
+		return ret;
+	data = dev_get_drvdata(dev);
+	client = data->client;
+	mutex_lock(&data->update_lock);
+
+	switch (type) {
+	case hwmon_fan:
+		switch (attr) {
+		case hwmon_fan_div:
+			switch (val) {
+			case 1:
+				div = 0;
+				break;
+			case 2:
+				div = 1;
+				break;
+			case 4:
+				div = 2;
+				break;
+			case 8:
+				div = 3;
+				break;
+			case 16:
+				div = 4;
+				break;
+			case 32:
+				div = 5;
+				break;
+			default:
+				ret = -EINVAL;
+				goto error;
+			}
+			data->fandyn[channel] &= 0x1F;
+			data->fandyn[channel] |= div << 5;
+			ret = i2c_smbus_write_byte_data(client, dyn_reg[channel],
+							data->fandyn[channel]);
+			break;
+		case hwmon_fan_target:
+			val = clamp_val(val, FAN_RPM_MIN, FAN_RPM_MAX);
+			div = max6620_fan_div_from_reg(data->fandyn[channel]);
+			tach = max6620_fan_rpm_to_tach(div, val);
+			val1 = (tach >> 3) & 0xff;
+			val2 = (tach << 5) & 0xe0;
+			ret = i2c_smbus_write_byte_data(client, target_reg[channel], val1);
+			if (ret < 0)
+				break;
+			ret = i2c_smbus_write_byte_data(client, target_reg[channel] + 1, val2);
+			if (ret < 0)
+				break;
+
+			/* Setting TACH count re-enables fan fault detection */
+			data->fault &= ~BIT(channel);
+
+			break;
+		default:
+			ret = -EOPNOTSUPP;
+			break;
+		}
+		break;
+
+	default:
+		ret = -EOPNOTSUPP;
+		break;
+	}
+
+error:
+	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static const struct hwmon_channel_info *max6620_info[] = {
+	HWMON_CHANNEL_INFO(fan,
+			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
+			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
+			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM,
+			   HWMON_F_INPUT | HWMON_F_DIV | HWMON_F_TARGET | HWMON_F_ALARM),
+	NULL
+};
+
+static const struct hwmon_ops max6620_hwmon_ops = {
+	.read = max6620_read,
+	.write = max6620_write,
+	.is_visible = max6620_is_visible,
+};
+
+static const struct hwmon_chip_info max6620_chip_info = {
+	.ops = &max6620_hwmon_ops,
+	.info = max6620_info,
+};
+
+static int max6620_init_client(struct max6620_data *data)
+{
+	struct i2c_client *client = data->client;
+	int config;
+	int err;
+	int i;
+	int reg;
+
+	config = i2c_smbus_read_byte_data(client, MAX6620_REG_CONFIG);
+	if (config < 0) {
+		dev_err(&client->dev, "Error reading config, aborting.\n");
+		return config;
+	}
+
+	/*
+	 * Set bit 4, disable other fans from going full speed on a fail
+	 * failure.
+	 */
+	err = i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10);
+	if (err < 0) {
+		dev_err(&client->dev, "Config write error, aborting.\n");
+		return err;
+	}
+
+	for (i = 0; i < 4; i++) {
+		reg = i2c_smbus_read_byte_data(client, config_reg[i]);
+		if (reg < 0)
+			return reg;
+		data->fancfg[i] = reg;
+
+		/* Enable RPM mode */
+		data->fancfg[i] |= 0xa8;
+		err = i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
+		if (err < 0)
+			return err;
+
+		/* 2 counts (001) and Rate change 100 (0.125 secs) */
+		data->fandyn[i] = 0x30;
+		err = i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int max6620_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct max6620_data *data;
+	struct device *hwmon_dev;
+	int err;
+
+	data = devm_kzalloc(dev, sizeof(struct max6620_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->client = client;
+	mutex_init(&data->update_lock);
+
+	err = max6620_init_client(data);
+	if (err)
+		return err;
+
+	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name,
+							 data,
+							 &max6620_chip_info,
+							 NULL);
+
+	return PTR_ERR_OR_ZERO(hwmon_dev);
+}
+
+static const struct i2c_device_id max6620_id[] = {
+	{ "max6620", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, max6620_id);
+
+static struct i2c_driver max6620_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "max6620",
+	},
+	.probe_new	= max6620_probe,
+	.id_table	= max6620_id,
+};
+
+module_i2c_driver(max6620_driver);
+
+MODULE_AUTHOR("Lucas Grunenberg");
+MODULE_DESCRIPTION("MAX6620 sensor driver");
+MODULE_LICENSE("GPL");