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, 835 insertions, 0 deletions

diff --git a/drivers/hwmon/stts751.c b/drivers/hwmon/stts751.c
new file mode 100644
index 000000000..2f67c6747
--- /dev/null
+++ b/drivers/hwmon/stts751.c
@@ -0,0 +1,835 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * STTS751 sensor driver
+ *
+ * Copyright (C) 2016-2017 Istituto Italiano di Tecnologia - RBCS - EDL
+ * Robotics, Brain and Cognitive Sciences department
+ * Electronic Design Laboratory
+ *
+ * Written by Andrea Merello <andrea.merello@gmail.com>
+ *
+ * Based on  LM95241 driver and LM90 driver
+ */
+
+#include <linux/bitops.h>
+#include <linux/err.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/util_macros.h>
+
+#define DEVNAME "stts751"
+
+static const unsigned short normal_i2c[] = {
+	0x48, 0x49, 0x38, 0x39,  /* STTS751-0 */
+	0x4A, 0x4B, 0x3A, 0x3B,  /* STTS751-1 */
+	I2C_CLIENT_END };
+
+#define STTS751_REG_TEMP_H	0x00
+#define STTS751_REG_STATUS	0x01
+#define STTS751_STATUS_TRIPT	BIT(0)
+#define STTS751_STATUS_TRIPL	BIT(5)
+#define STTS751_STATUS_TRIPH	BIT(6)
+#define STTS751_REG_TEMP_L	0x02
+#define STTS751_REG_CONF	0x03
+#define STTS751_CONF_RES_MASK	0x0C
+#define STTS751_CONF_RES_SHIFT  2
+#define STTS751_CONF_EVENT_DIS  BIT(7)
+#define STTS751_CONF_STOP	BIT(6)
+#define STTS751_REG_RATE	0x04
+#define STTS751_REG_HLIM_H	0x05
+#define STTS751_REG_HLIM_L	0x06
+#define STTS751_REG_LLIM_H	0x07
+#define STTS751_REG_LLIM_L	0x08
+#define STTS751_REG_TLIM	0x20
+#define STTS751_REG_HYST	0x21
+#define STTS751_REG_SMBUS_TO	0x22
+
+#define STTS751_REG_PROD_ID	0xFD
+#define STTS751_REG_MAN_ID	0xFE
+#define STTS751_REG_REV_ID	0xFF
+
+#define STTS751_0_PROD_ID	0x00
+#define STTS751_1_PROD_ID	0x01
+#define ST_MAN_ID		0x53
+
+/*
+ * Possible update intervals are (in mS):
+ * 16000, 8000, 4000, 2000, 1000, 500, 250, 125, 62.5, 31.25
+ * However we are not going to complicate things too much and we stick to the
+ * approx value in mS.
+ */
+static const int stts751_intervals[] = {
+	16000, 8000, 4000, 2000, 1000, 500, 250, 125, 63, 31
+};
+
+static const struct i2c_device_id stts751_id[] = {
+	{ "stts751", 0 },
+	{ }
+};
+
+static const struct of_device_id __maybe_unused stts751_of_match[] = {
+	{ .compatible = "stts751" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, stts751_of_match);
+
+struct stts751_priv {
+	struct device *dev;
+	struct i2c_client *client;
+	struct mutex access_lock;
+	u8 interval;
+	int res;
+	int event_max, event_min;
+	int therm;
+	int hyst;
+	bool smbus_timeout;
+	int temp;
+	unsigned long last_update, last_alert_update;
+	u8 config;
+	bool min_alert, max_alert, therm_trip;
+	bool data_valid, alert_valid;
+	bool notify_max, notify_min;
+};
+
+/*
+ * These functions converts temperature from HW format to integer format and
+ * vice-vers. They are (mostly) taken from lm90 driver. Unit is in mC.
+ */
+static int stts751_to_deg(s16 hw_val)
+{
+	return hw_val * 125 / 32;
+}
+
+static s32 stts751_to_hw(int val)
+{
+	return DIV_ROUND_CLOSEST(val, 125) * 32;
+}
+
+static int stts751_adjust_resolution(struct stts751_priv *priv)
+{
+	u8 res;
+
+	switch (priv->interval) {
+	case 9:
+		/* 10 bits */
+		res = 0;
+		break;
+	case 8:
+		/* 11 bits */
+		res = 1;
+		break;
+	default:
+		/* 12 bits */
+		res = 3;
+		break;
+	}
+
+	if (priv->res == res)
+		return 0;
+
+	priv->config &= ~STTS751_CONF_RES_MASK;
+	priv->config |= res << STTS751_CONF_RES_SHIFT;
+	dev_dbg(&priv->client->dev, "setting res %d. config %x",
+		res, priv->config);
+	priv->res = res;
+
+	return i2c_smbus_write_byte_data(priv->client,
+				STTS751_REG_CONF, priv->config);
+}
+
+static int stts751_update_temp(struct stts751_priv *priv)
+{
+	s32 integer1, integer2, frac;
+
+	/*
+	 * There is a trick here, like in the lm90 driver. We have to read two
+	 * registers to get the sensor temperature, but we have to beware a
+	 * conversion could occur between the readings. We could use the
+	 * one-shot conversion register, but we don't want to do this (disables
+	 * hardware monitoring). So the solution used here is to read the high
+	 * byte once, then the low byte, then the high byte again. If the new
+	 * high byte matches the old one, then we have a valid reading. Else we
+	 * have to read the low byte again, and now we believe we have a correct
+	 * reading.
+	 */
+	integer1 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
+	if (integer1 < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C read failed (temp H). ret: %x\n", integer1);
+		return integer1;
+	}
+
+	frac = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_L);
+	if (frac < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C read failed (temp L). ret: %x\n", frac);
+		return frac;
+	}
+
+	integer2 = i2c_smbus_read_byte_data(priv->client, STTS751_REG_TEMP_H);
+	if (integer2 < 0) {
+		dev_dbg(&priv->client->dev,
+			"I2C 2nd read failed (temp H). ret: %x\n", integer2);
+		return integer2;
+	}
+
+	if (integer1 != integer2) {
+		frac = i2c_smbus_read_byte_data(priv->client,
+						STTS751_REG_TEMP_L);
+		if (frac < 0) {
+			dev_dbg(&priv->client->dev,
+				"I2C 2nd read failed (temp L). ret: %x\n",
+				frac);
+			return frac;
+		}
+	}
+
+	priv->temp = stts751_to_deg((integer1 << 8) | frac);
+	return 0;
+}
+
+static int stts751_set_temp_reg16(struct stts751_priv *priv, int temp,
+				  u8 hreg, u8 lreg)
+{
+	s32 hwval;
+	int ret;
+
+	hwval = stts751_to_hw(temp);
+
+	ret = i2c_smbus_write_byte_data(priv->client, hreg, hwval >> 8);
+	if (ret)
+		return ret;
+
+	return i2c_smbus_write_byte_data(priv->client, lreg, hwval & 0xff);
+}
+
+static int stts751_set_temp_reg8(struct stts751_priv *priv, int temp, u8 reg)
+{
+	s32 hwval;
+
+	hwval = stts751_to_hw(temp);
+	return i2c_smbus_write_byte_data(priv->client, reg, hwval >> 8);
+}
+
+static int stts751_read_reg16(struct stts751_priv *priv, int *temp,
+			      u8 hreg, u8 lreg)
+{
+	int integer, frac;
+
+	integer = i2c_smbus_read_byte_data(priv->client, hreg);
+	if (integer < 0)
+		return integer;
+
+	frac = i2c_smbus_read_byte_data(priv->client, lreg);
+	if (frac < 0)
+		return frac;
+
+	*temp = stts751_to_deg((integer << 8) | frac);
+
+	return 0;
+}
+
+static int stts751_read_reg8(struct stts751_priv *priv, int *temp, u8 reg)
+{
+	int integer;
+
+	integer = i2c_smbus_read_byte_data(priv->client, reg);
+	if (integer < 0)
+		return integer;
+
+	*temp = stts751_to_deg(integer << 8);
+
+	return 0;
+}
+
+/*
+ * Update alert flags without waiting for cache to expire. We detects alerts
+ * immediately for the sake of the alert handler; we still need to deal with
+ * caching to workaround the fact that alarm flags int the status register,
+ * despite what the datasheet claims, gets always cleared on read.
+ */
+static int stts751_update_alert(struct stts751_priv *priv)
+{
+	int ret;
+	bool conv_done;
+	int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
+
+	/*
+	 * Add another 10% because if we run faster than the HW conversion
+	 * rate we will end up in reporting incorrectly alarms.
+	 */
+	cache_time += cache_time / 10;
+
+	ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_STATUS);
+	if (ret < 0)
+		return ret;
+
+	dev_dbg(&priv->client->dev, "status reg %x\n", ret);
+	conv_done = ret & (STTS751_STATUS_TRIPH | STTS751_STATUS_TRIPL);
+	/*
+	 * Reset the cache if the cache time expired, or if we are sure
+	 * we have valid data from a device conversion, or if we know
+	 * our cache has been never written.
+	 *
+	 * Note that when the cache has been never written the point is
+	 * to correctly initialize the timestamp, rather than clearing
+	 * the cache values.
+	 *
+	 * Note that updating the cache timestamp when we get an alarm flag
+	 * is required, otherwise we could incorrectly report alarms to be zero.
+	 */
+	if (time_after(jiffies,	priv->last_alert_update + cache_time) ||
+	    conv_done || !priv->alert_valid) {
+		priv->max_alert = false;
+		priv->min_alert = false;
+		priv->alert_valid = true;
+		priv->last_alert_update = jiffies;
+		dev_dbg(&priv->client->dev, "invalidating alert cache\n");
+	}
+
+	priv->max_alert |= !!(ret & STTS751_STATUS_TRIPH);
+	priv->min_alert |= !!(ret & STTS751_STATUS_TRIPL);
+	priv->therm_trip = !!(ret & STTS751_STATUS_TRIPT);
+
+	dev_dbg(&priv->client->dev, "max_alert: %d, min_alert: %d, therm_trip: %d\n",
+		priv->max_alert, priv->min_alert, priv->therm_trip);
+
+	return 0;
+}
+
+static void stts751_alert(struct i2c_client *client,
+			  enum i2c_alert_protocol type, unsigned int data)
+{
+	int ret;
+	struct stts751_priv *priv = i2c_get_clientdata(client);
+
+	if (type != I2C_PROTOCOL_SMBUS_ALERT)
+		return;
+
+	dev_dbg(&client->dev, "alert!");
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update_alert(priv);
+	if (ret < 0) {
+		/* default to worst case */
+		priv->max_alert = true;
+		priv->min_alert = true;
+
+		dev_warn(priv->dev,
+			 "Alert received, but can't communicate to the device. Triggering all alarms!");
+	}
+
+	if (priv->max_alert) {
+		if (priv->notify_max)
+			dev_notice(priv->dev, "got alert for HIGH temperature");
+		priv->notify_max = false;
+
+		/* unblock alert poll */
+		sysfs_notify(&priv->dev->kobj, NULL, "temp1_max_alarm");
+	}
+
+	if (priv->min_alert) {
+		if (priv->notify_min)
+			dev_notice(priv->dev, "got alert for LOW temperature");
+		priv->notify_min = false;
+
+		/* unblock alert poll */
+		sysfs_notify(&priv->dev->kobj, NULL, "temp1_min_alarm");
+	}
+
+	if (priv->min_alert || priv->max_alert)
+		kobject_uevent(&priv->dev->kobj, KOBJ_CHANGE);
+
+	mutex_unlock(&priv->access_lock);
+}
+
+static int stts751_update(struct stts751_priv *priv)
+{
+	int ret;
+	int cache_time = msecs_to_jiffies(stts751_intervals[priv->interval]);
+
+	if (time_after(jiffies,	priv->last_update + cache_time) ||
+	    !priv->data_valid) {
+		ret = stts751_update_temp(priv);
+		if (ret)
+			return ret;
+
+		ret = stts751_update_alert(priv);
+		if (ret)
+			return ret;
+		priv->data_valid = true;
+		priv->last_update = jiffies;
+	}
+
+	return 0;
+}
+
+static ssize_t max_alarm_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	int ret;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update(priv);
+	if (!ret)
+		priv->notify_max = true;
+	mutex_unlock(&priv->access_lock);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", priv->max_alert);
+}
+
+static ssize_t min_alarm_show(struct device *dev,
+			      struct device_attribute *attr, char *buf)
+{
+	int ret;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update(priv);
+	if (!ret)
+		priv->notify_min = true;
+	mutex_unlock(&priv->access_lock);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", priv->min_alert);
+}
+
+static ssize_t input_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	int ret;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update(priv);
+	mutex_unlock(&priv->access_lock);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", priv->temp);
+}
+
+static ssize_t therm_show(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", priv->therm);
+}
+
+static ssize_t therm_store(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	/* HW works in range -64C to +127.937C */
+	temp = clamp_val(temp, -64000, 127937);
+	mutex_lock(&priv->access_lock);
+	ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_TLIM);
+	if (ret)
+		goto exit;
+
+	dev_dbg(&priv->client->dev, "setting therm %ld", temp);
+
+	/*
+	 * hysteresis reg is relative to therm, so the HW does not need to be
+	 * adjusted, we need to update our local copy only.
+	 */
+	priv->hyst = temp - (priv->therm - priv->hyst);
+	priv->therm = temp;
+
+exit:
+	mutex_unlock(&priv->access_lock);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t hyst_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", priv->hyst);
+}
+
+static ssize_t hyst_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	mutex_lock(&priv->access_lock);
+	/* HW works in range -64C to +127.937C */
+	temp = clamp_val(temp, -64000, priv->therm);
+	priv->hyst = temp;
+	dev_dbg(&priv->client->dev, "setting hyst %ld", temp);
+	temp = priv->therm - temp;
+	ret = stts751_set_temp_reg8(priv, temp, STTS751_REG_HYST);
+	mutex_unlock(&priv->access_lock);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t therm_trip_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	int ret;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	mutex_lock(&priv->access_lock);
+	ret = stts751_update(priv);
+	mutex_unlock(&priv->access_lock);
+	if (ret < 0)
+		return ret;
+
+	return sysfs_emit(buf, "%d\n", priv->therm_trip);
+}
+
+static ssize_t max_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", priv->event_max);
+}
+
+static ssize_t max_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	mutex_lock(&priv->access_lock);
+	/* HW works in range -64C to +127.937C */
+	temp = clamp_val(temp, priv->event_min, 127937);
+	ret = stts751_set_temp_reg16(priv, temp,
+				     STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
+	if (ret)
+		goto exit;
+
+	dev_dbg(&priv->client->dev, "setting event max %ld", temp);
+	priv->event_max = temp;
+	ret = count;
+exit:
+	mutex_unlock(&priv->access_lock);
+	return ret;
+}
+
+static ssize_t min_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n", priv->event_min);
+}
+
+static ssize_t min_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	int ret;
+	long temp;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtol(buf, 10, &temp) < 0)
+		return -EINVAL;
+
+	mutex_lock(&priv->access_lock);
+	/* HW works in range -64C to +127.937C */
+	temp = clamp_val(temp, -64000, priv->event_max);
+	ret = stts751_set_temp_reg16(priv, temp,
+				     STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
+	if (ret)
+		goto exit;
+
+	dev_dbg(&priv->client->dev, "setting event min %ld", temp);
+	priv->event_min = temp;
+	ret = count;
+exit:
+	mutex_unlock(&priv->access_lock);
+	return ret;
+}
+
+static ssize_t interval_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	return sysfs_emit(buf, "%d\n",
+			  stts751_intervals[priv->interval]);
+}
+
+static ssize_t interval_store(struct device *dev,
+			      struct device_attribute *attr, const char *buf,
+			      size_t count)
+{
+	unsigned long val;
+	int idx;
+	int ret = count;
+	struct stts751_priv *priv = dev_get_drvdata(dev);
+
+	if (kstrtoul(buf, 10, &val) < 0)
+		return -EINVAL;
+
+	idx = find_closest_descending(val, stts751_intervals,
+				      ARRAY_SIZE(stts751_intervals));
+
+	dev_dbg(&priv->client->dev, "setting interval. req:%lu, idx: %d, val: %d",
+		val, idx, stts751_intervals[idx]);
+
+	mutex_lock(&priv->access_lock);
+	if (priv->interval == idx)
+		goto exit;
+
+	/*
+	 * In early development stages I've become suspicious about the chip
+	 * starting to misbehave if I ever set, even briefly, an invalid
+	 * configuration. While I'm not sure this is really needed, be
+	 * conservative and set rate/resolution in such an order that avoids
+	 * passing through an invalid configuration.
+	 */
+
+	/* speed up: lower the resolution, then modify convrate */
+	if (priv->interval < idx) {
+		dev_dbg(&priv->client->dev, "lower resolution, then modify convrate");
+		priv->interval = idx;
+		ret = stts751_adjust_resolution(priv);
+		if (ret)
+			goto exit;
+	}
+
+	ret = i2c_smbus_write_byte_data(priv->client, STTS751_REG_RATE, idx);
+	if (ret)
+		goto exit;
+	/* slow down: modify convrate, then raise resolution */
+	if (priv->interval != idx) {
+		dev_dbg(&priv->client->dev, "modify convrate, then raise resolution");
+		priv->interval = idx;
+		ret = stts751_adjust_resolution(priv);
+		if (ret)
+			goto exit;
+	}
+	ret = count;
+exit:
+	mutex_unlock(&priv->access_lock);
+
+	return ret;
+}
+
+static int stts751_detect(struct i2c_client *new_client,
+			  struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = new_client->adapter;
+	const char *name;
+	int tmp;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_MAN_ID);
+	if (tmp != ST_MAN_ID)
+		return -ENODEV;
+
+	/* lower temperaure registers always have bits 0-3 set to zero */
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_TEMP_L);
+	if (tmp & 0xf)
+		return -ENODEV;
+
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_HLIM_L);
+	if (tmp & 0xf)
+		return -ENODEV;
+
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_LLIM_L);
+	if (tmp & 0xf)
+		return -ENODEV;
+
+	/* smbus timeout register always have bits 0-7 set to zero */
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_SMBUS_TO);
+	if (tmp & 0x7f)
+		return -ENODEV;
+
+	tmp = i2c_smbus_read_byte_data(new_client, STTS751_REG_PROD_ID);
+
+	switch (tmp) {
+	case STTS751_0_PROD_ID:
+		name = "STTS751-0";
+		break;
+	case STTS751_1_PROD_ID:
+		name = "STTS751-1";
+		break;
+	default:
+		return -ENODEV;
+	}
+	dev_dbg(&new_client->dev, "Chip %s detected", name);
+
+	strscpy(info->type, stts751_id[0].name, I2C_NAME_SIZE);
+	return 0;
+}
+
+static int stts751_read_chip_config(struct stts751_priv *priv)
+{
+	int ret;
+	int tmp;
+
+	ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_CONF);
+	if (ret < 0)
+		return ret;
+	priv->config = ret;
+	priv->res = (ret & STTS751_CONF_RES_MASK) >> STTS751_CONF_RES_SHIFT;
+
+	ret = i2c_smbus_read_byte_data(priv->client, STTS751_REG_RATE);
+	if (ret < 0)
+		return ret;
+	if (ret >= ARRAY_SIZE(stts751_intervals)) {
+		dev_err(priv->dev, "Unrecognized conversion rate 0x%x\n", ret);
+		return -ENODEV;
+	}
+	priv->interval = ret;
+
+	ret = stts751_read_reg16(priv, &priv->event_max,
+				 STTS751_REG_HLIM_H, STTS751_REG_HLIM_L);
+	if (ret)
+		return ret;
+
+	ret = stts751_read_reg16(priv, &priv->event_min,
+				 STTS751_REG_LLIM_H, STTS751_REG_LLIM_L);
+	if (ret)
+		return ret;
+
+	ret = stts751_read_reg8(priv, &priv->therm, STTS751_REG_TLIM);
+	if (ret)
+		return ret;
+
+	ret = stts751_read_reg8(priv, &tmp, STTS751_REG_HYST);
+	if (ret)
+		return ret;
+	priv->hyst = priv->therm - tmp;
+
+	return 0;
+}
+
+static SENSOR_DEVICE_ATTR_RO(temp1_input, input, 0);
+static SENSOR_DEVICE_ATTR_RW(temp1_min, min, 0);
+static SENSOR_DEVICE_ATTR_RW(temp1_max, max, 0);
+static SENSOR_DEVICE_ATTR_RO(temp1_min_alarm, min_alarm, 0);
+static SENSOR_DEVICE_ATTR_RO(temp1_max_alarm, max_alarm, 0);
+static SENSOR_DEVICE_ATTR_RW(temp1_crit, therm, 0);
+static SENSOR_DEVICE_ATTR_RW(temp1_crit_hyst, hyst, 0);
+static SENSOR_DEVICE_ATTR_RO(temp1_crit_alarm, therm_trip, 0);
+static SENSOR_DEVICE_ATTR_RW(update_interval, interval, 0);
+
+static struct attribute *stts751_attrs[] = {
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
+	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_update_interval.dev_attr.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(stts751);
+
+static int stts751_probe(struct i2c_client *client)
+{
+	struct stts751_priv *priv;
+	int ret;
+	bool smbus_nto;
+	int rev_id;
+
+	priv = devm_kzalloc(&client->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->client = client;
+	priv->notify_max = true;
+	priv->notify_min = true;
+	i2c_set_clientdata(client, priv);
+	mutex_init(&priv->access_lock);
+
+	if (device_property_present(&client->dev,
+				    "smbus-timeout-disable")) {
+		smbus_nto = device_property_read_bool(&client->dev,
+						      "smbus-timeout-disable");
+
+		ret = i2c_smbus_write_byte_data(client,	STTS751_REG_SMBUS_TO,
+						smbus_nto ? 0 : 0x80);
+		if (ret)
+			return ret;
+	}
+
+	rev_id = i2c_smbus_read_byte_data(client, STTS751_REG_REV_ID);
+	if (rev_id < 0)
+		return -ENODEV;
+	if (rev_id != 0x1) {
+		dev_dbg(&client->dev, "Chip revision 0x%x is untested\n",
+			rev_id);
+	}
+
+	ret = stts751_read_chip_config(priv);
+	if (ret)
+		return ret;
+
+	priv->config &= ~(STTS751_CONF_STOP | STTS751_CONF_EVENT_DIS);
+	ret = i2c_smbus_write_byte_data(client,	STTS751_REG_CONF, priv->config);
+	if (ret)
+		return ret;
+
+	priv->dev = devm_hwmon_device_register_with_groups(&client->dev,
+							client->name, priv,
+							stts751_groups);
+	return PTR_ERR_OR_ZERO(priv->dev);
+}
+
+MODULE_DEVICE_TABLE(i2c, stts751_id);
+
+static struct i2c_driver stts751_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= DEVNAME,
+		.of_match_table = of_match_ptr(stts751_of_match),
+	},
+	.probe_new	= stts751_probe,
+	.id_table	= stts751_id,
+	.detect		= stts751_detect,
+	.alert		= stts751_alert,
+	.address_list	= normal_i2c,
+};
+
+module_i2c_driver(stts751_driver);
+
+MODULE_AUTHOR("Andrea Merello <andrea.merello@gmail.com>");
+MODULE_DESCRIPTION("STTS751 sensor driver");
+MODULE_LICENSE("GPL");