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, 699 insertions, 0 deletions

diff --git a/drivers/iio/chemical/scd4x.c b/drivers/iio/chemical/scd4x.c
new file mode 100644
index 000000000..f7ed9455b
--- /dev/null
+++ b/drivers/iio/chemical/scd4x.c
@@ -0,0 +1,699 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Sensirion SCD4X carbon dioxide sensor i2c driver
+ *
+ * Copyright (C) 2021 Protonic Holland
+ * Author: Roan van Dijk <roan@protonic.nl>
+ *
+ * I2C slave address: 0x62
+ *
+ * Datasheets:
+ * https://www.sensirion.com/file/datasheet_scd4x
+ */
+
+#include <asm/unaligned.h>
+#include <linux/crc8.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/types.h>
+#include <linux/kernel.h>
+#include <linux/mutex.h>
+#include <linux/string.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+
+#define SCD4X_CRC8_POLYNOMIAL 0x31
+#define SCD4X_TIMEOUT_ERR 1000
+#define SCD4X_READ_BUF_SIZE 9
+#define SCD4X_COMMAND_BUF_SIZE 2
+#define SCD4X_WRITE_BUF_SIZE 5
+#define SCD4X_FRC_MIN_PPM 0
+#define SCD4X_FRC_MAX_PPM 2000
+#define SCD4X_READY_MASK 0x01
+
+/*Commands SCD4X*/
+enum scd4x_cmd {
+	CMD_START_MEAS          = 0x21b1,
+	CMD_READ_MEAS           = 0xec05,
+	CMD_STOP_MEAS           = 0x3f86,
+	CMD_SET_TEMP_OFFSET     = 0x241d,
+	CMD_GET_TEMP_OFFSET     = 0x2318,
+	CMD_FRC                 = 0x362f,
+	CMD_SET_ASC             = 0x2416,
+	CMD_GET_ASC             = 0x2313,
+	CMD_GET_DATA_READY      = 0xe4b8,
+};
+
+enum scd4x_channel_idx {
+	SCD4X_CO2,
+	SCD4X_TEMP,
+	SCD4X_HR,
+};
+
+struct scd4x_state {
+	struct i2c_client *client;
+	/* maintain access to device, to prevent concurrent reads/writes */
+	struct mutex lock;
+	struct regulator *vdd;
+};
+
+DECLARE_CRC8_TABLE(scd4x_crc8_table);
+
+static int scd4x_i2c_xfer(struct scd4x_state *state, char *txbuf, int txsize,
+				char *rxbuf, int rxsize)
+{
+	struct i2c_client *client = state->client;
+	int ret;
+
+	ret = i2c_master_send(client, txbuf, txsize);
+
+	if (ret < 0)
+		return ret;
+	if (ret != txsize)
+		return -EIO;
+
+	if (rxsize == 0)
+		return 0;
+
+	ret = i2c_master_recv(client, rxbuf, rxsize);
+	if (ret < 0)
+		return ret;
+	if (ret != rxsize)
+		return -EIO;
+
+	return 0;
+}
+
+static int scd4x_send_command(struct scd4x_state *state, enum scd4x_cmd cmd)
+{
+	char buf[SCD4X_COMMAND_BUF_SIZE];
+	int ret;
+
+	/*
+	 * Measurement needs to be stopped before sending commands.
+	 * Except stop and start command.
+	 */
+	if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) {
+
+		ret = scd4x_send_command(state, CMD_STOP_MEAS);
+		if (ret)
+			return ret;
+
+		/* execution time for stopping measurement */
+		msleep_interruptible(500);
+	}
+
+	put_unaligned_be16(cmd, buf);
+	ret = scd4x_i2c_xfer(state, buf, 2, buf, 0);
+	if (ret)
+		return ret;
+
+	if ((cmd != CMD_STOP_MEAS) && (cmd != CMD_START_MEAS)) {
+		ret = scd4x_send_command(state, CMD_START_MEAS);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int scd4x_read(struct scd4x_state *state, enum scd4x_cmd cmd,
+			void *response, int response_sz)
+{
+	struct i2c_client *client = state->client;
+	char buf[SCD4X_READ_BUF_SIZE];
+	char *rsp = response;
+	int i, ret;
+	char crc;
+
+	/*
+	 * Measurement needs to be stopped before sending commands.
+	 * Except for reading measurement and data ready command.
+	 */
+	if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS)) {
+		ret = scd4x_send_command(state, CMD_STOP_MEAS);
+		if (ret)
+			return ret;
+
+		/* execution time for stopping measurement */
+		msleep_interruptible(500);
+	}
+
+	/* CRC byte for every 2 bytes of data */
+	response_sz += response_sz / 2;
+
+	put_unaligned_be16(cmd, buf);
+	ret = scd4x_i2c_xfer(state, buf, 2, buf, response_sz);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < response_sz; i += 3) {
+		crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
+		if (crc != buf[i + 2]) {
+			dev_err(&client->dev, "CRC error\n");
+			return -EIO;
+		}
+
+		*rsp++ = buf[i];
+		*rsp++ = buf[i + 1];
+	}
+
+	/* start measurement */
+	if ((cmd != CMD_GET_DATA_READY) && (cmd != CMD_READ_MEAS)) {
+		ret = scd4x_send_command(state, CMD_START_MEAS);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int scd4x_write(struct scd4x_state *state, enum scd4x_cmd cmd, uint16_t arg)
+{
+	char buf[SCD4X_WRITE_BUF_SIZE];
+	int ret;
+	char crc;
+
+	put_unaligned_be16(cmd, buf);
+	put_unaligned_be16(arg, buf + 2);
+
+	crc = crc8(scd4x_crc8_table, buf + 2, 2, CRC8_INIT_VALUE);
+	buf[4] = crc;
+
+	/* measurement needs to be stopped before sending commands */
+	ret = scd4x_send_command(state, CMD_STOP_MEAS);
+	if (ret)
+		return ret;
+
+	/* execution time */
+	msleep_interruptible(500);
+
+	ret = scd4x_i2c_xfer(state, buf, SCD4X_WRITE_BUF_SIZE, buf, 0);
+	if (ret)
+		return ret;
+
+	/* start measurement, except for forced calibration command */
+	if (cmd != CMD_FRC) {
+		ret = scd4x_send_command(state, CMD_START_MEAS);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int scd4x_write_and_fetch(struct scd4x_state *state, enum scd4x_cmd cmd,
+				uint16_t arg, void *response, int response_sz)
+{
+	struct i2c_client *client = state->client;
+	char buf[SCD4X_READ_BUF_SIZE];
+	char *rsp = response;
+	int i, ret;
+	char crc;
+
+	ret = scd4x_write(state, CMD_FRC, arg);
+	if (ret)
+		goto err;
+
+	/* execution time */
+	msleep_interruptible(400);
+
+	/* CRC byte for every 2 bytes of data */
+	response_sz += response_sz / 2;
+
+	ret = i2c_master_recv(client, buf, response_sz);
+	if (ret < 0)
+		goto err;
+	if (ret != response_sz) {
+		ret = -EIO;
+		goto err;
+	}
+
+	for (i = 0; i < response_sz; i += 3) {
+		crc = crc8(scd4x_crc8_table, buf + i, 2, CRC8_INIT_VALUE);
+		if (crc != buf[i + 2]) {
+			dev_err(&client->dev, "CRC error\n");
+			ret = -EIO;
+			goto err;
+		}
+
+		*rsp++ = buf[i];
+		*rsp++ = buf[i + 1];
+	}
+
+	return scd4x_send_command(state, CMD_START_MEAS);
+
+err:
+	/*
+	 * on error try to start the measurement,
+	 * puts sensor back into continuous measurement
+	 */
+	scd4x_send_command(state, CMD_START_MEAS);
+
+	return ret;
+}
+
+static int scd4x_read_meas(struct scd4x_state *state, uint16_t *meas)
+{
+	int i, ret;
+	__be16 buf[3];
+
+	ret = scd4x_read(state, CMD_READ_MEAS, buf, sizeof(buf));
+	if (ret)
+		return ret;
+
+	for (i = 0; i < ARRAY_SIZE(buf); i++)
+		meas[i] = be16_to_cpu(buf[i]);
+
+	return 0;
+}
+
+static int scd4x_wait_meas_poll(struct scd4x_state *state)
+{
+	struct i2c_client *client = state->client;
+	int tries = 6;
+	int ret;
+
+	do {
+		__be16 bval;
+		uint16_t val;
+
+		ret = scd4x_read(state, CMD_GET_DATA_READY, &bval, sizeof(bval));
+		if (ret)
+			return -EIO;
+		val = be16_to_cpu(bval);
+
+		/* new measurement available */
+		if (val & 0x7FF)
+			return 0;
+
+		msleep_interruptible(1000);
+	} while (--tries);
+
+	/* try to start sensor on timeout */
+	ret = scd4x_send_command(state, CMD_START_MEAS);
+	if (ret)
+		dev_err(&client->dev, "failed to start measurement: %d\n", ret);
+
+	return -ETIMEDOUT;
+}
+
+static int scd4x_read_poll(struct scd4x_state *state, uint16_t *buf)
+{
+	int ret;
+
+	ret = scd4x_wait_meas_poll(state);
+	if (ret)
+		return ret;
+
+	return scd4x_read_meas(state, buf);
+}
+
+static int scd4x_read_channel(struct scd4x_state *state, int chan)
+{
+	int ret;
+	uint16_t buf[3];
+
+	ret = scd4x_read_poll(state, buf);
+	if (ret)
+		return ret;
+
+	return buf[chan];
+}
+
+static int scd4x_read_raw(struct iio_dev *indio_dev,
+			struct iio_chan_spec const *chan, int *val,
+			int *val2, long mask)
+{
+	struct scd4x_state *state = iio_priv(indio_dev);
+	int ret;
+	__be16 tmp;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(indio_dev);
+		if (ret)
+			return ret;
+
+		mutex_lock(&state->lock);
+		ret = scd4x_read_channel(state, chan->address);
+		mutex_unlock(&state->lock);
+
+		iio_device_release_direct_mode(indio_dev);
+		if (ret < 0)
+			return ret;
+
+		*val = ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		if (chan->type == IIO_CONCENTRATION) {
+			*val = 0;
+			*val2 = 100;
+			return IIO_VAL_INT_PLUS_MICRO;
+		} else if (chan->type == IIO_TEMP) {
+			*val = 175000;
+			*val2 = 65536;
+			return IIO_VAL_FRACTIONAL;
+		} else if (chan->type == IIO_HUMIDITYRELATIVE) {
+			*val = 100000;
+			*val2 = 65536;
+			return IIO_VAL_FRACTIONAL;
+		}
+		return -EINVAL;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = -16852;
+		*val2 = 114286;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		mutex_lock(&state->lock);
+		ret = scd4x_read(state, CMD_GET_TEMP_OFFSET, &tmp, sizeof(tmp));
+		mutex_unlock(&state->lock);
+		if (ret)
+			return ret;
+
+		*val = be16_to_cpu(tmp);
+
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int scd4x_write_raw(struct iio_dev *indio_dev, struct iio_chan_spec const *chan,
+				int val, int val2, long mask)
+{
+	struct scd4x_state *state = iio_priv(indio_dev);
+	int ret = 0;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBBIAS:
+		mutex_lock(&state->lock);
+		ret = scd4x_write(state, CMD_SET_TEMP_OFFSET, val);
+		mutex_unlock(&state->lock);
+
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static ssize_t calibration_auto_enable_show(struct device *dev,
+			struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct scd4x_state *state = iio_priv(indio_dev);
+	int ret;
+	__be16 bval;
+	u16 val;
+
+	mutex_lock(&state->lock);
+	ret = scd4x_read(state, CMD_GET_ASC, &bval, sizeof(bval));
+	mutex_unlock(&state->lock);
+	if (ret) {
+		dev_err(dev, "failed to read automatic calibration");
+		return ret;
+	}
+
+	val = (be16_to_cpu(bval) & SCD4X_READY_MASK) ? 1 : 0;
+
+	return sysfs_emit(buf, "%d\n", val);
+}
+
+static ssize_t calibration_auto_enable_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct scd4x_state *state = iio_priv(indio_dev);
+	bool val;
+	int ret;
+	uint16_t value;
+
+	ret = kstrtobool(buf, &val);
+	if (ret)
+		return ret;
+
+	value = val;
+
+	mutex_lock(&state->lock);
+	ret = scd4x_write(state, CMD_SET_ASC, value);
+	mutex_unlock(&state->lock);
+	if (ret)
+		dev_err(dev, "failed to set automatic calibration");
+
+	return ret ?: len;
+}
+
+static ssize_t calibration_forced_value_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct scd4x_state *state = iio_priv(indio_dev);
+	uint16_t val, arg;
+	int ret;
+
+	ret = kstrtou16(buf, 0, &arg);
+	if (ret)
+		return ret;
+
+	if (arg < SCD4X_FRC_MIN_PPM || arg > SCD4X_FRC_MAX_PPM)
+		return -EINVAL;
+
+	mutex_lock(&state->lock);
+	ret = scd4x_write_and_fetch(state, CMD_FRC, arg, &val, sizeof(val));
+	mutex_unlock(&state->lock);
+
+	if (ret)
+		return ret;
+
+	if (val == 0xff) {
+		dev_err(dev, "forced calibration has failed");
+		return -EINVAL;
+	}
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR_RW(calibration_auto_enable, 0);
+static IIO_DEVICE_ATTR_WO(calibration_forced_value, 0);
+
+static IIO_CONST_ATTR(calibration_forced_value_available,
+	       __stringify([SCD4X_FRC_MIN_PPM 1 SCD4X_FRC_MAX_PPM]));
+
+static struct attribute *scd4x_attrs[] = {
+	&iio_dev_attr_calibration_auto_enable.dev_attr.attr,
+	&iio_dev_attr_calibration_forced_value.dev_attr.attr,
+	&iio_const_attr_calibration_forced_value_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group scd4x_attr_group = {
+	.attrs = scd4x_attrs,
+};
+
+static const struct iio_info scd4x_info = {
+	.attrs = &scd4x_attr_group,
+	.read_raw = scd4x_read_raw,
+	.write_raw = scd4x_write_raw,
+};
+
+static const struct iio_chan_spec scd4x_channels[] = {
+	{
+		.type = IIO_CONCENTRATION,
+		.channel2 = IIO_MOD_CO2,
+		.modified = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+					BIT(IIO_CHAN_INFO_SCALE),
+		.address = SCD4X_CO2,
+		.scan_index = SCD4X_CO2,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_BE,
+		},
+	},
+	{
+		.type = IIO_TEMP,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+					BIT(IIO_CHAN_INFO_SCALE) |
+					BIT(IIO_CHAN_INFO_OFFSET) |
+					BIT(IIO_CHAN_INFO_CALIBBIAS),
+		.address = SCD4X_TEMP,
+		.scan_index = SCD4X_TEMP,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_BE,
+		},
+	},
+	{
+		.type = IIO_HUMIDITYRELATIVE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+					BIT(IIO_CHAN_INFO_SCALE),
+		.address = SCD4X_HR,
+		.scan_index = SCD4X_HR,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_BE,
+		},
+	},
+};
+
+static int scd4x_suspend(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct scd4x_state *state  = iio_priv(indio_dev);
+	int ret;
+
+	ret = scd4x_send_command(state, CMD_STOP_MEAS);
+	if (ret)
+		return ret;
+
+	return regulator_disable(state->vdd);
+}
+
+static int scd4x_resume(struct device *dev)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct scd4x_state *state = iio_priv(indio_dev);
+	int ret;
+
+	ret = regulator_enable(state->vdd);
+	if (ret)
+		return ret;
+
+	return scd4x_send_command(state, CMD_START_MEAS);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(scd4x_pm_ops, scd4x_suspend, scd4x_resume);
+
+static void scd4x_stop_meas(void *state)
+{
+	scd4x_send_command(state, CMD_STOP_MEAS);
+}
+
+static void scd4x_disable_regulator(void *data)
+{
+	struct scd4x_state *state = data;
+
+	regulator_disable(state->vdd);
+}
+
+static irqreturn_t scd4x_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct scd4x_state *state = iio_priv(indio_dev);
+	struct {
+		uint16_t data[3];
+		int64_t ts __aligned(8);
+	} scan;
+	int ret;
+
+	memset(&scan, 0, sizeof(scan));
+	mutex_lock(&state->lock);
+	ret = scd4x_read_poll(state, scan.data);
+	mutex_unlock(&state->lock);
+	if (ret)
+		goto out;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev));
+out:
+	iio_trigger_notify_done(indio_dev->trig);
+	return IRQ_HANDLED;
+}
+
+static int scd4x_probe(struct i2c_client *client)
+{
+	static const unsigned long scd4x_scan_masks[] = { 0x07, 0x00 };
+	struct device *dev = &client->dev;
+	struct iio_dev *indio_dev;
+	struct scd4x_state *state;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	state = iio_priv(indio_dev);
+	mutex_init(&state->lock);
+	state->client = client;
+	crc8_populate_msb(scd4x_crc8_table, SCD4X_CRC8_POLYNOMIAL);
+
+	indio_dev->info = &scd4x_info;
+	indio_dev->name = client->name;
+	indio_dev->channels = scd4x_channels;
+	indio_dev->num_channels = ARRAY_SIZE(scd4x_channels);
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->available_scan_masks = scd4x_scan_masks;
+
+	state->vdd = devm_regulator_get(dev, "vdd");
+	if (IS_ERR(state->vdd))
+		return dev_err_probe(dev, PTR_ERR(state->vdd), "failed to get regulator\n");
+
+	ret = regulator_enable(state->vdd);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, scd4x_disable_regulator, state);
+	if (ret)
+		return ret;
+
+	ret = scd4x_send_command(state, CMD_STOP_MEAS);
+	if (ret) {
+		dev_err(dev, "failed to stop measurement: %d\n", ret);
+		return ret;
+	}
+
+	/* execution time */
+	msleep_interruptible(500);
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL, scd4x_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
+	ret = scd4x_send_command(state, CMD_START_MEAS);
+	if (ret) {
+		dev_err(dev, "failed to start measurement: %d\n", ret);
+		return ret;
+	}
+
+	ret = devm_add_action_or_reset(dev, scd4x_stop_meas, state);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id scd4x_dt_ids[] = {
+	{ .compatible = "sensirion,scd40" },
+	{ .compatible = "sensirion,scd41" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, scd4x_dt_ids);
+
+static struct i2c_driver scd4x_i2c_driver = {
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = scd4x_dt_ids,
+		.pm = pm_sleep_ptr(&scd4x_pm_ops),
+	},
+	.probe_new = scd4x_probe,
+};
+module_i2c_driver(scd4x_i2c_driver);
+
+MODULE_AUTHOR("Roan van Dijk <roan@protonic.nl>");
+MODULE_DESCRIPTION("Sensirion SCD4X carbon dioxide sensor core driver");
+MODULE_LICENSE("GPL v2");