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, 722 insertions, 0 deletions

diff --git a/drivers/iio/dummy/iio_simple_dummy.c b/drivers/iio/dummy/iio_simple_dummy.c
new file mode 100644
index 000000000..c24f609c2
--- /dev/null
+++ b/drivers/iio/dummy/iio_simple_dummy.c
@@ -0,0 +1,722 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * A reference industrial I/O driver to illustrate the functionality available.
+ *
+ * There are numerous real drivers to illustrate the finer points.
+ * The purpose of this driver is to provide a driver with far more comments
+ * and explanatory notes than any 'real' driver would have.
+ * Anyone starting out writing an IIO driver should first make sure they
+ * understand all of this driver except those bits specifically marked
+ * as being present to allow us to 'fake' the presence of hardware.
+ */
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/events.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/sw_device.h>
+#include "iio_simple_dummy.h"
+
+static const struct config_item_type iio_dummy_type = {
+	.ct_owner = THIS_MODULE,
+};
+
+/**
+ * struct iio_dummy_accel_calibscale - realworld to register mapping
+ * @val: first value in read_raw - here integer part.
+ * @val2: second value in read_raw etc - here micro part.
+ * @regval: register value - magic device specific numbers.
+ */
+struct iio_dummy_accel_calibscale {
+	int val;
+	int val2;
+	int regval; /* what would be written to hardware */
+};
+
+static const struct iio_dummy_accel_calibscale dummy_scales[] = {
+	{ 0, 100, 0x8 }, /* 0.000100 */
+	{ 0, 133, 0x7 }, /* 0.000133 */
+	{ 733, 13, 0x9 }, /* 733.000013 */
+};
+
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+
+/*
+ * simple event - triggered when value rises above
+ * a threshold
+ */
+static const struct iio_event_spec iio_dummy_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_RISING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple step detect event - triggered when a step is detected
+ */
+static const struct iio_event_spec step_detect_event = {
+	.type = IIO_EV_TYPE_CHANGE,
+	.dir = IIO_EV_DIR_NONE,
+	.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple transition event - triggered when the reported running confidence
+ * value rises above a threshold value
+ */
+static const struct iio_event_spec iio_running_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_RISING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+
+/*
+ * simple transition event - triggered when the reported walking confidence
+ * value falls under a threshold value
+ */
+static const struct iio_event_spec iio_walking_event = {
+	.type = IIO_EV_TYPE_THRESH,
+	.dir = IIO_EV_DIR_FALLING,
+	.mask_separate = BIT(IIO_EV_INFO_VALUE) | BIT(IIO_EV_INFO_ENABLE),
+};
+#endif
+
+/*
+ * iio_dummy_channels - Description of available channels
+ *
+ * This array of structures tells the IIO core about what the device
+ * actually provides for a given channel.
+ */
+static const struct iio_chan_spec iio_dummy_channels[] = {
+	/* indexed ADC channel in_voltage0_raw etc */
+	{
+		.type = IIO_VOLTAGE,
+		/* Channel has a numeric index of 0 */
+		.indexed = 1,
+		.channel = 0,
+		/* What other information is available? */
+		.info_mask_separate =
+		/*
+		 * in_voltage0_raw
+		 * Raw (unscaled no bias removal etc) measurement
+		 * from the device.
+		 */
+		BIT(IIO_CHAN_INFO_RAW) |
+		/*
+		 * in_voltage0_offset
+		 * Offset for userspace to apply prior to scale
+		 * when converting to standard units (microvolts)
+		 */
+		BIT(IIO_CHAN_INFO_OFFSET) |
+		/*
+		 * in_voltage0_scale
+		 * Multipler for userspace to apply post offset
+		 * when converting to standard units (microvolts)
+		 */
+		BIT(IIO_CHAN_INFO_SCALE),
+		/*
+		 * sampling_frequency
+		 * The frequency in Hz at which the channels are sampled
+		 */
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		/* The ordering of elements in the buffer via an enum */
+		.scan_index = DUMMY_INDEX_VOLTAGE_0,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 'u', /* unsigned */
+			.realbits = 13, /* 13 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_dummy_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	/* Differential ADC channel in_voltage1-voltage2_raw etc*/
+	{
+		.type = IIO_VOLTAGE,
+		.differential = 1,
+		/*
+		 * Indexing for differential channels uses channel
+		 * for the positive part, channel2 for the negative.
+		 */
+		.indexed = 1,
+		.channel = 1,
+		.channel2 = 2,
+		/*
+		 * in_voltage1-voltage2_raw
+		 * Raw (unscaled no bias removal etc) measurement
+		 * from the device.
+		 */
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		/*
+		 * in_voltage-voltage_scale
+		 * Shared version of scale - shared by differential
+		 * input channels of type IIO_VOLTAGE.
+		 */
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		/*
+		 * sampling_frequency
+		 * The frequency in Hz at which the channels are sampled
+		 */
+		.scan_index = DUMMY_INDEX_DIFFVOLTAGE_1M2,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 's', /* signed */
+			.realbits = 12, /* 12 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+	},
+	/* Differential ADC channel in_voltage3-voltage4_raw etc*/
+	{
+		.type = IIO_VOLTAGE,
+		.differential = 1,
+		.indexed = 1,
+		.channel = 3,
+		.channel2 = 4,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = DUMMY_INDEX_DIFFVOLTAGE_3M4,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 11,
+			.storagebits = 16,
+			.shift = 0,
+		},
+	},
+	/*
+	 * 'modified' (i.e. axis specified) acceleration channel
+	 * in_accel_z_raw
+	 */
+	{
+		.type = IIO_ACCEL,
+		.modified = 1,
+		/* Channel 2 is use for modifiers */
+		.channel2 = IIO_MOD_X,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+		/*
+		 * Internal bias and gain correction values. Applied
+		 * by the hardware or driver prior to userspace
+		 * seeing the readings. Typically part of hardware
+		 * calibration.
+		 */
+		BIT(IIO_CHAN_INFO_CALIBSCALE) |
+		BIT(IIO_CHAN_INFO_CALIBBIAS),
+		.info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.scan_index = DUMMY_INDEX_ACCELX,
+		.scan_type = { /* Description of storage in buffer */
+			.sign = 's', /* signed */
+			.realbits = 16, /* 16 bits */
+			.storagebits = 16, /* 16 bits used for storage */
+			.shift = 0, /* zero shift */
+		},
+	},
+	/*
+	 * Convenience macro for timestamps. 4 is the index in
+	 * the buffer.
+	 */
+	IIO_CHAN_SOFT_TIMESTAMP(4),
+	/* DAC channel out_voltage0_raw */
+	{
+		.type = IIO_VOLTAGE,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.scan_index = -1, /* No buffer support */
+		.output = 1,
+		.indexed = 1,
+		.channel = 0,
+	},
+	{
+		.type = IIO_STEPS,
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_ENABLE) |
+			BIT(IIO_CHAN_INFO_CALIBHEIGHT),
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &step_detect_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	{
+		.type = IIO_ACTIVITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_RUNNING,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_running_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+	{
+		.type = IIO_ACTIVITY,
+		.modified = 1,
+		.channel2 = IIO_MOD_WALKING,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.scan_index = -1, /* No buffer support */
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+		.event_spec = &iio_walking_event,
+		.num_event_specs = 1,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+	},
+};
+
+/**
+ * iio_dummy_read_raw() - data read function.
+ * @indio_dev:	the struct iio_dev associated with this device instance
+ * @chan:	the channel whose data is to be read
+ * @val:	first element of returned value (typically INT)
+ * @val2:	second element of returned value (typically MICRO)
+ * @mask:	what we actually want to read as per the info_mask_*
+ *		in iio_chan_spec.
+ */
+static int iio_dummy_read_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int *val,
+			      int *val2,
+			      long mask)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+	int ret = -EINVAL;
+
+	mutex_lock(&st->lock);
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW: /* magic value - channel value read */
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chan->output) {
+				/* Set integer part to cached value */
+				*val = st->dac_val;
+				ret = IIO_VAL_INT;
+			} else if (chan->differential) {
+				if (chan->channel == 1)
+					*val = st->differential_adc_val[0];
+				else
+					*val = st->differential_adc_val[1];
+				ret = IIO_VAL_INT;
+			} else {
+				*val = st->single_ended_adc_val;
+				ret = IIO_VAL_INT;
+			}
+			break;
+		case IIO_ACCEL:
+			*val = st->accel_val;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->steps;
+			ret = IIO_VAL_INT;
+			break;
+		case IIO_ACTIVITY:
+			switch (chan->channel2) {
+			case IIO_MOD_RUNNING:
+				*val = st->activity_running;
+				ret = IIO_VAL_INT;
+				break;
+			case IIO_MOD_WALKING:
+				*val = st->activity_walking;
+				ret = IIO_VAL_INT;
+				break;
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_OFFSET:
+		/* only single ended adc -> 7 */
+		*val = 7;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			switch (chan->differential) {
+			case 0:
+				/* only single ended adc -> 0.001333 */
+				*val = 0;
+				*val2 = 1333;
+				ret = IIO_VAL_INT_PLUS_MICRO;
+				break;
+			case 1:
+				/* all differential adc -> 0.000001344 */
+				*val = 0;
+				*val2 = 1344;
+				ret = IIO_VAL_INT_PLUS_NANO;
+			}
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		/* only the acceleration axis - read from cache */
+		*val = st->accel_calibbias;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		*val = st->accel_calibscale->val;
+		*val2 = st->accel_calibscale->val2;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*val = 3;
+		*val2 = 33;
+		ret = IIO_VAL_INT_PLUS_NANO;
+		break;
+	case IIO_CHAN_INFO_ENABLE:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->steps_enabled;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_CALIBHEIGHT:
+		switch (chan->type) {
+		case IIO_STEPS:
+			*val = st->height;
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			break;
+		}
+		break;
+
+	default:
+		break;
+	}
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+/**
+ * iio_dummy_write_raw() - data write function.
+ * @indio_dev:	the struct iio_dev associated with this device instance
+ * @chan:	the channel whose data is to be written
+ * @val:	first element of value to set (typically INT)
+ * @val2:	second element of value to set (typically MICRO)
+ * @mask:	what we actually want to write as per the info_mask_*
+ *		in iio_chan_spec.
+ *
+ * Note that all raw writes are assumed IIO_VAL_INT and info mask elements
+ * are assumed to be IIO_INT_PLUS_MICRO unless the callback write_raw_get_fmt
+ * in struct iio_info is provided by the driver.
+ */
+static int iio_dummy_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	int i;
+	int ret = 0;
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			if (chan->output == 0)
+				return -EINVAL;
+
+			/* Locking not required as writing single value */
+			mutex_lock(&st->lock);
+			st->dac_val = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (chan->type) {
+		case IIO_STEPS:
+			mutex_lock(&st->lock);
+			st->steps = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		case IIO_ACTIVITY:
+			if (val < 0)
+				val = 0;
+			if (val > 100)
+				val = 100;
+			switch (chan->channel2) {
+			case IIO_MOD_RUNNING:
+				st->activity_running = val;
+				return 0;
+			case IIO_MOD_WALKING:
+				st->activity_walking = val;
+				return 0;
+			default:
+				return -EINVAL;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_CALIBSCALE:
+		mutex_lock(&st->lock);
+		/* Compare against table - hard matching here */
+		for (i = 0; i < ARRAY_SIZE(dummy_scales); i++)
+			if (val == dummy_scales[i].val &&
+			    val2 == dummy_scales[i].val2)
+				break;
+		if (i == ARRAY_SIZE(dummy_scales))
+			ret = -EINVAL;
+		else
+			st->accel_calibscale = &dummy_scales[i];
+		mutex_unlock(&st->lock);
+		return ret;
+	case IIO_CHAN_INFO_CALIBBIAS:
+		mutex_lock(&st->lock);
+		st->accel_calibbias = val;
+		mutex_unlock(&st->lock);
+		return 0;
+	case IIO_CHAN_INFO_ENABLE:
+		switch (chan->type) {
+		case IIO_STEPS:
+			mutex_lock(&st->lock);
+			st->steps_enabled = val;
+			mutex_unlock(&st->lock);
+			return 0;
+		default:
+			return -EINVAL;
+		}
+	case IIO_CHAN_INFO_CALIBHEIGHT:
+		switch (chan->type) {
+		case IIO_STEPS:
+			st->height = val;
+			return 0;
+		default:
+			return -EINVAL;
+		}
+
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Device type specific information.
+ */
+static const struct iio_info iio_dummy_info = {
+	.read_raw = &iio_dummy_read_raw,
+	.write_raw = &iio_dummy_write_raw,
+#ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
+	.read_event_config = &iio_simple_dummy_read_event_config,
+	.write_event_config = &iio_simple_dummy_write_event_config,
+	.read_event_value = &iio_simple_dummy_read_event_value,
+	.write_event_value = &iio_simple_dummy_write_event_value,
+#endif /* CONFIG_IIO_SIMPLE_DUMMY_EVENTS */
+};
+
+/**
+ * iio_dummy_init_device() - device instance specific init
+ * @indio_dev: the iio device structure
+ *
+ * Most drivers have one of these to set up default values,
+ * reset the device to known state etc.
+ */
+static int iio_dummy_init_device(struct iio_dev *indio_dev)
+{
+	struct iio_dummy_state *st = iio_priv(indio_dev);
+
+	st->dac_val = 0;
+	st->single_ended_adc_val = 73;
+	st->differential_adc_val[0] = 33;
+	st->differential_adc_val[1] = -34;
+	st->accel_val = 34;
+	st->accel_calibbias = -7;
+	st->accel_calibscale = &dummy_scales[0];
+	st->steps = 47;
+	st->activity_running = 98;
+	st->activity_walking = 4;
+
+	return 0;
+}
+
+/**
+ * iio_dummy_probe() - device instance probe
+ * @name: name of this instance.
+ *
+ * Arguments are bus type specific.
+ * I2C: iio_dummy_probe(struct i2c_client *client,
+ *                      const struct i2c_device_id *id)
+ * SPI: iio_dummy_probe(struct spi_device *spi)
+ */
+static struct iio_sw_device *iio_dummy_probe(const char *name)
+{
+	int ret;
+	struct iio_dev *indio_dev;
+	struct iio_dummy_state *st;
+	struct iio_sw_device *swd;
+	struct device *parent = NULL;
+
+	/*
+	 * With hardware: Set the parent device.
+	 * parent = &spi->dev;
+	 * parent = &client->dev;
+	 */
+
+	swd = kzalloc(sizeof(*swd), GFP_KERNEL);
+	if (!swd)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Allocate an IIO device.
+	 *
+	 * This structure contains all generic state
+	 * information about the device instance.
+	 * It also has a region (accessed by iio_priv()
+	 * for chip specific state information.
+	 */
+	indio_dev = iio_device_alloc(parent, sizeof(*st));
+	if (!indio_dev) {
+		ret = -ENOMEM;
+		goto error_free_swd;
+	}
+
+	st = iio_priv(indio_dev);
+	mutex_init(&st->lock);
+
+	iio_dummy_init_device(indio_dev);
+
+	 /*
+	 * Make the iio_dev struct available to remove function.
+	 * Bus equivalents
+	 * i2c_set_clientdata(client, indio_dev);
+	 * spi_set_drvdata(spi, indio_dev);
+	 */
+	swd->device = indio_dev;
+
+	/*
+	 * Set the device name.
+	 *
+	 * This is typically a part number and obtained from the module
+	 * id table.
+	 * e.g. for i2c and spi:
+	 *    indio_dev->name = id->name;
+	 *    indio_dev->name = spi_get_device_id(spi)->name;
+	 */
+	indio_dev->name = kstrdup(name, GFP_KERNEL);
+	if (!indio_dev->name) {
+		ret = -ENOMEM;
+		goto error_free_device;
+	}
+
+	/* Provide description of available channels */
+	indio_dev->channels = iio_dummy_channels;
+	indio_dev->num_channels = ARRAY_SIZE(iio_dummy_channels);
+
+	/*
+	 * Provide device type specific interface functions and
+	 * constant data.
+	 */
+	indio_dev->info = &iio_dummy_info;
+
+	/* Specify that device provides sysfs type interfaces */
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_simple_dummy_events_register(indio_dev);
+	if (ret < 0)
+		goto error_free_name;
+
+	ret = iio_simple_dummy_configure_buffer(indio_dev);
+	if (ret < 0)
+		goto error_unregister_events;
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0)
+		goto error_unconfigure_buffer;
+
+	iio_swd_group_init_type_name(swd, name, &iio_dummy_type);
+
+	return swd;
+error_unconfigure_buffer:
+	iio_simple_dummy_unconfigure_buffer(indio_dev);
+error_unregister_events:
+	iio_simple_dummy_events_unregister(indio_dev);
+error_free_name:
+	kfree(indio_dev->name);
+error_free_device:
+	iio_device_free(indio_dev);
+error_free_swd:
+	kfree(swd);
+	return ERR_PTR(ret);
+}
+
+/**
+ * iio_dummy_remove() - device instance removal function
+ * @swd: pointer to software IIO device abstraction
+ *
+ * Parameters follow those of iio_dummy_probe for buses.
+ */
+static int iio_dummy_remove(struct iio_sw_device *swd)
+{
+	/*
+	 * Get a pointer to the device instance iio_dev structure
+	 * from the bus subsystem. E.g.
+	 * struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	 * struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	 */
+	struct iio_dev *indio_dev = swd->device;
+
+	/* Unregister the device */
+	iio_device_unregister(indio_dev);
+
+	/* Device specific code to power down etc */
+
+	/* Buffered capture related cleanup */
+	iio_simple_dummy_unconfigure_buffer(indio_dev);
+
+	iio_simple_dummy_events_unregister(indio_dev);
+
+	/* Free all structures */
+	kfree(indio_dev->name);
+	iio_device_free(indio_dev);
+
+	return 0;
+}
+
+/*
+ * module_iio_sw_device_driver() -  device driver registration
+ *
+ * Varies depending on bus type of the device. As there is no device
+ * here, call probe directly. For information on device registration
+ * i2c:
+ * Documentation/i2c/writing-clients.rst
+ * spi:
+ * Documentation/spi/spi-summary.rst
+ */
+static const struct iio_sw_device_ops iio_dummy_device_ops = {
+	.probe = iio_dummy_probe,
+	.remove = iio_dummy_remove,
+};
+
+static struct iio_sw_device_type iio_dummy_device = {
+	.name = "dummy",
+	.owner = THIS_MODULE,
+	.ops = &iio_dummy_device_ops,
+};
+
+module_iio_sw_device_driver(iio_dummy_device);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
+MODULE_DESCRIPTION("IIO dummy driver");
+MODULE_LICENSE("GPL v2");