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, 999 insertions, 0 deletions

diff --git a/tools/iio/iio_utils.c b/tools/iio/iio_utils.c
new file mode 100644
index 000000000..8d35893b2
--- /dev/null
+++ b/tools/iio/iio_utils.c
@@ -0,0 +1,999 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* IIO - useful set of util functionality
+ *
+ * Copyright (c) 2008 Jonathan Cameron
+ */
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <dirent.h>
+#include <errno.h>
+#include <ctype.h>
+#include "iio_utils.h"
+
+const char *iio_dir = "/sys/bus/iio/devices/";
+
+static char * const iio_direction[] = {
+	"in",
+	"out",
+};
+
+/**
+ * iioutils_break_up_name() - extract generic name from full channel name
+ * @full_name: the full channel name
+ * @generic_name: the output generic channel name
+ *
+ * Returns 0 on success, or a negative error code if string extraction failed.
+ **/
+int iioutils_break_up_name(const char *full_name, char **generic_name)
+{
+	char *current;
+	char *w, *r;
+	char *working, *prefix = "";
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(iio_direction); i++)
+		if (!strncmp(full_name, iio_direction[i],
+			     strlen(iio_direction[i]))) {
+			prefix = iio_direction[i];
+			break;
+		}
+
+	current = strdup(full_name + strlen(prefix) + 1);
+	if (!current)
+		return -ENOMEM;
+
+	working = strtok(current, "_\0");
+	if (!working) {
+		free(current);
+		return -EINVAL;
+	}
+
+	w = working;
+	r = working;
+
+	while (*r != '\0') {
+		if (!isdigit(*r)) {
+			*w = *r;
+			w++;
+		}
+
+		r++;
+	}
+	*w = '\0';
+	ret = asprintf(generic_name, "%s_%s", prefix, working);
+	free(current);
+
+	return (ret == -1) ? -ENOMEM : 0;
+}
+
+/**
+ * iioutils_get_type() - find and process _type attribute data
+ * @is_signed: output whether channel is signed
+ * @bytes: output how many bytes the channel storage occupies
+ * @bits_used: output number of valid bits of data
+ * @shift: output amount of bits to shift right data before applying bit mask
+ * @mask: output a bit mask for the raw data
+ * @be: output if data in big endian
+ * @device_dir: the IIO device directory
+ * @buffer_idx: the IIO buffer index
+ * @name: the channel name
+ * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+static int iioutils_get_type(unsigned int *is_signed, unsigned int *bytes,
+			     unsigned int *bits_used, unsigned int *shift,
+			     uint64_t *mask, unsigned int *be,
+			     const char *device_dir, int buffer_idx,
+			     const char *name, const char *generic_name)
+{
+	FILE *sysfsfp;
+	int ret;
+	DIR *dp;
+	char *scan_el_dir, *builtname, *builtname_generic, *filename = 0;
+	char signchar, endianchar;
+	unsigned padint;
+	const struct dirent *ent;
+
+	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir, buffer_idx);
+	if (ret < 0)
+		return -ENOMEM;
+
+	ret = asprintf(&builtname, FORMAT_TYPE_FILE, name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_scan_el_dir;
+	}
+	ret = asprintf(&builtname_generic, FORMAT_TYPE_FILE, generic_name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_builtname;
+	}
+
+	dp = opendir(scan_el_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_builtname_generic;
+	}
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
+		if ((strcmp(builtname, ent->d_name) == 0) ||
+		    (strcmp(builtname_generic, ent->d_name) == 0)) {
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_closedir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
+				goto error_free_filename;
+			}
+
+			ret = fscanf(sysfsfp,
+				     "%ce:%c%u/%u>>%u",
+				     &endianchar,
+				     &signchar,
+				     bits_used,
+				     &padint, shift);
+			if (ret < 0) {
+				ret = -errno;
+				fprintf(stderr,
+					"failed to pass scan type description\n");
+				goto error_close_sysfsfp;
+			} else if (ret != 5) {
+				ret = -EIO;
+				fprintf(stderr,
+					"scan type description didn't match\n");
+				goto error_close_sysfsfp;
+			}
+
+			*be = (endianchar == 'b');
+			*bytes = padint / 8;
+			if (*bits_used == 64)
+				*mask = ~(0ULL);
+			else
+				*mask = (1ULL << *bits_used) - 1ULL;
+
+			*is_signed = (signchar == 's');
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				fprintf(stderr, "Failed to close %s\n",
+					filename);
+				goto error_free_filename;
+			}
+
+			sysfsfp = 0;
+			free(filename);
+			filename = 0;
+
+			/*
+			 * Avoid having a more generic entry overwriting
+			 * the settings.
+			 */
+			if (strcmp(builtname, ent->d_name) == 0)
+				break;
+		}
+
+error_close_sysfsfp:
+	if (sysfsfp)
+		if (fclose(sysfsfp))
+			perror("iioutils_get_type(): Failed to close file");
+
+error_free_filename:
+	if (filename)
+		free(filename);
+
+error_closedir:
+	if (closedir(dp) == -1)
+		perror("iioutils_get_type(): Failed to close directory");
+
+error_free_builtname_generic:
+	free(builtname_generic);
+error_free_builtname:
+	free(builtname);
+error_free_scan_el_dir:
+	free(scan_el_dir);
+
+	return ret;
+}
+
+/**
+ * iioutils_get_param_float() - read a float value from a channel parameter
+ * @output: output the float value
+ * @param_name: the parameter name to read
+ * @device_dir: the IIO device directory in sysfs
+ * @name: the channel name
+ * @generic_name: the channel type name
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int iioutils_get_param_float(float *output, const char *param_name,
+			     const char *device_dir, const char *name,
+			     const char *generic_name)
+{
+	FILE *sysfsfp;
+	int ret;
+	DIR *dp;
+	char *builtname, *builtname_generic;
+	char *filename = NULL;
+	const struct dirent *ent;
+
+	ret = asprintf(&builtname, "%s_%s", name, param_name);
+	if (ret < 0)
+		return -ENOMEM;
+
+	ret = asprintf(&builtname_generic,
+		       "%s_%s", generic_name, param_name);
+	if (ret < 0) {
+		ret = -ENOMEM;
+		goto error_free_builtname;
+	}
+
+	dp = opendir(device_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_builtname_generic;
+	}
+
+	ret = -ENOENT;
+	while (ent = readdir(dp), ent)
+		if ((strcmp(builtname, ent->d_name) == 0) ||
+		    (strcmp(builtname_generic, ent->d_name) == 0)) {
+			ret = asprintf(&filename,
+				       "%s/%s", device_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_closedir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				goto error_free_filename;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%f", output) != 1)
+				ret = errno ? -errno : -ENODATA;
+
+			break;
+		}
+error_free_filename:
+	if (filename)
+		free(filename);
+
+error_closedir:
+	if (closedir(dp) == -1)
+		perror("iioutils_get_param_float(): Failed to close directory");
+
+error_free_builtname_generic:
+	free(builtname_generic);
+error_free_builtname:
+	free(builtname);
+
+	return ret;
+}
+
+/**
+ * bsort_channel_array_by_index() - sort the array in index order
+ * @ci_array: the iio_channel_info array to be sorted
+ * @cnt: the amount of array elements
+ **/
+
+void bsort_channel_array_by_index(struct iio_channel_info *ci_array, int cnt)
+{
+	struct iio_channel_info temp;
+	int x, y;
+
+	for (x = 0; x < cnt; x++)
+		for (y = 0; y < (cnt - 1); y++)
+			if (ci_array[y].index > ci_array[y + 1].index) {
+				temp = ci_array[y + 1];
+				ci_array[y + 1] = ci_array[y];
+				ci_array[y] = temp;
+			}
+}
+
+/**
+ * build_channel_array() - function to figure out what channels are present
+ * @device_dir: the IIO device directory in sysfs
+ * @buffer_idx: the IIO buffer for this channel array
+ * @ci_array: output the resulting array of iio_channel_info
+ * @counter: output the amount of array elements
+ *
+ * Returns 0 on success, otherwise a negative error code.
+ **/
+int build_channel_array(const char *device_dir, int buffer_idx,
+			struct iio_channel_info **ci_array, int *counter)
+{
+	DIR *dp;
+	FILE *sysfsfp;
+	int count = 0, i;
+	struct iio_channel_info *current;
+	int ret;
+	const struct dirent *ent;
+	char *scan_el_dir;
+	char *filename;
+
+	*counter = 0;
+	ret = asprintf(&scan_el_dir, FORMAT_SCAN_ELEMENTS_DIR, device_dir, buffer_idx);
+	if (ret < 0)
+		return -ENOMEM;
+
+	dp = opendir(scan_el_dir);
+	if (!dp) {
+		ret = -errno;
+		goto error_free_name;
+	}
+
+	while (ent = readdir(dp), ent)
+		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
+			   "_en") == 0) {
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				goto error_close_dir;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				free(filename);
+				goto error_close_dir;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &ret) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_close_dir;
+			}
+			if (ret == 1)
+				(*counter)++;
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_close_dir;
+			}
+
+			free(filename);
+		}
+
+	*ci_array = malloc(sizeof(**ci_array) * (*counter));
+	if (!*ci_array) {
+		ret = -ENOMEM;
+		goto error_close_dir;
+	}
+
+	seekdir(dp, 0);
+	while (ent = readdir(dp), ent) {
+		if (strcmp(ent->d_name + strlen(ent->d_name) - strlen("_en"),
+			   "_en") == 0) {
+			int current_enabled = 0;
+
+			current = &(*ci_array)[count++];
+			ret = asprintf(&filename,
+				       "%s/%s", scan_el_dir, ent->d_name);
+			if (ret < 0) {
+				ret = -ENOMEM;
+				/* decrement count to avoid freeing name */
+				count--;
+				goto error_cleanup_array;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%i", &current_enabled) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			if (!current_enabled) {
+				free(filename);
+				count--;
+				continue;
+			}
+
+			current->scale = 1.0;
+			current->offset = 0;
+			current->name = strndup(ent->d_name,
+						strlen(ent->d_name) -
+						strlen("_en"));
+			if (!current->name) {
+				free(filename);
+				ret = -ENOMEM;
+				count--;
+				goto error_cleanup_array;
+			}
+
+			/* Get the generic and specific name elements */
+			ret = iioutils_break_up_name(current->name,
+						     &current->generic_name);
+			if (ret) {
+				free(filename);
+				free(current->name);
+				count--;
+				goto error_cleanup_array;
+			}
+
+			ret = asprintf(&filename,
+				       "%s/%s_index",
+				       scan_el_dir,
+				       current->name);
+			if (ret < 0) {
+				free(filename);
+				ret = -ENOMEM;
+				goto error_cleanup_array;
+			}
+
+			sysfsfp = fopen(filename, "r");
+			if (!sysfsfp) {
+				ret = -errno;
+				fprintf(stderr, "failed to open %s\n",
+					filename);
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			errno = 0;
+			if (fscanf(sysfsfp, "%u", &current->index) != 1) {
+				ret = errno ? -errno : -ENODATA;
+				if (fclose(sysfsfp))
+					perror("build_channel_array(): Failed to close file");
+
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			if (fclose(sysfsfp)) {
+				ret = -errno;
+				free(filename);
+				goto error_cleanup_array;
+			}
+
+			free(filename);
+			/* Find the scale */
+			ret = iioutils_get_param_float(&current->scale,
+						       "scale",
+						       device_dir,
+						       current->name,
+						       current->generic_name);
+			if ((ret < 0) && (ret != -ENOENT))
+				goto error_cleanup_array;
+
+			ret = iioutils_get_param_float(&current->offset,
+						       "offset",
+						       device_dir,
+						       current->name,
+						       current->generic_name);
+			if ((ret < 0) && (ret != -ENOENT))
+				goto error_cleanup_array;
+
+			ret = iioutils_get_type(&current->is_signed,
+						&current->bytes,
+						&current->bits_used,
+						&current->shift,
+						&current->mask,
+						&current->be,
+						device_dir,
+						buffer_idx,
+						current->name,
+						current->generic_name);
+			if (ret < 0)
+				goto error_cleanup_array;
+		}
+	}
+
+	if (closedir(dp) == -1) {
+		ret = -errno;
+		goto error_cleanup_array;
+	}
+
+	free(scan_el_dir);
+	/* reorder so that the array is in index order */
+	bsort_channel_array_by_index(*ci_array, *counter);
+
+	return 0;
+
+error_cleanup_array:
+	for (i = count - 1;  i >= 0; i--) {
+		free((*ci_array)[i].name);
+		free((*ci_array)[i].generic_name);
+	}
+	free(*ci_array);
+	*ci_array = NULL;
+	*counter = 0;
+error_close_dir:
+	if (dp)
+		if (closedir(dp) == -1)
+			perror("build_channel_array(): Failed to close dir");
+
+error_free_name:
+	free(scan_el_dir);
+
+	return ret;
+}
+
+static int calc_digits(int num)
+{
+	int count = 0;
+
+	/* It takes a digit to represent zero */
+	if (!num)
+		return 1;
+
+	while (num != 0) {
+		num /= 10;
+		count++;
+	}
+
+	return count;
+}
+
+/**
+ * find_type_by_name() - function to match top level types by name
+ * @name: top level type instance name
+ * @type: the type of top level instance being searched
+ *
+ * Returns the device number of a matched IIO device on success, otherwise a
+ * negative error code.
+ * Typical types this is used for are device and trigger.
+ **/
+int find_type_by_name(const char *name, const char *type)
+{
+	const struct dirent *ent;
+	int number, numstrlen, ret;
+
+	FILE *namefp;
+	DIR *dp;
+	char thisname[IIO_MAX_NAME_LENGTH];
+	char *filename;
+
+	dp = opendir(iio_dir);
+	if (!dp) {
+		fprintf(stderr, "No industrialio devices available\n");
+		return -ENODEV;
+	}
+
+	while (ent = readdir(dp), ent) {
+		if (strcmp(ent->d_name, ".") != 0 &&
+		    strcmp(ent->d_name, "..") != 0 &&
+		    strlen(ent->d_name) > strlen(type) &&
+		    strncmp(ent->d_name, type, strlen(type)) == 0) {
+			errno = 0;
+			ret = sscanf(ent->d_name + strlen(type), "%d", &number);
+			if (ret < 0) {
+				ret = -errno;
+				fprintf(stderr,
+					"failed to read element number\n");
+				goto error_close_dir;
+			} else if (ret != 1) {
+				ret = -EIO;
+				fprintf(stderr,
+					"failed to match element number\n");
+				goto error_close_dir;
+			}
+
+			numstrlen = calc_digits(number);
+			/* verify the next character is not a colon */
+			if (strncmp(ent->d_name + strlen(type) + numstrlen,
+			    ":", 1) != 0) {
+				filename = malloc(strlen(iio_dir) + strlen(type)
+						  + numstrlen + 6);
+				if (!filename) {
+					ret = -ENOMEM;
+					goto error_close_dir;
+				}
+
+				ret = sprintf(filename, "%s%s%d/name", iio_dir,
+					      type, number);
+				if (ret < 0) {
+					free(filename);
+					goto error_close_dir;
+				}
+
+				namefp = fopen(filename, "r");
+				if (!namefp) {
+					free(filename);
+					continue;
+				}
+
+				free(filename);
+				errno = 0;
+				if (fscanf(namefp, "%s", thisname) != 1) {
+					ret = errno ? -errno : -ENODATA;
+					goto error_close_dir;
+				}
+
+				if (fclose(namefp)) {
+					ret = -errno;
+					goto error_close_dir;
+				}
+
+				if (strcmp(name, thisname) == 0) {
+					if (closedir(dp) == -1)
+						return -errno;
+
+					return number;
+				}
+			}
+		}
+	}
+	if (closedir(dp) == -1)
+		return -errno;
+
+	return -ENODEV;
+
+error_close_dir:
+	if (closedir(dp) == -1)
+		perror("find_type_by_name(): Failed to close directory");
+
+	return ret;
+}
+
+static int _write_sysfs_int(const char *filename, const char *basedir, int val,
+			    int verify)
+{
+	int ret = 0;
+	FILE *sysfsfp;
+	int test;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp)
+		return -ENOMEM;
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "w");
+	if (!sysfsfp) {
+		ret = -errno;
+		fprintf(stderr, "failed to open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%d", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_int(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp)) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	if (verify) {
+		sysfsfp = fopen(temp, "r");
+		if (!sysfsfp) {
+			ret = -errno;
+			fprintf(stderr, "failed to open %s\n", temp);
+			goto error_free;
+		}
+
+		if (fscanf(sysfsfp, "%d", &test) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_int(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
+			ret = -errno;
+			goto error_free;
+		}
+
+		if (test != val) {
+			fprintf(stderr,
+				"Possible failure in int write %d to %s/%s\n",
+				val, basedir, filename);
+			ret = -1;
+		}
+	}
+
+error_free:
+	free(temp);
+	return ret;
+}
+
+/**
+ * write_sysfs_int() - write an integer value to a sysfs file
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int(const char *filename, const char *basedir, int val)
+{
+	return _write_sysfs_int(filename, basedir, val, 0);
+}
+
+/**
+ * write_sysfs_int_and_verify() - write an integer value to a sysfs file
+ *				  and verify
+ * @filename: name of the file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: integer value to write to file
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_int_and_verify(const char *filename, const char *basedir,
+			       int val)
+{
+	return _write_sysfs_int(filename, basedir, val, 1);
+}
+
+static int _write_sysfs_string(const char *filename, const char *basedir,
+			       const char *val, int verify)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed\n");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "w");
+	if (!sysfsfp) {
+		ret = -errno;
+		fprintf(stderr, "Could not open %s\n", temp);
+		goto error_free;
+	}
+
+	ret = fprintf(sysfsfp, "%s", val);
+	if (ret < 0) {
+		if (fclose(sysfsfp))
+			perror("_write_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp)) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	if (verify) {
+		sysfsfp = fopen(temp, "r");
+		if (!sysfsfp) {
+			ret = -errno;
+			fprintf(stderr, "Could not open file to verify\n");
+			goto error_free;
+		}
+
+		if (fscanf(sysfsfp, "%s", temp) != 1) {
+			ret = errno ? -errno : -ENODATA;
+			if (fclose(sysfsfp))
+				perror("_write_sysfs_string(): Failed to close dir");
+
+			goto error_free;
+		}
+
+		if (fclose(sysfsfp)) {
+			ret = -errno;
+			goto error_free;
+		}
+
+		if (strcmp(temp, val) != 0) {
+			fprintf(stderr,
+				"Possible failure in string write of %s "
+				"Should be %s written to %s/%s\n", temp, val,
+				basedir, filename);
+			ret = -1;
+		}
+	}
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * write_sysfs_string_and_verify() - string write, readback and verify
+ * @filename: name of file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_string_and_verify(const char *filename, const char *basedir,
+				  const char *val)
+{
+	return _write_sysfs_string(filename, basedir, val, 1);
+}
+
+/**
+ * write_sysfs_string() - write string to a sysfs file
+ * @filename: name of file to write to
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: the string to write
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int write_sysfs_string(const char *filename, const char *basedir,
+		       const char *val)
+{
+	return _write_sysfs_string(filename, basedir, val, 0);
+}
+
+/**
+ * read_sysfs_posint() - read an integer value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ *
+ * Returns the read integer value >= 0 on success, otherwise a negative error
+ * code.
+ **/
+int read_sysfs_posint(const char *filename, const char *basedir)
+{
+	int ret;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%d\n", &ret) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_posint(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * read_sysfs_float() - read a float value from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @val: output the read float value
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int read_sysfs_float(const char *filename, const char *basedir, float *val)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%f\n", val) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_float(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}
+
+/**
+ * read_sysfs_string() - read a string from file
+ * @filename: name of file to read from
+ * @basedir: the sysfs directory in which the file is to be found
+ * @str: output the read string
+ *
+ * Returns a value >= 0 on success, otherwise a negative error code.
+ **/
+int read_sysfs_string(const char *filename, const char *basedir, char *str)
+{
+	int ret = 0;
+	FILE  *sysfsfp;
+	char *temp = malloc(strlen(basedir) + strlen(filename) + 2);
+
+	if (!temp) {
+		fprintf(stderr, "Memory allocation failed");
+		return -ENOMEM;
+	}
+
+	ret = sprintf(temp, "%s/%s", basedir, filename);
+	if (ret < 0)
+		goto error_free;
+
+	sysfsfp = fopen(temp, "r");
+	if (!sysfsfp) {
+		ret = -errno;
+		goto error_free;
+	}
+
+	errno = 0;
+	if (fscanf(sysfsfp, "%s\n", str) != 1) {
+		ret = errno ? -errno : -ENODATA;
+		if (fclose(sysfsfp))
+			perror("read_sysfs_string(): Failed to close dir");
+
+		goto error_free;
+	}
+
+	if (fclose(sysfsfp))
+		ret = -errno;
+
+error_free:
+	free(temp);
+
+	return ret;
+}