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().
  ...

3 files changed, 739 insertions, 0 deletions

diff --git a/drivers/staging/iio/resolver/Kconfig b/drivers/staging/iio/resolver/Kconfig
new file mode 100644
index 000000000..6d1e2622e
--- /dev/null
+++ b/drivers/staging/iio/resolver/Kconfig
@@ -0,0 +1,18 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Resolver/Synchro drivers
+#
+menu "Resolver to digital converters"
+
+config AD2S1210
+	tristate "Analog Devices ad2s1210 driver"
+	depends on SPI
+	depends on GPIOLIB || COMPILE_TEST
+	help
+	  Say yes here to build support for Analog Devices spi resolver
+	  to digital converters, ad2s1210, provides direct access via sysfs.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad2s1210.
+
+endmenu
diff --git a/drivers/staging/iio/resolver/Makefile b/drivers/staging/iio/resolver/Makefile
new file mode 100644
index 000000000..398631f7e
--- /dev/null
+++ b/drivers/staging/iio/resolver/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for Resolver/Synchro drivers
+#
+
+obj-$(CONFIG_AD2S1210) += ad2s1210.o
diff --git a/drivers/staging/iio/resolver/ad2s1210.c b/drivers/staging/iio/resolver/ad2s1210.c
new file mode 100644
index 000000000..e4cf42438
--- /dev/null
+++ b/drivers/staging/iio/resolver/ad2s1210.c
@@ -0,0 +1,715 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ad2s1210.c support for the ADI Resolver to Digital Converters: AD2S1210
+ *
+ * Copyright (c) 2010-2010 Analog Devices Inc.
+ */
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+
+#define DRV_NAME "ad2s1210"
+
+#define AD2S1210_DEF_CONTROL		0x7E
+
+#define AD2S1210_MSB_IS_HIGH		0x80
+#define AD2S1210_MSB_IS_LOW		0x7F
+#define AD2S1210_PHASE_LOCK_RANGE_44	0x20
+#define AD2S1210_ENABLE_HYSTERESIS	0x10
+#define AD2S1210_SET_ENRES1		0x08
+#define AD2S1210_SET_ENRES0		0x04
+#define AD2S1210_SET_RES1		0x02
+#define AD2S1210_SET_RES0		0x01
+
+#define AD2S1210_SET_RESOLUTION		(AD2S1210_SET_RES1 | AD2S1210_SET_RES0)
+
+#define AD2S1210_REG_POSITION		0x80
+#define AD2S1210_REG_VELOCITY		0x82
+#define AD2S1210_REG_LOS_THRD		0x88
+#define AD2S1210_REG_DOS_OVR_THRD	0x89
+#define AD2S1210_REG_DOS_MIS_THRD	0x8A
+#define AD2S1210_REG_DOS_RST_MAX_THRD	0x8B
+#define AD2S1210_REG_DOS_RST_MIN_THRD	0x8C
+#define AD2S1210_REG_LOT_HIGH_THRD	0x8D
+#define AD2S1210_REG_LOT_LOW_THRD	0x8E
+#define AD2S1210_REG_EXCIT_FREQ		0x91
+#define AD2S1210_REG_CONTROL		0x92
+#define AD2S1210_REG_SOFT_RESET		0xF0
+#define AD2S1210_REG_FAULT		0xFF
+
+#define AD2S1210_MIN_CLKIN	6144000
+#define AD2S1210_MAX_CLKIN	10240000
+#define AD2S1210_MIN_EXCIT	2000
+#define AD2S1210_MAX_EXCIT	20000
+#define AD2S1210_MIN_FCW	0x4
+#define AD2S1210_MAX_FCW	0x50
+
+#define AD2S1210_DEF_EXCIT	10000
+
+enum ad2s1210_mode {
+	MOD_POS = 0,
+	MOD_VEL,
+	MOD_CONFIG,
+	MOD_RESERVED,
+};
+
+enum ad2s1210_gpios {
+	AD2S1210_SAMPLE,
+	AD2S1210_A0,
+	AD2S1210_A1,
+	AD2S1210_RES0,
+	AD2S1210_RES1,
+};
+
+struct ad2s1210_gpio {
+	const char *name;
+	unsigned long flags;
+};
+
+static const struct ad2s1210_gpio gpios[] = {
+	[AD2S1210_SAMPLE] = { .name = "adi,sample", .flags = GPIOD_OUT_LOW },
+	[AD2S1210_A0] = { .name = "adi,a0", .flags = GPIOD_OUT_LOW },
+	[AD2S1210_A1] = { .name = "adi,a1", .flags = GPIOD_OUT_LOW },
+	[AD2S1210_RES0] = { .name = "adi,res0", .flags = GPIOD_OUT_LOW },
+	[AD2S1210_RES1] = { .name = "adi,res1", .flags = GPIOD_OUT_LOW },
+};
+
+static const unsigned int ad2s1210_resolution_value[] = { 10, 12, 14, 16 };
+
+struct ad2s1210_state {
+	struct mutex lock;
+	struct spi_device *sdev;
+	struct gpio_desc *gpios[5];
+	unsigned int fclkin;
+	unsigned int fexcit;
+	bool hysteresis;
+	u8 resolution;
+	enum ad2s1210_mode mode;
+	u8 rx[2] __aligned(IIO_DMA_MINALIGN);
+	u8 tx[2];
+};
+
+static const int ad2s1210_mode_vals[4][2] = {
+	[MOD_POS] = { 0, 0 },
+	[MOD_VEL] = { 0, 1 },
+	[MOD_CONFIG] = { 1, 0 },
+};
+
+static inline void ad2s1210_set_mode(enum ad2s1210_mode mode,
+				     struct ad2s1210_state *st)
+{
+	gpiod_set_value(st->gpios[AD2S1210_A0], ad2s1210_mode_vals[mode][0]);
+	gpiod_set_value(st->gpios[AD2S1210_A1], ad2s1210_mode_vals[mode][1]);
+	st->mode = mode;
+}
+
+/* write 1 bytes (address or data) to the chip */
+static int ad2s1210_config_write(struct ad2s1210_state *st, u8 data)
+{
+	int ret;
+
+	ad2s1210_set_mode(MOD_CONFIG, st);
+	st->tx[0] = data;
+	ret = spi_write(st->sdev, st->tx, 1);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+/* read value from one of the registers */
+static int ad2s1210_config_read(struct ad2s1210_state *st,
+				unsigned char address)
+{
+	struct spi_transfer xfers[] = {
+		{
+			.len = 1,
+			.rx_buf = &st->rx[0],
+			.tx_buf = &st->tx[0],
+			.cs_change = 1,
+		}, {
+			.len = 1,
+			.rx_buf = &st->rx[1],
+			.tx_buf = &st->tx[1],
+		},
+	};
+	int ret = 0;
+
+	ad2s1210_set_mode(MOD_CONFIG, st);
+	st->tx[0] = address | AD2S1210_MSB_IS_HIGH;
+	st->tx[1] = AD2S1210_REG_FAULT;
+	ret = spi_sync_transfer(st->sdev, xfers, 2);
+	if (ret < 0)
+		return ret;
+
+	return st->rx[1];
+}
+
+static inline
+int ad2s1210_update_frequency_control_word(struct ad2s1210_state *st)
+{
+	int ret;
+	unsigned char fcw;
+
+	fcw = (unsigned char)(st->fexcit * (1 << 15) / st->fclkin);
+	if (fcw < AD2S1210_MIN_FCW || fcw > AD2S1210_MAX_FCW) {
+		dev_err(&st->sdev->dev, "ad2s1210: FCW out of range\n");
+		return -ERANGE;
+	}
+
+	ret = ad2s1210_config_write(st, AD2S1210_REG_EXCIT_FREQ);
+	if (ret < 0)
+		return ret;
+
+	return ad2s1210_config_write(st, fcw);
+}
+
+static const int ad2s1210_res_pins[4][2] = {
+	{ 0, 0 }, {0, 1}, {1, 0}, {1, 1}
+};
+
+static inline void ad2s1210_set_resolution_pin(struct ad2s1210_state *st)
+{
+	gpiod_set_value(st->gpios[AD2S1210_RES0],
+			ad2s1210_res_pins[(st->resolution - 10) / 2][0]);
+	gpiod_set_value(st->gpios[AD2S1210_RES1],
+			ad2s1210_res_pins[(st->resolution - 10) / 2][1]);
+}
+
+static inline int ad2s1210_soft_reset(struct ad2s1210_state *st)
+{
+	int ret;
+
+	ret = ad2s1210_config_write(st, AD2S1210_REG_SOFT_RESET);
+	if (ret < 0)
+		return ret;
+
+	return ad2s1210_config_write(st, 0x0);
+}
+
+static ssize_t ad2s1210_show_fclkin(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+
+	return sprintf(buf, "%u\n", st->fclkin);
+}
+
+static ssize_t ad2s1210_store_fclkin(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf,
+				     size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned int fclkin;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &fclkin);
+	if (ret)
+		return ret;
+	if (fclkin < AD2S1210_MIN_CLKIN || fclkin > AD2S1210_MAX_CLKIN) {
+		dev_err(dev, "ad2s1210: fclkin out of range\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&st->lock);
+	st->fclkin = fclkin;
+
+	ret = ad2s1210_update_frequency_control_word(st);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_soft_reset(st);
+error_ret:
+	mutex_unlock(&st->lock);
+
+	return ret < 0 ? ret : len;
+}
+
+static ssize_t ad2s1210_show_fexcit(struct device *dev,
+				    struct device_attribute *attr,
+				    char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+
+	return sprintf(buf, "%u\n", st->fexcit);
+}
+
+static ssize_t ad2s1210_store_fexcit(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned int fexcit;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &fexcit);
+	if (ret < 0)
+		return ret;
+	if (fexcit < AD2S1210_MIN_EXCIT || fexcit > AD2S1210_MAX_EXCIT) {
+		dev_err(dev,
+			"ad2s1210: excitation frequency out of range\n");
+		return -EINVAL;
+	}
+	mutex_lock(&st->lock);
+	st->fexcit = fexcit;
+	ret = ad2s1210_update_frequency_control_word(st);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_soft_reset(st);
+error_ret:
+	mutex_unlock(&st->lock);
+
+	return ret < 0 ? ret : len;
+}
+
+static ssize_t ad2s1210_show_control(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	int ret;
+
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
+	mutex_unlock(&st->lock);
+	return ret < 0 ? ret : sprintf(buf, "0x%x\n", ret);
+}
+
+static ssize_t ad2s1210_store_control(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned char udata;
+	unsigned char data;
+	int ret;
+
+	ret = kstrtou8(buf, 16, &udata);
+	if (ret)
+		return -EINVAL;
+
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	data = udata & AD2S1210_MSB_IS_LOW;
+	ret = ad2s1210_config_write(st, data);
+	if (ret < 0)
+		goto error_ret;
+
+	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	if (ret & AD2S1210_MSB_IS_HIGH) {
+		ret = -EIO;
+		dev_err(dev,
+			"ad2s1210: write control register fail\n");
+		goto error_ret;
+	}
+	st->resolution =
+		ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
+	ad2s1210_set_resolution_pin(st);
+	ret = len;
+	st->hysteresis = !!(data & AD2S1210_ENABLE_HYSTERESIS);
+
+error_ret:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+static ssize_t ad2s1210_show_resolution(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+
+	return sprintf(buf, "%d\n", st->resolution);
+}
+
+static ssize_t ad2s1210_store_resolution(struct device *dev,
+					 struct device_attribute *attr,
+					 const char *buf, size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned char data;
+	unsigned char udata;
+	int ret;
+
+	ret = kstrtou8(buf, 10, &udata);
+	if (ret || udata < 10 || udata > 16) {
+		dev_err(dev, "ad2s1210: resolution out of range\n");
+		return -EINVAL;
+	}
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	data = ret;
+	data &= ~AD2S1210_SET_RESOLUTION;
+	data |= (udata - 10) >> 1;
+	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_config_write(st, data & AD2S1210_MSB_IS_LOW);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	data = ret;
+	if (data & AD2S1210_MSB_IS_HIGH) {
+		ret = -EIO;
+		dev_err(dev, "ad2s1210: setting resolution fail\n");
+		goto error_ret;
+	}
+	st->resolution =
+		ad2s1210_resolution_value[data & AD2S1210_SET_RESOLUTION];
+	ad2s1210_set_resolution_pin(st);
+	ret = len;
+error_ret:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+/* read the fault register since last sample */
+static ssize_t ad2s1210_show_fault(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	int ret;
+
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_read(st, AD2S1210_REG_FAULT);
+	mutex_unlock(&st->lock);
+
+	return ret ? ret : sprintf(buf, "0x%x\n", ret);
+}
+
+static ssize_t ad2s1210_clear_fault(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf,
+				    size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	int ret;
+
+	mutex_lock(&st->lock);
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
+	/* delay (2 * tck + 20) nano seconds */
+	udelay(1);
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
+	ret = ad2s1210_config_read(st, AD2S1210_REG_FAULT);
+	if (ret < 0)
+		goto error_ret;
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
+error_ret:
+	mutex_unlock(&st->lock);
+
+	return ret < 0 ? ret : len;
+}
+
+static ssize_t ad2s1210_show_reg(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
+	int ret;
+
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_read(st, iattr->address);
+	mutex_unlock(&st->lock);
+
+	return ret < 0 ? ret : sprintf(buf, "%d\n", ret);
+}
+
+static ssize_t ad2s1210_store_reg(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t len)
+{
+	struct ad2s1210_state *st = iio_priv(dev_to_iio_dev(dev));
+	unsigned char data;
+	int ret;
+	struct iio_dev_attr *iattr = to_iio_dev_attr(attr);
+
+	ret = kstrtou8(buf, 10, &data);
+	if (ret)
+		return -EINVAL;
+	mutex_lock(&st->lock);
+	ret = ad2s1210_config_write(st, iattr->address);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_config_write(st, data & AD2S1210_MSB_IS_LOW);
+error_ret:
+	mutex_unlock(&st->lock);
+	return ret < 0 ? ret : len;
+}
+
+static int ad2s1210_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val,
+			     int *val2,
+			     long m)
+{
+	struct ad2s1210_state *st = iio_priv(indio_dev);
+	u16 negative;
+	int ret = 0;
+	u16 pos;
+	s16 vel;
+
+	mutex_lock(&st->lock);
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 0);
+	/* delay (6 * tck + 20) nano seconds */
+	udelay(1);
+
+	switch (chan->type) {
+	case IIO_ANGL:
+		ad2s1210_set_mode(MOD_POS, st);
+		break;
+	case IIO_ANGL_VEL:
+		ad2s1210_set_mode(MOD_VEL, st);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+	if (ret < 0)
+		goto error_ret;
+	ret = spi_read(st->sdev, st->rx, 2);
+	if (ret < 0)
+		goto error_ret;
+
+	switch (chan->type) {
+	case IIO_ANGL:
+		pos = be16_to_cpup((__be16 *)st->rx);
+		if (st->hysteresis)
+			pos >>= 16 - st->resolution;
+		*val = pos;
+		ret = IIO_VAL_INT;
+		break;
+	case IIO_ANGL_VEL:
+		vel = be16_to_cpup((__be16 *)st->rx);
+		vel >>= 16 - st->resolution;
+		if (vel & 0x8000) {
+			negative = (0xffff >> st->resolution) << st->resolution;
+			vel |= negative;
+		}
+		*val = vel;
+		ret = IIO_VAL_INT;
+		break;
+	default:
+		mutex_unlock(&st->lock);
+		return -EINVAL;
+	}
+
+error_ret:
+	gpiod_set_value(st->gpios[AD2S1210_SAMPLE], 1);
+	/* delay (2 * tck + 20) nano seconds */
+	udelay(1);
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+static IIO_DEVICE_ATTR(fclkin, 0644,
+		       ad2s1210_show_fclkin, ad2s1210_store_fclkin, 0);
+static IIO_DEVICE_ATTR(fexcit, 0644,
+		       ad2s1210_show_fexcit,	ad2s1210_store_fexcit, 0);
+static IIO_DEVICE_ATTR(control, 0644,
+		       ad2s1210_show_control, ad2s1210_store_control, 0);
+static IIO_DEVICE_ATTR(bits, 0644,
+		       ad2s1210_show_resolution, ad2s1210_store_resolution, 0);
+static IIO_DEVICE_ATTR(fault, 0644,
+		       ad2s1210_show_fault, ad2s1210_clear_fault, 0);
+
+static IIO_DEVICE_ATTR(los_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_LOS_THRD);
+static IIO_DEVICE_ATTR(dos_ovr_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_DOS_OVR_THRD);
+static IIO_DEVICE_ATTR(dos_mis_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_DOS_MIS_THRD);
+static IIO_DEVICE_ATTR(dos_rst_max_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_DOS_RST_MAX_THRD);
+static IIO_DEVICE_ATTR(dos_rst_min_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_DOS_RST_MIN_THRD);
+static IIO_DEVICE_ATTR(lot_high_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_LOT_HIGH_THRD);
+static IIO_DEVICE_ATTR(lot_low_thrd, 0644,
+		       ad2s1210_show_reg, ad2s1210_store_reg,
+		       AD2S1210_REG_LOT_LOW_THRD);
+
+static const struct iio_chan_spec ad2s1210_channels[] = {
+	{
+		.type = IIO_ANGL,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	}, {
+		.type = IIO_ANGL_VEL,
+		.indexed = 1,
+		.channel = 0,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	}
+};
+
+static struct attribute *ad2s1210_attributes[] = {
+	&iio_dev_attr_fclkin.dev_attr.attr,
+	&iio_dev_attr_fexcit.dev_attr.attr,
+	&iio_dev_attr_control.dev_attr.attr,
+	&iio_dev_attr_bits.dev_attr.attr,
+	&iio_dev_attr_fault.dev_attr.attr,
+	&iio_dev_attr_los_thrd.dev_attr.attr,
+	&iio_dev_attr_dos_ovr_thrd.dev_attr.attr,
+	&iio_dev_attr_dos_mis_thrd.dev_attr.attr,
+	&iio_dev_attr_dos_rst_max_thrd.dev_attr.attr,
+	&iio_dev_attr_dos_rst_min_thrd.dev_attr.attr,
+	&iio_dev_attr_lot_high_thrd.dev_attr.attr,
+	&iio_dev_attr_lot_low_thrd.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad2s1210_attribute_group = {
+	.attrs = ad2s1210_attributes,
+};
+
+static int ad2s1210_initial(struct ad2s1210_state *st)
+{
+	unsigned char data;
+	int ret;
+
+	mutex_lock(&st->lock);
+	ad2s1210_set_resolution_pin(st);
+
+	ret = ad2s1210_config_write(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+	data = AD2S1210_DEF_CONTROL & ~(AD2S1210_SET_RESOLUTION);
+	data |= (st->resolution - 10) >> 1;
+	ret = ad2s1210_config_write(st, data);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_config_read(st, AD2S1210_REG_CONTROL);
+	if (ret < 0)
+		goto error_ret;
+
+	if (ret & AD2S1210_MSB_IS_HIGH) {
+		ret = -EIO;
+		goto error_ret;
+	}
+
+	ret = ad2s1210_update_frequency_control_word(st);
+	if (ret < 0)
+		goto error_ret;
+	ret = ad2s1210_soft_reset(st);
+error_ret:
+	mutex_unlock(&st->lock);
+	return ret;
+}
+
+static const struct iio_info ad2s1210_info = {
+	.read_raw = ad2s1210_read_raw,
+	.attrs = &ad2s1210_attribute_group,
+};
+
+static int ad2s1210_setup_gpios(struct ad2s1210_state *st)
+{
+	struct spi_device *spi = st->sdev;
+	int i, ret;
+
+	for (i = 0; i < ARRAY_SIZE(gpios); i++) {
+		st->gpios[i] = devm_gpiod_get(&spi->dev, gpios[i].name,
+					      gpios[i].flags);
+		if (IS_ERR(st->gpios[i])) {
+			ret = PTR_ERR(st->gpios[i]);
+			dev_err(&spi->dev,
+				"ad2s1210: failed to request %s GPIO: %d\n",
+				gpios[i].name, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ad2s1210_probe(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev;
+	struct ad2s1210_state *st;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+	st = iio_priv(indio_dev);
+	ret = ad2s1210_setup_gpios(st);
+	if (ret < 0)
+		return ret;
+
+	spi_set_drvdata(spi, indio_dev);
+
+	mutex_init(&st->lock);
+	st->sdev = spi;
+	st->hysteresis = true;
+	st->mode = MOD_CONFIG;
+	st->resolution = 12;
+	st->fexcit = AD2S1210_DEF_EXCIT;
+
+	indio_dev->info = &ad2s1210_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = ad2s1210_channels;
+	indio_dev->num_channels = ARRAY_SIZE(ad2s1210_channels);
+	indio_dev->name = spi_get_device_id(spi)->name;
+
+	ret = devm_iio_device_register(&spi->dev, indio_dev);
+	if (ret)
+		return ret;
+
+	st->fclkin = spi->max_speed_hz;
+	spi->mode = SPI_MODE_3;
+	spi_setup(spi);
+	ad2s1210_initial(st);
+
+	return 0;
+}
+
+static const struct of_device_id ad2s1210_of_match[] = {
+	{ .compatible = "adi,ad2s1210", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ad2s1210_of_match);
+
+static const struct spi_device_id ad2s1210_id[] = {
+	{ "ad2s1210" },
+	{}
+};
+MODULE_DEVICE_TABLE(spi, ad2s1210_id);
+
+static struct spi_driver ad2s1210_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = of_match_ptr(ad2s1210_of_match),
+	},
+	.probe = ad2s1210_probe,
+	.id_table = ad2s1210_id,
+};
+module_spi_driver(ad2s1210_driver);
+
+MODULE_AUTHOR("Graff Yang <graff.yang@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices AD2S1210 Resolver to Digital SPI driver");
+MODULE_LICENSE("GPL v2");