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, 622 insertions, 0 deletions

diff --git a/drivers/iio/adc/hx711.c b/drivers/iio/adc/hx711.c
new file mode 100644
index 000000000..f7ee856a6
--- /dev/null
+++ b/drivers/iio/adc/hx711.c
@@ -0,0 +1,622 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * HX711: analog to digital converter for weight sensor module
+ *
+ * Copyright (c) 2016 Andreas Klinger <ak@it-klinger.de>
+ */
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
+
+/* gain to pulse and scale conversion */
+#define HX711_GAIN_MAX		3
+#define HX711_RESET_GAIN	128
+
+struct hx711_gain_to_scale {
+	int			gain;
+	int			gain_pulse;
+	int			scale;
+	int			channel;
+};
+
+/*
+ * .scale depends on AVDD which in turn is known as soon as the regulator
+ * is available
+ * therefore we set .scale in hx711_probe()
+ *
+ * channel A in documentation is channel 0 in source code
+ * channel B in documentation is channel 1 in source code
+ */
+static struct hx711_gain_to_scale hx711_gain_to_scale[HX711_GAIN_MAX] = {
+	{ 128, 1, 0, 0 },
+	{  32, 2, 0, 1 },
+	{  64, 3, 0, 0 }
+};
+
+static int hx711_get_gain_to_pulse(int gain)
+{
+	int i;
+
+	for (i = 0; i < HX711_GAIN_MAX; i++)
+		if (hx711_gain_to_scale[i].gain == gain)
+			return hx711_gain_to_scale[i].gain_pulse;
+	return 1;
+}
+
+static int hx711_get_gain_to_scale(int gain)
+{
+	int i;
+
+	for (i = 0; i < HX711_GAIN_MAX; i++)
+		if (hx711_gain_to_scale[i].gain == gain)
+			return hx711_gain_to_scale[i].scale;
+	return 0;
+}
+
+static int hx711_get_scale_to_gain(int scale)
+{
+	int i;
+
+	for (i = 0; i < HX711_GAIN_MAX; i++)
+		if (hx711_gain_to_scale[i].scale == scale)
+			return hx711_gain_to_scale[i].gain;
+	return -EINVAL;
+}
+
+struct hx711_data {
+	struct device		*dev;
+	struct gpio_desc	*gpiod_pd_sck;
+	struct gpio_desc	*gpiod_dout;
+	struct regulator	*reg_avdd;
+	int			gain_set;	/* gain set on device */
+	int			gain_chan_a;	/* gain for channel A */
+	struct mutex		lock;
+	/*
+	 * triggered buffer
+	 * 2x32-bit channel + 64-bit naturally aligned timestamp
+	 */
+	u32			buffer[4] __aligned(8);
+	/*
+	 * delay after a rising edge on SCK until the data is ready DOUT
+	 * this is dependent on the hx711 where the datasheet tells a
+	 * maximum value of 100 ns
+	 * but also on potential parasitic capacities on the wiring
+	 */
+	u32			data_ready_delay_ns;
+	u32			clock_frequency;
+};
+
+static int hx711_cycle(struct hx711_data *hx711_data)
+{
+	unsigned long flags;
+
+	/*
+	 * if preempted for more then 60us while PD_SCK is high:
+	 * hx711 is going in reset
+	 * ==> measuring is false
+	 */
+	local_irq_save(flags);
+	gpiod_set_value(hx711_data->gpiod_pd_sck, 1);
+
+	/*
+	 * wait until DOUT is ready
+	 * it turned out that parasitic capacities are extending the time
+	 * until DOUT has reached it's value
+	 */
+	ndelay(hx711_data->data_ready_delay_ns);
+
+	/*
+	 * here we are not waiting for 0.2 us as suggested by the datasheet,
+	 * because the oscilloscope showed in a test scenario
+	 * at least 1.15 us for PD_SCK high (T3 in datasheet)
+	 * and 0.56 us for PD_SCK low on TI Sitara with 800 MHz
+	 */
+	gpiod_set_value(hx711_data->gpiod_pd_sck, 0);
+	local_irq_restore(flags);
+
+	/*
+	 * make it a square wave for addressing cases with capacitance on
+	 * PC_SCK
+	 */
+	ndelay(hx711_data->data_ready_delay_ns);
+
+	/* sample as late as possible */
+	return gpiod_get_value(hx711_data->gpiod_dout);
+}
+
+static int hx711_read(struct hx711_data *hx711_data)
+{
+	int i, ret;
+	int value = 0;
+	int val = gpiod_get_value(hx711_data->gpiod_dout);
+
+	/* we double check if it's really down */
+	if (val)
+		return -EIO;
+
+	for (i = 0; i < 24; i++) {
+		value <<= 1;
+		ret = hx711_cycle(hx711_data);
+		if (ret)
+			value++;
+	}
+
+	value ^= 0x800000;
+
+	for (i = 0; i < hx711_get_gain_to_pulse(hx711_data->gain_set); i++)
+		hx711_cycle(hx711_data);
+
+	return value;
+}
+
+static int hx711_wait_for_ready(struct hx711_data *hx711_data)
+{
+	int i, val;
+
+	/*
+	 * in some rare cases the reset takes quite a long time
+	 * especially when the channel is changed.
+	 * Allow up to one second for it
+	 */
+	for (i = 0; i < 100; i++) {
+		val = gpiod_get_value(hx711_data->gpiod_dout);
+		if (!val)
+			break;
+		/* sleep at least 10 ms */
+		msleep(10);
+	}
+	if (val)
+		return -EIO;
+
+	return 0;
+}
+
+static int hx711_reset(struct hx711_data *hx711_data)
+{
+	int val = hx711_wait_for_ready(hx711_data);
+
+	if (val) {
+		/*
+		 * an examination with the oszilloscope indicated
+		 * that the first value read after the reset is not stable
+		 * if we reset too short;
+		 * the shorter the reset cycle
+		 * the less reliable the first value after reset is;
+		 * there were no problems encountered with a value
+		 * of 10 ms or higher
+		 */
+		gpiod_set_value(hx711_data->gpiod_pd_sck, 1);
+		msleep(10);
+		gpiod_set_value(hx711_data->gpiod_pd_sck, 0);
+
+		val = hx711_wait_for_ready(hx711_data);
+
+		/* after a reset the gain is 128 */
+		hx711_data->gain_set = HX711_RESET_GAIN;
+	}
+
+	return val;
+}
+
+static int hx711_set_gain_for_channel(struct hx711_data *hx711_data, int chan)
+{
+	int ret;
+
+	if (chan == 0) {
+		if (hx711_data->gain_set == 32) {
+			hx711_data->gain_set = hx711_data->gain_chan_a;
+
+			ret = hx711_read(hx711_data);
+			if (ret < 0)
+				return ret;
+
+			ret = hx711_wait_for_ready(hx711_data);
+			if (ret)
+				return ret;
+		}
+	} else {
+		if (hx711_data->gain_set != 32) {
+			hx711_data->gain_set = 32;
+
+			ret = hx711_read(hx711_data);
+			if (ret < 0)
+				return ret;
+
+			ret = hx711_wait_for_ready(hx711_data);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int hx711_reset_read(struct hx711_data *hx711_data, int chan)
+{
+	int ret;
+	int val;
+
+	/*
+	 * hx711_reset() must be called from here
+	 * because it could be calling hx711_read() by itself
+	 */
+	if (hx711_reset(hx711_data)) {
+		dev_err(hx711_data->dev, "reset failed!");
+		return -EIO;
+	}
+
+	ret = hx711_set_gain_for_channel(hx711_data, chan);
+	if (ret < 0)
+		return ret;
+
+	val = hx711_read(hx711_data);
+
+	return val;
+}
+
+static int hx711_read_raw(struct iio_dev *indio_dev,
+				const struct iio_chan_spec *chan,
+				int *val, int *val2, long mask)
+{
+	struct hx711_data *hx711_data = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&hx711_data->lock);
+
+		*val = hx711_reset_read(hx711_data, chan->channel);
+
+		mutex_unlock(&hx711_data->lock);
+
+		if (*val < 0)
+			return *val;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		*val = 0;
+		mutex_lock(&hx711_data->lock);
+
+		*val2 = hx711_get_gain_to_scale(hx711_data->gain_set);
+
+		mutex_unlock(&hx711_data->lock);
+
+		return IIO_VAL_INT_PLUS_NANO;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int hx711_write_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int val,
+				int val2,
+				long mask)
+{
+	struct hx711_data *hx711_data = iio_priv(indio_dev);
+	int ret;
+	int gain;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SCALE:
+		/*
+		 * a scale greater than 1 mV per LSB is not possible
+		 * with the HX711, therefore val must be 0
+		 */
+		if (val != 0)
+			return -EINVAL;
+
+		mutex_lock(&hx711_data->lock);
+
+		gain = hx711_get_scale_to_gain(val2);
+		if (gain < 0) {
+			mutex_unlock(&hx711_data->lock);
+			return gain;
+		}
+
+		if (gain != hx711_data->gain_set) {
+			hx711_data->gain_set = gain;
+			if (gain != 32)
+				hx711_data->gain_chan_a = gain;
+
+			ret = hx711_read(hx711_data);
+			if (ret < 0) {
+				mutex_unlock(&hx711_data->lock);
+				return ret;
+			}
+		}
+
+		mutex_unlock(&hx711_data->lock);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int hx711_write_raw_get_fmt(struct iio_dev *indio_dev,
+		struct iio_chan_spec const *chan,
+		long mask)
+{
+	return IIO_VAL_INT_PLUS_NANO;
+}
+
+static irqreturn_t hx711_trigger(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct hx711_data *hx711_data = iio_priv(indio_dev);
+	int i, j = 0;
+
+	mutex_lock(&hx711_data->lock);
+
+	memset(hx711_data->buffer, 0, sizeof(hx711_data->buffer));
+
+	for (i = 0; i < indio_dev->masklength; i++) {
+		if (!test_bit(i, indio_dev->active_scan_mask))
+			continue;
+
+		hx711_data->buffer[j] = hx711_reset_read(hx711_data,
+					indio_dev->channels[i].channel);
+		j++;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, hx711_data->buffer,
+							pf->timestamp);
+
+	mutex_unlock(&hx711_data->lock);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static ssize_t hx711_scale_available_show(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct iio_dev_attr *iio_attr = to_iio_dev_attr(attr);
+	int channel = iio_attr->address;
+	int i, len = 0;
+
+	for (i = 0; i < HX711_GAIN_MAX; i++)
+		if (hx711_gain_to_scale[i].channel == channel)
+			len += sprintf(buf + len, "0.%09d ",
+					hx711_gain_to_scale[i].scale);
+
+	len += sprintf(buf + len, "\n");
+
+	return len;
+}
+
+static IIO_DEVICE_ATTR(in_voltage0_scale_available, S_IRUGO,
+	hx711_scale_available_show, NULL, 0);
+
+static IIO_DEVICE_ATTR(in_voltage1_scale_available, S_IRUGO,
+	hx711_scale_available_show, NULL, 1);
+
+static struct attribute *hx711_attributes[] = {
+	&iio_dev_attr_in_voltage0_scale_available.dev_attr.attr,
+	&iio_dev_attr_in_voltage1_scale_available.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group hx711_attribute_group = {
+	.attrs = hx711_attributes,
+};
+
+static const struct iio_info hx711_iio_info = {
+	.read_raw		= hx711_read_raw,
+	.write_raw		= hx711_write_raw,
+	.write_raw_get_fmt	= hx711_write_raw_get_fmt,
+	.attrs			= &hx711_attribute_group,
+};
+
+static const struct iio_chan_spec hx711_chan_spec[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.channel = 0,
+		.indexed = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 24,
+			.storagebits = 32,
+			.endianness = IIO_CPU,
+		},
+	},
+	{
+		.type = IIO_VOLTAGE,
+		.channel = 1,
+		.indexed = 1,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 24,
+			.storagebits = 32,
+			.endianness = IIO_CPU,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(2),
+};
+
+static int hx711_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct hx711_data *hx711_data;
+	struct iio_dev *indio_dev;
+	int ret;
+	int i;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(struct hx711_data));
+	if (!indio_dev) {
+		dev_err(dev, "failed to allocate IIO device\n");
+		return -ENOMEM;
+	}
+
+	hx711_data = iio_priv(indio_dev);
+	hx711_data->dev = dev;
+
+	mutex_init(&hx711_data->lock);
+
+	/*
+	 * PD_SCK stands for power down and serial clock input of HX711
+	 * in the driver it is an output
+	 */
+	hx711_data->gpiod_pd_sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW);
+	if (IS_ERR(hx711_data->gpiod_pd_sck)) {
+		dev_err(dev, "failed to get sck-gpiod: err=%ld\n",
+					PTR_ERR(hx711_data->gpiod_pd_sck));
+		return PTR_ERR(hx711_data->gpiod_pd_sck);
+	}
+
+	/*
+	 * DOUT stands for serial data output of HX711
+	 * for the driver it is an input
+	 */
+	hx711_data->gpiod_dout = devm_gpiod_get(dev, "dout", GPIOD_IN);
+	if (IS_ERR(hx711_data->gpiod_dout)) {
+		dev_err(dev, "failed to get dout-gpiod: err=%ld\n",
+					PTR_ERR(hx711_data->gpiod_dout));
+		return PTR_ERR(hx711_data->gpiod_dout);
+	}
+
+	hx711_data->reg_avdd = devm_regulator_get(dev, "avdd");
+	if (IS_ERR(hx711_data->reg_avdd))
+		return PTR_ERR(hx711_data->reg_avdd);
+
+	ret = regulator_enable(hx711_data->reg_avdd);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * with
+	 * full scale differential input range: AVDD / GAIN
+	 * full scale output data: 2^24
+	 * we can say:
+	 *     AVDD / GAIN = 2^24
+	 * therefore:
+	 *     1 LSB = AVDD / GAIN / 2^24
+	 * AVDD is in uV, but we need 10^-9 mV
+	 * approximately to fit into a 32 bit number:
+	 * 1 LSB = (AVDD * 100) / GAIN / 1678 [10^-9 mV]
+	 */
+	ret = regulator_get_voltage(hx711_data->reg_avdd);
+	if (ret < 0)
+		goto error_regulator;
+
+	/* we need 10^-9 mV */
+	ret *= 100;
+
+	for (i = 0; i < HX711_GAIN_MAX; i++)
+		hx711_gain_to_scale[i].scale =
+			ret / hx711_gain_to_scale[i].gain / 1678;
+
+	hx711_data->gain_set = 128;
+	hx711_data->gain_chan_a = 128;
+
+	hx711_data->clock_frequency = 400000;
+	ret = of_property_read_u32(np, "clock-frequency",
+					&hx711_data->clock_frequency);
+
+	/*
+	 * datasheet says the high level of PD_SCK has a maximum duration
+	 * of 50 microseconds
+	 */
+	if (hx711_data->clock_frequency < 20000) {
+		dev_warn(dev, "clock-frequency too low - assuming 400 kHz\n");
+		hx711_data->clock_frequency = 400000;
+	}
+
+	hx711_data->data_ready_delay_ns =
+				1000000000 / hx711_data->clock_frequency;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	indio_dev->name = "hx711";
+	indio_dev->info = &hx711_iio_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = hx711_chan_spec;
+	indio_dev->num_channels = ARRAY_SIZE(hx711_chan_spec);
+
+	ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
+							hx711_trigger, NULL);
+	if (ret < 0) {
+		dev_err(dev, "setup of iio triggered buffer failed\n");
+		goto error_regulator;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret < 0) {
+		dev_err(dev, "Couldn't register the device\n");
+		goto error_buffer;
+	}
+
+	return 0;
+
+error_buffer:
+	iio_triggered_buffer_cleanup(indio_dev);
+
+error_regulator:
+	regulator_disable(hx711_data->reg_avdd);
+
+	return ret;
+}
+
+static int hx711_remove(struct platform_device *pdev)
+{
+	struct hx711_data *hx711_data;
+	struct iio_dev *indio_dev;
+
+	indio_dev = platform_get_drvdata(pdev);
+	hx711_data = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	regulator_disable(hx711_data->reg_avdd);
+
+	return 0;
+}
+
+static const struct of_device_id of_hx711_match[] = {
+	{ .compatible = "avia,hx711", },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, of_hx711_match);
+
+static struct platform_driver hx711_driver = {
+	.probe		= hx711_probe,
+	.remove		= hx711_remove,
+	.driver		= {
+		.name		= "hx711-gpio",
+		.of_match_table	= of_hx711_match,
+	},
+};
+
+module_platform_driver(hx711_driver);
+
+MODULE_AUTHOR("Andreas Klinger <ak@it-klinger.de>");
+MODULE_DESCRIPTION("HX711 bitbanging driver - ADC for weight cells");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:hx711-gpio");
+