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, 894 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-stm32f4.c b/drivers/i2c/busses/i2c-stm32f4.c
new file mode 100644
index 000000000..eebce7ece
--- /dev/null
+++ b/drivers/i2c/busses/i2c-stm32f4.c
@@ -0,0 +1,894 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for STMicroelectronics STM32 I2C controller
+ *
+ * This I2C controller is described in the STM32F429/439 Soc reference manual.
+ * Please see below a link to the documentation:
+ * http://www.st.com/resource/en/reference_manual/DM00031020.pdf
+ *
+ * Copyright (C) M'boumba Cedric Madianga 2016
+ * Copyright (C) STMicroelectronics 2017
+ * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *
+ * This driver is based on i2c-st.c
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+
+#include "i2c-stm32.h"
+
+/* STM32F4 I2C offset registers */
+#define STM32F4_I2C_CR1			0x00
+#define STM32F4_I2C_CR2			0x04
+#define STM32F4_I2C_DR			0x10
+#define STM32F4_I2C_SR1			0x14
+#define STM32F4_I2C_SR2			0x18
+#define STM32F4_I2C_CCR			0x1C
+#define STM32F4_I2C_TRISE		0x20
+#define STM32F4_I2C_FLTR		0x24
+
+/* STM32F4 I2C control 1*/
+#define STM32F4_I2C_CR1_POS		BIT(11)
+#define STM32F4_I2C_CR1_ACK		BIT(10)
+#define STM32F4_I2C_CR1_STOP		BIT(9)
+#define STM32F4_I2C_CR1_START		BIT(8)
+#define STM32F4_I2C_CR1_PE		BIT(0)
+
+/* STM32F4 I2C control 2 */
+#define STM32F4_I2C_CR2_FREQ_MASK	GENMASK(5, 0)
+#define STM32F4_I2C_CR2_FREQ(n)		((n) & STM32F4_I2C_CR2_FREQ_MASK)
+#define STM32F4_I2C_CR2_ITBUFEN		BIT(10)
+#define STM32F4_I2C_CR2_ITEVTEN		BIT(9)
+#define STM32F4_I2C_CR2_ITERREN		BIT(8)
+#define STM32F4_I2C_CR2_IRQ_MASK	(STM32F4_I2C_CR2_ITBUFEN | \
+					 STM32F4_I2C_CR2_ITEVTEN | \
+					 STM32F4_I2C_CR2_ITERREN)
+
+/* STM32F4 I2C Status 1 */
+#define STM32F4_I2C_SR1_AF		BIT(10)
+#define STM32F4_I2C_SR1_ARLO		BIT(9)
+#define STM32F4_I2C_SR1_BERR		BIT(8)
+#define STM32F4_I2C_SR1_TXE		BIT(7)
+#define STM32F4_I2C_SR1_RXNE		BIT(6)
+#define STM32F4_I2C_SR1_BTF		BIT(2)
+#define STM32F4_I2C_SR1_ADDR		BIT(1)
+#define STM32F4_I2C_SR1_SB		BIT(0)
+#define STM32F4_I2C_SR1_ITEVTEN_MASK	(STM32F4_I2C_SR1_BTF | \
+					 STM32F4_I2C_SR1_ADDR | \
+					 STM32F4_I2C_SR1_SB)
+#define STM32F4_I2C_SR1_ITBUFEN_MASK	(STM32F4_I2C_SR1_TXE | \
+					 STM32F4_I2C_SR1_RXNE)
+#define STM32F4_I2C_SR1_ITERREN_MASK	(STM32F4_I2C_SR1_AF | \
+					 STM32F4_I2C_SR1_ARLO | \
+					 STM32F4_I2C_SR1_BERR)
+
+/* STM32F4 I2C Status 2 */
+#define STM32F4_I2C_SR2_BUSY		BIT(1)
+
+/* STM32F4 I2C Control Clock */
+#define STM32F4_I2C_CCR_CCR_MASK	GENMASK(11, 0)
+#define STM32F4_I2C_CCR_CCR(n)		((n) & STM32F4_I2C_CCR_CCR_MASK)
+#define STM32F4_I2C_CCR_FS		BIT(15)
+#define STM32F4_I2C_CCR_DUTY		BIT(14)
+
+/* STM32F4 I2C Trise */
+#define STM32F4_I2C_TRISE_VALUE_MASK	GENMASK(5, 0)
+#define STM32F4_I2C_TRISE_VALUE(n)	((n) & STM32F4_I2C_TRISE_VALUE_MASK)
+
+#define STM32F4_I2C_MIN_STANDARD_FREQ	2U
+#define STM32F4_I2C_MIN_FAST_FREQ	6U
+#define STM32F4_I2C_MAX_FREQ		46U
+#define HZ_TO_MHZ			1000000
+
+/**
+ * struct stm32f4_i2c_msg - client specific data
+ * @addr: 8-bit slave addr, including r/w bit
+ * @count: number of bytes to be transferred
+ * @buf: data buffer
+ * @result: result of the transfer
+ * @stop: last I2C msg to be sent, i.e. STOP to be generated
+ */
+struct stm32f4_i2c_msg {
+	u8 addr;
+	u32 count;
+	u8 *buf;
+	int result;
+	bool stop;
+};
+
+/**
+ * struct stm32f4_i2c_dev - private data of the controller
+ * @adap: I2C adapter for this controller
+ * @dev: device for this controller
+ * @base: virtual memory area
+ * @complete: completion of I2C message
+ * @clk: hw i2c clock
+ * @speed: I2C clock frequency of the controller. Standard or Fast are supported
+ * @parent_rate: I2C clock parent rate in MHz
+ * @msg: I2C transfer information
+ */
+struct stm32f4_i2c_dev {
+	struct i2c_adapter adap;
+	struct device *dev;
+	void __iomem *base;
+	struct completion complete;
+	struct clk *clk;
+	int speed;
+	int parent_rate;
+	struct stm32f4_i2c_msg msg;
+};
+
+static inline void stm32f4_i2c_set_bits(void __iomem *reg, u32 mask)
+{
+	writel_relaxed(readl_relaxed(reg) | mask, reg);
+}
+
+static inline void stm32f4_i2c_clr_bits(void __iomem *reg, u32 mask)
+{
+	writel_relaxed(readl_relaxed(reg) & ~mask, reg);
+}
+
+static void stm32f4_i2c_disable_irq(struct stm32f4_i2c_dev *i2c_dev)
+{
+	void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+	stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_IRQ_MASK);
+}
+
+static int stm32f4_i2c_set_periph_clk_freq(struct stm32f4_i2c_dev *i2c_dev)
+{
+	u32 freq;
+	u32 cr2 = 0;
+
+	i2c_dev->parent_rate = clk_get_rate(i2c_dev->clk);
+	freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
+
+	if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) {
+		/*
+		 * To reach 100 kHz, the parent clk frequency should be between
+		 * a minimum value of 2 MHz and a maximum value of 46 MHz due
+		 * to hardware limitation
+		 */
+		if (freq < STM32F4_I2C_MIN_STANDARD_FREQ ||
+		    freq > STM32F4_I2C_MAX_FREQ) {
+			dev_err(i2c_dev->dev,
+				"bad parent clk freq for standard mode\n");
+			return -EINVAL;
+		}
+	} else {
+		/*
+		 * To be as close as possible to 400 kHz, the parent clk
+		 * frequency should be between a minimum value of 6 MHz and a
+		 * maximum value of 46 MHz due to hardware limitation
+		 */
+		if (freq < STM32F4_I2C_MIN_FAST_FREQ ||
+		    freq > STM32F4_I2C_MAX_FREQ) {
+			dev_err(i2c_dev->dev,
+				"bad parent clk freq for fast mode\n");
+			return -EINVAL;
+		}
+	}
+
+	cr2 |= STM32F4_I2C_CR2_FREQ(freq);
+	writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2);
+
+	return 0;
+}
+
+static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev)
+{
+	u32 freq = DIV_ROUND_UP(i2c_dev->parent_rate, HZ_TO_MHZ);
+	u32 trise;
+
+	/*
+	 * These bits must be programmed with the maximum SCL rise time given in
+	 * the I2C bus specification, incremented by 1.
+	 *
+	 * In standard mode, the maximum allowed SCL rise time is 1000 ns.
+	 * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
+	 * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
+	 * programmed with 0x9. (1000 ns / 125 ns + 1)
+	 * So, for I2C standard mode TRISE = FREQ[5:0] + 1
+	 *
+	 * In fast mode, the maximum allowed SCL rise time is 300 ns.
+	 * If, in the I2C_CR2 register, the value of FREQ[5:0] bits is equal to
+	 * 0x08 so period = 125 ns therefore the TRISE[5:0] bits must be
+	 * programmed with 0x3. (300 ns / 125 ns + 1)
+	 * So, for I2C fast mode TRISE = FREQ[5:0] * 300 / 1000 + 1
+	 *
+	 * Function stm32f4_i2c_set_periph_clk_freq made sure that parent rate
+	 * is not higher than 46 MHz . As a result trise is at most 4 bits wide
+	 * and so fits into the TRISE bits [5:0].
+	 */
+	if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD)
+		trise = freq + 1;
+	else
+		trise = freq * 3 / 10 + 1;
+
+	writel_relaxed(STM32F4_I2C_TRISE_VALUE(trise),
+		       i2c_dev->base + STM32F4_I2C_TRISE);
+}
+
+static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev)
+{
+	u32 val;
+	u32 ccr = 0;
+
+	if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) {
+		/*
+		 * In standard mode:
+		 * t_scl_high = t_scl_low = CCR * I2C parent clk period
+		 * So to reach 100 kHz, we have:
+		 * CCR = I2C parent rate / (100 kHz * 2)
+		 *
+		 * For example with parent rate = 2 MHz:
+		 * CCR = 2000000 / (100000 * 2) = 10
+		 * t_scl_high = t_scl_low = 10 * (1 / 2000000) = 5000 ns
+		 * t_scl_high + t_scl_low = 10000 ns so 100 kHz is reached
+		 *
+		 * Function stm32f4_i2c_set_periph_clk_freq made sure that
+		 * parent rate is not higher than 46 MHz . As a result val
+		 * is at most 8 bits wide and so fits into the CCR bits [11:0].
+		 */
+		val = i2c_dev->parent_rate / (I2C_MAX_STANDARD_MODE_FREQ * 2);
+	} else {
+		/*
+		 * In fast mode, we compute CCR with duty = 0 as with low
+		 * frequencies we are not able to reach 400 kHz.
+		 * In that case:
+		 * t_scl_high = CCR * I2C parent clk period
+		 * t_scl_low = 2 * CCR * I2C parent clk period
+		 * So, CCR = I2C parent rate / (400 kHz * 3)
+		 *
+		 * For example with parent rate = 6 MHz:
+		 * CCR = 6000000 / (400000 * 3) = 5
+		 * t_scl_high = 5 * (1 / 6000000) = 833 ns > 600 ns
+		 * t_scl_low = 2 * 5 * (1 / 6000000) = 1667 ns > 1300 ns
+		 * t_scl_high + t_scl_low = 2500 ns so 400 kHz is reached
+		 *
+		 * Function stm32f4_i2c_set_periph_clk_freq made sure that
+		 * parent rate is not higher than 46 MHz . As a result val
+		 * is at most 6 bits wide and so fits into the CCR bits [11:0].
+		 */
+		val = DIV_ROUND_UP(i2c_dev->parent_rate, I2C_MAX_FAST_MODE_FREQ * 3);
+
+		/* Select Fast mode */
+		ccr |= STM32F4_I2C_CCR_FS;
+	}
+
+	ccr |= STM32F4_I2C_CCR_CCR(val);
+	writel_relaxed(ccr, i2c_dev->base + STM32F4_I2C_CCR);
+}
+
+/**
+ * stm32f4_i2c_hw_config() - Prepare I2C block
+ * @i2c_dev: Controller's private data
+ */
+static int stm32f4_i2c_hw_config(struct stm32f4_i2c_dev *i2c_dev)
+{
+	int ret;
+
+	ret = stm32f4_i2c_set_periph_clk_freq(i2c_dev);
+	if (ret)
+		return ret;
+
+	stm32f4_i2c_set_rise_time(i2c_dev);
+
+	stm32f4_i2c_set_speed_mode(i2c_dev);
+
+	/* Enable I2C */
+	writel_relaxed(STM32F4_I2C_CR1_PE, i2c_dev->base + STM32F4_I2C_CR1);
+
+	return 0;
+}
+
+static int stm32f4_i2c_wait_free_bus(struct stm32f4_i2c_dev *i2c_dev)
+{
+	u32 status;
+	int ret;
+
+	ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F4_I2C_SR2,
+					 status,
+					 !(status & STM32F4_I2C_SR2_BUSY),
+					 10, 1000);
+	if (ret) {
+		dev_dbg(i2c_dev->dev, "bus not free\n");
+		ret = -EBUSY;
+	}
+
+	return ret;
+}
+
+/**
+ * stm32f4_i2c_write_byte() - Write a byte in the data register
+ * @i2c_dev: Controller's private data
+ * @byte: Data to write in the register
+ */
+static void stm32f4_i2c_write_byte(struct stm32f4_i2c_dev *i2c_dev, u8 byte)
+{
+	writel_relaxed(byte, i2c_dev->base + STM32F4_I2C_DR);
+}
+
+/**
+ * stm32f4_i2c_write_msg() - Fill the data register in write mode
+ * @i2c_dev: Controller's private data
+ *
+ * This function fills the data register with I2C transfer buffer
+ */
+static void stm32f4_i2c_write_msg(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+
+	stm32f4_i2c_write_byte(i2c_dev, *msg->buf++);
+	msg->count--;
+}
+
+static void stm32f4_i2c_read_msg(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	u32 rbuf;
+
+	rbuf = readl_relaxed(i2c_dev->base + STM32F4_I2C_DR);
+	*msg->buf++ = rbuf;
+	msg->count--;
+}
+
+static void stm32f4_i2c_terminate_xfer(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	void __iomem *reg;
+
+	stm32f4_i2c_disable_irq(i2c_dev);
+
+	reg = i2c_dev->base + STM32F4_I2C_CR1;
+	if (msg->stop)
+		stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+	else
+		stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+
+	complete(&i2c_dev->complete);
+}
+
+/**
+ * stm32f4_i2c_handle_write() - Handle FIFO empty interrupt in case of write
+ * @i2c_dev: Controller's private data
+ */
+static void stm32f4_i2c_handle_write(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+	if (msg->count) {
+		stm32f4_i2c_write_msg(i2c_dev);
+		if (!msg->count) {
+			/*
+			 * Disable buffer interrupts for RX not empty and TX
+			 * empty events
+			 */
+			stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN);
+		}
+	} else {
+		stm32f4_i2c_terminate_xfer(i2c_dev);
+	}
+}
+
+/**
+ * stm32f4_i2c_handle_read() - Handle FIFO empty interrupt in case of read
+ * @i2c_dev: Controller's private data
+ *
+ * This function is called when a new data is received in data register
+ */
+static void stm32f4_i2c_handle_read(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR2;
+
+	switch (msg->count) {
+	case 1:
+		stm32f4_i2c_disable_irq(i2c_dev);
+		stm32f4_i2c_read_msg(i2c_dev);
+		complete(&i2c_dev->complete);
+		break;
+	/*
+	 * For 2-byte reception, 3-byte reception and for Data N-2, N-1 and N
+	 * for N-byte reception with N > 3, we do not have to read the data
+	 * register when RX not empty event occurs as we have to wait for byte
+	 * transferred finished event before reading data.
+	 * So, here we just disable buffer interrupt in order to avoid another
+	 * system preemption due to RX not empty event.
+	 */
+	case 2:
+	case 3:
+		stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR2_ITBUFEN);
+		break;
+	/*
+	 * For N byte reception with N > 3 we directly read data register
+	 * until N-2 data.
+	 */
+	default:
+		stm32f4_i2c_read_msg(i2c_dev);
+	}
+}
+
+/**
+ * stm32f4_i2c_handle_rx_done() - Handle byte transfer finished interrupt
+ * in case of read
+ * @i2c_dev: Controller's private data
+ *
+ * This function is called when a new data is received in the shift register
+ * but data register has not been read yet.
+ */
+static void stm32f4_i2c_handle_rx_done(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	void __iomem *reg;
+	u32 mask;
+	int i;
+
+	switch (msg->count) {
+	case 2:
+		/*
+		 * In order to correctly send the Stop or Repeated Start
+		 * condition on the I2C bus, the STOP/START bit has to be set
+		 * before reading the last two bytes (data N-1 and N).
+		 * After that, we could read the last two bytes, disable
+		 * remaining interrupts and notify the end of xfer to the
+		 * client
+		 */
+		reg = i2c_dev->base + STM32F4_I2C_CR1;
+		if (msg->stop)
+			stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+		else
+			stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+
+		for (i = 2; i > 0; i--)
+			stm32f4_i2c_read_msg(i2c_dev);
+
+		reg = i2c_dev->base + STM32F4_I2C_CR2;
+		mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN;
+		stm32f4_i2c_clr_bits(reg, mask);
+
+		complete(&i2c_dev->complete);
+		break;
+	case 3:
+		/*
+		 * In order to correctly generate the NACK pulse after the last
+		 * received data byte, we have to enable NACK before reading N-2
+		 * data
+		 */
+		reg = i2c_dev->base + STM32F4_I2C_CR1;
+		stm32f4_i2c_clr_bits(reg, STM32F4_I2C_CR1_ACK);
+		stm32f4_i2c_read_msg(i2c_dev);
+		break;
+	default:
+		stm32f4_i2c_read_msg(i2c_dev);
+	}
+}
+
+/**
+ * stm32f4_i2c_handle_rx_addr() - Handle address matched interrupt in case of
+ * master receiver
+ * @i2c_dev: Controller's private data
+ */
+static void stm32f4_i2c_handle_rx_addr(struct stm32f4_i2c_dev *i2c_dev)
+{
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	u32 cr1;
+
+	switch (msg->count) {
+	case 0:
+		stm32f4_i2c_terminate_xfer(i2c_dev);
+
+		/* Clear ADDR flag */
+		readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+		break;
+	case 1:
+		/*
+		 * Single byte reception:
+		 * Enable NACK and reset POS (Acknowledge position).
+		 * Then, clear ADDR flag and set STOP or RepSTART.
+		 * In that way, the NACK and STOP or RepStart pulses will be
+		 * sent as soon as the byte will be received in shift register
+		 */
+		cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+		cr1 &= ~(STM32F4_I2C_CR1_ACK | STM32F4_I2C_CR1_POS);
+		writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+		readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+
+		if (msg->stop)
+			cr1 |= STM32F4_I2C_CR1_STOP;
+		else
+			cr1 |= STM32F4_I2C_CR1_START;
+		writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+		break;
+	case 2:
+		/*
+		 * 2-byte reception:
+		 * Enable NACK, set POS (NACK position) and clear ADDR flag.
+		 * In that way, NACK will be sent for the next byte which will
+		 * be received in the shift register instead of the current
+		 * one.
+		 */
+		cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+		cr1 &= ~STM32F4_I2C_CR1_ACK;
+		cr1 |= STM32F4_I2C_CR1_POS;
+		writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+		readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+		break;
+
+	default:
+		/*
+		 * N-byte reception:
+		 * Enable ACK, reset POS (ACK position) and clear ADDR flag.
+		 * In that way, ACK will be sent as soon as the current byte
+		 * will be received in the shift register
+		 */
+		cr1 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR1);
+		cr1 |= STM32F4_I2C_CR1_ACK;
+		cr1 &= ~STM32F4_I2C_CR1_POS;
+		writel_relaxed(cr1, i2c_dev->base + STM32F4_I2C_CR1);
+
+		readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+		break;
+	}
+}
+
+/**
+ * stm32f4_i2c_isr_event() - Interrupt routine for I2C bus event
+ * @irq: interrupt number
+ * @data: Controller's private data
+ */
+static irqreturn_t stm32f4_i2c_isr_event(int irq, void *data)
+{
+	struct stm32f4_i2c_dev *i2c_dev = data;
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	u32 possible_status = STM32F4_I2C_SR1_ITEVTEN_MASK;
+	u32 status, ien, event, cr2;
+
+	cr2 = readl_relaxed(i2c_dev->base + STM32F4_I2C_CR2);
+	ien = cr2 & STM32F4_I2C_CR2_IRQ_MASK;
+
+	/* Update possible_status if buffer interrupt is enabled */
+	if (ien & STM32F4_I2C_CR2_ITBUFEN)
+		possible_status |= STM32F4_I2C_SR1_ITBUFEN_MASK;
+
+	status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1);
+	event = status & possible_status;
+	if (!event) {
+		dev_dbg(i2c_dev->dev,
+			"spurious evt irq (status=0x%08x, ien=0x%08x)\n",
+			status, ien);
+		return IRQ_NONE;
+	}
+
+	/* Start condition generated */
+	if (event & STM32F4_I2C_SR1_SB)
+		stm32f4_i2c_write_byte(i2c_dev, msg->addr);
+
+	/* I2C Address sent */
+	if (event & STM32F4_I2C_SR1_ADDR) {
+		if (msg->addr & I2C_M_RD)
+			stm32f4_i2c_handle_rx_addr(i2c_dev);
+		else
+			readl_relaxed(i2c_dev->base + STM32F4_I2C_SR2);
+
+		/*
+		 * Enable buffer interrupts for RX not empty and TX empty
+		 * events
+		 */
+		cr2 |= STM32F4_I2C_CR2_ITBUFEN;
+		writel_relaxed(cr2, i2c_dev->base + STM32F4_I2C_CR2);
+	}
+
+	/* TX empty */
+	if ((event & STM32F4_I2C_SR1_TXE) && !(msg->addr & I2C_M_RD))
+		stm32f4_i2c_handle_write(i2c_dev);
+
+	/* RX not empty */
+	if ((event & STM32F4_I2C_SR1_RXNE) && (msg->addr & I2C_M_RD))
+		stm32f4_i2c_handle_read(i2c_dev);
+
+	/*
+	 * The BTF (Byte Transfer finished) event occurs when:
+	 * - in reception : a new byte is received in the shift register
+	 * but the previous byte has not been read yet from data register
+	 * - in transmission: a new byte should be sent but the data register
+	 * has not been written yet
+	 */
+	if (event & STM32F4_I2C_SR1_BTF) {
+		if (msg->addr & I2C_M_RD)
+			stm32f4_i2c_handle_rx_done(i2c_dev);
+		else
+			stm32f4_i2c_handle_write(i2c_dev);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * stm32f4_i2c_isr_error() - Interrupt routine for I2C bus error
+ * @irq: interrupt number
+ * @data: Controller's private data
+ */
+static irqreturn_t stm32f4_i2c_isr_error(int irq, void *data)
+{
+	struct stm32f4_i2c_dev *i2c_dev = data;
+	struct stm32f4_i2c_msg *msg = &i2c_dev->msg;
+	void __iomem *reg;
+	u32 status;
+
+	status = readl_relaxed(i2c_dev->base + STM32F4_I2C_SR1);
+
+	/* Arbitration lost */
+	if (status & STM32F4_I2C_SR1_ARLO) {
+		status &= ~STM32F4_I2C_SR1_ARLO;
+		writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+		msg->result = -EAGAIN;
+	}
+
+	/*
+	 * Acknowledge failure:
+	 * In master transmitter mode a Stop must be generated by software
+	 */
+	if (status & STM32F4_I2C_SR1_AF) {
+		if (!(msg->addr & I2C_M_RD)) {
+			reg = i2c_dev->base + STM32F4_I2C_CR1;
+			stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_STOP);
+		}
+		status &= ~STM32F4_I2C_SR1_AF;
+		writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+		msg->result = -EIO;
+	}
+
+	/* Bus error */
+	if (status & STM32F4_I2C_SR1_BERR) {
+		status &= ~STM32F4_I2C_SR1_BERR;
+		writel_relaxed(status, i2c_dev->base + STM32F4_I2C_SR1);
+		msg->result = -EIO;
+	}
+
+	stm32f4_i2c_disable_irq(i2c_dev);
+	complete(&i2c_dev->complete);
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * stm32f4_i2c_xfer_msg() - Transfer a single I2C message
+ * @i2c_dev: Controller's private data
+ * @msg: I2C message to transfer
+ * @is_first: first message of the sequence
+ * @is_last: last message of the sequence
+ */
+static int stm32f4_i2c_xfer_msg(struct stm32f4_i2c_dev *i2c_dev,
+				struct i2c_msg *msg, bool is_first,
+				bool is_last)
+{
+	struct stm32f4_i2c_msg *f4_msg = &i2c_dev->msg;
+	void __iomem *reg = i2c_dev->base + STM32F4_I2C_CR1;
+	unsigned long timeout;
+	u32 mask;
+	int ret;
+
+	f4_msg->addr = i2c_8bit_addr_from_msg(msg);
+	f4_msg->buf = msg->buf;
+	f4_msg->count = msg->len;
+	f4_msg->result = 0;
+	f4_msg->stop = is_last;
+
+	reinit_completion(&i2c_dev->complete);
+
+	/* Enable events and errors interrupts */
+	mask = STM32F4_I2C_CR2_ITEVTEN | STM32F4_I2C_CR2_ITERREN;
+	stm32f4_i2c_set_bits(i2c_dev->base + STM32F4_I2C_CR2, mask);
+
+	if (is_first) {
+		ret = stm32f4_i2c_wait_free_bus(i2c_dev);
+		if (ret)
+			return ret;
+
+		/* START generation */
+		stm32f4_i2c_set_bits(reg, STM32F4_I2C_CR1_START);
+	}
+
+	timeout = wait_for_completion_timeout(&i2c_dev->complete,
+					      i2c_dev->adap.timeout);
+	ret = f4_msg->result;
+
+	if (!timeout)
+		ret = -ETIMEDOUT;
+
+	return ret;
+}
+
+/**
+ * stm32f4_i2c_xfer() - Transfer combined I2C message
+ * @i2c_adap: Adapter pointer to the controller
+ * @msgs: Pointer to data to be written.
+ * @num: Number of messages to be executed
+ */
+static int stm32f4_i2c_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg msgs[],
+			    int num)
+{
+	struct stm32f4_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
+	int ret, i;
+
+	ret = clk_enable(i2c_dev->clk);
+	if (ret) {
+		dev_err(i2c_dev->dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	for (i = 0; i < num && !ret; i++)
+		ret = stm32f4_i2c_xfer_msg(i2c_dev, &msgs[i], i == 0,
+					   i == num - 1);
+
+	clk_disable(i2c_dev->clk);
+
+	return (ret < 0) ? ret : num;
+}
+
+static u32 stm32f4_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm stm32f4_i2c_algo = {
+	.master_xfer = stm32f4_i2c_xfer,
+	.functionality = stm32f4_i2c_func,
+};
+
+static int stm32f4_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct stm32f4_i2c_dev *i2c_dev;
+	struct resource *res;
+	u32 irq_event, irq_error, clk_rate;
+	struct i2c_adapter *adap;
+	struct reset_control *rst;
+	int ret;
+
+	i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
+	if (!i2c_dev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	i2c_dev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(i2c_dev->base))
+		return PTR_ERR(i2c_dev->base);
+
+	irq_event = irq_of_parse_and_map(np, 0);
+	if (!irq_event) {
+		dev_err(&pdev->dev, "IRQ event missing or invalid\n");
+		return -EINVAL;
+	}
+
+	irq_error = irq_of_parse_and_map(np, 1);
+	if (!irq_error) {
+		dev_err(&pdev->dev, "IRQ error missing or invalid\n");
+		return -EINVAL;
+	}
+
+	i2c_dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(i2c_dev->clk)) {
+		dev_err(&pdev->dev, "Error: Missing controller clock\n");
+		return PTR_ERR(i2c_dev->clk);
+	}
+	ret = clk_prepare_enable(i2c_dev->clk);
+	if (ret) {
+		dev_err(i2c_dev->dev, "Failed to prepare_enable clock\n");
+		return ret;
+	}
+
+	rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
+	if (IS_ERR(rst)) {
+		ret = dev_err_probe(&pdev->dev, PTR_ERR(rst),
+				    "Error: Missing reset ctrl\n");
+		goto clk_free;
+	}
+	reset_control_assert(rst);
+	udelay(2);
+	reset_control_deassert(rst);
+
+	i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
+	ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
+	if (!ret && clk_rate >= I2C_MAX_FAST_MODE_FREQ)
+		i2c_dev->speed = STM32_I2C_SPEED_FAST;
+
+	i2c_dev->dev = &pdev->dev;
+
+	ret = devm_request_irq(&pdev->dev, irq_event, stm32f4_i2c_isr_event, 0,
+			       pdev->name, i2c_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request irq event %i\n",
+			irq_event);
+		goto clk_free;
+	}
+
+	ret = devm_request_irq(&pdev->dev, irq_error, stm32f4_i2c_isr_error, 0,
+			       pdev->name, i2c_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "Failed to request irq error %i\n",
+			irq_error);
+		goto clk_free;
+	}
+
+	ret = stm32f4_i2c_hw_config(i2c_dev);
+	if (ret)
+		goto clk_free;
+
+	adap = &i2c_dev->adap;
+	i2c_set_adapdata(adap, i2c_dev);
+	snprintf(adap->name, sizeof(adap->name), "STM32 I2C(%pa)", &res->start);
+	adap->owner = THIS_MODULE;
+	adap->timeout = 2 * HZ;
+	adap->retries = 0;
+	adap->algo = &stm32f4_i2c_algo;
+	adap->dev.parent = &pdev->dev;
+	adap->dev.of_node = pdev->dev.of_node;
+
+	init_completion(&i2c_dev->complete);
+
+	ret = i2c_add_adapter(adap);
+	if (ret)
+		goto clk_free;
+
+	platform_set_drvdata(pdev, i2c_dev);
+
+	clk_disable(i2c_dev->clk);
+
+	dev_info(i2c_dev->dev, "STM32F4 I2C driver registered\n");
+
+	return 0;
+
+clk_free:
+	clk_disable_unprepare(i2c_dev->clk);
+	return ret;
+}
+
+static int stm32f4_i2c_remove(struct platform_device *pdev)
+{
+	struct stm32f4_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&i2c_dev->adap);
+
+	clk_unprepare(i2c_dev->clk);
+
+	return 0;
+}
+
+static const struct of_device_id stm32f4_i2c_match[] = {
+	{ .compatible = "st,stm32f4-i2c", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32f4_i2c_match);
+
+static struct platform_driver stm32f4_i2c_driver = {
+	.driver = {
+		.name = "stm32f4-i2c",
+		.of_match_table = stm32f4_i2c_match,
+	},
+	.probe = stm32f4_i2c_probe,
+	.remove = stm32f4_i2c_remove,
+};
+
+module_platform_driver(stm32f4_i2c_driver);
+
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32F4 I2C driver");
+MODULE_LICENSE("GPL v2");