Merge branch 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull more i2c updates from Wolfram Sang:
 "I2C has two more new drivers: Altera FPGA and STM32F7"

* 'i2c/for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: i2c-stm32f7: add driver
  i2c: i2c-stm32f4: use generic definition of speed enum
  dt-bindings: i2c-stm32: Document the STM32F7 I2C bindings
  i2c: altera: Add Altera I2C Controller driver
  dt-bindings: i2c: Add Altera I2C Controller

Documentation/devicetree/bindings/i2c/i2c-altera.txt

+* Altera I2C Controller
+* This is Altera's synthesizable logic block I2C Controller for use
+* in Altera's FPGAs.
+
+Required properties :
+ - compatible : should be "altr,softip-i2c-v1.0"
+ - reg        : Offset and length of the register set for the device
+ - interrupts : <IRQ> where IRQ is the interrupt number.
+ - clocks     : phandle to input clock.
+ - #address-cells = <1>;
+ - #size-cells = <0>;
+
+Recommended properties :
+ - clock-frequency : desired I2C bus clock frequency in Hz.
+
+Optional properties :
+ - fifo-size : Size of the RX and TX FIFOs in bytes.
+ - Child nodes conforming to i2c bus binding
+
+Example :
+
+	i2c@100080000 {
+		compatible = "altr,softip-i2c-v1.0";
+		reg = <0x00000001 0x00080000 0x00000040>;
+		interrupt-parent = <&intc>;
+		interrupts = <0 43 4>;
+		clocks = <&clk_0>;
+		clock-frequency = <100000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+		fifo-size = <4>;
+
+		eeprom@51 {
+			compatible = "atmel,24c32";
+			reg = <0x51>;
+			pagesize = <32>;
+		};
+	};
+

Documentation/devicetree/bindings/i2c/i2c-stm32.txt

 * I2C controller embedded in STMicroelectronics STM32 I2C platform
 
 Required properties :
-- compatible : Must be "st,stm32f4-i2c"
+- compatible : Must be one of the following
+  - "st,stm32f4-i2c"
+  - "st,stm32f7-i2c"
 - reg : Offset and length of the register set for the device
 - interrupts : Must contain the interrupt id for I2C event and then the
   interrupt id for I2C error.
@@ -14,8 +16,16 @@ Required properties :
 
 Optional properties :
 - clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
-  the default 100 kHz frequency will be used. As only Normal and Fast modes
-  are supported, possible values are 100000 and 400000.
+  the default 100 kHz frequency will be used.
+  For STM32F4 SoC Standard-mode and Fast-mode are supported, possible values are
+  100000 and 400000.
+  For STM32F7 SoC, Standard-mode, Fast-mode and Fast-mode Plus are supported,
+  possible values are 100000, 400000 and 1000000.
+- i2c-scl-rising-time-ns : Only for STM32F7, I2C SCL Rising time for the board
+  (default: 25)
+- i2c-scl-falling-time-ns : Only for STM32F7, I2C SCL Falling time for the board
+  (default: 10)
+  I2C Timings are derived from these 2 values
 
 Example :
 
@@ -31,3 +41,16 @@ Example :
 		pinctrl-0 = <&i2c1_sda_pin>, <&i2c1_scl_pin>;
 		pinctrl-names = "default";
 	};
+
+	i2c@40005400 {
+		compatible = "st,stm32f7-i2c";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x40005400 0x400>;
+		interrupts = <31>,
+			     <32>;
+		resets = <&rcc STM32F7_APB1_RESET(I2C1)>;
+		clocks = <&rcc 1 CLK_I2C1>;
+		pinctrl-0 = <&i2c1_sda_pin>, <&i2c1_scl_pin>;
+		pinctrl-names = "default";
+	};

MAINTAINERS

@@ -644,6 +644,11 @@ ALPS PS/2 TOUCHPAD DRIVER
 R:	Pali Rohár <pali.rohar@gmail.com>
 F:	drivers/input/mouse/alps.*
 
+ALTERA I2C CONTROLLER DRIVER
+M:	Thor Thayer <thor.thayer@linux.intel.com>
+S:	Maintained
+F:	drivers/i2c/busses/i2c-altera.c
+
 ALTERA MAILBOX DRIVER
 M:	Ley Foon Tan <lftan@altera.com>
 L:	nios2-dev@lists.rocketboards.org (moderated for non-subscribers)

drivers/i2c/busses/Kconfig

@@ -336,6 +336,16 @@ config I2C_POWERMAC
 
 comment "I2C system bus drivers (mostly embedded / system-on-chip)"
 
+config I2C_ALTERA
+	tristate "Altera Soft IP I2C"
+	depends on (ARCH_SOCFPGA || NIOS2) && OF
+	help
+	  If you say yes to this option, support will be included for the
+	  Altera Soft IP I2C interfaces on SoCFPGA and Nios2 architectures.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-altera.
+
 config I2C_ASPEED
 	tristate "Aspeed I2C Controller"
 	depends on ARCH_ASPEED || COMPILE_TEST
@@ -935,6 +945,16 @@ config I2C_STM32F4
 	  This driver can also be built as module. If so, the module
 	  will be called i2c-stm32f4.
 
+config I2C_STM32F7
+	tristate "STMicroelectronics STM32F7 I2C support"
+	depends on ARCH_STM32 || COMPILE_TEST
+	help
+	  Enable this option to add support for STM32 I2C controller embedded
+	  in STM32F7 SoCs.
+
+	  This driver can also be built as module. If so, the module
+	  will be called i2c-stm32f7.
+
 config I2C_STU300
 	tristate "ST Microelectronics DDC I2C interface"
 	depends on MACH_U300

drivers/i2c/busses/Makefile

@@ -30,6 +30,7 @@ obj-$(CONFIG_I2C_HYDRA)		+= i2c-hydra.o
 obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 
 # Embedded system I2C/SMBus host controller drivers
+obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 obj-$(CONFIG_I2C_AU1550)	+= i2c-au1550.o
@@ -93,6 +94,7 @@ obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
 obj-$(CONFIG_I2C_SPRD)		+= i2c-sprd.o
 obj-$(CONFIG_I2C_ST)		+= i2c-st.o
 obj-$(CONFIG_I2C_STM32F4)	+= i2c-stm32f4.o
+obj-$(CONFIG_I2C_STM32F7)	+= i2c-stm32f7.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_SUN6I_P2WI)	+= i2c-sun6i-p2wi.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o

drivers/i2c/busses/i2c-altera.c

+/*
+ *  Copyright Intel Corporation (C) 2017.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Based on the i2c-axxia.c driver.
+ */
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/iopoll.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+
+#define ALTR_I2C_TFR_CMD	0x00	/* Transfer Command register */
+#define     ALTR_I2C_TFR_CMD_STA	BIT(9)	/* send START before byte */
+#define     ALTR_I2C_TFR_CMD_STO	BIT(8)	/* send STOP after byte */
+#define     ALTR_I2C_TFR_CMD_RW_D	BIT(0)	/* Direction of transfer */
+#define ALTR_I2C_RX_DATA	0x04	/* RX data FIFO register */
+#define ALTR_I2C_CTRL		0x08	/* Control register */
+#define     ALTR_I2C_CTRL_RXT_SHFT	4	/* RX FIFO Threshold */
+#define     ALTR_I2C_CTRL_TCT_SHFT	2	/* TFER CMD FIFO Threshold */
+#define     ALTR_I2C_CTRL_BSPEED	BIT(1)	/* Bus Speed (1=Fast) */
+#define     ALTR_I2C_CTRL_EN	BIT(0)	/* Enable Core (1=Enable) */
+#define ALTR_I2C_ISER		0x0C	/* Interrupt Status Enable register */
+#define     ALTR_I2C_ISER_RXOF_EN	BIT(4)	/* Enable RX OVERFLOW IRQ */
+#define     ALTR_I2C_ISER_ARB_EN	BIT(3)	/* Enable ARB LOST IRQ */
+#define     ALTR_I2C_ISER_NACK_EN	BIT(2)	/* Enable NACK DET IRQ */
+#define     ALTR_I2C_ISER_RXRDY_EN	BIT(1)	/* Enable RX Ready IRQ */
+#define     ALTR_I2C_ISER_TXRDY_EN	BIT(0)	/* Enable TX Ready IRQ */
+#define ALTR_I2C_ISR		0x10	/* Interrupt Status register */
+#define     ALTR_I2C_ISR_RXOF		BIT(4)	/* RX OVERFLOW IRQ */
+#define     ALTR_I2C_ISR_ARB		BIT(3)	/* ARB LOST IRQ */
+#define     ALTR_I2C_ISR_NACK		BIT(2)	/* NACK DET IRQ */
+#define     ALTR_I2C_ISR_RXRDY		BIT(1)	/* RX Ready IRQ */
+#define     ALTR_I2C_ISR_TXRDY		BIT(0)	/* TX Ready IRQ */
+#define ALTR_I2C_STATUS		0x14	/* Status register */
+#define     ALTR_I2C_STAT_CORE		BIT(0)	/* Core Status (0=idle) */
+#define ALTR_I2C_TC_FIFO_LVL	0x18	/* Transfer FIFO LVL register */
+#define ALTR_I2C_RX_FIFO_LVL	0x1C	/* Receive FIFO LVL register */
+#define ALTR_I2C_SCL_LOW	0x20	/* SCL low count register */
+#define ALTR_I2C_SCL_HIGH	0x24	/* SCL high count register */
+#define ALTR_I2C_SDA_HOLD	0x28	/* SDA hold count register */
+
+#define ALTR_I2C_ALL_IRQ	(ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | \
+				 ALTR_I2C_ISR_NACK | ALTR_I2C_ISR_RXRDY | \
+				 ALTR_I2C_ISR_TXRDY)
+
+#define ALTR_I2C_THRESHOLD	0	/* IRQ Threshold at 1 element */
+#define ALTR_I2C_DFLT_FIFO_SZ	4
+#define ALTR_I2C_TIMEOUT	100000	/* 100ms */
+#define ALTR_I2C_XFER_TIMEOUT	(msecs_to_jiffies(250))
+
+/**
+ * altr_i2c_dev - I2C device context
+ * @base: pointer to register struct
+ * @msg: pointer to current message
+ * @msg_len: number of bytes transferred in msg
+ * @msg_err: error code for completed message
+ * @msg_complete: xfer completion object
+ * @dev: device reference
+ * @adapter: core i2c abstraction
+ * @i2c_clk: clock reference for i2c input clock
+ * @bus_clk_rate: current i2c bus clock rate
+ * @buf: ptr to msg buffer for easier use.
+ * @fifo_size: size of the FIFO passed in.
+ * @isr_mask: cached copy of local ISR enables.
+ * @isr_status: cached copy of local ISR status.
+ * @lock: spinlock for IRQ synchronization.
+ */
+struct altr_i2c_dev {
+	void __iomem *base;
+	struct i2c_msg *msg;
+	size_t msg_len;
+	int msg_err;
+	struct completion msg_complete;
+	struct device *dev;
+	struct i2c_adapter adapter;
+	struct clk *i2c_clk;
+	u32 bus_clk_rate;
+	u8 *buf;
+	u32 fifo_size;
+	u32 isr_mask;
+	u32 isr_status;
+	spinlock_t lock;	/* IRQ synchronization */
+};
+
+static void
+altr_i2c_int_enable(struct altr_i2c_dev *idev, u32 mask, bool enable)
+{
+	unsigned long flags;
+	u32 int_en;
+
+	spin_lock_irqsave(&idev->lock, flags);
+
+	int_en = readl(idev->base + ALTR_I2C_ISER);
+	if (enable)
+		idev->isr_mask = int_en | mask;
+	else
+		idev->isr_mask = int_en & ~mask;
+
+	writel(idev->isr_mask, idev->base + ALTR_I2C_ISER);
+
+	spin_unlock_irqrestore(&idev->lock, flags);
+}
+
+static void altr_i2c_int_clear(struct altr_i2c_dev *idev, u32 mask)
+{
+	u32 int_en = readl(idev->base + ALTR_I2C_ISR);
+
+	writel(int_en | mask, idev->base + ALTR_I2C_ISR);
+}
+
+static void altr_i2c_core_disable(struct altr_i2c_dev *idev)
+{
+	u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
+
+	writel(tmp & ~ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
+}
+
+static void altr_i2c_core_enable(struct altr_i2c_dev *idev)
+{
+	u32 tmp = readl(idev->base + ALTR_I2C_CTRL);
+
+	writel(tmp | ALTR_I2C_CTRL_EN, idev->base + ALTR_I2C_CTRL);
+}
+
+static void altr_i2c_reset(struct altr_i2c_dev *idev)
+{
+	altr_i2c_core_disable(idev);
+	altr_i2c_core_enable(idev);
+}
+
+static inline void altr_i2c_stop(struct altr_i2c_dev *idev)
+{
+	writel(ALTR_I2C_TFR_CMD_STO, idev->base + ALTR_I2C_TFR_CMD);
+}
+
+static void altr_i2c_init(struct altr_i2c_dev *idev)
+{
+	u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
+	u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
+	u32 tmp = (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_RXT_SHFT) |
+		  (ALTR_I2C_THRESHOLD << ALTR_I2C_CTRL_TCT_SHFT);
+	u32 t_high, t_low;
+
+	if (idev->bus_clk_rate <= 100000) {
+		tmp &= ~ALTR_I2C_CTRL_BSPEED;
+		/* Standard mode SCL 50/50 */
+		t_high = divisor * 1 / 2;
+		t_low = divisor * 1 / 2;
+	} else {
+		tmp |= ALTR_I2C_CTRL_BSPEED;
+		/* Fast mode SCL 33/66 */
+		t_high = divisor * 1 / 3;
+		t_low = divisor * 2 / 3;
+	}
+	writel(tmp, idev->base + ALTR_I2C_CTRL);
+
+	dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
+		idev->bus_clk_rate, clk_mhz, divisor);
+
+	/* Reset controller */
+	altr_i2c_reset(idev);
+
+	/* SCL High Time */
+	writel(t_high, idev->base + ALTR_I2C_SCL_HIGH);
+	/* SCL Low Time */
+	writel(t_low, idev->base + ALTR_I2C_SCL_LOW);
+	/* SDA Hold Time, 300ns */
+	writel(div_u64(300 * clk_mhz, 1000), idev->base + ALTR_I2C_SDA_HOLD);
+
+	/* Mask all master interrupt bits */
+	altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
+}
+
+/**
+ * altr_i2c_transfer - On the last byte to be transmitted, send
+ * a Stop bit on the last byte.
+ */
+static void altr_i2c_transfer(struct altr_i2c_dev *idev, u32 data)
+{
+	/* On the last byte to be transmitted, send STOP */
+	if (idev->msg_len == 1)
+		data |= ALTR_I2C_TFR_CMD_STO;
+	if (idev->msg_len > 0)
+		writel(data, idev->base + ALTR_I2C_TFR_CMD);
+}
+
+/**
+ * altr_i2c_empty_rx_fifo - Fetch data from RX FIFO until end of
+ * transfer. Send a Stop bit on the last byte.
+ */
+static void altr_i2c_empty_rx_fifo(struct altr_i2c_dev *idev)
+{
+	size_t rx_fifo_avail = readl(idev->base + ALTR_I2C_RX_FIFO_LVL);
+	int bytes_to_transfer = min(rx_fifo_avail, idev->msg_len);
+
+	while (bytes_to_transfer-- > 0) {
+		*idev->buf++ = readl(idev->base + ALTR_I2C_RX_DATA);
+		idev->msg_len--;
+		altr_i2c_transfer(idev, 0);
+	}
+}
+
+/**
+ * altr_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
+ * @return: Number of bytes left to transfer.
+ */
+static int altr_i2c_fill_tx_fifo(struct altr_i2c_dev *idev)
+{
+	size_t tx_fifo_avail = idev->fifo_size - readl(idev->base +
+						       ALTR_I2C_TC_FIFO_LVL);
+	int bytes_to_transfer = min(tx_fifo_avail, idev->msg_len);
+	int ret = idev->msg_len - bytes_to_transfer;
+
+	while (bytes_to_transfer-- > 0) {
+		altr_i2c_transfer(idev, *idev->buf++);
+		idev->msg_len--;
+	}
+
+	return ret;
+}
+
+static irqreturn_t altr_i2c_isr_quick(int irq, void *_dev)
+{
+	struct altr_i2c_dev *idev = _dev;
+	irqreturn_t ret = IRQ_HANDLED;
+
+	/* Read IRQ status but only interested in Enabled IRQs. */
+	idev->isr_status = readl(idev->base + ALTR_I2C_ISR) & idev->isr_mask;
+	if (idev->isr_status)
+		ret = IRQ_WAKE_THREAD;
+
+	return ret;
+}
+
+static irqreturn_t altr_i2c_isr(int irq, void *_dev)
+{
+	int ret;
+	bool read, finish = false;
+	struct altr_i2c_dev *idev = _dev;
+	u32 status = idev->isr_status;
+
+	if (!idev->msg) {
+		dev_warn(idev->dev, "unexpected interrupt\n");
+		altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
+		return IRQ_HANDLED;
+	}
+	read = (idev->msg->flags & I2C_M_RD) != 0;
+
+	/* handle Lost Arbitration */
+	if (unlikely(status & ALTR_I2C_ISR_ARB)) {
+		altr_i2c_int_clear(idev, ALTR_I2C_ISR_ARB);
+		idev->msg_err = -EAGAIN;
+		finish = true;
+	} else if (unlikely(status & ALTR_I2C_ISR_NACK)) {
+		dev_dbg(idev->dev, "Could not get ACK\n");
+		idev->msg_err = -ENXIO;
+		altr_i2c_int_clear(idev, ALTR_I2C_ISR_NACK);
+		altr_i2c_stop(idev);
+		finish = true;
+	} else if (read && unlikely(status & ALTR_I2C_ISR_RXOF)) {
+		/* handle RX FIFO Overflow */
+		altr_i2c_empty_rx_fifo(idev);
+		altr_i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
+		altr_i2c_stop(idev);
+		dev_err(idev->dev, "RX FIFO Overflow\n");
+		finish = true;
+	} else if (read && (status & ALTR_I2C_ISR_RXRDY)) {
+		/* RX FIFO needs service? */
+		altr_i2c_empty_rx_fifo(idev);
+		altr_i2c_int_clear(idev, ALTR_I2C_ISR_RXRDY);
+		if (!idev->msg_len)
+			finish = true;
+	} else if (!read && (status & ALTR_I2C_ISR_TXRDY)) {
+		/* TX FIFO needs service? */
+		altr_i2c_int_clear(idev, ALTR_I2C_ISR_TXRDY);
+		if (idev->msg_len > 0)
+			altr_i2c_fill_tx_fifo(idev);
+		else
+			finish = true;
+	} else {
+		dev_warn(idev->dev, "Unexpected interrupt: 0x%x\n", status);
+		altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
+	}
+
+	if (finish) {
+		/* Wait for the Core to finish */
+		ret = readl_poll_timeout_atomic(idev->base + ALTR_I2C_STATUS,
+						status,
+						!(status & ALTR_I2C_STAT_CORE),
+						1, ALTR_I2C_TIMEOUT);
+		if (ret)
+			dev_err(idev->dev, "message timeout\n");
+		altr_i2c_int_enable(idev, ALTR_I2C_ALL_IRQ, false);
+		altr_i2c_int_clear(idev, ALTR_I2C_ALL_IRQ);
+		complete(&idev->msg_complete);
+		dev_dbg(idev->dev, "Message Complete\n");
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int altr_i2c_xfer_msg(struct altr_i2c_dev *idev, struct i2c_msg *msg)
+{
+	u32 imask = ALTR_I2C_ISR_RXOF | ALTR_I2C_ISR_ARB | ALTR_I2C_ISR_NACK;
+	unsigned long time_left;
+	u32 value;
+	u8 addr = i2c_8bit_addr_from_msg(msg);
+
+	idev->msg = msg;
+	idev->msg_len = msg->len;
+	idev->buf = msg->buf;
+	idev->msg_err = 0;
+	reinit_completion(&idev->msg_complete);
+	altr_i2c_core_enable(idev);
+
+	/* Make sure RX FIFO is empty */
+	do {
+		readl(idev->base + ALTR_I2C_RX_DATA);
+	} while (readl(idev->base + ALTR_I2C_RX_FIFO_LVL));
+
+	writel(ALTR_I2C_TFR_CMD_STA | addr, idev->base + ALTR_I2C_TFR_CMD);
+
+	if ((msg->flags & I2C_M_RD) != 0) {
+		imask |= ALTR_I2C_ISER_RXOF_EN | ALTR_I2C_ISER_RXRDY_EN;
+		altr_i2c_int_enable(idev, imask, true);
+		/* write the first byte to start the RX */
+		altr_i2c_transfer(idev, 0);
+	} else {
+		imask |= ALTR_I2C_ISR_TXRDY;
+		altr_i2c_int_enable(idev, imask, true);
+		altr_i2c_fill_tx_fifo(idev);
+	}
+
+	time_left = wait_for_completion_timeout(&idev->msg_complete,
+						ALTR_I2C_XFER_TIMEOUT);
+	altr_i2c_int_enable(idev, imask, false);
+
+	value = readl(idev->base + ALTR_I2C_STATUS) & ALTR_I2C_STAT_CORE;
+	if (value)
+		dev_err(idev->dev, "Core Status not IDLE...\n");
+
+	if (time_left == 0) {
+		idev->msg_err = -ETIMEDOUT;
+		dev_dbg(idev->dev, "Transaction timed out.\n");
+	}
+
+	altr_i2c_core_disable(idev);
+
+	return idev->msg_err;
+}
+
+static int
+altr_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct altr_i2c_dev *idev = i2c_get_adapdata(adap);
+	int i, ret;
+
+	for (i = 0; i < num; i++) {
+		ret = altr_i2c_xfer_msg(idev, msgs++);
+		if (ret)
+			return ret;
+	}
+	return num;
+}
+
+static u32 altr_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static const struct i2c_algorithm altr_i2c_algo = {
+	.master_xfer = altr_i2c_xfer,
+	.functionality = altr_i2c_func,
+};
+
+static int altr_i2c_probe(struct platform_device *pdev)
+{
+	struct altr_i2c_dev *idev = NULL;
+	struct resource *res;
+	int irq, ret;
+	u32 val;
+
+	idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
+	if (!idev)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	idev->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(idev->base))
+		return PTR_ERR(idev->base);
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "missing interrupt resource\n");
+		return irq;
+	}
+
+	idev->i2c_clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(idev->i2c_clk)) {
+		dev_err(&pdev->dev, "missing clock\n");
+		return PTR_ERR(idev->i2c_clk);
+	}
+
+	idev->dev = &pdev->dev;
+	init_completion(&idev->msg_complete);
+	spin_lock_init(&idev->lock);
+
+	val = device_property_read_u32(idev->dev, "fifo-size",
+				       &idev->fifo_size);
+	if (val) {
+		dev_err(&pdev->dev, "FIFO size set to default of %d\n",
+			ALTR_I2C_DFLT_FIFO_SZ);
+		idev->fifo_size = ALTR_I2C_DFLT_FIFO_SZ;
+	}
+
+	val = device_property_read_u32(idev->dev, "clock-frequency",
+				       &idev->bus_clk_rate);
+	if (val) {
+		dev_err(&pdev->dev, "Default to 100kHz\n");
+		idev->bus_clk_rate = 100000;	/* default clock rate */
+	}
+
+	if (idev->bus_clk_rate > 400000) {
+		dev_err(&pdev->dev, "invalid clock-frequency %d\n",
+			idev->bus_clk_rate);
+		return -EINVAL;
+	}
+
+	ret = devm_request_threaded_irq(&pdev->dev, irq, altr_i2c_isr_quick,
+					altr_i2c_isr, IRQF_ONESHOT,
+					pdev->name, idev);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to claim IRQ %d\n", irq);
+		return ret;
+	}
+
+	ret = clk_prepare_enable(idev->i2c_clk);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to enable clock\n");
+		return ret;
+	}
+
+	altr_i2c_init(idev);
+
+	i2c_set_adapdata(&idev->adapter, idev);
+	strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
+	idev->adapter.owner = THIS_MODULE;
+	idev->adapter.algo = &altr_i2c_algo;
+	idev->adapter.dev.parent = &pdev->dev;
+	idev->adapter.dev.of_node = pdev->dev.of_node;
+
+	platform_set_drvdata(pdev, idev);
+
+	ret = i2c_add_adapter(&idev->adapter);
+	if (ret) {
+		clk_disable_unprepare(idev->i2c_clk);
+		return ret;
+	}
+	dev_info(&pdev->dev, "Altera SoftIP I2C Probe Complete\n");
+
+	return 0;
+}
+
+static int altr_i2c_remove(struct platform_device *pdev)
+{
+	struct altr_i2c_dev *idev = platform_get_drvdata(pdev);
+
+	clk_disable_unprepare(idev->i2c_clk);
+	i2c_del_adapter(&idev->adapter);
+
+	return 0;
+}
+
+/* Match table for of_platform binding */
+static const struct of_device_id altr_i2c_of_match[] = {
+	{ .compatible = "altr,softip-i2c-v1.0" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, altr_i2c_of_match);
+
+static struct platform_driver altr_i2c_driver = {
+	.probe = altr_i2c_probe,
+	.remove = altr_i2c_remove,
+	.driver = {
+		.name = "altera-i2c",
+		.of_match_table = altr_i2c_of_match,
+	},
+};
+
+module_platform_driver(altr_i2c_driver);
+
+MODULE_DESCRIPTION("Altera Soft IP I2C bus driver");
+MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
+MODULE_LICENSE("GPL v2");

drivers/i2c/busses/i2c-stm32.h

+/*
+ * i2c-stm32.h
+ *
+ * Copyright (C) M'boumba Cedric Madianga 2017
+ * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+
+#ifndef _I2C_STM32_H
+#define _I2C_STM32_H
+
+enum stm32_i2c_speed {
+	STM32_I2C_SPEED_STANDARD, /* 100 kHz */
+	STM32_I2C_SPEED_FAST, /* 400 kHz */
+	STM32_I2C_SPEED_FAST_PLUS, /* 1 MHz */
+	STM32_I2C_SPEED_END,
+};
+
+#endif /* _I2C_STM32_H */

drivers/i2c/busses/i2c-stm32f4.c

@@ -27,6 +27,8 @@
 #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
@@ -90,12 +92,6 @@
 #define STM32F4_I2C_MAX_FREQ		46U
 #define HZ_TO_MHZ			1000000
 
-enum stm32f4_i2c_speed {
-	STM32F4_I2C_SPEED_STANDARD, /* 100 kHz */
-	STM32F4_I2C_SPEED_FAST, /* 400 kHz */
-	STM32F4_I2C_SPEED_END,
-};
-
 /**
  * struct stm32f4_i2c_msg - client specific data
  * @addr: 8-bit slave addr, including r/w bit
@@ -159,7 +155,7 @@ static int stm32f4_i2c_set_periph_clk_freq(struct stm32f4_i2c_dev *i2c_dev)
 	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 == STM32F4_I2C_SPEED_STANDARD) {
+	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
@@ -216,7 +212,7 @@ static void stm32f4_i2c_set_rise_time(struct stm32f4_i2c_dev *i2c_dev)
 	 * 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 == STM32F4_I2C_SPEED_STANDARD)
+	if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD)
 		trise = freq + 1;
 	else
 		trise = freq * 3 / 10 + 1;
@@ -230,7 +226,7 @@ static void stm32f4_i2c_set_speed_mode(struct stm32f4_i2c_dev *i2c_dev)
 	u32 val;
 	u32 ccr = 0;
 
-	if (i2c_dev->speed == STM32F4_I2C_SPEED_STANDARD) {
+	if (i2c_dev->speed == STM32_I2C_SPEED_STANDARD) {
 		/*
 		 * In standard mode:
 		 * t_scl_high = t_scl_low = CCR * I2C parent clk period
@@ -808,10 +804,10 @@ static int stm32f4_i2c_probe(struct platform_device *pdev)
 	udelay(2);
 	reset_control_deassert(rst);
 
-	i2c_dev->speed = STM32F4_I2C_SPEED_STANDARD;
+	i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
 	ret = of_property_read_u32(np, "clock-frequency", &clk_rate);
 	if (!ret && clk_rate >= 400000)
-		i2c_dev->speed = STM32F4_I2C_SPEED_FAST;
+		i2c_dev->speed = STM32_I2C_SPEED_FAST;
 
 	i2c_dev->dev = &pdev->dev;
 

drivers/i2c/busses/i2c-stm32f7.c

+/*
+ * Driver for STMicroelectronics STM32F7 I2C controller
+ *
+ * This I2C controller is described in the STM32F75xxx and STM32F74xxx Soc
+ * reference manual.
+ * Please see below a link to the documentation:
+ * http://www.st.com/resource/en/reference_manual/dm00124865.pdf
+ *
+ * Copyright (C) M'boumba Cedric Madianga 2017
+ * Author: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
+ *
+ * This driver is based on i2c-stm32f4.c
+ *
+ * License terms:  GNU General Public License (GPL), version 2
+ */
+#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.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#include "i2c-stm32.h"
+
+/* STM32F7 I2C registers */
+#define STM32F7_I2C_CR1				0x00
+#define STM32F7_I2C_CR2				0x04
+#define STM32F7_I2C_TIMINGR			0x10
+#define STM32F7_I2C_ISR				0x18
+#define STM32F7_I2C_ICR				0x1C
+#define STM32F7_I2C_RXDR			0x24
+#define STM32F7_I2C_TXDR			0x28
+
+/* STM32F7 I2C control 1 */
+#define STM32F7_I2C_CR1_ANFOFF			BIT(12)
+#define STM32F7_I2C_CR1_ERRIE			BIT(7)
+#define STM32F7_I2C_CR1_TCIE			BIT(6)
+#define STM32F7_I2C_CR1_STOPIE			BIT(5)
+#define STM32F7_I2C_CR1_NACKIE			BIT(4)
+#define STM32F7_I2C_CR1_ADDRIE			BIT(3)
+#define STM32F7_I2C_CR1_RXIE			BIT(2)
+#define STM32F7_I2C_CR1_TXIE			BIT(1)
+#define STM32F7_I2C_CR1_PE			BIT(0)
+#define STM32F7_I2C_ALL_IRQ_MASK		(STM32F7_I2C_CR1_ERRIE \
+						| STM32F7_I2C_CR1_TCIE \
+						| STM32F7_I2C_CR1_STOPIE \
+						| STM32F7_I2C_CR1_NACKIE \
+						| STM32F7_I2C_CR1_RXIE \
+						| STM32F7_I2C_CR1_TXIE)
+
+/* STM32F7 I2C control 2 */
+#define STM32F7_I2C_CR2_RELOAD			BIT(24)
+#define STM32F7_I2C_CR2_NBYTES_MASK		GENMASK(23, 16)
+#define STM32F7_I2C_CR2_NBYTES(n)		(((n) & 0xff) << 16)
+#define STM32F7_I2C_CR2_NACK			BIT(15)
+#define STM32F7_I2C_CR2_STOP			BIT(14)
+#define STM32F7_I2C_CR2_START			BIT(13)
+#define STM32F7_I2C_CR2_RD_WRN			BIT(10)
+#define STM32F7_I2C_CR2_SADD7_MASK		GENMASK(7, 1)
+#define STM32F7_I2C_CR2_SADD7(n)		(((n) & 0x7f) << 1)
+
+/* STM32F7 I2C Interrupt Status */
+#define STM32F7_I2C_ISR_BUSY			BIT(15)
+#define STM32F7_I2C_ISR_ARLO			BIT(9)
+#define STM32F7_I2C_ISR_BERR			BIT(8)
+#define STM32F7_I2C_ISR_TCR			BIT(7)
+#define STM32F7_I2C_ISR_TC			BIT(6)
+#define STM32F7_I2C_ISR_STOPF			BIT(5)
+#define STM32F7_I2C_ISR_NACKF			BIT(4)
+#define STM32F7_I2C_ISR_RXNE			BIT(2)
+#define STM32F7_I2C_ISR_TXIS			BIT(1)
+
+/* STM32F7 I2C Interrupt Clear */
+#define STM32F7_I2C_ICR_ARLOCF			BIT(9)
+#define STM32F7_I2C_ICR_BERRCF			BIT(8)
+#define STM32F7_I2C_ICR_STOPCF			BIT(5)
+#define STM32F7_I2C_ICR_NACKCF			BIT(4)
+
+/* STM32F7 I2C Timing */
+#define STM32F7_I2C_TIMINGR_PRESC(n)		(((n) & 0xf) << 28)
+#define STM32F7_I2C_TIMINGR_SCLDEL(n)		(((n) & 0xf) << 20)
+#define STM32F7_I2C_TIMINGR_SDADEL(n)		(((n) & 0xf) << 16)
+#define STM32F7_I2C_TIMINGR_SCLH(n)		(((n) & 0xff) << 8)
+#define STM32F7_I2C_TIMINGR_SCLL(n)		((n) & 0xff)
+
+#define STM32F7_I2C_MAX_LEN			0xff
+
+#define STM32F7_I2C_DNF_DEFAULT			0
+#define STM32F7_I2C_DNF_MAX			16
+
+#define STM32F7_I2C_ANALOG_FILTER_ENABLE	1
+#define STM32F7_I2C_ANALOG_FILTER_DELAY_MIN	50	/* ns */
+#define STM32F7_I2C_ANALOG_FILTER_DELAY_MAX	260	/* ns */
+
+#define STM32F7_I2C_RISE_TIME_DEFAULT		25	/* ns */
+#define STM32F7_I2C_FALL_TIME_DEFAULT		10	/* ns */
+
+#define STM32F7_PRESC_MAX			BIT(4)
+#define STM32F7_SCLDEL_MAX			BIT(4)
+#define STM32F7_SDADEL_MAX			BIT(4)
+#define STM32F7_SCLH_MAX			BIT(8)
+#define STM32F7_SCLL_MAX			BIT(8)
+
+/**
+ * struct stm32f7_i2c_spec - private i2c specification timing
+ * @rate: I2C bus speed (Hz)
+ * @rate_min: 80% of I2C bus speed (Hz)
+ * @rate_max: 100% of I2C bus speed (Hz)
+ * @fall_max: Max fall time of both SDA and SCL signals (ns)
+ * @rise_max: Max rise time of both SDA and SCL signals (ns)
+ * @hddat_min: Min data hold time (ns)
+ * @vddat_max: Max data valid time (ns)
+ * @sudat_min: Min data setup time (ns)
+ * @l_min: Min low period of the SCL clock (ns)
+ * @h_min: Min high period of the SCL clock (ns)
+ */
+struct stm32f7_i2c_spec {
+	u32 rate;
+	u32 rate_min;
+	u32 rate_max;
+	u32 fall_max;
+	u32 rise_max;
+	u32 hddat_min;
+	u32 vddat_max;
+	u32 sudat_min;
+	u32 l_min;
+	u32 h_min;
+};
+
+/**
+ * struct stm32f7_i2c_setup - private I2C timing setup parameters
+ * @speed: I2C speed mode (standard, Fast Plus)
+ * @speed_freq: I2C speed frequency  (Hz)
+ * @clock_src: I2C clock source frequency (Hz)
+ * @rise_time: Rise time (ns)
+ * @fall_time: Fall time (ns)
+ * @dnf: Digital filter coefficient (0-16)
+ * @analog_filter: Analog filter delay (On/Off)
+ */
+struct stm32f7_i2c_setup {
+	enum stm32_i2c_speed speed;
+	u32 speed_freq;
+	u32 clock_src;
+	u32 rise_time;
+	u32 fall_time;
+	u8 dnf;
+	bool analog_filter;
+};
+
+/**
+ * struct stm32f7_i2c_timings - private I2C output parameters
+ * @prec: Prescaler value
+ * @scldel: Data setup time
+ * @sdadel: Data hold time
+ * @sclh: SCL high period (master mode)
+ * @sclh: SCL low period (master mode)
+ */
+struct stm32f7_i2c_timings {
+	struct list_head node;
+	u8 presc;
+	u8 scldel;
+	u8 sdadel;
+	u8 sclh;
+	u8 scll;
+};
+
+/**
+ * struct stm32f7_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 stm32f7_i2c_msg {
+	u8 addr;
+	u32 count;
+	u8 *buf;
+	int result;
+	bool stop;
+};
+
+/**
+ * struct stm32f7_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, Fast or Fast+
+ * @msg: Pointer to data to be written
+ * @msg_num: number of I2C messages to be executed
+ * @msg_id: message identifiant
+ * @f7_msg: customized i2c msg for driver usage
+ * @setup: I2C timing input setup
+ * @timing: I2C computed timings
+ */
+struct stm32f7_i2c_dev {
+	struct i2c_adapter adap;
+	struct device *dev;
+	void __iomem *base;
+	struct completion complete;
+	struct clk *clk;
+	int speed;
+	struct i2c_msg *msg;
+	unsigned int msg_num;
+	unsigned int msg_id;
+	struct stm32f7_i2c_msg f7_msg;
+	struct stm32f7_i2c_setup *setup;
+	struct stm32f7_i2c_timings timing;
+};
+
+/**
+ * All these values are coming from I2C Specification, Version 6.0, 4th of
+ * April 2014.
+ *
+ * Table10. Characteristics of the SDA and SCL bus lines for Standard, Fast,
+ * and Fast-mode Plus I2C-bus devices
+ */
+static struct stm32f7_i2c_spec i2c_specs[] = {
+	[STM32_I2C_SPEED_STANDARD] = {
+		.rate = 100000,
+		.rate_min = 80000,
+		.rate_max = 100000,
+		.fall_max = 300,
+		.rise_max = 1000,
+		.hddat_min = 0,
+		.vddat_max = 3450,
+		.sudat_min = 250,
+		.l_min = 4700,
+		.h_min = 4000,
+	},
+	[STM32_I2C_SPEED_FAST] = {
+		.rate = 400000,
+		.rate_min = 320000,
+		.rate_max = 400000,
+		.fall_max = 300,
+		.rise_max = 300,
+		.hddat_min = 0,
+		.vddat_max = 900,
+		.sudat_min = 100,
+		.l_min = 1300,
+		.h_min = 600,
+	},
+	[STM32_I2C_SPEED_FAST_PLUS] = {
+		.rate = 1000000,
+		.rate_min = 800000,
+		.rate_max = 1000000,
+		.fall_max = 100,
+		.rise_max = 120,
+		.hddat_min = 0,
+		.vddat_max = 450,
+		.sudat_min = 50,
+		.l_min = 500,
+		.h_min = 260,
+	},
+};
+
+struct stm32f7_i2c_setup stm32f7_setup = {
+	.rise_time = STM32F7_I2C_RISE_TIME_DEFAULT,
+	.fall_time = STM32F7_I2C_FALL_TIME_DEFAULT,
+	.dnf = STM32F7_I2C_DNF_DEFAULT,
+	.analog_filter = STM32F7_I2C_ANALOG_FILTER_ENABLE,
+};
+
+static inline void stm32f7_i2c_set_bits(void __iomem *reg, u32 mask)
+{
+	writel_relaxed(readl_relaxed(reg) | mask, reg);
+}
+
+static inline void stm32f7_i2c_clr_bits(void __iomem *reg, u32 mask)
+{
+	writel_relaxed(readl_relaxed(reg) & ~mask, reg);
+}
+
+static int stm32f7_i2c_compute_timing(struct stm32f7_i2c_dev *i2c_dev,
+				      struct stm32f7_i2c_setup *setup,
+				      struct stm32f7_i2c_timings *output)
+{
+	u32 p_prev = STM32F7_PRESC_MAX;
+	u32 i2cclk = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
+				       setup->clock_src);
+	u32 i2cbus = DIV_ROUND_CLOSEST(NSEC_PER_SEC,
+				       setup->speed_freq);
+	u32 clk_error_prev = i2cbus;
+	u32 tsync;
+	u32 af_delay_min, af_delay_max;
+	u32 dnf_delay;
+	u32 clk_min, clk_max;
+	int sdadel_min, sdadel_max;
+	int scldel_min;
+	struct stm32f7_i2c_timings *v, *_v, *s;
+	struct list_head solutions;
+	u16 p, l, a, h;
+	int ret = 0;
+
+	if (setup->speed >= STM32_I2C_SPEED_END) {
+		dev_err(i2c_dev->dev, "speed out of bound {%d/%d}\n",
+			setup->speed, STM32_I2C_SPEED_END - 1);
+		return -EINVAL;
+	}
+
+	if ((setup->rise_time > i2c_specs[setup->speed].rise_max) ||
+	    (setup->fall_time > i2c_specs[setup->speed].fall_max)) {
+		dev_err(i2c_dev->dev,
+			"timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
+			setup->rise_time, i2c_specs[setup->speed].rise_max,
+			setup->fall_time, i2c_specs[setup->speed].fall_max);
+		return -EINVAL;
+	}
+
+	if (setup->dnf > STM32F7_I2C_DNF_MAX) {
+		dev_err(i2c_dev->dev,
+			"DNF out of bound %d/%d\n",
+			setup->dnf, STM32F7_I2C_DNF_MAX);
+		return -EINVAL;
+	}
+
+	if (setup->speed_freq > i2c_specs[setup->speed].rate) {
+		dev_err(i2c_dev->dev, "ERROR: Freq {%d/%d}\n",
+			setup->speed_freq, i2c_specs[setup->speed].rate);
+		return -EINVAL;
+	}
+
+	/*  Analog and Digital Filters */
+	af_delay_min =
+		(setup->analog_filter ?
+		 STM32F7_I2C_ANALOG_FILTER_DELAY_MIN : 0);
+	af_delay_max =
+		(setup->analog_filter ?
+		 STM32F7_I2C_ANALOG_FILTER_DELAY_MAX : 0);
+	dnf_delay = setup->dnf * i2cclk;
+
+	sdadel_min = setup->fall_time - i2c_specs[setup->speed].hddat_min -
+		af_delay_min - (setup->dnf + 3) * i2cclk;
+
+	sdadel_max = i2c_specs[setup->speed].vddat_max - setup->rise_time -
+		af_delay_max - (setup->dnf + 4) * i2cclk;
+
+	scldel_min = setup->rise_time + i2c_specs[setup->speed].sudat_min;
+
+	if (sdadel_min < 0)
+		sdadel_min = 0;
+	if (sdadel_max < 0)
+		sdadel_max = 0;
+
+	dev_dbg(i2c_dev->dev, "SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n",
+		sdadel_min, sdadel_max, scldel_min);
+
+	INIT_LIST_HEAD(&solutions);
+	/* Compute possible values for PRESC, SCLDEL and SDADEL */
+	for (p = 0; p < STM32F7_PRESC_MAX; p++) {
+		for (l = 0; l < STM32F7_SCLDEL_MAX; l++) {
+			u32 scldel = (l + 1) * (p + 1) * i2cclk;
+
+			if (scldel < scldel_min)
+				continue;
+
+			for (a = 0; a < STM32F7_SDADEL_MAX; a++) {
+				u32 sdadel = (a * (p + 1) + 1) * i2cclk;
+
+				if (((sdadel >= sdadel_min) &&
+				     (sdadel <= sdadel_max)) &&
+				    (p != p_prev)) {
+					v = kmalloc(sizeof(*v), GFP_KERNEL);
+					if (!v) {
+						ret = -ENOMEM;
+						goto exit;
+					}
+
+					v->presc = p;
+					v->scldel = l;
+					v->sdadel = a;
+					p_prev = p;
+
+					list_add_tail(&v->node,
+						      &solutions);
+				}
+			}
+		}
+	}
+
+	if (list_empty(&solutions)) {
+		dev_err(i2c_dev->dev, "no Prescaler solution\n");
+		ret = -EPERM;
+		goto exit;
+	}
+
+	tsync = af_delay_min + dnf_delay + (2 * i2cclk);
+	s = NULL;
+	clk_max = NSEC_PER_SEC / i2c_specs[setup->speed].rate_min;
+	clk_min = NSEC_PER_SEC / i2c_specs[setup->speed].rate_max;
+
+	/*
+	 * Among Prescaler possibilities discovered above figures out SCL Low
+	 * and High Period. Provided:
+	 * - SCL Low Period has to be higher than SCL Clock Low Period
+	 *   defined by I2C Specification. I2C Clock has to be lower than
+	 *   (SCL Low Period - Analog/Digital filters) / 4.
+	 * - SCL High Period has to be lower than SCL Clock High Period
+	 *   defined by I2C Specification
+	 * - I2C Clock has to be lower than SCL High Period
+	 */
+	list_for_each_entry(v, &solutions, node) {
+		u32 prescaler = (v->presc + 1) * i2cclk;
+
+		for (l = 0; l < STM32F7_SCLL_MAX; l++) {
+			u32 tscl_l = (l + 1) * prescaler + tsync;
+
+			if ((tscl_l < i2c_specs[setup->speed].l_min) ||
+			    (i2cclk >=
+			     ((tscl_l - af_delay_min - dnf_delay) / 4))) {
+				continue;
+			}
+
+			for (h = 0; h < STM32F7_SCLH_MAX; h++) {
+				u32 tscl_h = (h + 1) * prescaler + tsync;
+				u32 tscl = tscl_l + tscl_h +
+					setup->rise_time + setup->fall_time;
+
+				if ((tscl >= clk_min) && (tscl <= clk_max) &&
+				    (tscl_h >= i2c_specs[setup->speed].h_min) &&
+				    (i2cclk < tscl_h)) {
+					int clk_error = tscl - i2cbus;
+
+					if (clk_error < 0)
+						clk_error = -clk_error;
+
+					if (clk_error < clk_error_prev) {
+						clk_error_prev = clk_error;
+						v->scll = l;
+						v->sclh = h;
+						s = v;
+					}
+				}
+			}
+		}
+	}
+
+	if (!s) {
+		dev_err(i2c_dev->dev, "no solution at all\n");
+		ret = -EPERM;
+		goto exit;
+	}
+
+	output->presc = s->presc;
+	output->scldel = s->scldel;
+	output->sdadel = s->sdadel;
+	output->scll = s->scll;
+	output->sclh = s->sclh;
+
+	dev_dbg(i2c_dev->dev,
+		"Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
+		output->presc,
+		output->scldel, output->sdadel,
+		output->scll, output->sclh);
+
+exit:
+	/* Release list and memory */
+	list_for_each_entry_safe(v, _v, &solutions, node) {
+		list_del(&v->node);
+		kfree(v);
+	}
+
+	return ret;
+}
+
+static int stm32f7_i2c_setup_timing(struct stm32f7_i2c_dev *i2c_dev,
+				    struct stm32f7_i2c_setup *setup)
+{
+	int ret = 0;
+
+	setup->speed = i2c_dev->speed;
+	setup->speed_freq = i2c_specs[setup->speed].rate;
+	setup->clock_src = clk_get_rate(i2c_dev->clk);
+
+	if (!setup->clock_src) {
+		dev_err(i2c_dev->dev, "clock rate is 0\n");
+		return -EINVAL;
+	}
+
+	do {
+		ret = stm32f7_i2c_compute_timing(i2c_dev, setup,
+						 &i2c_dev->timing);
+		if (ret) {
+			dev_err(i2c_dev->dev,
+				"failed to compute I2C timings.\n");
+			if (i2c_dev->speed > STM32_I2C_SPEED_STANDARD) {
+				i2c_dev->speed--;
+				setup->speed = i2c_dev->speed;
+				setup->speed_freq =
+					i2c_specs[setup->speed].rate;
+				dev_warn(i2c_dev->dev,
+					 "downgrade I2C Speed Freq to (%i)\n",
+					 i2c_specs[setup->speed].rate);
+			} else {
+				break;
+			}
+		}
+	} while (ret);
+
+	if (ret) {
+		dev_err(i2c_dev->dev, "Impossible to compute I2C timings.\n");
+		return ret;
+	}
+
+	dev_dbg(i2c_dev->dev, "I2C Speed(%i), Freq(%i), Clk Source(%i)\n",
+		setup->speed, setup->speed_freq, setup->clock_src);
+	dev_dbg(i2c_dev->dev, "I2C Rise(%i) and Fall(%i) Time\n",
+		setup->rise_time, setup->fall_time);
+	dev_dbg(i2c_dev->dev, "I2C Analog Filter(%s), DNF(%i)\n",
+		(setup->analog_filter ? "On" : "Off"), setup->dnf);
+
+	return 0;
+}
+
+static void stm32f7_i2c_hw_config(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_timings *t = &i2c_dev->timing;
+	u32 timing = 0;
+
+	/* Timing settings */
+	timing |= STM32F7_I2C_TIMINGR_PRESC(t->presc);
+	timing |= STM32F7_I2C_TIMINGR_SCLDEL(t->scldel);
+	timing |= STM32F7_I2C_TIMINGR_SDADEL(t->sdadel);
+	timing |= STM32F7_I2C_TIMINGR_SCLH(t->sclh);
+	timing |= STM32F7_I2C_TIMINGR_SCLL(t->scll);
+	writel_relaxed(timing, i2c_dev->base + STM32F7_I2C_TIMINGR);
+
+	/* Enable I2C */
+	if (i2c_dev->setup->analog_filter)
+		stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1,
+				     STM32F7_I2C_CR1_ANFOFF);
+	else
+		stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
+				     STM32F7_I2C_CR1_ANFOFF);
+	stm32f7_i2c_set_bits(i2c_dev->base + STM32F7_I2C_CR1,
+			     STM32F7_I2C_CR1_PE);
+}
+
+static void stm32f7_i2c_write_tx_data(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	void __iomem *base = i2c_dev->base;
+
+	if (f7_msg->count) {
+		writeb_relaxed(*f7_msg->buf++, base + STM32F7_I2C_TXDR);
+		f7_msg->count--;
+	}
+}
+
+static void stm32f7_i2c_read_rx_data(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	void __iomem *base = i2c_dev->base;
+
+	if (f7_msg->count) {
+		*f7_msg->buf++ = readb_relaxed(base + STM32F7_I2C_RXDR);
+		f7_msg->count--;
+	}
+}
+
+static void stm32f7_i2c_reload(struct stm32f7_i2c_dev *i2c_dev)
+{
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	u32 cr2;
+
+	cr2 = readl_relaxed(i2c_dev->base + STM32F7_I2C_CR2);
+
+	cr2 &= ~STM32F7_I2C_CR2_NBYTES_MASK;
+	if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
+		cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
+	} else {
+		cr2 &= ~STM32F7_I2C_CR2_RELOAD;
+		cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
+	}
+
+	writel_relaxed(cr2, i2c_dev->base + STM32F7_I2C_CR2);
+}
+
+static int stm32f7_i2c_wait_free_bus(struct stm32f7_i2c_dev *i2c_dev)
+{
+	u32 status;
+	int ret;
+
+	ret = readl_relaxed_poll_timeout(i2c_dev->base + STM32F7_I2C_ISR,
+					 status,
+					 !(status & STM32F7_I2C_ISR_BUSY),
+					 10, 1000);
+	if (ret) {
+		dev_dbg(i2c_dev->dev, "bus busy\n");
+		ret = -EBUSY;
+	}
+
+	return ret;
+}
+
+static void stm32f7_i2c_xfer_msg(struct stm32f7_i2c_dev *i2c_dev,
+				 struct i2c_msg *msg)
+{
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	void __iomem *base = i2c_dev->base;
+	u32 cr1, cr2;
+
+	f7_msg->addr = msg->addr;
+	f7_msg->buf = msg->buf;
+	f7_msg->count = msg->len;
+	f7_msg->result = 0;
+	f7_msg->stop = (i2c_dev->msg_id >= i2c_dev->msg_num - 1);
+
+	reinit_completion(&i2c_dev->complete);
+
+	cr1 = readl_relaxed(base + STM32F7_I2C_CR1);
+	cr2 = readl_relaxed(base + STM32F7_I2C_CR2);
+
+	/* Set transfer direction */
+	cr2 &= ~STM32F7_I2C_CR2_RD_WRN;
+	if (msg->flags & I2C_M_RD)
+		cr2 |= STM32F7_I2C_CR2_RD_WRN;
+
+	/* Set slave address */
+	cr2 &= ~STM32F7_I2C_CR2_SADD7_MASK;
+	cr2 |= STM32F7_I2C_CR2_SADD7(f7_msg->addr);
+
+	/* Set nb bytes to transfer and reload if needed */
+	cr2 &= ~(STM32F7_I2C_CR2_NBYTES_MASK | STM32F7_I2C_CR2_RELOAD);
+	if (f7_msg->count > STM32F7_I2C_MAX_LEN) {
+		cr2 |= STM32F7_I2C_CR2_NBYTES(STM32F7_I2C_MAX_LEN);
+		cr2 |= STM32F7_I2C_CR2_RELOAD;
+	} else {
+		cr2 |= STM32F7_I2C_CR2_NBYTES(f7_msg->count);
+	}
+
+	/* Enable NACK, STOP, error and transfer complete interrupts */
+	cr1 |= STM32F7_I2C_CR1_ERRIE | STM32F7_I2C_CR1_TCIE |
+		STM32F7_I2C_CR1_STOPIE | STM32F7_I2C_CR1_NACKIE;
+
+	/* Clear TX/RX interrupt */
+	cr1 &= ~(STM32F7_I2C_CR1_RXIE | STM32F7_I2C_CR1_TXIE);
+
+	/* Enable RX/TX interrupt according to msg direction */
+	if (msg->flags & I2C_M_RD)
+		cr1 |= STM32F7_I2C_CR1_RXIE;
+	else
+		cr1 |= STM32F7_I2C_CR1_TXIE;
+
+	/* Configure Start/Repeated Start */
+	cr2 |= STM32F7_I2C_CR2_START;
+
+	/* Write configurations registers */
+	writel_relaxed(cr1, base + STM32F7_I2C_CR1);
+	writel_relaxed(cr2, base + STM32F7_I2C_CR2);
+}
+
+static void stm32f7_i2c_disable_irq(struct stm32f7_i2c_dev *i2c_dev, u32 mask)
+{
+	stm32f7_i2c_clr_bits(i2c_dev->base + STM32F7_I2C_CR1, mask);
+}
+
+static irqreturn_t stm32f7_i2c_isr_event(int irq, void *data)
+{
+	struct stm32f7_i2c_dev *i2c_dev = data;
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	void __iomem *base = i2c_dev->base;
+	u32 status, mask;
+
+	status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
+
+	/* Tx empty */
+	if (status & STM32F7_I2C_ISR_TXIS)
+		stm32f7_i2c_write_tx_data(i2c_dev);
+
+	/* RX not empty */
+	if (status & STM32F7_I2C_ISR_RXNE)
+		stm32f7_i2c_read_rx_data(i2c_dev);
+
+	/* NACK received */
+	if (status & STM32F7_I2C_ISR_NACKF) {
+		dev_dbg(i2c_dev->dev, "<%s>: Receive NACK\n", __func__);
+		writel_relaxed(STM32F7_I2C_ICR_NACKCF, base + STM32F7_I2C_ICR);
+		f7_msg->result = -ENXIO;
+	}
+
+	/* STOP detection flag */
+	if (status & STM32F7_I2C_ISR_STOPF) {
+		/* Disable interrupts */
+		stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+
+		/* Clear STOP flag */
+		writel_relaxed(STM32F7_I2C_ICR_STOPCF, base + STM32F7_I2C_ICR);
+
+		complete(&i2c_dev->complete);
+	}
+
+	/* Transfer complete */
+	if (status & STM32F7_I2C_ISR_TC) {
+		if (f7_msg->stop) {
+			mask = STM32F7_I2C_CR2_STOP;
+			stm32f7_i2c_set_bits(base + STM32F7_I2C_CR2, mask);
+		} else {
+			i2c_dev->msg_id++;
+			i2c_dev->msg++;
+			stm32f7_i2c_xfer_msg(i2c_dev, i2c_dev->msg);
+		}
+	}
+
+	/*
+	 * Transfer Complete Reload: 255 data bytes have been transferred
+	 * We have to prepare the I2C controller to transfer the remaining
+	 * data.
+	 */
+	if (status & STM32F7_I2C_ISR_TCR)
+		stm32f7_i2c_reload(i2c_dev);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t stm32f7_i2c_isr_error(int irq, void *data)
+{
+	struct stm32f7_i2c_dev *i2c_dev = data;
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	void __iomem *base = i2c_dev->base;
+	struct device *dev = i2c_dev->dev;
+	u32 status;
+
+	status = readl_relaxed(i2c_dev->base + STM32F7_I2C_ISR);
+
+	/* Bus error */
+	if (status & STM32F7_I2C_ISR_BERR) {
+		dev_err(dev, "<%s>: Bus error\n", __func__);
+		writel_relaxed(STM32F7_I2C_ICR_BERRCF, base + STM32F7_I2C_ICR);
+		f7_msg->result = -EIO;
+	}
+
+	/* Arbitration loss */
+	if (status & STM32F7_I2C_ISR_ARLO) {
+		dev_dbg(dev, "<%s>: Arbitration loss\n", __func__);
+		writel_relaxed(STM32F7_I2C_ICR_ARLOCF, base + STM32F7_I2C_ICR);
+		f7_msg->result = -EAGAIN;
+	}
+
+	stm32f7_i2c_disable_irq(i2c_dev, STM32F7_I2C_ALL_IRQ_MASK);
+
+	complete(&i2c_dev->complete);
+
+	return IRQ_HANDLED;
+}
+
+static int stm32f7_i2c_xfer(struct i2c_adapter *i2c_adap,
+			    struct i2c_msg msgs[], int num)
+{
+	struct stm32f7_i2c_dev *i2c_dev = i2c_get_adapdata(i2c_adap);
+	struct stm32f7_i2c_msg *f7_msg = &i2c_dev->f7_msg;
+	unsigned long time_left;
+	int ret;
+
+	i2c_dev->msg = msgs;
+	i2c_dev->msg_num = num;
+	i2c_dev->msg_id = 0;
+
+	ret = clk_enable(i2c_dev->clk);
+	if (ret) {
+		dev_err(i2c_dev->dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	ret = stm32f7_i2c_wait_free_bus(i2c_dev);
+	if (ret)
+		goto clk_free;
+
+	stm32f7_i2c_xfer_msg(i2c_dev, msgs);
+
+	time_left = wait_for_completion_timeout(&i2c_dev->complete,
+						i2c_dev->adap.timeout);
+	ret = f7_msg->result;
+
+	if (!time_left) {
+		dev_dbg(i2c_dev->dev, "Access to slave 0x%x timed out\n",
+			i2c_dev->msg->addr);
+		ret = -ETIMEDOUT;
+	}
+
+clk_free:
+	clk_disable(i2c_dev->clk);
+
+	return (ret < 0) ? ret : num;
+}
+
+static u32 stm32f7_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm stm32f7_i2c_algo = {
+	.master_xfer = stm32f7_i2c_xfer,
+	.functionality = stm32f7_i2c_func,
+};
+
+static int stm32f7_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct stm32f7_i2c_dev *i2c_dev;
+	const struct stm32f7_i2c_setup *setup;
+	struct resource *res;
+	u32 irq_error, irq_event, clk_rate, rise_time, fall_time;
+	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(&pdev->dev, "Failed to prepare_enable clock\n");
+		return ret;
+	}
+
+	i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
+	ret = device_property_read_u32(&pdev->dev, "clock-frequency",
+				       &clk_rate);
+	if (!ret && clk_rate >= 1000000)
+		i2c_dev->speed = STM32_I2C_SPEED_FAST_PLUS;
+	else if (!ret && clk_rate >= 400000)
+		i2c_dev->speed = STM32_I2C_SPEED_FAST;
+	else if (!ret && clk_rate >= 100000)
+		i2c_dev->speed = STM32_I2C_SPEED_STANDARD;
+
+	rst = devm_reset_control_get(&pdev->dev, NULL);
+	if (IS_ERR(rst)) {
+		dev_err(&pdev->dev, "Error: Missing controller reset\n");
+		ret = PTR_ERR(rst);
+		goto clk_free;
+	}
+	reset_control_assert(rst);
+	udelay(2);
+	reset_control_deassert(rst);
+
+	i2c_dev->dev = &pdev->dev;
+
+	ret = devm_request_irq(&pdev->dev, irq_event, stm32f7_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, stm32f7_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;
+	}
+
+	setup = of_device_get_match_data(&pdev->dev);
+	i2c_dev->setup->rise_time = setup->rise_time;
+	i2c_dev->setup->fall_time = setup->fall_time;
+	i2c_dev->setup->dnf = setup->dnf;
+	i2c_dev->setup->analog_filter = setup->analog_filter;
+
+	ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-rising-time-ns",
+				       &rise_time);
+	if (!ret)
+		i2c_dev->setup->rise_time = rise_time;
+
+	ret = device_property_read_u32(i2c_dev->dev, "i2c-scl-falling-time-ns",
+				       &fall_time);
+	if (!ret)
+		i2c_dev->setup->fall_time = fall_time;
+
+	ret = stm32f7_i2c_setup_timing(i2c_dev, i2c_dev->setup);
+	if (ret)
+		goto clk_free;
+
+	stm32f7_i2c_hw_config(i2c_dev);
+
+	adap = &i2c_dev->adap;
+	i2c_set_adapdata(adap, i2c_dev);
+	snprintf(adap->name, sizeof(adap->name), "STM32F7 I2C(%pa)",
+		 &res->start);
+	adap->owner = THIS_MODULE;
+	adap->timeout = 2 * HZ;
+	adap->retries = 3;
+	adap->algo = &stm32f7_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, "STM32F7 I2C-%d bus adapter\n", adap->nr);
+
+	return 0;
+
+clk_free:
+	clk_disable_unprepare(i2c_dev->clk);
+
+	return ret;
+}
+
+static int stm32f7_i2c_remove(struct platform_device *pdev)
+{
+	struct stm32f7_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 stm32f7_i2c_match[] = {
+	{ .compatible = "st,stm32f7-i2c", .data = &stm32f7_setup},
+	{},
+};
+MODULE_DEVICE_TABLE(of, stm32f7_i2c_match);
+
+static struct platform_driver stm32f7_i2c_driver = {
+	.driver = {
+		.name = "stm32f7-i2c",
+		.of_match_table = stm32f7_i2c_match,
+	},
+	.probe = stm32f7_i2c_probe,
+	.remove = stm32f7_i2c_remove,
+};
+
+module_platform_driver(stm32f7_i2c_driver);
+
+MODULE_AUTHOR("M'boumba Cedric Madianga <cedric.madianga@gmail.com>");
+MODULE_DESCRIPTION("STMicroelectronics STM32F7 I2C driver");
+MODULE_LICENSE("GPL v2");