Merge git://git.denx.de/u-boot-i2c

doc/device-tree-bindings/i2c/i2c-stm32.txt

@@ -0,0 +1,30 @@
+* I2C controller embedded in STMicroelectronis STM32 platforms
+
+Required properties :
+- compatible : Must be "st,stm32f7-i2c"
+- reg : Offset and length of the register set for the device
+- resets: Must contain the phandle to the reset controller
+- clocks: Must contain the input clock of the I2C instance
+- A pinctrl state named "default" must be defined to set pins in mode of
+  operation for I2C transfer
+- #address-cells = <1>;
+- #size-cells = <0>;
+
+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, Fast and Fast+
+  modes are implemented, possible values are 100000, 400000 and 1000000.
+
+Example :
+
+	i2c1: i2c@40005400 {
+		compatible = "st,stm32f7-i2c";
+		reg = <0x40005400 0x400>;
+		resets = <&rcc 181>;
+		clocks = <&clk_pclk1>;
+		pinctrl-names = "default";
+		pinctrl-0 = <&pinctrl_i2c1>;
+		clock-frequency = <400000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};

drivers/i2c/Kconfig

@@ -174,6 +174,26 @@ config SYS_I2C_S3C24X0
 	help
 	  Support for Samsung I2C controller as Samsung SoCs.
 
+config SYS_I2C_STM32F7
+	bool "STMicroelectronics STM32F7 I2C support"
+	depends on (STM32F7 || STM32H7) && DM_I2C
+	help
+	  Enable this option to add support for STM32 I2C controller
+	  introduced with STM32F7/H7 SoCs. This I2C controller supports :
+	   _ Slave and master modes
+	   _ Multimaster capability
+	   _ Standard-mode (up to 100 kHz)
+	   _ Fast-mode (up to 400 kHz)
+	   _ Fast-mode Plus (up to 1 MHz)
+	   _ 7-bit and 10-bit addressing mode
+	   _ Multiple 7-bit slave addresses (2 addresses, 1 with configurable mask)
+	   _ All 7-bit addresses acknowledge mode
+	   _ General call
+	   _ Programmable setup and hold times
+	   _ Easy to use event management
+	   _ Optional clock stretching
+	   _ Software reset
+
 config SYS_I2C_UNIPHIER
 	bool "UniPhier I2C driver"
 	depends on ARCH_UNIPHIER && DM_I2C

drivers/i2c/Makefile

@@ -37,6 +37,7 @@ obj-$(CONFIG_SYS_I2C_S3C24X0) += s3c24x0_i2c.o exynos_hs_i2c.o
 obj-$(CONFIG_SYS_I2C_SANDBOX) += sandbox_i2c.o i2c-emul-uclass.o
 obj-$(CONFIG_SYS_I2C_SH) += sh_i2c.o
 obj-$(CONFIG_SYS_I2C_SOFT) += soft_i2c.o
+obj-$(CONFIG_SYS_I2C_STM32F7) += stm32f7_i2c.o
 obj-$(CONFIG_SYS_I2C_TEGRA) += tegra_i2c.o
 obj-$(CONFIG_SYS_I2C_UNIPHIER) += i2c-uniphier.o
 obj-$(CONFIG_SYS_I2C_UNIPHIER_F) += i2c-uniphier-f.o

drivers/i2c/muxes/Kconfig

@@ -34,3 +34,12 @@ config I2C_MUX_PCA954x
 	  paritioning I2C bus and connect multiple devices with the same address
 	  to the same I2C controller where driver handles proper routing to
 	  target i2c device. PCA9544 and PCA9548 are supported.
+
+config I2C_MUX_GPIO
+        tristate "GPIO-based I2C multiplexer"
+	depends on I2C_MUX && DM_GPIO
+	help
+	  If you say yes to this option, support will be included for
+	  a GPIO based I2C multiplexer. This driver provides access to
+	  I2C busses connected through a MUX, which is controlled
+	  through GPIO pins.

drivers/i2c/muxes/Makefile

@@ -6,3 +6,4 @@
 obj-$(CONFIG_I2C_ARB_GPIO_CHALLENGE) += i2c-arb-gpio-challenge.o
 obj-$(CONFIG_$(SPL_)I2C_MUX) += i2c-mux-uclass.o
 obj-$(CONFIG_I2C_MUX_PCA954x) += pca954x.o
+obj-$(CONFIG_I2C_MUX_GPIO) += i2c-mux-gpio.o

drivers/i2c/muxes/i2c-mux-gpio.c

@@ -0,0 +1,138 @@
+/*
+ * I2C multiplexer using GPIO API
+ *
+ * Copyright 2017 NXP
+ *
+ * Peng Fan <peng.fan@nxp.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
+#include <common.h>
+#include <dm.h>
+#include <dm/pinctrl.h>
+#include <fdtdec.h>
+#include <i2c.h>
+#include <linux/errno.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+/**
+ * struct i2c_mux_gpio_priv - private data for i2c mux gpio
+ *
+ * @values: the reg value of each child node
+ * @n_values: num of regs
+ * @gpios: the mux-gpios array
+ * @n_gpios: num of gpios in mux-gpios
+ * @idle: the value of idle-state
+ */
+struct i2c_mux_gpio_priv {
+	u32 *values;
+	int n_values;
+	struct gpio_desc *gpios;
+	int n_gpios;
+	u32 idle;
+};
+
+
+static int i2c_mux_gpio_select(struct udevice *dev, struct udevice *bus,
+			       uint channel)
+{
+	struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
+	int i, ret;
+
+	for (i = 0; i < priv->n_gpios; i++) {
+		ret = dm_gpio_set_value(&priv->gpios[i], (channel >> i) & 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int i2c_mux_gpio_deselect(struct udevice *dev, struct udevice *bus,
+				 uint channel)
+{
+	struct i2c_mux_gpio_priv *priv = dev_get_priv(dev);
+	int i, ret;
+
+	for (i = 0; i < priv->n_gpios; i++) {
+		ret = dm_gpio_set_value(&priv->gpios[i], (priv->idle >> i) & 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int i2c_mux_gpio_probe(struct udevice *dev)
+{
+	const void *fdt = gd->fdt_blob;
+	int node = dev_of_offset(dev);
+	struct i2c_mux_gpio_priv *mux = dev_get_priv(dev);
+	struct gpio_desc *gpios;
+	u32 *values;
+	int i = 0, subnode, ret;
+
+	mux->n_values = fdtdec_get_child_count(fdt, node);
+	values = devm_kzalloc(dev, sizeof(*mux->values) * mux->n_values,
+			      GFP_KERNEL);
+	if (!values) {
+		dev_err(dev, "Cannot alloc values array");
+		return -ENOMEM;
+	}
+
+	fdt_for_each_subnode(subnode, fdt, node) {
+		*(values + i) = fdtdec_get_uint(fdt, subnode, "reg", -1);
+		i++;
+	}
+
+	mux->values = values;
+
+	mux->idle = fdtdec_get_uint(fdt, node, "idle-state", -1);
+
+	mux->n_gpios = gpio_get_list_count(dev, "mux-gpios");
+	if (mux->n_gpios < 0) {
+		dev_err(dev, "Missing mux-gpios property\n");
+		return -EINVAL;
+	}
+
+	gpios = devm_kzalloc(dev, sizeof(struct gpio_desc) * mux->n_gpios,
+			     GFP_KERNEL);
+	if (!gpios) {
+		dev_err(dev, "Cannot allocate gpios array\n");
+		return -ENOMEM;
+	}
+
+	ret = gpio_request_list_by_name(dev, "mux-gpios", gpios, mux->n_gpios,
+					GPIOD_IS_OUT_ACTIVE);
+	if (ret <= 0) {
+		dev_err(dev, "Failed to request mux-gpios\n");
+		return ret;
+	}
+
+	mux->gpios = gpios;
+
+	return 0;
+}
+
+static const struct i2c_mux_ops i2c_mux_gpio_ops = {
+	.select = i2c_mux_gpio_select,
+	.deselect = i2c_mux_gpio_deselect,
+};
+
+static const struct udevice_id i2c_mux_gpio_ids[] = {
+	{ .compatible = "i2c-mux-gpio", },
+	{}
+};
+
+U_BOOT_DRIVER(i2c_mux_gpio) = {
+	.name = "i2c_mux_gpio",
+	.id = UCLASS_I2C_MUX,
+	.of_match = i2c_mux_gpio_ids,
+	.ops = &i2c_mux_gpio_ops,
+	.probe = i2c_mux_gpio_probe,
+	.priv_auto_alloc_size = sizeof(struct i2c_mux_gpio_priv),
+};

drivers/i2c/stm32f7_i2c.c

@@ -0,0 +1,882 @@
+/*
+ * (C) Copyright 2017 STMicroelectronics
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <reset.h>
+
+#include <dm/device.h>
+#include <linux/io.h>
+
+/* STM32 I2C registers */
+struct stm32_i2c_regs {
+	u32 cr1;	/* I2C control register 1 */
+	u32 cr2;	/* I2C control register 2 */
+	u32 oar1;	/* I2C own address 1 register */
+	u32 oar2;	/* I2C own address 2 register */
+	u32 timingr;	/* I2C timing register */
+	u32 timeoutr;	/* I2C timeout register */
+	u32 isr;	/* I2C interrupt and status register */
+	u32 icr;	/* I2C interrupt clear register */
+	u32 pecr;	/* I2C packet error checking register */
+	u32 rxdr;	/* I2C receive data register */
+	u32 txdr;	/* I2C transmit data register */
+};
+
+#define STM32_I2C_CR1				0x00
+#define STM32_I2C_CR2				0x04
+#define STM32_I2C_TIMINGR			0x10
+#define STM32_I2C_ISR				0x18
+#define STM32_I2C_ICR				0x1C
+#define STM32_I2C_RXDR				0x24
+#define STM32_I2C_TXDR				0x28
+
+/* STM32 I2C control 1 */
+#define STM32_I2C_CR1_ANFOFF			BIT(12)
+#define STM32_I2C_CR1_ERRIE			BIT(7)
+#define STM32_I2C_CR1_TCIE			BIT(6)
+#define STM32_I2C_CR1_STOPIE			BIT(5)
+#define STM32_I2C_CR1_NACKIE			BIT(4)
+#define STM32_I2C_CR1_ADDRIE			BIT(3)
+#define STM32_I2C_CR1_RXIE			BIT(2)
+#define STM32_I2C_CR1_TXIE			BIT(1)
+#define STM32_I2C_CR1_PE			BIT(0)
+
+/* STM32 I2C control 2 */
+#define STM32_I2C_CR2_AUTOEND			BIT(25)
+#define STM32_I2C_CR2_RELOAD			BIT(24)
+#define STM32_I2C_CR2_NBYTES_MASK		GENMASK(23, 16)
+#define STM32_I2C_CR2_NBYTES(n)			((n & 0xff) << 16)
+#define STM32_I2C_CR2_NACK			BIT(15)
+#define STM32_I2C_CR2_STOP			BIT(14)
+#define STM32_I2C_CR2_START			BIT(13)
+#define STM32_I2C_CR2_HEAD10R			BIT(12)
+#define STM32_I2C_CR2_ADD10			BIT(11)
+#define STM32_I2C_CR2_RD_WRN			BIT(10)
+#define STM32_I2C_CR2_SADD10_MASK		GENMASK(9, 0)
+#define STM32_I2C_CR2_SADD10(n)			((n & STM32_I2C_CR2_SADD10_MASK))
+#define STM32_I2C_CR2_SADD7_MASK		GENMASK(7, 1)
+#define STM32_I2C_CR2_SADD7(n)			((n & 0x7f) << 1)
+#define STM32_I2C_CR2_RESET_MASK		(STM32_I2C_CR2_HEAD10R \
+						| STM32_I2C_CR2_NBYTES_MASK \
+						| STM32_I2C_CR2_SADD7_MASK \
+						| STM32_I2C_CR2_RELOAD \
+						| STM32_I2C_CR2_RD_WRN)
+
+/* STM32 I2C Interrupt Status */
+#define STM32_I2C_ISR_BUSY			BIT(15)
+#define STM32_I2C_ISR_ARLO			BIT(9)
+#define STM32_I2C_ISR_BERR			BIT(8)
+#define STM32_I2C_ISR_TCR			BIT(7)
+#define STM32_I2C_ISR_TC			BIT(6)
+#define STM32_I2C_ISR_STOPF			BIT(5)
+#define STM32_I2C_ISR_NACKF			BIT(4)
+#define STM32_I2C_ISR_ADDR			BIT(3)
+#define STM32_I2C_ISR_RXNE			BIT(2)
+#define STM32_I2C_ISR_TXIS			BIT(1)
+#define STM32_I2C_ISR_TXE			BIT(0)
+#define STM32_I2C_ISR_ERRORS			(STM32_I2C_ISR_BERR \
+						| STM32_I2C_ISR_ARLO)
+
+/* STM32 I2C Interrupt Clear */
+#define STM32_I2C_ICR_ARLOCF			BIT(9)
+#define STM32_I2C_ICR_BERRCF			BIT(8)
+#define STM32_I2C_ICR_STOPCF			BIT(5)
+#define STM32_I2C_ICR_NACKCF			BIT(4)
+
+/* STM32 I2C Timing */
+#define STM32_I2C_TIMINGR_PRESC(n)		((n & 0xf) << 28)
+#define STM32_I2C_TIMINGR_SCLDEL(n)		((n & 0xf) << 20)
+#define STM32_I2C_TIMINGR_SDADEL(n)		((n & 0xf) << 16)
+#define STM32_I2C_TIMINGR_SCLH(n)		((n & 0xff) << 8)
+#define STM32_I2C_TIMINGR_SCLL(n)		(n & 0xff)
+
+#define STM32_I2C_MAX_LEN			0xff
+
+#define STM32_I2C_DNF_DEFAULT			0
+#define STM32_I2C_DNF_MAX			16
+
+#define STM32_I2C_ANALOG_FILTER_ENABLE	1
+#define STM32_I2C_ANALOG_FILTER_DELAY_MIN	50	/* ns */
+#define STM32_I2C_ANALOG_FILTER_DELAY_MAX	260	/* ns */
+
+#define STM32_I2C_RISE_TIME_DEFAULT		25	/* ns */
+#define STM32_I2C_FALL_TIME_DEFAULT		10	/* ns */
+
+#define STM32_PRESC_MAX				BIT(4)
+#define STM32_SCLDEL_MAX			BIT(4)
+#define STM32_SDADEL_MAX			BIT(4)
+#define STM32_SCLH_MAX				BIT(8)
+#define STM32_SCLL_MAX				BIT(8)
+
+#define STM32_NSEC_PER_SEC			1000000000L
+
+#define STANDARD_RATE				100000
+#define FAST_RATE				400000
+#define FAST_PLUS_RATE				1000000
+
+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,
+};
+
+/**
+ * struct stm32_i2c_spec - private i2c specification timing
+ * @rate: I2C bus speed (Hz)
+ * @rate_min: 80% of I2C bus speed (Hz)
+ * @rate_max: 120% 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 stm32_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 stm32_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 stm32_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 stm32_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 stm32_i2c_timings {
+	struct list_head node;
+	u8 presc;
+	u8 scldel;
+	u8 sdadel;
+	u8 sclh;
+	u8 scll;
+};
+
+struct stm32_i2c_priv {
+	struct stm32_i2c_regs *regs;
+	struct clk clk;
+	struct stm32_i2c_setup *setup;
+	int speed;
+};
+
+static struct stm32_i2c_spec i2c_specs[] = {
+	[STM32_I2C_SPEED_STANDARD] = {
+		.rate = STANDARD_RATE,
+		.rate_min = 8000,
+		.rate_max = 120000,
+		.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 = FAST_RATE,
+		.rate_min = 320000,
+		.rate_max = 480000,
+		.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 = FAST_PLUS_RATE,
+		.rate_min = 800000,
+		.rate_max = 1200000,
+		.fall_max = 100,
+		.rise_max = 120,
+		.hddat_min = 0,
+		.vddat_max = 450,
+		.sudat_min = 50,
+		.l_min = 500,
+		.h_min = 260,
+	},
+};
+
+static struct stm32_i2c_setup stm32f7_setup = {
+	.rise_time = STM32_I2C_RISE_TIME_DEFAULT,
+	.fall_time = STM32_I2C_FALL_TIME_DEFAULT,
+	.dnf = STM32_I2C_DNF_DEFAULT,
+	.analog_filter = STM32_I2C_ANALOG_FILTER_ENABLE,
+};
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static int stm32_i2c_check_device_busy(struct stm32_i2c_priv *i2c_priv)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 status = readl(&regs->isr);
+
+	if (status & STM32_I2C_ISR_BUSY)
+		return -EBUSY;
+
+	return 0;
+}
+
+static void stm32_i2c_message_start(struct stm32_i2c_priv *i2c_priv,
+				      struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 cr2 = readl(&regs->cr2);
+
+	/* Set transfer direction */
+	cr2 &= ~STM32_I2C_CR2_RD_WRN;
+	if (msg->flags & I2C_M_RD)
+		cr2 |= STM32_I2C_CR2_RD_WRN;
+
+	/* Set slave address */
+	cr2 &= ~(STM32_I2C_CR2_HEAD10R | STM32_I2C_CR2_ADD10);
+	if (msg->flags & I2C_M_TEN) {
+		cr2 &= ~STM32_I2C_CR2_SADD10_MASK;
+		cr2 |= STM32_I2C_CR2_SADD10(msg->addr);
+		cr2 |= STM32_I2C_CR2_ADD10;
+	} else {
+		cr2 &= ~STM32_I2C_CR2_SADD7_MASK;
+		cr2 |= STM32_I2C_CR2_SADD7(msg->addr);
+	}
+
+	/* Set nb bytes to transfer and reload or autoend bits */
+	cr2 &= ~(STM32_I2C_CR2_NBYTES_MASK | STM32_I2C_CR2_RELOAD |
+		 STM32_I2C_CR2_AUTOEND);
+	if (msg->len > STM32_I2C_MAX_LEN) {
+		cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
+		cr2 |= STM32_I2C_CR2_RELOAD;
+	} else {
+		cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
+	}
+
+	/* Write configurations register */
+	writel(cr2, &regs->cr2);
+
+	/* START/ReSTART generation */
+	setbits_le32(&regs->cr2, STM32_I2C_CR2_START);
+}
+
+/*
+ * RELOAD mode must be selected if total number of data bytes to be
+ * sent is greater than MAX_LEN
+ */
+
+static void stm32_i2c_handle_reload(struct stm32_i2c_priv *i2c_priv,
+				      struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 cr2 = readl(&regs->cr2);
+
+	cr2 &= ~STM32_I2C_CR2_NBYTES_MASK;
+
+	if (msg->len > STM32_I2C_MAX_LEN) {
+		cr2 |= STM32_I2C_CR2_NBYTES(STM32_I2C_MAX_LEN);
+	} else {
+		cr2 &= ~STM32_I2C_CR2_RELOAD;
+		cr2 |= STM32_I2C_CR2_NBYTES(msg->len);
+	}
+
+	writel(cr2, &regs->cr2);
+}
+
+static int stm32_i2c_wait_flags(struct stm32_i2c_priv *i2c_priv,
+				  u32 flags, u32 *status)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 time_start = get_timer(0);
+
+	*status = readl(&regs->isr);
+	while (!(*status & flags)) {
+		if (get_timer(time_start) > CONFIG_SYS_HZ) {
+			debug("%s: i2c timeout\n", __func__);
+			return -ETIMEDOUT;
+		}
+
+		*status = readl(&regs->isr);
+	}
+
+	return 0;
+}
+
+static int stm32_i2c_check_end_of_message(struct stm32_i2c_priv *i2c_priv)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 mask = STM32_I2C_ISR_ERRORS | STM32_I2C_ISR_NACKF |
+		   STM32_I2C_ISR_STOPF;
+	u32 status;
+	int ret;
+
+	ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+	if (ret)
+		return ret;
+
+	if (status & STM32_I2C_ISR_BERR) {
+		debug("%s: Bus error\n", __func__);
+
+		/* Clear BERR flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_BERRCF);
+
+		return -EIO;
+	}
+
+	if (status & STM32_I2C_ISR_ARLO) {
+		debug("%s: Arbitration lost\n", __func__);
+
+		/* Clear ARLO flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_ARLOCF);
+
+		return -EAGAIN;
+	}
+
+	if (status & STM32_I2C_ISR_NACKF) {
+		debug("%s: Receive NACK\n", __func__);
+
+		/* Clear NACK flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_NACKCF);
+
+		/* Wait until STOPF flag is set */
+		mask = STM32_I2C_ISR_STOPF;
+		ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+		if (ret)
+			return ret;
+
+		ret = -EIO;
+	}
+
+	if (status & STM32_I2C_ISR_STOPF) {
+		/* Clear STOP flag */
+		setbits_le32(&regs->icr, STM32_I2C_ICR_STOPCF);
+
+		/* Clear control register 2 */
+		setbits_le32(&regs->cr2, STM32_I2C_CR2_RESET_MASK);
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_message_xfer(struct stm32_i2c_priv *i2c_priv,
+				    struct i2c_msg *msg, bool stop)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	u32 status;
+	u32 mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
+		   STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
+	int bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
+			  STM32_I2C_MAX_LEN : msg->len;
+	int ret = 0;
+
+	/* Add errors */
+	mask |= STM32_I2C_ISR_ERRORS;
+
+	stm32_i2c_message_start(i2c_priv, msg, stop);
+
+	while (msg->len) {
+		/*
+		 * Wait until TXIS/NACKF/BERR/ARLO flags or
+		 * RXNE/BERR/ARLO flags are set
+		 */
+		ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+		if (ret)
+			break;
+
+		if (status & (STM32_I2C_ISR_NACKF | STM32_I2C_ISR_ERRORS))
+			break;
+
+		if (status & STM32_I2C_ISR_RXNE) {
+			*msg->buf++ = readb(&regs->rxdr);
+			msg->len--;
+			bytes_to_rw--;
+		}
+
+		if (status & STM32_I2C_ISR_TXIS) {
+			writeb(*msg->buf++, &regs->txdr);
+			msg->len--;
+			bytes_to_rw--;
+		}
+
+		if (!bytes_to_rw && msg->len) {
+			/* Wait until TCR flag is set */
+			mask = STM32_I2C_ISR_TCR;
+			ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+			if (ret)
+				break;
+
+			bytes_to_rw = msg->len > STM32_I2C_MAX_LEN ?
+				      STM32_I2C_MAX_LEN : msg->len;
+			mask = msg->flags & I2C_M_RD ? STM32_I2C_ISR_RXNE :
+			       STM32_I2C_ISR_TXIS | STM32_I2C_ISR_NACKF;
+
+			stm32_i2c_handle_reload(i2c_priv, msg, stop);
+		} else if (!bytes_to_rw) {
+			/* Wait until TC flag is set */
+			mask = STM32_I2C_ISR_TC;
+			ret = stm32_i2c_wait_flags(i2c_priv, mask, &status);
+			if (ret)
+				break;
+
+			if (!stop)
+				/* Message sent, new message has to be sent */
+				return 0;
+		}
+	}
+
+	/* End of transfer, send stop condition */
+	mask = STM32_I2C_CR2_STOP;
+	setbits_le32(&regs->cr2, mask);
+
+	return stm32_i2c_check_end_of_message(i2c_priv);
+}
+
+static int stm32_i2c_xfer(struct udevice *bus, struct i2c_msg *msg,
+			    int nmsgs)
+{
+	struct stm32_i2c_priv *i2c_priv = dev_get_priv(bus);
+	int ret;
+
+	ret = stm32_i2c_check_device_busy(i2c_priv);
+	if (ret)
+		return ret;
+
+	for (; nmsgs > 0; nmsgs--, msg++) {
+		ret = stm32_i2c_message_xfer(i2c_priv, msg, nmsgs == 1);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int stm32_i2c_compute_solutions(struct stm32_i2c_setup *setup,
+				       struct list_head *solutions)
+{
+	struct stm32_i2c_timings *v;
+	u32 p_prev = STM32_PRESC_MAX;
+	u32 i2cclk = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
+				       setup->clock_src);
+	u32 af_delay_min, af_delay_max;
+	u16 p, l, a;
+	int sdadel_min, sdadel_max, scldel_min;
+	int ret = 0;
+
+	af_delay_min = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
+	af_delay_max = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MAX : 0;
+
+	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;
+
+	debug("%s: SDADEL(min/max): %i/%i, SCLDEL(Min): %i\n", __func__,
+	      sdadel_min, sdadel_max, scldel_min);
+
+	/* Compute possible values for PRESC, SCLDEL and SDADEL */
+	for (p = 0; p < STM32_PRESC_MAX; p++) {
+		for (l = 0; l < STM32_SCLDEL_MAX; l++) {
+			u32 scldel = (l + 1) * (p + 1) * i2cclk;
+
+			if (scldel < scldel_min)
+				continue;
+
+			for (a = 0; a < STM32_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)
+						return -ENOMEM;
+
+					v->presc = p;
+					v->scldel = l;
+					v->sdadel = a;
+					p_prev = p;
+
+					list_add_tail(&v->node, solutions);
+				}
+			}
+		}
+	}
+
+	if (list_empty(solutions)) {
+		error("%s: no Prescaler solution\n", __func__);
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_choose_solution(struct stm32_i2c_setup *setup,
+				     struct list_head *solutions,
+				     struct stm32_i2c_timings *s)
+{
+	struct stm32_i2c_timings *v;
+	u32 i2cbus = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
+				       setup->speed_freq);
+	u32 clk_error_prev = i2cbus;
+	u32 i2cclk = DIV_ROUND_CLOSEST(STM32_NSEC_PER_SEC,
+				       setup->clock_src);
+	u32 clk_min, clk_max;
+	u32 af_delay_min;
+	u32 dnf_delay;
+	u32 tsync;
+	u16 l, h;
+	int ret = 0;
+
+	af_delay_min = setup->analog_filter ?
+		       STM32_I2C_ANALOG_FILTER_DELAY_MIN : 0;
+	dnf_delay = setup->dnf * i2cclk;
+
+	tsync = af_delay_min + dnf_delay + (2 * i2cclk);
+	clk_max = STM32_NSEC_PER_SEC / i2c_specs[setup->speed].rate_min;
+	clk_min = STM32_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 Low Period of the SCL Clock
+	 *   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 High Period of the SCL Clock
+	 *   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 < STM32_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 < STM32_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) {
+		error("%s: no solution at all\n", __func__);
+		ret = -EPERM;
+	}
+
+	return ret;
+}
+
+static int stm32_i2c_compute_timing(struct stm32_i2c_priv *i2c_priv,
+				      struct stm32_i2c_setup *setup,
+				      struct stm32_i2c_timings *output)
+{
+	struct stm32_i2c_timings *v, *_v, *s;
+	struct list_head solutions;
+	int ret;
+
+	if (setup->speed >= STM32_I2C_SPEED_END) {
+		error("%s: speed out of bound {%d/%d}\n", __func__,
+		      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)) {
+		error("%s :timings out of bound Rise{%d>%d}/Fall{%d>%d}\n",
+		      __func__,
+		      setup->rise_time, i2c_specs[setup->speed].rise_max,
+		      setup->fall_time, i2c_specs[setup->speed].fall_max);
+		return -EINVAL;
+	}
+
+	if (setup->dnf > STM32_I2C_DNF_MAX) {
+		error("%s: DNF out of bound %d/%d\n", __func__,
+		      setup->dnf, STM32_I2C_DNF_MAX);
+		return -EINVAL;
+	}
+
+	if (setup->speed_freq > i2c_specs[setup->speed].rate) {
+		error("%s: Freq {%d/%d}\n", __func__,
+		      setup->speed_freq, i2c_specs[setup->speed].rate);
+		return -EINVAL;
+	}
+
+	s = NULL;
+	INIT_LIST_HEAD(&solutions);
+	ret = stm32_i2c_compute_solutions(setup, &solutions);
+	if (ret)
+		goto exit;
+
+	ret = stm32_i2c_choose_solution(setup, &solutions, s);
+	if (ret)
+		goto exit;
+
+	output->presc = s->presc;
+	output->scldel = s->scldel;
+	output->sdadel = s->sdadel;
+	output->scll = s->scll;
+	output->sclh = s->sclh;
+
+	debug("%s: Presc: %i, scldel: %i, sdadel: %i, scll: %i, sclh: %i\n",
+	      __func__, 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 stm32_i2c_setup_timing(struct stm32_i2c_priv *i2c_priv,
+				    struct stm32_i2c_timings *timing)
+{
+	struct stm32_i2c_setup *setup = i2c_priv->setup;
+	int ret = 0;
+
+	setup->speed = i2c_priv->speed;
+	setup->speed_freq = i2c_specs[setup->speed].rate;
+	setup->clock_src = clk_get_rate(&i2c_priv->clk);
+
+	if (!setup->clock_src) {
+		error("%s: clock rate is 0\n", __func__);
+		return -EINVAL;
+	}
+
+	do {
+		ret = stm32_i2c_compute_timing(i2c_priv, setup, timing);
+		if (ret) {
+			debug("%s: failed to compute I2C timings.\n",
+			      __func__);
+			if (i2c_priv->speed > STM32_I2C_SPEED_STANDARD) {
+				i2c_priv->speed--;
+				setup->speed = i2c_priv->speed;
+				setup->speed_freq =
+					i2c_specs[setup->speed].rate;
+				debug("%s: downgrade I2C Speed Freq to (%i)\n",
+				      __func__, i2c_specs[setup->speed].rate);
+			} else {
+				break;
+			}
+		}
+	} while (ret);
+
+	if (ret) {
+		error("%s: impossible to compute I2C timings.\n", __func__);
+		return ret;
+	}
+
+	debug("%s: I2C Speed(%i), Freq(%i), Clk Source(%i)\n", __func__,
+	      setup->speed, setup->speed_freq, setup->clock_src);
+	debug("%s: I2C Rise(%i) and Fall(%i) Time\n", __func__,
+	      setup->rise_time, setup->fall_time);
+	debug("%s: I2C Analog Filter(%s), DNF(%i)\n", __func__,
+	      setup->analog_filter ? "On" : "Off", setup->dnf);
+
+	return 0;
+}
+
+static int stm32_i2c_hw_config(struct stm32_i2c_priv *i2c_priv)
+{
+	struct stm32_i2c_regs *regs = i2c_priv->regs;
+	struct stm32_i2c_timings t;
+	int ret;
+	u32 timing = 0;
+
+	ret = stm32_i2c_setup_timing(i2c_priv, &t);
+	if (ret)
+		return ret;
+
+	/* Disable I2C */
+	clrbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
+
+	/* Timing settings */
+	timing |= STM32_I2C_TIMINGR_PRESC(t.presc);
+	timing |= STM32_I2C_TIMINGR_SCLDEL(t.scldel);
+	timing |= STM32_I2C_TIMINGR_SDADEL(t.sdadel);
+	timing |= STM32_I2C_TIMINGR_SCLH(t.sclh);
+	timing |= STM32_I2C_TIMINGR_SCLL(t.scll);
+	writel(timing, &regs->timingr);
+
+	/* Enable I2C */
+	if (i2c_priv->setup->analog_filter)
+		clrbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
+	else
+		setbits_le32(&regs->cr1, STM32_I2C_CR1_ANFOFF);
+	setbits_le32(&regs->cr1, STM32_I2C_CR1_PE);
+
+	return 0;
+}
+
+static int stm32_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+	struct stm32_i2c_priv *i2c_priv = dev_get_priv(bus);
+
+	switch (speed) {
+	case STANDARD_RATE:
+		i2c_priv->speed = STM32_I2C_SPEED_STANDARD;
+		break;
+	case FAST_RATE:
+		i2c_priv->speed = STM32_I2C_SPEED_FAST;
+		break;
+	case FAST_PLUS_RATE:
+		i2c_priv->speed = STM32_I2C_SPEED_FAST_PLUS;
+		break;
+	default:
+		debug("%s: Speed %d not supported\n", __func__, speed);
+		return -EINVAL;
+	}
+
+	return stm32_i2c_hw_config(i2c_priv);
+}
+
+static int stm32_i2c_probe(struct udevice *dev)
+{
+	struct stm32_i2c_priv *i2c_priv = dev_get_priv(dev);
+	struct reset_ctl reset_ctl;
+	fdt_addr_t addr;
+	int ret;
+
+	addr = dev_read_addr(dev);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	i2c_priv->regs = (struct stm32_i2c_regs *)addr;
+
+	ret = clk_get_by_index(dev, 0, &i2c_priv->clk);
+	if (ret)
+		return ret;
+
+	ret = clk_enable(&i2c_priv->clk);
+	if (ret)
+		goto clk_free;
+
+	ret = reset_get_by_index(dev, 0, &reset_ctl);
+	if (ret)
+		goto clk_disable;
+
+	reset_assert(&reset_ctl);
+	udelay(2);
+	reset_deassert(&reset_ctl);
+
+	return 0;
+
+clk_disable:
+	clk_disable(&i2c_priv->clk);
+clk_free:
+	clk_free(&i2c_priv->clk);
+
+	return ret;
+}
+
+static int stm32_ofdata_to_platdata(struct udevice *dev)
+{
+	struct stm32_i2c_priv *i2c_priv = dev_get_priv(dev);
+	u32 rise_time, fall_time;
+
+	i2c_priv->setup = (struct stm32_i2c_setup *)dev_get_driver_data(dev);
+	if (!i2c_priv->setup)
+		return -EINVAL;
+
+	rise_time = dev_read_u32_default(dev, "i2c-scl-rising-time-ns", 0);
+	if (rise_time)
+		i2c_priv->setup->rise_time = rise_time;
+
+	fall_time = dev_read_u32_default(dev, "i2c-scl-falling-time-ns", 0);
+	if (fall_time)
+		i2c_priv->setup->fall_time = fall_time;
+
+	return 0;
+}
+
+static const struct dm_i2c_ops stm32_i2c_ops = {
+	.xfer = stm32_i2c_xfer,
+	.set_bus_speed = stm32_i2c_set_bus_speed,
+};
+
+static const struct udevice_id stm32_i2c_of_match[] = {
+	{ .compatible = "st,stm32f7-i2c", .data = (ulong)&stm32f7_setup },
+	{}
+};
+
+U_BOOT_DRIVER(stm32f7_i2c) = {
+	.name = "stm32f7-i2c",
+	.id = UCLASS_I2C,
+	.of_match = stm32_i2c_of_match,
+	.ofdata_to_platdata = stm32_ofdata_to_platdata,
+	.probe = stm32_i2c_probe,
+	.priv_auto_alloc_size = sizeof(struct stm32_i2c_priv),
+	.ops = &stm32_i2c_ops,
+};