Merge branch 'i2c/for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux

Pull i2c updates from Wolfram Sang:
"I2C has not so much stuff this time. Mostly driver enablement for new
SoCs, some driver bugfixes, and some cleanups"

* 'i2c/for-4.20' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: (35 commits)
MAINTAINERS: add maintainer for Renesas RIIC driver
i2c: sh_mobile: Remove dummy runtime PM callbacks
i2c: uniphier-f: fix race condition when IRQ is cleared
i2c: uniphier-f: fix occasional timeout error
i2c: uniphier-f: make driver robust against concurrency
i2c: i2c-qcom-geni: Simplify irq handler
i2c: i2c-qcom-geni: Simplify tx/rx functions
i2c: designware: Set IRQF_NO_SUSPEND flag for all BYT and CHT controllers
i2c: mux: mlxcpld: simplify code to reach the adapter
i2c: mux: ltc4306: simplify code to reach the adapter
i2c: mux: pca954x: simplify code to reach the adapter
i2c: core: remove level of indentation in i2c_transfer
i2c: core: remove outdated DEBUG output
i2c: zx2967: use core to detect 'no zero length' quirk
i2c: tegra: use core to detect 'no zero length' quirk
i2c: qup: use core to detect 'no zero length' quirk
i2c: omap: use core to detect 'no zero length' quirk
i2c: Convert to using %pOFn instead of device_node.name
i2c: brcmstb: Allow enabling the driver on DSL SoCs
eeprom: at24: fix unexpected timeout under high load
...

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

···
 Required properties :
 
  - compatible : should be "snps,designware-i2c"
+                or "mscc,ocelot-i2c" with "snps,designware-i2c" for fallback
  - reg : Offset and length of the register set for the device
  - interrupts : <IRQ> where IRQ is the interrupt number.
 
···
  - clock-frequency : desired I2C bus clock frequency in Hz.
 
 Optional properties :
+ - reg : for "mscc,ocelot-i2c", a second register set to configure the SDA hold
+   time, named ICPU_CFG:TWI_DELAY in the datasheet.
+
  - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds.
-   This option is only supported in hardware blocks version 1.11a or newer.
+   This option is only supported in hardware blocks version 1.11a or newer and
+   on Microsemi SoCs ("mscc,ocelot-i2c" compatible).
 
  - i2c-scl-falling-time-ns : should contain the SCL falling time in nanoseconds.
    This value which is by default 300ns is used to compute the tLOW period.

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

···
 Required properties:
 - compatible:
 	"renesas,i2c-r8a7743" if the device is a part of a R8A7743 SoC.
+	"renesas,i2c-r8a7744" if the device is a part of a R8A7744 SoC.
 	"renesas,i2c-r8a7745" if the device is a part of a R8A7745 SoC.
+	"renesas,i2c-r8a77470" if the device is a part of a R8A77470 SoC.
 	"renesas,i2c-r8a774a1" if the device is a part of a R8A774A1 SoC.
 	"renesas,i2c-r8a7778" if the device is a part of a R8A7778 SoC.
 	"renesas,i2c-r8a7779" if the device is a part of a R8A7779 SoC.

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

···
 			- "renesas,iic-r8a73a4" (R-Mobile APE6)
 			- "renesas,iic-r8a7740" (R-Mobile A1)
 			- "renesas,iic-r8a7743" (RZ/G1M)
+			- "renesas,iic-r8a7744" (RZ/G1N)
 			- "renesas,iic-r8a7745" (RZ/G1E)
 			- "renesas,iic-r8a774a1" (RZ/G2M)
 			- "renesas,iic-r8a7790" (R-Car H2)

MAINTAINERS

···
 F:	drivers/i2c/busses/i2c-rcar.c
 F:	drivers/i2c/busses/i2c-sh_mobile.c
 
+RENESAS RIIC DRIVER
+M:	Chris Brandt <[e-mail]>
+S:	Supported
+F:	Documentation/devicetree/bindings/i2c/i2c-riic.txt
+F:	drivers/i2c/busses/i2c-riic.c
+
 RENESAS USB PHY DRIVER
 M:	Yoshihiro Shimoda <[e-mail]>
 L:	[e-mail]

drivers/i2c/busses/Kconfig

···
 	  If you do not need KONA I2C interface, say N.
 
 config I2C_BRCMSTB
-	tristate "BRCM Settop I2C controller"
-	depends on ARCH_BRCMSTB || BMIPS_GENERIC || COMPILE_TEST
+	tristate "BRCM Settop/DSL I2C controller"
+	depends on ARCH_BRCMSTB || BMIPS_GENERIC || ARCH_BCM_63XX || \
+		   COMPILE_TEST
 	default y
 	help
 	  If you say yes to this option, support will be included for the
-	  I2C interface on the Broadcom Settop SoCs.
+	  I2C interface on the Broadcom Settop/DSL SoCs.
 
 	  If you do not need I2C interface, say N.
 

drivers/i2c/busses/i2c-aspeed.c

···
 #define ASPEED_I2CD_INTR_RX_DONE			BIT(2)
 #define ASPEED_I2CD_INTR_TX_NAK				BIT(1)
 #define ASPEED_I2CD_INTR_TX_ACK				BIT(0)
+#define ASPEED_I2CD_INTR_MASTER_ERRORS					       \
+		(ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |			       \
+		 ASPEED_I2CD_INTR_SCL_TIMEOUT |				       \
+		 ASPEED_I2CD_INTR_ABNORMAL |				       \
+		 ASPEED_I2CD_INTR_ARBIT_LOSS)
 #define ASPEED_I2CD_INTR_ALL						       \
 		(ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |			       \
 		 ASPEED_I2CD_INTR_BUS_RECOVER_DONE |			       \
···
 	/* Synchronizes I/O mem access to base. */
 	spinlock_t			lock;
 	struct completion		cmd_complete;
-	u32				(*get_clk_reg_val)(u32 divisor);
+	u32				(*get_clk_reg_val)(struct device *dev,
+							   u32 divisor);
 	unsigned long			parent_clk_frequency;
 	u32				bus_frequency;
 	/* Transaction state. */
···
 }
 
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
-static bool aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus)
+static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 {
-	u32 command, irq_status, status_ack = 0;
+	u32 command, irq_handled = 0;
 	struct i2c_client *slave = bus->slave;
-	bool irq_handled = true;
 	u8 value;
 
-	if (!slave) {
-		irq_handled = false;
-		goto out;
-	}
+	if (!slave)
+		return 0;
 
 	command = readl(bus->base + ASPEED_I2C_CMD_REG);
-	irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
 
 	/* Slave was requested, restart state machine. */
 	if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
-		status_ack |= ASPEED_I2CD_INTR_SLAVE_MATCH;
+		irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
 		bus->slave_state = ASPEED_I2C_SLAVE_START;
 	}
 
 	/* Slave is not currently active, irq was for someone else. */
-	if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
-		irq_handled = false;
-		goto out;
-	}
+	if (bus->slave_state == ASPEED_I2C_SLAVE_STOP)
+		return irq_handled;
 
 	dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
 		irq_status, command);
···
 				bus->slave_state =
 						ASPEED_I2C_SLAVE_WRITE_REQUESTED;
 		}
-		status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+		irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
 	}
 
 	/* Slave was asked to stop. */
 	if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
-		status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+		irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
 		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
 	}
 	if (irq_status & ASPEED_I2CD_INTR_TX_NAK) {
-		status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+		irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 		bus->slave_state = ASPEED_I2C_SLAVE_STOP;
 	}
+	if (irq_status & ASPEED_I2CD_INTR_TX_ACK)
+		irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
 
 	switch (bus->slave_state) {
 	case ASPEED_I2C_SLAVE_READ_REQUESTED:
 		if (irq_status & ASPEED_I2CD_INTR_TX_ACK)
 			dev_err(bus->dev, "Unexpected ACK on read request.\n");
 		bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;
-
 		i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
 		writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
 		writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
 		break;
 	case ASPEED_I2C_SLAVE_READ_PROCESSED:
-		status_ack |= ASPEED_I2CD_INTR_TX_ACK;
 		if (!(irq_status & ASPEED_I2CD_INTR_TX_ACK))
 			dev_err(bus->dev,
 				"Expected ACK after processed read.\n");
···
 		break;
 	}
 
-	if (status_ack != irq_status)
-		dev_err(bus->dev,
-			"irq handled != irq. expected %x, but was %x\n",
-			irq_status, status_ack);
-	writel(status_ack, bus->base + ASPEED_I2C_INTR_STS_REG);
-
-out:
 	return irq_handled;
 }
 #endif /* CONFIG_I2C_SLAVE */
···
 	return 0;
 }
 
-static bool aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus)
+static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 {
-	u32 irq_status, status_ack = 0, command = 0;
+	u32 irq_handled = 0, command = 0;
 	struct i2c_msg *msg;
 	u8 recv_byte;
 	int ret;
 
-	irq_status = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
-	/* Ack all interrupt bits. */
-	writel(irq_status, bus->base + ASPEED_I2C_INTR_STS_REG);
-
 	if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
 		bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
-		status_ack |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
+		irq_handled |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
 		goto out_complete;
+	} else {
+		/* Master is not currently active, irq was for someone else. */
+		if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE)
+			goto out_no_complete;
 	}
 
 	/*
···
 	 * INACTIVE state.
 	 */
 	ret = aspeed_i2c_is_irq_error(irq_status);
-	if (ret < 0) {
+	if (ret) {
 		dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
 			irq_status);
 		bus->cmd_err = ret;
 		bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+		irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
 		goto out_complete;
 	}
 
 	/* We are in an invalid state; reset bus to a known state. */
 	if (!bus->msgs) {
-		dev_err(bus->dev, "bus in unknown state\n");
+		dev_err(bus->dev, "bus in unknown state. irq_status: 0x%x\n",
+			irq_status);
 		bus->cmd_err = -EIO;
-		if (bus->master_state != ASPEED_I2C_MASTER_STOP)
+		if (bus->master_state != ASPEED_I2C_MASTER_STOP &&
+		    bus->master_state != ASPEED_I2C_MASTER_INACTIVE)
 			aspeed_i2c_do_stop(bus);
 		goto out_no_complete;
 	}
···
 	 */
 	if (bus->master_state == ASPEED_I2C_MASTER_START) {
 		if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
+			if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_NAK))) {
+				bus->cmd_err = -ENXIO;
+				bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
+				goto out_complete;
+			}
 			pr_devel("no slave present at %02x\n", msg->addr);
-			status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+			irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 			bus->cmd_err = -ENXIO;
 			aspeed_i2c_do_stop(bus);
 			goto out_no_complete;
 		}
-		status_ack |= ASPEED_I2CD_INTR_TX_ACK;
+		irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
 		if (msg->len == 0) { /* SMBUS_QUICK */
 			aspeed_i2c_do_stop(bus);
 			goto out_no_complete;
···
 	case ASPEED_I2C_MASTER_TX:
 		if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
 			dev_dbg(bus->dev, "slave NACKed TX\n");
-			status_ack |= ASPEED_I2CD_INTR_TX_NAK;
+			irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 			goto error_and_stop;
 		} else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
 			dev_err(bus->dev, "slave failed to ACK TX\n");
 			goto error_and_stop;
 		}
-		status_ack |= ASPEED_I2CD_INTR_TX_ACK;
-		/* fallthrough intended */
+		irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
+		/* fall through */
 	case ASPEED_I2C_MASTER_TX_FIRST:
 		if (bus->buf_index < msg->len) {
 			bus->master_state = ASPEED_I2C_MASTER_TX;
···
 		/* RX may not have completed yet (only address cycle) */
 		if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
 			goto out_no_complete;
-		/* fallthrough intended */
+		/* fall through */
 	case ASPEED_I2C_MASTER_RX:
 		if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
 			dev_err(bus->dev, "master failed to RX\n");
 			goto error_and_stop;
 		}
-		status_ack |= ASPEED_I2CD_INTR_RX_DONE;
+		irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
 
 		recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
 		msg->buf[bus->buf_index++] = recv_byte;
···
 		goto out_no_complete;
 	case ASPEED_I2C_MASTER_STOP:
 		if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) {
-			dev_err(bus->dev, "master failed to STOP\n");
+			dev_err(bus->dev,
+				"master failed to STOP. irq_status:0x%x\n",
+				irq_status);
 			bus->cmd_err = -EIO;
 			/* Do not STOP as we have already tried. */
 		} else {
-			status_ack |= ASPEED_I2CD_INTR_NORMAL_STOP;
+			irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
 		}
 
 		bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
···
 		bus->master_xfer_result = bus->msgs_index + 1;
 	complete(&bus->cmd_complete);
 out_no_complete:
-	if (irq_status != status_ack)
-		dev_err(bus->dev,
-			"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
-			irq_status, status_ack);
-	return !!irq_status;
+	return irq_handled;
 }
 
 static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
 {
 	struct aspeed_i2c_bus *bus = dev_id;
-	bool ret;
+	u32 irq_received, irq_remaining, irq_handled;
 
 	spin_lock(&bus->lock);
+	irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
+	/* Ack all interrupts except for Rx done */
+	writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
+	       bus->base + ASPEED_I2C_INTR_STS_REG);
+	irq_remaining = irq_received;
 
 #if IS_ENABLED(CONFIG_I2C_SLAVE)
-	if (aspeed_i2c_slave_irq(bus)) {
-		dev_dbg(bus->dev, "irq handled by slave.\n");
-		ret = true;
-		goto out;
+	/*
+	 * In most cases, interrupt bits will be set one by one, although
+	 * multiple interrupt bits could be set at the same time. It's also
+	 * possible that master interrupt bits could be set along with slave
+	 * interrupt bits. Each case needs to be handled using corresponding
+	 * handlers depending on the current state.
+	 */
+	if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
+		irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
+		irq_remaining &= ~irq_handled;
+		if (irq_remaining)
+			irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);
+	} else {
+		irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);
+		irq_remaining &= ~irq_handled;
+		if (irq_remaining)
+			irq_handled |= aspeed_i2c_master_irq(bus,
+							     irq_remaining);
 	}
+#else
+	irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
 #endif /* CONFIG_I2C_SLAVE */
 
-	ret = aspeed_i2c_master_irq(bus);
+	irq_remaining &= ~irq_handled;
+	if (irq_remaining)
+		dev_err(bus->dev,
+			"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
+			irq_received, irq_handled);
 
-out:
+	/* Ack Rx done */
+	if (irq_received & ASPEED_I2CD_INTR_RX_DONE)
+		writel(ASPEED_I2CD_INTR_RX_DONE,
+		       bus->base + ASPEED_I2C_INTR_STS_REG);
 	spin_unlock(&bus->lock);
-	return ret ? IRQ_HANDLED : IRQ_NONE;
+	return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
 }
 
 static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
···
 #endif /* CONFIG_I2C_SLAVE */
 };
 
-static u32 aspeed_i2c_get_clk_reg_val(u32 clk_high_low_max, u32 divisor)
+static u32 aspeed_i2c_get_clk_reg_val(struct device *dev,
+				      u32 clk_high_low_mask,
+				      u32 divisor)
 {
-	u32 base_clk, clk_high, clk_low, tmp;
+	u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp;
+
+	/*
+	 * SCL_high and SCL_low represent a value 1 greater than what is stored
+	 * since a zero divider is meaningless. Thus, the max value each can
+	 * store is every bit set + 1. Since SCL_high and SCL_low are added
+	 * together (see below), the max value of both is the max value of one
+	 * them times two.
+	 */
+	clk_high_low_max = (clk_high_low_mask + 1) * 2;
 
 	/*
 	 * The actual clock frequency of SCL is:
 	 *	SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low))
 	 *		 = APB_freq / divisor
 	 * where base_freq is a programmable clock divider; its value is
-	 *	base_freq = 1 << base_clk
+	 *	base_freq = 1 << base_clk_divisor
 	 * SCL_high is the number of base_freq clock cycles that SCL stays high
 	 * and SCL_low is the number of base_freq clock cycles that SCL stays
 	 * low for a period of SCL.
···
 	 *	SCL_low	 = clk_low + 1
 	 * Thus,
 	 *	SCL_freq = APB_freq /
-	 *		((1 << base_clk) * (clk_high + 1 + clk_low + 1))
+	 *		((1 << base_clk_divisor) * (clk_high + 1 + clk_low + 1))
 	 * The documentation recommends clk_high >= clk_high_max / 2 and
 	 * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint
 	 * gives us the following solution:
 	 */
-	base_clk = divisor > clk_high_low_max ?
+	base_clk_divisor = divisor > clk_high_low_max ?
 			ilog2((divisor - 1) / clk_high_low_max) + 1 : 0;
-	tmp = (divisor + (1 << base_clk) - 1) >> base_clk;
-	clk_low = tmp / 2;
-	clk_high = tmp - clk_low;
 
-	if (clk_high)
-		clk_high--;
+	if (base_clk_divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) {
+		base_clk_divisor = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK;
+		clk_low = clk_high_low_mask;
+		clk_high = clk_high_low_mask;
+		dev_err(dev,
+			"clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n",
+			divisor, (1 << base_clk_divisor) * clk_high_low_max);
+	} else {
+		tmp = (divisor + (1 << base_clk_divisor) - 1)
+				>> base_clk_divisor;
+		clk_low = tmp / 2;
+		clk_high = tmp - clk_low;
 
-	if (clk_low)
-		clk_low--;
+		if (clk_high)
+			clk_high--;
+
+		if (clk_low)
+			clk_low--;
+	}
 
 
 	return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
 		& ASPEED_I2CD_TIME_SCL_HIGH_MASK)
 			| ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
 			   & ASPEED_I2CD_TIME_SCL_LOW_MASK)
-			| (base_clk & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
+			| (base_clk_divisor
+			   & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
 }
 
-static u32 aspeed_i2c_24xx_get_clk_reg_val(u32 divisor)
+static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor)
 {
 	/*
 	 * clk_high and clk_low are each 3 bits wide, so each can hold a max
 	 * value of 8 giving a clk_high_low_max of 16.
 	 */
-	return aspeed_i2c_get_clk_reg_val(16, divisor);
+	return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor);
 }
 
-static u32 aspeed_i2c_25xx_get_clk_reg_val(u32 divisor)
+static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor)
 {
 	/*
 	 * clk_high and clk_low are each 4 bits wide, so each can hold a max
 	 * value of 16 giving a clk_high_low_max of 32.
 	 */
-	return aspeed_i2c_get_clk_reg_val(32, divisor);
+	return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor);
 }
 
 /* precondition: bus.lock has been acquired. */
···
 	clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK |
 			ASPEED_I2CD_TIME_THDSTA_MASK |
 			ASPEED_I2CD_TIME_TACST_MASK);
-	clk_reg_val |= bus->get_clk_reg_val(divisor);
+	clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor);
 	writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
 	writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);
 
···
 	if (!match)
 		bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val;
 	else
-		bus->get_clk_reg_val = (u32 (*)(u32))match->data;
+		bus->get_clk_reg_val = (u32 (*)(struct device *, u32))
+				match->data;
 
 	/* Initialize the I2C adapter */
 	spin_lock_init(&bus->lock);

drivers/i2c/busses/i2c-designware-baytrail.c

···
 	dev_info(dev->dev, "I2C bus managed by PUNIT\n");
 	dev->acquire_lock = baytrail_i2c_acquire;
 	dev->release_lock = baytrail_i2c_release;
-	dev->pm_disabled = true;
+	dev->shared_with_punit = true;
 
 	pm_qos_add_request(&dev->pm_qos, PM_QOS_CPU_DMA_LATENCY,
 			   PM_QOS_DEFAULT_VALUE);

drivers/i2c/busses/i2c-designware-common.c

···
 		dev_dbg(dev->dev, "SDA Hold Time TX:RX = %d:%d\n",
 			dev->sda_hold_time & ~(u32)DW_IC_SDA_HOLD_RX_MASK,
 			dev->sda_hold_time >> DW_IC_SDA_HOLD_RX_SHIFT);
+	} else if (dev->set_sda_hold_time) {
+		dev->set_sda_hold_time(dev);
 	} else if (dev->sda_hold_time) {
 		dev_warn(dev->dev,
 			"Hardware too old to adjust SDA hold time.\n");

drivers/i2c/busses/i2c-designware-core.h

···
  * @pm_qos: pm_qos_request used while holding a hardware lock on the bus
  * @acquire_lock: function to acquire a hardware lock on the bus
  * @release_lock: function to release a hardware lock on the bus
- * @pm_disabled: true if power-management should be disabled for this i2c-bus
+ * @shared_with_punit: true if this bus is shared with the SoCs PUNIT
  * @disable: function to disable the controller
  * @disable_int: function to disable all interrupts
  * @init: function to initialize the I2C hardware
···
 struct dw_i2c_dev {
 	struct device		*dev;
 	void __iomem		*base;
+	void __iomem		*ext;
 	struct completion	cmd_complete;
 	struct clk		*clk;
 	struct reset_control	*rst;
···
 	struct pm_qos_request	pm_qos;
 	int			(*acquire_lock)(struct dw_i2c_dev *dev);
 	void			(*release_lock)(struct dw_i2c_dev *dev);
-	bool			pm_disabled;
+	bool			shared_with_punit;
 	void			(*disable)(struct dw_i2c_dev *dev);
 	void			(*disable_int)(struct dw_i2c_dev *dev);
 	int			(*init)(struct dw_i2c_dev *dev);
+	int			(*set_sda_hold_time)(struct dw_i2c_dev *dev);
 	int			mode;
 	struct i2c_bus_recovery_info rinfo;
 };
···
 #define ACCESS_SWAP		0x00000001
 #define ACCESS_16BIT		0x00000002
 #define ACCESS_INTR_MASK	0x00000004
+#define ACCESS_NO_IRQ_SUSPEND	0x00000008
 
 #define MODEL_CHERRYTRAIL	0x00000100
+#define MODEL_MSCC_OCELOT	0x00000200
+#define MODEL_MASK		0x00000f00
 
 u32 dw_readl(struct dw_i2c_dev *dev, int offset);
 void dw_writel(struct dw_i2c_dev *dev, u32 b, int offset);

drivers/i2c/busses/i2c-designware-master.c

···
 	adap->dev.parent = dev->dev;
 	i2c_set_adapdata(adap, dev);
 
-	if (dev->pm_disabled) {
+	if (dev->flags & ACCESS_NO_IRQ_SUSPEND) {
 		irq_flags = IRQF_NO_SUSPEND;
 	} else {
 		irq_flags = IRQF_SHARED | IRQF_COND_SUSPEND;

drivers/i2c/busses/i2c-designware-platdrv.c

···
 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
 	struct i2c_timings *t = &dev->timings;
 	u32 ss_ht = 0, fp_ht = 0, hs_ht = 0, fs_ht = 0;
-	acpi_handle handle = ACPI_HANDLE(&pdev->dev);
-	const struct acpi_device_id *id;
-	struct acpi_device *adev;
-	const char *uid;
 
 	dev->adapter.nr = -1;
 	dev->tx_fifo_depth = 32;
···
 		break;
 	}
 
-	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
-	if (id && id->driver_data)
-		dev->flags |= (u32)id->driver_data;
-
-	if (acpi_bus_get_device(handle, &adev))
-		return -ENODEV;
-
-	/*
-	 * Cherrytrail I2C7 gets used for the PMIC which gets accessed
-	 * through ACPI opregions during late suspend / early resume
-	 * disable pm for it.
-	 */
-	uid = adev->pnp.unique_id;
-	if ((dev->flags & MODEL_CHERRYTRAIL) && !strcmp(uid, "7"))
-		dev->pm_disabled = true;
-
 	return 0;
 }
 
···
 	{ "INT33C3", 0 },
 	{ "INT3432", 0 },
 	{ "INT3433", 0 },
-	{ "80860F41", 0 },
-	{ "808622C1", MODEL_CHERRYTRAIL },
+	{ "80860F41", ACCESS_NO_IRQ_SUSPEND },
+	{ "808622C1", ACCESS_NO_IRQ_SUSPEND | MODEL_CHERRYTRAIL },
 	{ "AMD0010", ACCESS_INTR_MASK },
 	{ "AMDI0010", ACCESS_INTR_MASK },
 	{ "AMDI0510", 0 },
···
 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);
 #else
 static inline int dw_i2c_acpi_configure(struct platform_device *pdev)
+{
+	return -ENODEV;
+}
+#endif
+
+#ifdef CONFIG_OF
+#define MSCC_ICPU_CFG_TWI_DELAY		0x0
+#define MSCC_ICPU_CFG_TWI_DELAY_ENABLE	BIT(0)
+#define MSCC_ICPU_CFG_TWI_SPIKE_FILTER	0x4
+
+static int mscc_twi_set_sda_hold_time(struct dw_i2c_dev *dev)
+{
+	writel((dev->sda_hold_time << 1) | MSCC_ICPU_CFG_TWI_DELAY_ENABLE,
+	       dev->ext + MSCC_ICPU_CFG_TWI_DELAY);
+
+	return 0;
+}
+
+static int dw_i2c_of_configure(struct platform_device *pdev)
+{
+	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+	struct resource *mem;
+
+	switch (dev->flags & MODEL_MASK) {
+	case MODEL_MSCC_OCELOT:
+		mem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+		dev->ext = devm_ioremap_resource(&pdev->dev, mem);
+		if (!IS_ERR(dev->ext))
+			dev->set_sda_hold_time = mscc_twi_set_sda_hold_time;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id dw_i2c_of_match[] = {
+	{ .compatible = "snps,designware-i2c", },
+	{ .compatible = "mscc,ocelot-i2c", .data = (void *)MODEL_MSCC_OCELOT },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
+#else
+static inline int dw_i2c_of_configure(struct platform_device *pdev)
 {
 	return -ENODEV;
 }
···
 {
 	pm_runtime_disable(dev->dev);
 
-	if (dev->pm_disabled)
+	if (dev->shared_with_punit)
 		pm_runtime_put_noidle(dev->dev);
 }
 
···
 	else
 		t->bus_freq_hz = 400000;
 
+	dev->flags |= (uintptr_t)device_get_match_data(&pdev->dev);
+
+	if (pdev->dev.of_node)
+		dw_i2c_of_configure(pdev);
+
 	if (has_acpi_companion(&pdev->dev))
 		dw_i2c_acpi_configure(pdev);
 
···
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
 
-	if (dev->pm_disabled)
+	if (dev->shared_with_punit)
 		pm_runtime_get_noresume(&pdev->dev);
 
 	pm_runtime_enable(&pdev->dev);
···
 	return 0;
 }
 
-#ifdef CONFIG_OF
-static const struct of_device_id dw_i2c_of_match[] = {
-	{ .compatible = "snps,designware-i2c", },
-	{},
-};
-MODULE_DEVICE_TABLE(of, dw_i2c_of_match);
-#endif
-
 #ifdef CONFIG_PM_SLEEP
 static int dw_i2c_plat_prepare(struct device *dev)
 {
···
 {
 	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
 
-	if (i_dev->pm_disabled)
+	if (i_dev->shared_with_punit)
 		return 0;
 
 	i_dev->disable(i_dev);
···
 {
 	struct dw_i2c_dev *i_dev = dev_get_drvdata(dev);
 
-	if (!i_dev->pm_disabled)
+	if (!i_dev->shared_with_punit)
 		i2c_dw_prepare_clk(i_dev, true);
 
 	i_dev->init(i_dev);

drivers/i2c/busses/i2c-mt65xx.c

···
 	u16 control_reg;
 	u16 restart_flag = 0;
 	u32 reg_4g_mode;
+	u8 *dma_rd_buf = NULL;
+	u8 *dma_wr_buf = NULL;
 	dma_addr_t rpaddr = 0;
 	dma_addr_t wpaddr = 0;
 	int ret;
···
 	if (i2c->op == I2C_MASTER_RD) {
 		writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
 		writel(I2C_DMA_CON_RX, i2c->pdmabase + OFFSET_CON);
-		rpaddr = dma_map_single(i2c->dev, msgs->buf,
-					msgs->len, DMA_FROM_DEVICE);
-		if (dma_mapping_error(i2c->dev, rpaddr))
+
+		dma_rd_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+		if (!dma_rd_buf)
 			return -ENOMEM;
+
+		rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
+					msgs->len, DMA_FROM_DEVICE);
+		if (dma_mapping_error(i2c->dev, rpaddr)) {
+			i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, false);
+
+			return -ENOMEM;
+		}
 
 		if (i2c->dev_comp->support_33bits) {
 			reg_4g_mode = mtk_i2c_set_4g_mode(rpaddr);
···
 	} else if (i2c->op == I2C_MASTER_WR) {
 		writel(I2C_DMA_INT_FLAG_NONE, i2c->pdmabase + OFFSET_INT_FLAG);
 		writel(I2C_DMA_CON_TX, i2c->pdmabase + OFFSET_CON);
-		wpaddr = dma_map_single(i2c->dev, msgs->buf,
-					msgs->len, DMA_TO_DEVICE);
-		if (dma_mapping_error(i2c->dev, wpaddr))
+
+		dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+		if (!dma_wr_buf)
 			return -ENOMEM;
+
+		wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
+					msgs->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(i2c->dev, wpaddr)) {
+			i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
+			return -ENOMEM;
+		}
 
 		if (i2c->dev_comp->support_33bits) {
 			reg_4g_mode = mtk_i2c_set_4g_mode(wpaddr);
···
 	} else {
 		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_INT_FLAG);
 		writel(I2C_DMA_CLR_FLAG, i2c->pdmabase + OFFSET_CON);
-		wpaddr = dma_map_single(i2c->dev, msgs->buf,
-					msgs->len, DMA_TO_DEVICE);
-		if (dma_mapping_error(i2c->dev, wpaddr))
+
+		dma_wr_buf = i2c_get_dma_safe_msg_buf(msgs, 0);
+		if (!dma_wr_buf)
 			return -ENOMEM;
-		rpaddr = dma_map_single(i2c->dev, (msgs + 1)->buf,
+
+		wpaddr = dma_map_single(i2c->dev, dma_wr_buf,
+					msgs->len, DMA_TO_DEVICE);
+		if (dma_mapping_error(i2c->dev, wpaddr)) {
+			i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
+			return -ENOMEM;
+		}
+
+		dma_rd_buf = i2c_get_dma_safe_msg_buf((msgs + 1), 0);
+		if (!dma_rd_buf) {
+			dma_unmap_single(i2c->dev, wpaddr,
+					 msgs->len, DMA_TO_DEVICE);
+
+			i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+
+			return -ENOMEM;
+		}
+
+		rpaddr = dma_map_single(i2c->dev, dma_rd_buf,
 					(msgs + 1)->len,
 					DMA_FROM_DEVICE);
 		if (dma_mapping_error(i2c->dev, rpaddr)) {
 			dma_unmap_single(i2c->dev, wpaddr,
 					 msgs->len, DMA_TO_DEVICE);
+
+			i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, false);
+			i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), false);
+
 			return -ENOMEM;
 		}
 
···
 	if (i2c->op == I2C_MASTER_WR) {
 		dma_unmap_single(i2c->dev, wpaddr,
 				 msgs->len, DMA_TO_DEVICE);
+
+		i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
 	} else if (i2c->op == I2C_MASTER_RD) {
 		dma_unmap_single(i2c->dev, rpaddr,
 				 msgs->len, DMA_FROM_DEVICE);
+
+		i2c_put_dma_safe_msg_buf(dma_rd_buf, msgs, true);
 	} else {
 		dma_unmap_single(i2c->dev, wpaddr, msgs->len,
 				 DMA_TO_DEVICE);
 		dma_unmap_single(i2c->dev, rpaddr, (msgs + 1)->len,
 				 DMA_FROM_DEVICE);
+
+		i2c_put_dma_safe_msg_buf(dma_wr_buf, msgs, true);
+		i2c_put_dma_safe_msg_buf(dma_rd_buf, (msgs + 1), true);
 	}
 
 	if (ret == 0) {

drivers/i2c/busses/i2c-omap.c

···
 	dev_dbg(omap->dev, "addr: 0x%04x, len: %d, flags: 0x%x, stop: %d\n",
 		msg->addr, msg->len, msg->flags, stop);
 
-	if (msg->len == 0)
-		return -EINVAL;
-
 	omap->receiver = !!(msg->flags & I2C_M_RD);
 	omap_i2c_resize_fifo(omap, msg->len, omap->receiver);
 
···
 	.functionality	= omap_i2c_func,
 };
 
+static const struct i2c_adapter_quirks omap_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
+};
+
 #ifdef CONFIG_OF
 static struct omap_i2c_bus_platform_data omap2420_pdata = {
 	.rev = OMAP_I2C_IP_VERSION_1,
···
 	adap->class = I2C_CLASS_DEPRECATED;
 	strlcpy(adap->name, "OMAP I2C adapter", sizeof(adap->name));
 	adap->algo = &omap_i2c_algo;
+	adap->quirks = &omap_i2c_quirks;
 	adap->dev.parent = &pdev->dev;
 	adap->dev.of_node = pdev->dev.of_node;
 	adap->bus_recovery_info = &omap_i2c_bus_recovery_info;

drivers/i2c/busses/i2c-powermac.c

···
 static int i2c_powermac_probe(struct platform_device *dev)
 {
 	struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
-	struct device_node *parent = NULL;
+	struct device_node *parent;
 	struct i2c_adapter *adapter;
-	const char *basename;
 	int rc;
 
 	if (bus == NULL)
···
 		parent = of_get_parent(pmac_i2c_get_controller(bus));
 		if (parent == NULL)
 			return -EINVAL;
-		basename = parent->name;
+		snprintf(adapter->name, sizeof(adapter->name), "%pOFn %d",
+			 parent,
+			 pmac_i2c_get_channel(bus));
+		of_node_put(parent);
 		break;
 	case pmac_i2c_bus_pmu:
-		basename = "pmu";
+		snprintf(adapter->name, sizeof(adapter->name), "pmu %d",
+			 pmac_i2c_get_channel(bus));
 		break;
 	case pmac_i2c_bus_smu:
 		/* This is not what we used to do but I'm fixing drivers at
 		 * the same time as this change
 		 */
-		basename = "smu";
+		snprintf(adapter->name, sizeof(adapter->name), "smu %d",
+			 pmac_i2c_get_channel(bus));
 		break;
 	default:
 		return -EINVAL;
 	}
-	snprintf(adapter->name, sizeof(adapter->name), "%s %d", basename,
-		 pmac_i2c_get_channel(bus));
-	of_node_put(parent);
 
 	platform_set_drvdata(dev, adapter);
 	adapter->algo = &i2c_powermac_algorithm;

drivers/i2c/busses/i2c-qcom-geni.c

···
 static irqreturn_t geni_i2c_irq(int irq, void *dev)
 {
 	struct geni_i2c_dev *gi2c = dev;
-	int j;
+	void __iomem *base = gi2c->se.base;
+	int j, p;
 	u32 m_stat;
 	u32 rx_st;
 	u32 dm_tx_st;
 	u32 dm_rx_st;
 	u32 dma;
+	u32 val;
 	struct i2c_msg *cur;
 	unsigned long flags;
 
 	spin_lock_irqsave(&gi2c->lock, flags);
-	m_stat = readl_relaxed(gi2c->se.base + SE_GENI_M_IRQ_STATUS);
-	rx_st = readl_relaxed(gi2c->se.base + SE_GENI_RX_FIFO_STATUS);
-	dm_tx_st = readl_relaxed(gi2c->se.base + SE_DMA_TX_IRQ_STAT);
-	dm_rx_st = readl_relaxed(gi2c->se.base + SE_DMA_RX_IRQ_STAT);
-	dma = readl_relaxed(gi2c->se.base + SE_GENI_DMA_MODE_EN);
+	m_stat = readl_relaxed(base + SE_GENI_M_IRQ_STATUS);
+	rx_st = readl_relaxed(base + SE_GENI_RX_FIFO_STATUS);
+	dm_tx_st = readl_relaxed(base + SE_DMA_TX_IRQ_STAT);
+	dm_rx_st = readl_relaxed(base + SE_DMA_RX_IRQ_STAT);
+	dma = readl_relaxed(base + SE_GENI_DMA_MODE_EN);
 	cur = gi2c->cur;
 
 	if (!cur ||
···
 
 		/* Disable the TX Watermark interrupt to stop TX */
 		if (!dma)
-			writel_relaxed(0, gi2c->se.base +
-					   SE_GENI_TX_WATERMARK_REG);
-		goto irqret;
-	}
-
-	if (dma) {
+			writel_relaxed(0, base + SE_GENI_TX_WATERMARK_REG);
+	} else if (dma) {
 		dev_dbg(gi2c->se.dev, "i2c dma tx:0x%x, dma rx:0x%x\n",
 			dm_tx_st, dm_rx_st);
-		goto irqret;
-	}
-
-	if (cur->flags & I2C_M_RD &&
-	    m_stat & (M_RX_FIFO_WATERMARK_EN | M_RX_FIFO_LAST_EN)) {
+	} else if (cur->flags & I2C_M_RD &&
+		   m_stat & (M_RX_FIFO_WATERMARK_EN | M_RX_FIFO_LAST_EN)) {
 		u32 rxcnt = rx_st & RX_FIFO_WC_MSK;
 
 		for (j = 0; j < rxcnt; j++) {
-			u32 val;
-			int p = 0;
-
-			val = readl_relaxed(gi2c->se.base + SE_GENI_RX_FIFOn);
+			p = 0;
+			val = readl_relaxed(base + SE_GENI_RX_FIFOn);
 			while (gi2c->cur_rd < cur->len && p < sizeof(val)) {
 				cur->buf[gi2c->cur_rd++] = val & 0xff;
 				val >>= 8;
···
 		   m_stat & M_TX_FIFO_WATERMARK_EN) {
 		for (j = 0; j < gi2c->tx_wm; j++) {
 			u32 temp;
-			u32 val = 0;
-			int p = 0;
 
+			val = 0;
+			p = 0;
 			while (gi2c->cur_wr < cur->len && p < sizeof(val)) {
 				temp = cur->buf[gi2c->cur_wr++];
 				val |= temp << (p * 8);
 				p++;
 			}
-			writel_relaxed(val, gi2c->se.base + SE_GENI_TX_FIFOn);
+			writel_relaxed(val, base + SE_GENI_TX_FIFOn);
 			/* TX Complete, Disable the TX Watermark interrupt */
 			if (gi2c->cur_wr == cur->len) {
-				writel_relaxed(0, gi2c->se.base +
-						SE_GENI_TX_WATERMARK_REG);
+				writel_relaxed(0, base + SE_GENI_TX_WATERMARK_REG);
 				break;
 			}
 		}
 	}
-irqret:
-	if (m_stat)
-		writel_relaxed(m_stat, gi2c->se.base + SE_GENI_M_IRQ_CLEAR);
 
-	if (dma) {
-		if (dm_tx_st)
-			writel_relaxed(dm_tx_st, gi2c->se.base +
-						SE_DMA_TX_IRQ_CLR);
-		if (dm_rx_st)
-			writel_relaxed(dm_rx_st, gi2c->se.base +
-						SE_DMA_RX_IRQ_CLR);
-	}
+	if (m_stat)
+		writel_relaxed(m_stat, base + SE_GENI_M_IRQ_CLEAR);
+
+	if (dma && dm_tx_st)
+		writel_relaxed(dm_tx_st, base + SE_DMA_TX_IRQ_CLR);
+	if (dma && dm_rx_st)
+		writel_relaxed(dm_rx_st, base + SE_DMA_RX_IRQ_CLR);
+
 	/* if this is err with done-bit not set, handle that through timeout. */
-	if (m_stat & M_CMD_DONE_EN || m_stat & M_CMD_ABORT_EN)
-		complete(&gi2c->done);
-	else if (dm_tx_st & TX_DMA_DONE || dm_tx_st & TX_RESET_DONE)
-		complete(&gi2c->done);
-	else if (dm_rx_st & RX_DMA_DONE || dm_rx_st & RX_RESET_DONE)
+	if (m_stat & M_CMD_DONE_EN || m_stat & M_CMD_ABORT_EN ||
+	    dm_tx_st & TX_DMA_DONE || dm_tx_st & TX_RESET_DONE ||
+	    dm_rx_st & RX_DMA_DONE || dm_rx_st & RX_RESET_DONE)
 		complete(&gi2c->done);
 
 	spin_unlock_irqrestore(&gi2c->lock, flags);
+
 	return IRQ_HANDLED;
 }
 
···
 				u32 m_param)
 {
 	dma_addr_t rx_dma;
-	enum geni_se_xfer_mode mode;
-	unsigned long time_left = XFER_TIMEOUT;
+	unsigned long time_left;
 	void *dma_buf;
+	struct geni_se *se = &gi2c->se;
+	size_t len = msg->len;
 
-	gi2c->cur = msg;
-	mode = GENI_SE_FIFO;
 	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
 	if (dma_buf)
-		mode = GENI_SE_DMA;
+		geni_se_select_mode(se, GENI_SE_DMA);
+	else
+		geni_se_select_mode(se, GENI_SE_FIFO);
 
-	geni_se_select_mode(&gi2c->se, mode);
-	writel_relaxed(msg->len, gi2c->se.base + SE_I2C_RX_TRANS_LEN);
-	geni_se_setup_m_cmd(&gi2c->se, I2C_READ, m_param);
-	if (mode == GENI_SE_DMA) {
-		int ret;
+	writel_relaxed(len, se->base + SE_I2C_RX_TRANS_LEN);
+	geni_se_setup_m_cmd(se, I2C_READ, m_param);
 
-		ret = geni_se_rx_dma_prep(&gi2c->se, dma_buf, msg->len,
-								&rx_dma);
-		if (ret) {
-			mode = GENI_SE_FIFO;
-			geni_se_select_mode(&gi2c->se, mode);
-			i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
-		}
+	if (dma_buf && geni_se_rx_dma_prep(se, dma_buf, len, &rx_dma)) {
+		geni_se_select_mode(se, GENI_SE_FIFO);
+		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
+		dma_buf = NULL;
 	}
 
 	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
···
 		geni_i2c_abort_xfer(gi2c);
 
 	gi2c->cur_rd = 0;
-	if (mode == GENI_SE_DMA) {
+	if (dma_buf) {
 		if (gi2c->err)
 			geni_i2c_rx_fsm_rst(gi2c);
-		geni_se_rx_dma_unprep(&gi2c->se, rx_dma, msg->len);
+		geni_se_rx_dma_unprep(se, rx_dma, len);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
 	}
+
 	return gi2c->err;
 }
 
···
 				u32 m_param)
 {
 	dma_addr_t tx_dma;
-	enum geni_se_xfer_mode mode;
 	unsigned long time_left;
 	void *dma_buf;
+	struct geni_se *se = &gi2c->se;
+	size_t len = msg->len;
 
-	gi2c->cur = msg;
-	mode = GENI_SE_FIFO;
 	dma_buf = i2c_get_dma_safe_msg_buf(msg, 32);
 	if (dma_buf)
-		mode = GENI_SE_DMA;
+		geni_se_select_mode(se, GENI_SE_DMA);
+	else
+		geni_se_select_mode(se, GENI_SE_FIFO);
 
-	geni_se_select_mode(&gi2c->se, mode);
-	writel_relaxed(msg->len, gi2c->se.base + SE_I2C_TX_TRANS_LEN);
-	geni_se_setup_m_cmd(&gi2c->se, I2C_WRITE, m_param);
-	if (mode == GENI_SE_DMA) {
-		int ret;
+	writel_relaxed(len, se->base + SE_I2C_TX_TRANS_LEN);
+	geni_se_setup_m_cmd(se, I2C_WRITE, m_param);
 
-		ret = geni_se_tx_dma_prep(&gi2c->se, dma_buf, msg->len,
-								&tx_dma);
-		if (ret) {
-			mode = GENI_SE_FIFO;
-			geni_se_select_mode(&gi2c->se, mode);
-			i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
-		}
+	if (dma_buf && geni_se_tx_dma_prep(se, dma_buf, len, &tx_dma)) {
+		geni_se_select_mode(se, GENI_SE_FIFO);
+		i2c_put_dma_safe_msg_buf(dma_buf, msg, false);
+		dma_buf = NULL;
 	}
 
-	if (mode == GENI_SE_FIFO) /* Get FIFO IRQ */
-		writel_relaxed(1, gi2c->se.base + SE_GENI_TX_WATERMARK_REG);
+	if (!dma_buf) /* Get FIFO IRQ */
+		writel_relaxed(1, se->base + SE_GENI_TX_WATERMARK_REG);
 
 	time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
 	if (!time_left)
 		geni_i2c_abort_xfer(gi2c);
 
 	gi2c->cur_wr = 0;
-	if (mode == GENI_SE_DMA) {
+	if (dma_buf) {
 		if (gi2c->err)
 			geni_i2c_tx_fsm_rst(gi2c);
-		geni_se_tx_dma_unprep(&gi2c->se, tx_dma, msg->len);
+		geni_se_tx_dma_unprep(se, tx_dma, len);
 		i2c_put_dma_safe_msg_buf(dma_buf, msg, !gi2c->err);
 	}
+
 	return gi2c->err;
 }
 
···
 
 		m_param |= ((msgs[i].addr << SLV_ADDR_SHFT) & SLV_ADDR_MSK);
 
+		gi2c->cur = &msgs[i];
 		if (msgs[i].flags & I2C_M_RD)
 			ret = geni_i2c_rx_one_msg(gi2c, &msgs[i], m_param);
 		else

drivers/i2c/busses/i2c-qup.c

···
 	writel(I2C_MINI_CORE | I2C_N_VAL, qup->base + QUP_CONFIG);
 
 	for (idx = 0; idx < num; idx++) {
-		if (msgs[idx].len == 0) {
-			ret = -EINVAL;
-			goto out;
-		}
-
 		if (qup_i2c_poll_state_i2c_master(qup)) {
 			ret = -EIO;
 			goto out;
···
 
 	/* All i2c_msgs should be transferred using either dma or cpu */
 	for (idx = 0; idx < num; idx++) {
-		if (msgs[idx].len == 0)
-			return -EINVAL;
-
 		if (msgs[idx].flags & I2C_M_RD)
 			max_rx_len = max_t(unsigned int, max_rx_len,
 					   msgs[idx].len);
···
  * which limits the possible read to 256 (QUP_READ_LIMIT) bytes.
  */
 static const struct i2c_adapter_quirks qup_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
 	.max_read_len = QUP_READ_LIMIT,
+};
+
+static const struct i2c_adapter_quirks qup_i2c_quirks_v2 = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
 };
 
 static void qup_i2c_enable_clocks(struct qup_i2c_dev *qup)
···
 		is_qup_v1 = true;
 	} else {
 		qup->adap.algo = &qup_i2c_algo_v2;
+		qup->adap.quirks = &qup_i2c_quirks_v2;
 		is_qup_v1 = false;
 		if (acpi_match_device(qup_i2c_acpi_match, qup->dev))
 			goto nodma;

drivers/i2c/busses/i2c-sh_mobile.c

···
 	return 0;
 }
 
-static int sh_mobile_i2c_runtime_nop(struct device *dev)
-{
-	/* Runtime PM callback shared between ->runtime_suspend()
-	 * and ->runtime_resume(). Simply returns success.
-	 *
-	 * This driver re-initializes all registers after
-	 * pm_runtime_get_sync() anyway so there is no need
-	 * to save and restore registers here.
-	 */
-	return 0;
-}
-
-static const struct dev_pm_ops sh_mobile_i2c_dev_pm_ops = {
-	.runtime_suspend = sh_mobile_i2c_runtime_nop,
-	.runtime_resume = sh_mobile_i2c_runtime_nop,
-};
-
 static struct platform_driver sh_mobile_i2c_driver = {
 	.driver		= {
 		.name		= "i2c-sh_mobile",
-		.pm		= &sh_mobile_i2c_dev_pm_ops,
 		.of_match_table = sh_mobile_i2c_dt_ids,
 	},
 	.probe		= sh_mobile_i2c_probe,

drivers/i2c/busses/i2c-synquacer.c

···
 		if (i2c->state == STATE_READ)
 			goto prepare_read;
 
-		/* fallthru */
+		/* fall through */
 
 	case STATE_WRITE:
 		if (bsr & SYNQUACER_I2C_BSR_LRB) {

drivers/i2c/busses/i2c-tegra.c

···
 
 	tegra_i2c_flush_fifos(i2c_dev);
 
-	if (msg->len == 0)
-		return -EINVAL;
-
 	i2c_dev->msg_buf = msg->buf;
 	i2c_dev->msg_buf_remaining = msg->len;
 	i2c_dev->msg_err = I2C_ERR_NONE;
···
 
 /* payload size is only 12 bit */
 static const struct i2c_adapter_quirks tegra_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
 	.max_read_len = 4096,
 	.max_write_len = 4096,
 };

drivers/i2c/busses/i2c-uniphier-f.c

···
 	unsigned int flags;
 	unsigned int busy_cnt;
 	unsigned int clk_cycle;
+	spinlock_t lock;	/* IRQ synchronization */
 };
 
 static void uniphier_fi2c_fill_txfifo(struct uniphier_fi2c_priv *priv,
···
 	writel(priv->enabled_irqs, priv->membase + UNIPHIER_FI2C_IE);
 }
 
-static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv)
+static void uniphier_fi2c_clear_irqs(struct uniphier_fi2c_priv *priv,
+				     u32 mask)
 {
-	writel(-1, priv->membase + UNIPHIER_FI2C_IC);
+	writel(mask, priv->membase + UNIPHIER_FI2C_IC);
 }
 
 static void uniphier_fi2c_stop(struct uniphier_fi2c_priv *priv)
···
 	struct uniphier_fi2c_priv *priv = dev_id;
 	u32 irq_status;
 
+	spin_lock(&priv->lock);
+
 	irq_status = readl(priv->membase + UNIPHIER_FI2C_INT);
+	irq_status &= priv->enabled_irqs;
 
 	dev_dbg(&priv->adap.dev,
 		"interrupt: enabled_irqs=%04x, irq_status=%04x\n",
 		priv->enabled_irqs, irq_status);
+
+	uniphier_fi2c_clear_irqs(priv, irq_status);
 
 	if (irq_status & UNIPHIER_FI2C_INT_STOP)
 		goto complete;
···
 		goto handled;
 	}
 
+	spin_unlock(&priv->lock);
+
 	return IRQ_NONE;
 
 data_done:
···
 	}
 
 handled:
-	uniphier_fi2c_clear_irqs(priv);
+	spin_unlock(&priv->lock);
 
 	return IRQ_HANDLED;
 }
···
 static void uniphier_fi2c_tx_init(struct uniphier_fi2c_priv *priv, u16 addr)
 {
 	priv->enabled_irqs |= UNIPHIER_FI2C_INT_TE;
+	uniphier_fi2c_set_irqs(priv);
+
 	/* do not use TX byte counter */
 	writel(0, priv->membase + UNIPHIER_FI2C_TBC);
 	/* set slave address */
···
 		priv->enabled_irqs |= UNIPHIER_FI2C_INT_RF;
 	}
 
+	uniphier_fi2c_set_irqs(priv);
+
 	/* set slave address with RD bit */
 	writel(UNIPHIER_FI2C_DTTX_CMD | UNIPHIER_FI2C_DTTX_RD | addr << 1,
 	       priv->membase + UNIPHIER_FI2C_DTTX);
···
 }
 
 static int uniphier_fi2c_master_xfer_one(struct i2c_adapter *adap,
-					 struct i2c_msg *msg, bool stop)
+					 struct i2c_msg *msg, bool repeat,
+					 bool stop)
 {
 	struct uniphier_fi2c_priv *priv = i2c_get_adapdata(adap);
 	bool is_read = msg->flags & I2C_M_RD;
-	unsigned long time_left;
+	unsigned long time_left, flags;
 
-	dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, stop=%d\n",
-		is_read ? "receive" : "transmit", msg->addr, msg->len, stop);
+	dev_dbg(&adap->dev, "%s: addr=0x%02x, len=%d, repeat=%d, stop=%d\n",
+		is_read ? "receive" : "transmit", msg->addr, msg->len,
+		repeat, stop);
 
 	priv->len = msg->len;
 	priv->buf = msg->buf;
···
 		priv->flags |= UNIPHIER_FI2C_STOP;
 
 	reinit_completion(&priv->comp);
-	uniphier_fi2c_clear_irqs(priv);
+	uniphier_fi2c_clear_irqs(priv, U32_MAX);
 	writel(UNIPHIER_FI2C_RST_TBRST | UNIPHIER_FI2C_RST_RBRST,
 	       priv->membase + UNIPHIER_FI2C_RST);	/* reset TX/RX FIFO */
+
+	spin_lock_irqsave(&priv->lock, flags);
 
 	if (is_read)
 		uniphier_fi2c_rx_init(priv, msg->addr);
 	else
 		uniphier_fi2c_tx_init(priv, msg->addr);
 
-	uniphier_fi2c_set_irqs(priv);
-
 	dev_dbg(&adap->dev, "start condition\n");
-	writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
-	       priv->membase + UNIPHIER_FI2C_CR);
+	/*
+	 * For a repeated START condition, writing a slave address to the FIFO
+	 * kicks the controller. So, the UNIPHIER_FI2C_CR register should be
+	 * written only for a non-repeated START condition.
+	 */
+	if (!repeat)
+		writel(UNIPHIER_FI2C_CR_MST | UNIPHIER_FI2C_CR_STA,
+		       priv->membase + UNIPHIER_FI2C_CR);
+
+	spin_unlock_irqrestore(&priv->lock, flags);
 
 	time_left = wait_for_completion_timeout(&priv->comp, adap->timeout);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	priv->enabled_irqs = 0;
+	uniphier_fi2c_set_irqs(priv);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
 	if (!time_left) {
 		dev_err(&adap->dev, "transaction timeout.\n");
 		uniphier_fi2c_recover(priv);
···
 				     struct i2c_msg *msgs, int num)
 {
 	struct i2c_msg *msg, *emsg = msgs + num;
+	bool repeat = false;
 	int ret;
 
 	ret = uniphier_fi2c_check_bus_busy(adap);
···
 		/* Emit STOP if it is the last message or I2C_M_STOP is set. */
 		bool stop = (msg + 1 == emsg) || (msg->flags & I2C_M_STOP);
 
-		ret = uniphier_fi2c_master_xfer_one(adap, msg, stop);
+		ret = uniphier_fi2c_master_xfer_one(adap, msg, repeat, stop);
 		if (ret)
 			return ret;
+
+		repeat = !stop;
 	}
 
 	return num;
···
 
 	priv->clk_cycle = clk_rate / bus_speed;
 	init_completion(&priv->comp);
+	spin_lock_init(&priv->lock);
 	priv->adap.owner = THIS_MODULE;
 	priv->adap.algo = &uniphier_fi2c_algo;
 	priv->adap.dev.parent = dev;

drivers/i2c/busses/i2c-zx2967.c

···
 	int ret;
 	int i;
 
-	if (msg->len == 0)
-		return -EINVAL;
-
 	zx2967_i2c_flush_fifos(i2c);
 
 	i2c->cur_trans = msg->buf;
···
 	.functionality = zx2967_i2c_func,
 };
 
+static const struct i2c_adapter_quirks zx2967_i2c_quirks = {
+	.flags = I2C_AQ_NO_ZERO_LEN,
+};
+
 static const struct of_device_id zx2967_i2c_of_match[] = {
 	{ .compatible = "zte,zx296718-i2c", },
 	{ },
···
 	strlcpy(i2c->adap.name, "zx2967 i2c adapter",
 		sizeof(i2c->adap.name));
 	i2c->adap.algo = &zx2967_i2c_algo;
+	i2c->adap.quirks = &zx2967_i2c_quirks;
 	i2c->adap.nr = pdev->id;
 	i2c->adap.dev.parent = &pdev->dev;
 	i2c->adap.dev.of_node = pdev->dev.of_node;

drivers/i2c/i2c-core-base.c

···
 {
 	int ret;
 
+	if (!adap->algo->master_xfer) {
+		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
+		return -EOPNOTSUPP;
+	}
+
 	/* REVISIT the fault reporting model here is weak:
 	 *
 	 *  - When we get an error after receiving N bytes from a slave,
···
 	 *    one (discarding status on the second message) or errno
 	 *    (discarding status on the first one).
 	 */
-
-	if (adap->algo->master_xfer) {
-#ifdef DEBUG
-		for (ret = 0; ret < num; ret++) {
-			dev_dbg(&adap->dev,
-				"master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
-				ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
-				msgs[ret].addr, msgs[ret].len,
-				(msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
-		}
-#endif
-
-		if (in_atomic() || irqs_disabled()) {
-			ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
-			if (!ret)
-				/* I2C activity is ongoing. */
-				return -EAGAIN;
-		} else {
-			i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
-		}
-
-		ret = __i2c_transfer(adap, msgs, num);
-		i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
-
-		return ret;
+	if (in_atomic() || irqs_disabled()) {
+		ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
+		if (!ret)
+			/* I2C activity is ongoing. */
+			return -EAGAIN;
 	} else {
-		dev_dbg(&adap->dev, "I2C level transfers not supported\n");
-		return -EOPNOTSUPP;
+		i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
 	}
+
+	ret = __i2c_transfer(adap, msgs, num);
+	i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
+
+	return ret;
 }
 EXPORT_SYMBOL(i2c_transfer);
 

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

···
 
 		ret = of_property_read_u32(child, "reg", &chan);
 		if (ret < 0) {
-			dev_err(dev, "no reg property for node '%s'\n",
-				child->name);
+			dev_err(dev, "no reg property for node '%pOFn'\n",
+				child);
 			goto err_children;
 		}
 

drivers/i2c/muxes/i2c-mux-ltc4306.c

···
 
 static int ltc4306_probe(struct i2c_client *client)
 {
-	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
+	struct i2c_adapter *adap = client->adapter;
 	const struct chip_desc *chip;
 	struct i2c_mux_core *muxc;
 	struct ltc4306 *data;

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

···
 static int mlxcpld_mux_probe(struct i2c_client *client,
 			     const struct i2c_device_id *id)
 {
-	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
+	struct i2c_adapter *adap = client->adapter;
 	struct mlxcpld_mux_plat_data *pdata = dev_get_platdata(&client->dev);
 	struct i2c_mux_core *muxc;
 	int num, force;

drivers/i2c/muxes/i2c-mux-pca954x.c

···
 static int pca954x_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
-	struct i2c_adapter *adap = to_i2c_adapter(client->dev.parent);
+	struct i2c_adapter *adap = client->adapter;
 	struct pca954x_platform_data *pdata = dev_get_platdata(&client->dev);
 	struct device *dev = &client->dev;
 	struct device_node *np = dev->of_node;

drivers/misc/eeprom/at24.c

···
 module_param_named(write_timeout, at24_write_timeout, uint, 0);
 MODULE_PARM_DESC(at24_write_timeout, "Time (in ms) to try writes (default 25)");
 
-/*
- * Both reads and writes fail if the previous write didn't complete yet. This
- * macro loops a few times waiting at least long enough for one entire page
- * write to work while making sure that at least one iteration is run before
- * checking the break condition.
- *
- * It takes two parameters: a variable in which the future timeout in jiffies
- * will be stored and a temporary variable holding the time of the last
- * iteration of processing the request. Both should be unsigned integers
- * holding at least 32 bits.
- */
-#define at24_loop_until_timeout(tout, op_time)				\
-	for (tout = jiffies + msecs_to_jiffies(at24_write_timeout),	\
-	     op_time = 0;						\
-	     op_time ? time_before(op_time, tout) : true;		\
-	     usleep_range(1000, 1500), op_time = jiffies)
-
 struct at24_chip_data {
 	/*
 	 * these fields mirror their equivalents in
···
 	/* adjust offset for mac and serial read ops */
 	offset += at24->offset_adj;
 
-	at24_loop_until_timeout(timeout, read_time) {
+	timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
+	do {
+		/*
+		 * The timestamp shall be taken before the actual operation
+		 * to avoid a premature timeout in case of high CPU load.
+		 */
+		read_time = jiffies;
+
 		ret = regmap_bulk_read(regmap, offset, buf, count);
 		dev_dbg(&client->dev, "read %zu@%d --> %d (%ld)\n",
 			count, offset, ret, jiffies);
 		if (!ret)
 			return count;
-	}
+
+		usleep_range(1000, 1500);
+	} while (time_before(read_time, timeout));
 
 	return -ETIMEDOUT;
 }
···
 	regmap = at24_client->regmap;
 	client = at24_client->client;
 	count = at24_adjust_write_count(at24, offset, count);
+	timeout = jiffies + msecs_to_jiffies(at24_write_timeout);
 
-	at24_loop_until_timeout(timeout, write_time) {
+	do {
+		/*
+		 * The timestamp shall be taken before the actual operation
+		 * to avoid a premature timeout in case of high CPU load.
+		 */
+		write_time = jiffies;
+
 		ret = regmap_bulk_write(regmap, offset, buf, count);
 		dev_dbg(&client->dev, "write %zu@%d --> %d (%ld)\n",
 			count, offset, ret, jiffies);
 		if (!ret)
 			return count;
-	}
+
+		usleep_range(1000, 1500);
+	} while (time_before(write_time, timeout));
 
 	return -ETIMEDOUT;
 }