Merge branch 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging

* 'i2c-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  i2c-viapro: Don't log nacks
  i2c/pca954x: Remove __devinit and __devexit from probe and remove functions
  MAINTAINERS: Add maintainer for PCA9541 I2C bus master selector driver
  i2c/mux: Driver for PCA9541 I2C Master Selector
  i2c: Optimize function i2c_detect()
  i2c: Discard warning message on device instantiation from user-space
  i2c-amd8111: Add proper error handling
  i2c: Change to new flag variable
  i2c: Remove unneeded inclusions of <linux/i2c-id.h>
  i2c: Let i2c_parent_is_i2c_adapter return the parent adapter
  i2c: Simplify i2c_parent_is_i2c_adapter
  i2c-pca-platform: Change device name of request_irq
  i2c: Fix Kconfig dependencies

24 files changed, 589 insertions, 113 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_i2c.h b/drivers/gpu/drm/nouveau/nouveau_i2c.h
index f71cb32f757..cfe7c8426d1 100644
--- a/drivers/gpu/drm/nouveau/nouveau_i2c.h
+++ b/drivers/gpu/drm/nouveau/nouveau_i2c.h
@@ -24,7 +24,6 @@
 #define __NOUVEAU_I2C_H__
 
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/i2c-algo-bit.h>
 #include "drm_dp_helper.h"
 
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 17a6602b588..454c1dc7ea4 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -36,7 +36,6 @@
 #include <drm_dp_helper.h>
 #include <drm_fixed.h>
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/i2c-algo-bit.h>
 
 struct radeon_bo;
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 30f06e956bf..b923074b2cb 100644
--- a/drivers/i2c/Kconfig
+++ b/drivers/i2c/Kconfig
@@ -75,7 +75,8 @@ config I2C_HELPER_AUTO
 	  In doubt, say Y.
 
 config I2C_SMBUS
-	tristate "SMBus-specific protocols" if !I2C_HELPER_AUTO
+	tristate
+	prompt "SMBus-specific protocols" if !I2C_HELPER_AUTO
 	help
 	  Say Y here if you want support for SMBus extensions to the I2C
 	  specification. At the moment, the only supported extension is
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index c00fd66388f..23ac61e2db3 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -9,6 +9,4 @@ obj-$(CONFIG_I2C_CHARDEV)	+= i2c-dev.o
 obj-$(CONFIG_I2C_MUX)		+= i2c-mux.o
 obj-y				+= algos/ busses/ muxes/
 
-ifeq ($(CONFIG_I2C_DEBUG_CORE),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_I2C_DEBUG_CORE) := -DDEBUG
diff --git a/drivers/i2c/algos/Kconfig b/drivers/i2c/algos/Kconfig
index 7b2ce4a0852..3998dd620a0 100644
--- a/drivers/i2c/algos/Kconfig
+++ b/drivers/i2c/algos/Kconfig
@@ -15,3 +15,15 @@ config I2C_ALGOPCA
 	tristate "I2C PCA 9564 interfaces"
 
 endmenu
+
+# In automatic configuration mode, we still have to define the
+# symbols to avoid unmet dependencies.
+
+if I2C_HELPER_AUTO
+config I2C_ALGOBIT
+	tristate
+config I2C_ALGOPCF
+	tristate
+config I2C_ALGOPCA
+	tristate
+endif
diff --git a/drivers/i2c/algos/Makefile b/drivers/i2c/algos/Makefile
index 18b3e962ec0..215303f60d6 100644
--- a/drivers/i2c/algos/Makefile
+++ b/drivers/i2c/algos/Makefile
@@ -6,6 +6,4 @@ obj-$(CONFIG_I2C_ALGOBIT)	+= i2c-algo-bit.o
 obj-$(CONFIG_I2C_ALGOPCF)	+= i2c-algo-pcf.o
 obj-$(CONFIG_I2C_ALGOPCA)	+= i2c-algo-pca.o
 
-ifeq ($(CONFIG_I2C_DEBUG_ALGO),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_I2C_DEBUG_ALGO) := -DDEBUG
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index c3ef49230cb..033ad413f32 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -76,6 +76,4 @@ obj-$(CONFIG_I2C_STUB)		+= i2c-stub.o
 obj-$(CONFIG_SCx200_ACB)	+= scx200_acb.o
 obj-$(CONFIG_SCx200_I2C)	+= scx200_i2c.o
 
-ifeq ($(CONFIG_I2C_DEBUG_BUS),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
diff --git a/drivers/i2c/busses/i2c-amd8111.c b/drivers/i2c/busses/i2c-amd8111.c
index af1e5e254b7..6b6a6b1d702 100644
--- a/drivers/i2c/busses/i2c-amd8111.c
+++ b/drivers/i2c/busses/i2c-amd8111.c
@@ -69,7 +69,7 @@ static struct pci_driver amd8111_driver;
  * ACPI 2.0 chapter 13 access of registers of the EC
  */
 
-static unsigned int amd_ec_wait_write(struct amd_smbus *smbus)
+static int amd_ec_wait_write(struct amd_smbus *smbus)
 {
 	int timeout = 500;
 
@@ -85,7 +85,7 @@ static unsigned int amd_ec_wait_write(struct amd_smbus *smbus)
 	return 0;
 }
 
-static unsigned int amd_ec_wait_read(struct amd_smbus *smbus)
+static int amd_ec_wait_read(struct amd_smbus *smbus)
 {
 	int timeout = 500;
 
@@ -101,7 +101,7 @@ static unsigned int amd_ec_wait_read(struct amd_smbus *smbus)
 	return 0;
 }
 
-static unsigned int amd_ec_read(struct amd_smbus *smbus, unsigned char address,
+static int amd_ec_read(struct amd_smbus *smbus, unsigned char address,
 		unsigned char *data)
 {
 	int status;
@@ -124,7 +124,7 @@ static unsigned int amd_ec_read(struct amd_smbus *smbus, unsigned char address,
 	return 0;
 }
 
-static unsigned int amd_ec_write(struct amd_smbus *smbus, unsigned char address,
+static int amd_ec_write(struct amd_smbus *smbus, unsigned char address,
 		unsigned char data)
 {
 	int status;
@@ -196,7 +196,7 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 {
 	struct amd_smbus *smbus = adap->algo_data;
 	unsigned char protocol, len, pec, temp[2];
-	int i;
+	int i, status;
 
 	protocol = (read_write == I2C_SMBUS_READ) ? AMD_SMB_PRTCL_READ
 						  : AMD_SMB_PRTCL_WRITE;
@@ -209,38 +209,62 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 			break;
 
 		case I2C_SMBUS_BYTE:
-			if (read_write == I2C_SMBUS_WRITE)
-				amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (read_write == I2C_SMBUS_WRITE) {
+				status = amd_ec_write(smbus, AMD_SMB_CMD,
+						      command);
+				if (status)
+					return status;
+			}
 			protocol |= AMD_SMB_PRTCL_BYTE;
 			break;
 
 		case I2C_SMBUS_BYTE_DATA:
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
-			if (read_write == I2C_SMBUS_WRITE)
-				amd_ec_write(smbus, AMD_SMB_DATA, data->byte);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
+			if (read_write == I2C_SMBUS_WRITE) {
+				status = amd_ec_write(smbus, AMD_SMB_DATA,
+						      data->byte);
+				if (status)
+					return status;
+			}
 			protocol |= AMD_SMB_PRTCL_BYTE_DATA;
 			break;
 
 		case I2C_SMBUS_WORD_DATA:
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
 			if (read_write == I2C_SMBUS_WRITE) {
-				amd_ec_write(smbus, AMD_SMB_DATA,
-					     data->word & 0xff);
-				amd_ec_write(smbus, AMD_SMB_DATA + 1,
-					     data->word >> 8);
+				status = amd_ec_write(smbus, AMD_SMB_DATA,
+						      data->word & 0xff);
+				if (status)
+					return status;
+				status = amd_ec_write(smbus, AMD_SMB_DATA + 1,
+						      data->word >> 8);
+				if (status)
+					return status;
 			}
 			protocol |= AMD_SMB_PRTCL_WORD_DATA | pec;
 			break;
 
 		case I2C_SMBUS_BLOCK_DATA:
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
 			if (read_write == I2C_SMBUS_WRITE) {
 				len = min_t(u8, data->block[0],
 					    I2C_SMBUS_BLOCK_MAX);
-				amd_ec_write(smbus, AMD_SMB_BCNT, len);
-				for (i = 0; i < len; i++)
-					amd_ec_write(smbus, AMD_SMB_DATA + i,
-						     data->block[i + 1]);
+				status = amd_ec_write(smbus, AMD_SMB_BCNT, len);
+				if (status)
+					return status;
+				for (i = 0; i < len; i++) {
+					status =
+					  amd_ec_write(smbus, AMD_SMB_DATA + i,
+						       data->block[i + 1]);
+					if (status)
+						return status;
+				}
 			}
 			protocol |= AMD_SMB_PRTCL_BLOCK_DATA | pec;
 			break;
@@ -248,19 +272,35 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 		case I2C_SMBUS_I2C_BLOCK_DATA:
 			len = min_t(u8, data->block[0],
 				    I2C_SMBUS_BLOCK_MAX);
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
-			amd_ec_write(smbus, AMD_SMB_BCNT, len);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
+			status = amd_ec_write(smbus, AMD_SMB_BCNT, len);
+			if (status)
+				return status;
 			if (read_write == I2C_SMBUS_WRITE)
-				for (i = 0; i < len; i++)
-					amd_ec_write(smbus, AMD_SMB_DATA + i,
-						     data->block[i + 1]);
+				for (i = 0; i < len; i++) {
+					status =
+					  amd_ec_write(smbus, AMD_SMB_DATA + i,
+						       data->block[i + 1]);
+					if (status)
+						return status;
+				}
 			protocol |= AMD_SMB_PRTCL_I2C_BLOCK_DATA;
 			break;
 
 		case I2C_SMBUS_PROC_CALL:
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
-			amd_ec_write(smbus, AMD_SMB_DATA, data->word & 0xff);
-			amd_ec_write(smbus, AMD_SMB_DATA + 1, data->word >> 8);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
+			status = amd_ec_write(smbus, AMD_SMB_DATA,
+					      data->word & 0xff);
+			if (status)
+				return status;
+			status = amd_ec_write(smbus, AMD_SMB_DATA + 1,
+					      data->word >> 8);
+			if (status)
+				return status;
 			protocol = AMD_SMB_PRTCL_PROC_CALL | pec;
 			read_write = I2C_SMBUS_READ;
 			break;
@@ -268,11 +308,18 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 		case I2C_SMBUS_BLOCK_PROC_CALL:
 			len = min_t(u8, data->block[0],
 				    I2C_SMBUS_BLOCK_MAX - 1);
-			amd_ec_write(smbus, AMD_SMB_CMD, command);
-			amd_ec_write(smbus, AMD_SMB_BCNT, len);
-			for (i = 0; i < len; i++)
-				amd_ec_write(smbus, AMD_SMB_DATA + i,
-					     data->block[i + 1]);
+			status = amd_ec_write(smbus, AMD_SMB_CMD, command);
+			if (status)
+				return status;
+			status = amd_ec_write(smbus, AMD_SMB_BCNT, len);
+			if (status)
+				return status;
+			for (i = 0; i < len; i++) {
+				status = amd_ec_write(smbus, AMD_SMB_DATA + i,
+						      data->block[i + 1]);
+				if (status)
+					return status;
+			}
 			protocol = AMD_SMB_PRTCL_BLOCK_PROC_CALL | pec;
 			read_write = I2C_SMBUS_READ;
 			break;
@@ -282,24 +329,29 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 			return -EOPNOTSUPP;
 	}
 
-	amd_ec_write(smbus, AMD_SMB_ADDR, addr << 1);
-	amd_ec_write(smbus, AMD_SMB_PRTCL, protocol);
+	status = amd_ec_write(smbus, AMD_SMB_ADDR, addr << 1);
+	if (status)
+		return status;
+	status = amd_ec_write(smbus, AMD_SMB_PRTCL, protocol);
+	if (status)
+		return status;
 
-	/* FIXME this discards status from ec_read(); so temp[0] will
-	 * hold stack garbage ... the rest of this routine will act
-	 * nonsensically.  Ignored ec_write() status might explain
-	 * some such failures...
-	 */
-	amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+	status = amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+	if (status)
+		return status;
 
 	if (~temp[0] & AMD_SMB_STS_DONE) {
 		udelay(500);
-		amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+		status = amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+		if (status)
+			return status;
 	}
 
 	if (~temp[0] & AMD_SMB_STS_DONE) {
 		msleep(1);
-		amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+		status = amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
+		if (status)
+			return status;
 	}
 
 	if ((~temp[0] & AMD_SMB_STS_DONE) || (temp[0] & AMD_SMB_STS_STATUS))
@@ -311,24 +363,35 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 	switch (size) {
 		case I2C_SMBUS_BYTE:
 		case I2C_SMBUS_BYTE_DATA:
-			amd_ec_read(smbus, AMD_SMB_DATA, &data->byte);
+			status = amd_ec_read(smbus, AMD_SMB_DATA, &data->byte);
+			if (status)
+				return status;
 			break;
 
 		case I2C_SMBUS_WORD_DATA:
 		case I2C_SMBUS_PROC_CALL:
-			amd_ec_read(smbus, AMD_SMB_DATA, temp + 0);
-			amd_ec_read(smbus, AMD_SMB_DATA + 1, temp + 1);
+			status = amd_ec_read(smbus, AMD_SMB_DATA, temp + 0);
+			if (status)
+				return status;
+			status = amd_ec_read(smbus, AMD_SMB_DATA + 1, temp + 1);
+			if (status)
+				return status;
 			data->word = (temp[1] << 8) | temp[0];
 			break;
 
 		case I2C_SMBUS_BLOCK_DATA:
 		case I2C_SMBUS_BLOCK_PROC_CALL:
-			amd_ec_read(smbus, AMD_SMB_BCNT, &len);
+			status = amd_ec_read(smbus, AMD_SMB_BCNT, &len);
+			if (status)
+				return status;
 			len = min_t(u8, len, I2C_SMBUS_BLOCK_MAX);
 		case I2C_SMBUS_I2C_BLOCK_DATA:
-			for (i = 0; i < len; i++)
-				amd_ec_read(smbus, AMD_SMB_DATA + i,
-					    data->block + i + 1);
+			for (i = 0; i < len; i++) {
+				status = amd_ec_read(smbus, AMD_SMB_DATA + i,
+						     data->block + i + 1);
+				if (status)
+					return status;
+			}
 			data->block[0] = len;
 			break;
 	}
diff --git a/drivers/i2c/busses/i2c-ibm_iic.c b/drivers/i2c/busses/i2c-ibm_iic.c
index 89eedf45d30..6e3c3824033 100644
--- a/drivers/i2c/busses/i2c-ibm_iic.c
+++ b/drivers/i2c/busses/i2c-ibm_iic.c
@@ -41,7 +41,6 @@
 #include <asm/irq.h>
 #include <linux/io.h>
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/of_platform.h>
 #include <linux/of_i2c.h>
 
diff --git a/drivers/i2c/busses/i2c-nuc900.c b/drivers/i2c/busses/i2c-nuc900.c
index 92d770d7bbc..72434263787 100644
--- a/drivers/i2c/busses/i2c-nuc900.c
+++ b/drivers/i2c/busses/i2c-nuc900.c
@@ -16,7 +16,6 @@
 #include <linux/module.h>
 
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/interrupt.h>
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index 5f6d7f89e22..ace67995d7d 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -224,7 +224,7 @@ static int __devinit i2c_pca_pf_probe(struct platform_device *pdev)
 
 	if (irq) {
 		ret = request_irq(irq, i2c_pca_pf_handler,
-			IRQF_TRIGGER_FALLING, i2c->adap.name, i2c);
+			IRQF_TRIGGER_FALLING, pdev->name, i2c);
 		if (ret)
 			goto e_reqirq;
 	}
diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
index c94e51b2651..f4c19a97e0b 100644
--- a/drivers/i2c/busses/i2c-pxa.c
+++ b/drivers/i2c/busses/i2c-pxa.c
@@ -22,7 +22,6 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/sched.h>
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index bf831bf8158..6a292ea5e35 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -24,7 +24,6 @@
 #include <linux/module.h>
 
 #include <linux/i2c.h>
-#include <linux/i2c-id.h>
 #include <linux/init.h>
 #include <linux/time.h>
 #include <linux/interrupt.h>
diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index 4c6fff5f330..0b012f1f8ac 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -185,14 +185,8 @@ static int vt596_transaction(u8 size)
 	}
 
 	if (temp & 0x04) {
-		int read = inb_p(SMBHSTADD) & 0x01;
 		result = -ENXIO;
-		/* The quick and receive byte commands are used to probe
-		   for chips, so errors are expected, and we don't want
-		   to frighten the user. */
-		if (!((size == VT596_QUICK && !read) ||
-		      (size == VT596_BYTE && read)))
-			dev_err(&vt596_adapter.dev, "Transaction error!\n");
+		dev_dbg(&vt596_adapter.dev, "No response\n");
 	}
 
 	/* Resetting status register */
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index bea4c5021d2..d231f683f57 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -425,14 +425,14 @@ static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 /* walk up mux tree */
 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 {
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 	int result;
 
 	result = device_for_each_child(&adapter->dev, &addr,
 					__i2c_check_addr_busy);
 
-	if (!result && i2c_parent_is_i2c_adapter(adapter))
-		result = i2c_check_mux_parents(
-				    to_i2c_adapter(adapter->dev.parent), addr);
+	if (!result && parent)
+		result = i2c_check_mux_parents(parent, addr);
 
 	return result;
 }
@@ -453,11 +453,11 @@ static int i2c_check_mux_children(struct device *dev, void *addrp)
 
 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 {
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 	int result = 0;
 
-	if (i2c_parent_is_i2c_adapter(adapter))
-		result = i2c_check_mux_parents(
-				    to_i2c_adapter(adapter->dev.parent), addr);
+	if (parent)
+		result = i2c_check_mux_parents(parent, addr);
 
 	if (!result)
 		result = device_for_each_child(&adapter->dev, &addr,
@@ -472,8 +472,10 @@ static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
  */
 void i2c_lock_adapter(struct i2c_adapter *adapter)
 {
-	if (i2c_parent_is_i2c_adapter(adapter))
-		i2c_lock_adapter(to_i2c_adapter(adapter->dev.parent));
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+
+	if (parent)
+		i2c_lock_adapter(parent);
 	else
 		rt_mutex_lock(&adapter->bus_lock);
 }
@@ -485,8 +487,10 @@ EXPORT_SYMBOL_GPL(i2c_lock_adapter);
  */
 static int i2c_trylock_adapter(struct i2c_adapter *adapter)
 {
-	if (i2c_parent_is_i2c_adapter(adapter))
-		return i2c_trylock_adapter(to_i2c_adapter(adapter->dev.parent));
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+
+	if (parent)
+		return i2c_trylock_adapter(parent);
 	else
 		return rt_mutex_trylock(&adapter->bus_lock);
 }
@@ -497,8 +501,10 @@ static int i2c_trylock_adapter(struct i2c_adapter *adapter)
  */
 void i2c_unlock_adapter(struct i2c_adapter *adapter)
 {
-	if (i2c_parent_is_i2c_adapter(adapter))
-		i2c_unlock_adapter(to_i2c_adapter(adapter->dev.parent));
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
+
+	if (parent)
+		i2c_unlock_adapter(parent);
 	else
 		rt_mutex_unlock(&adapter->bus_lock);
 }
@@ -677,8 +683,6 @@ i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 	char *blank, end;
 	int res;
 
-	dev_warn(dev, "The new_device interface is still experimental "
-		 "and may change in a near future\n");
 	memset(&info, 0, sizeof(struct i2c_board_info));
 
 	blank = strchr(buf, ' ');
@@ -1504,26 +1508,25 @@ static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
 	if (!driver->detect || !address_list)
 		return 0;
 
+	/* Stop here if the classes do not match */
+	if (!(adapter->class & driver->class))
+		return 0;
+
 	/* Set up a temporary client to help detect callback */
 	temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
 	if (!temp_client)
 		return -ENOMEM;
 	temp_client->adapter = adapter;
 
-	/* Stop here if the classes do not match */
-	if (!(adapter->class & driver->class))
-		goto exit_free;
-
 	for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
 		dev_dbg(&adapter->dev, "found normal entry for adapter %d, "
 			"addr 0x%02x\n", adap_id, address_list[i]);
 		temp_client->addr = address_list[i];
 		err = i2c_detect_address(temp_client, driver);
-		if (err)
-			goto exit_free;
+		if (unlikely(err))
+			break;
 	}
 
- exit_free:
 	kfree(temp_client);
 	return err;
 }
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index 5f3a52d517c..cec0f3ba97f 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -192,13 +192,12 @@ static int i2cdev_check(struct device *dev, void *addrp)
 /* walk up mux tree */
 static int i2cdev_check_mux_parents(struct i2c_adapter *adapter, int addr)
 {
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 	int result;
 
 	result = device_for_each_child(&adapter->dev, &addr, i2cdev_check);
-
-	if (!result && i2c_parent_is_i2c_adapter(adapter))
-		result = i2cdev_check_mux_parents(
-				    to_i2c_adapter(adapter->dev.parent), addr);
+	if (!result && parent)
+		result = i2cdev_check_mux_parents(parent, addr);
 
 	return result;
 }
@@ -222,11 +221,11 @@ static int i2cdev_check_mux_children(struct device *dev, void *addrp)
    driver bound to it, as NOT busy. */
 static int i2cdev_check_addr(struct i2c_adapter *adapter, unsigned int addr)
 {
+	struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 	int result = 0;
 
-	if (i2c_parent_is_i2c_adapter(adapter))
-		result = i2cdev_check_mux_parents(
-				    to_i2c_adapter(adapter->dev.parent), addr);
+	if (parent)
+		result = i2cdev_check_mux_parents(parent, addr);
 
 	if (!result)
 		result = device_for_each_child(&adapter->dev, &addr,
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 4c9a99c4fcb..4d91d80bfd2 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -5,6 +5,16 @@
 menu "Multiplexer I2C Chip support"
 	depends on I2C_MUX
 
+config I2C_MUX_PCA9541
+	tristate "NXP PCA9541 I2C Master Selector"
+	depends on EXPERIMENTAL
+	help
+	  If you say yes here you get support for the NXP PCA9541
+	  I2C Master Selector.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called pca9541.
+
 config I2C_MUX_PCA954x
 	tristate "Philips PCA954x I2C Mux/switches"
 	depends on EXPERIMENTAL
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index bd83b527481..d743806d9b4 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -1,8 +1,7 @@
 #
 # Makefile for multiplexer I2C chip drivers.
 
+obj-$(CONFIG_I2C_MUX_PCA9541)	+= pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)	+= pca954x.o
 
-ifeq ($(CONFIG_I2C_DEBUG_BUS),y)
-EXTRA_CFLAGS += -DDEBUG
-endif
+ccflags-$(CONFIG_I2C_DEBUG_BUS) := -DDEBUG
diff --git a/drivers/i2c/muxes/pca9541.c b/drivers/i2c/muxes/pca9541.c
new file mode 100644
index 00000000000..ed699c5aa79
--- /dev/null
+++ b/drivers/i2c/muxes/pca9541.c
@@ -0,0 +1,411 @@
+/*
+ * I2C multiplexer driver for PCA9541 bus master selector
+ *
+ * Copyright (c) 2010 Ericsson AB.
+ *
+ * Author: Guenter Roeck <guenter.roeck@ericsson.com>
+ *
+ * Derived from:
+ *  pca954x.c
+ *
+ *  Copyright (c) 2008-2009 Rodolfo Giometti <giometti@linux.it>
+ *  Copyright (c) 2008-2009 Eurotech S.p.A. <info@eurotech.it>
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+
+#include <linux/i2c/pca954x.h>
+
+/*
+ * The PCA9541 is a bus master selector. It supports two I2C masters connected
+ * to a single slave bus.
+ *
+ * Before each bus transaction, a master has to acquire bus ownership. After the
+ * transaction is complete, bus ownership has to be released. This fits well
+ * into the I2C multiplexer framework, which provides select and release
+ * functions for this purpose. For this reason, this driver is modeled as
+ * single-channel I2C bus multiplexer.
+ *
+ * This driver assumes that the two bus masters are controlled by two different
+ * hosts. If a single host controls both masters, platform code has to ensure
+ * that only one of the masters is instantiated at any given time.
+ */
+
+#define PCA9541_CONTROL		0x01
+#define PCA9541_ISTAT		0x02
+
+#define PCA9541_CTL_MYBUS	(1 << 0)
+#define PCA9541_CTL_NMYBUS	(1 << 1)
+#define PCA9541_CTL_BUSON	(1 << 2)
+#define PCA9541_CTL_NBUSON	(1 << 3)
+#define PCA9541_CTL_BUSINIT	(1 << 4)
+#define PCA9541_CTL_TESTON	(1 << 6)
+#define PCA9541_CTL_NTESTON	(1 << 7)
+
+#define PCA9541_ISTAT_INTIN	(1 << 0)
+#define PCA9541_ISTAT_BUSINIT	(1 << 1)
+#define PCA9541_ISTAT_BUSOK	(1 << 2)
+#define PCA9541_ISTAT_BUSLOST	(1 << 3)
+#define PCA9541_ISTAT_MYTEST	(1 << 6)
+#define PCA9541_ISTAT_NMYTEST	(1 << 7)
+
+#define BUSON		(PCA9541_CTL_BUSON | PCA9541_CTL_NBUSON)
+#define MYBUS		(PCA9541_CTL_MYBUS | PCA9541_CTL_NMYBUS)
+#define mybus(x)	(!((x) & MYBUS) || ((x) & MYBUS) == MYBUS)
+#define busoff(x)	(!((x) & BUSON) || ((x) & BUSON) == BUSON)
+
+/* arbitration timeouts, in jiffies */
+#define ARB_TIMEOUT	(HZ / 8)	/* 125 ms until forcing bus ownership */
+#define ARB2_TIMEOUT	(HZ / 4)	/* 250 ms until acquisition failure */
+
+/* arbitration retry delays, in us */
+#define SELECT_DELAY_SHORT	50
+#define SELECT_DELAY_LONG	1000
+
+struct pca9541 {
+	struct i2c_adapter *mux_adap;
+	unsigned long select_timeout;
+	unsigned long arb_timeout;
+};
+
+static const struct i2c_device_id pca9541_id[] = {
+	{"pca9541", 0},
+	{}
+};
+
+MODULE_DEVICE_TABLE(i2c, pca9541_id);
+
+/*
+ * Write to chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
+ * as they will try to lock the adapter a second time.
+ */
+static int pca9541_reg_write(struct i2c_client *client, u8 command, u8 val)
+{
+	struct i2c_adapter *adap = client->adapter;
+	int ret;
+
+	if (adap->algo->master_xfer) {
+		struct i2c_msg msg;
+		char buf[2];
+
+		msg.addr = client->addr;
+		msg.flags = 0;
+		msg.len = 2;
+		buf[0] = command;
+		buf[1] = val;
+		msg.buf = buf;
+		ret = adap->algo->master_xfer(adap, &msg, 1);
+	} else {
+		union i2c_smbus_data data;
+
+		data.byte = val;
+		ret = adap->algo->smbus_xfer(adap, client->addr,
+					     client->flags,
+					     I2C_SMBUS_WRITE,
+					     command,
+					     I2C_SMBUS_BYTE_DATA, &data);
+	}
+
+	return ret;
+}
+
+/*
+ * Read from chip register. Don't use i2c_transfer()/i2c_smbus_xfer()
+ * as they will try to lock adapter a second time.
+ */
+static int pca9541_reg_read(struct i2c_client *client, u8 command)
+{
+	struct i2c_adapter *adap = client->adapter;
+	int ret;
+	u8 val;
+
+	if (adap->algo->master_xfer) {
+		struct i2c_msg msg[2] = {
+			{
+				.addr = client->addr,
+				.flags = 0,
+				.len = 1,
+				.buf = &command
+			},
+			{
+				.addr = client->addr,
+				.flags = I2C_M_RD,
+				.len = 1,
+				.buf = &val
+			}
+		};
+		ret = adap->algo->master_xfer(adap, msg, 2);
+		if (ret == 2)
+			ret = val;
+		else if (ret >= 0)
+			ret = -EIO;
+	} else {
+		union i2c_smbus_data data;
+
+		ret = adap->algo->smbus_xfer(adap, client->addr,
+					     client->flags,
+					     I2C_SMBUS_READ,
+					     command,
+					     I2C_SMBUS_BYTE_DATA, &data);
+		if (!ret)
+			ret = data.byte;
+	}
+	return ret;
+}
+
+/*
+ * Arbitration management functions
+ */
+
+/* Release bus. Also reset NTESTON and BUSINIT if it was set. */
+static void pca9541_release_bus(struct i2c_client *client)
+{
+	int reg;
+
+	reg = pca9541_reg_read(client, PCA9541_CONTROL);
+	if (reg >= 0 && !busoff(reg) && mybus(reg))
+		pca9541_reg_write(client, PCA9541_CONTROL,
+				  (reg & PCA9541_CTL_NBUSON) >> 1);
+}
+
+/*
+ * Arbitration is defined as a two-step process. A bus master can only activate
+ * the slave bus if it owns it; otherwise it has to request ownership first.
+ * This multi-step process ensures that access contention is resolved