12 files changed, 362 insertions, 48 deletions

diff --git a/Documentation/i2c/muxes/gpio-i2cmux b/Documentation/i2c/muxes/gpio-i2cmux
new file mode 100644
index 000000000000..811cd78d4cdc
--- /dev/null
+++ b/Documentation/i2c/muxes/gpio-i2cmux
@@ -0,0 +1,65 @@
+Kernel driver gpio-i2cmux
+
+Author: Peter Korsgaard <peter.korsgaard@barco.com>
+
+Description
+-----------
+
+gpio-i2cmux is an i2c mux driver providing access to I2C bus segments
+from a master I2C bus and a hardware MUX controlled through GPIO pins.
+
+E.G.:
+
+  ----------              ----------  Bus segment 1   - - - - -
+ |          | SCL/SDA    |          |-------------- |           |
+ |          |------------|          |
+ |          |            |          | Bus segment 2 |           |
+ |  Linux   | GPIO 1..N  |   MUX    |---------------   Devices
+ |          |------------|          |               |           |
+ |          |            |          | Bus segment M
+ |          |            |          |---------------|           |
+  ----------              ----------                  - - - - -
+
+SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M
+according to the settings of the GPIO pins 1..N.
+
+Usage
+-----
+
+gpio-i2cmux uses the platform bus, so you need to provide a struct
+platform_device with the platform_data pointing to a struct
+gpio_i2cmux_platform_data with the I2C adapter number of the master
+bus, the number of bus segments to create and the GPIO pins used
+to control it. See include/linux/gpio-i2cmux.h for details.
+
+E.G. something like this for a MUX providing 4 bus segments
+controlled through 3 GPIO pins:
+
+#include <linux/gpio-i2cmux.h>
+#include <linux/platform_device.h>
+
+static const unsigned myboard_gpiomux_gpios[] = {
+        AT91_PIN_PC26, AT91_PIN_PC25, AT91_PIN_PC24
+};
+
+static const unsigned myboard_gpiomux_values[] = {
+        0, 1, 2, 3
+};
+
+static struct gpio_i2cmux_platform_data myboard_i2cmux_data = {
+        .parent         = 1,
+        .base_nr        = 2, /* optional */
+        .values         = myboard_gpiomux_values,
+        .n_values       = ARRAY_SIZE(myboard_gpiomux_values),
+        .gpios          = myboard_gpiomux_gpios,
+        .n_gpios        = ARRAY_SIZE(myboard_gpiomux_gpios),
+        .idle           = 4, /* optional */
+};
+
+static struct platform_device myboard_i2cmux = {
+        .name           = "gpio-i2cmux",
+        .id             = 0,
+        .dev            = {
+                .platform_data  = &myboard_i2cmux_data,
+        },
+};
diff --git a/MAINTAINERS b/MAINTAINERS
index ad600c54c7bf..bb6c1ac85138 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2692,6 +2692,14 @@ S:	Supported
 F:      drivers/i2c/busses/i2c-gpio.c
 F:      include/linux/i2c-gpio.h
 
+GENERIC GPIO I2C MULTIPLEXER DRIVER
+M:      Peter Korsgaard <peter.korsgaard@barco.com>
+L:      linux-i2c@vger.kernel.org
+S:      Supported
+F:      drivers/i2c/muxes/gpio-i2cmux.c
+F:      include/linux/gpio-i2cmux.h
+F:      Documentation/i2c/muxes/gpio-i2cmux
+
 GENERIC HDLC (WAN) DRIVERS
 M:      Krzysztof Halasa <khc@pm.waw.pl>
 W:      http://www.kernel.org/pub/linux/utils/net/hdlc/
diff --git a/drivers/i2c/algos/i2c-algo-bit.c b/drivers/i2c/algos/i2c-algo-bit.c
index a39e6cff86e7..38319a69bd0a 100644
--- a/drivers/i2c/algos/i2c-algo-bit.c
+++ b/drivers/i2c/algos/i2c-algo-bit.c
@@ -600,12 +600,14 @@ static const struct i2c_algorithm i2c_bit_algo = {
 /*
  * registering functions to load algorithms at runtime
  */
-static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
+static int __i2c_bit_add_bus(struct i2c_adapter *adap,
+                             int (*add_adapter)(struct i2c_adapter *))
 {
         struct i2c_algo_bit_data *bit_adap = adap->algo_data;
+        int ret;
 
         if (bit_test) {
-                int ret = test_bus(bit_adap, adap->name);
+                ret = test_bus(bit_adap, adap->name);
                 if (ret < 0)
                         return -ENODEV;
         }
@@ -614,30 +616,27 @@ static int i2c_bit_prepare_bus(struct i2c_adapter *adap)
         adap->algo = &i2c_bit_algo;
         adap->retries = 3;
 
+        ret = add_adapter(adap);
+        if (ret < 0)
+                return ret;
+
+        /* Complain if SCL can't be read */
+        if (bit_adap->getscl == NULL) {
+                dev_warn(&adap->dev, "Not I2C compliant: can't read SCL\n");
+                dev_warn(&adap->dev, "Bus may be unreliable\n");
+        }
         return 0;
 }
 
 int i2c_bit_add_bus(struct i2c_adapter *adap)
 {
-        int err;
-
-        err = i2c_bit_prepare_bus(adap);
-        if (err)
-                return err;
-
-        return i2c_add_adapter(adap);
+        return __i2c_bit_add_bus(adap, i2c_add_adapter);
 }
 EXPORT_SYMBOL(i2c_bit_add_bus);
 
 int i2c_bit_add_numbered_bus(struct i2c_adapter *adap)
 {
-        int err;
-
-        err = i2c_bit_prepare_bus(adap);
-        if (err)
-                return err;
-
-        return i2c_add_numbered_adapter(adap);
+        return __i2c_bit_add_bus(adap, i2c_add_numbered_adapter);
 }
 EXPORT_SYMBOL(i2c_bit_add_numbered_bus);
 
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 02835ce7ff4b..7979aef7ee7b 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -72,6 +72,7 @@
 #include <linux/acpi.h>
 #include <linux/io.h>
 #include <linux/dmi.h>
+#include <linux/slab.h>
 
 /* I801 SMBus address offsets */
 #define SMBHSTSTS(p)    (0 + (p)->smba)
diff --git a/drivers/i2c/busses/i2c-nforce2.c b/drivers/i2c/busses/i2c-nforce2.c
index a605a5029cfe..ff1e127dfea8 100644
--- a/drivers/i2c/busses/i2c-nforce2.c
+++ b/drivers/i2c/busses/i2c-nforce2.c
@@ -432,7 +432,7 @@ static int __devinit nforce2_probe(struct pci_dev *dev, const struct pci_device_
 
 static void __devexit nforce2_remove(struct pci_dev *dev)
 {
-        struct nforce2_smbus *smbuses = (void*) pci_get_drvdata(dev);
+        struct nforce2_smbus *smbuses = pci_get_drvdata(dev);
 
         nforce2_set_reference(NULL);
         if (smbuses[0].base) {
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 6b4cc567645b..c7db6980e3a3 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1362,7 +1362,7 @@ EXPORT_SYMBOL(i2c_transfer);
  *
  * Returns negative errno, or else the number of bytes written.
  */
-int i2c_master_send(struct i2c_client *client, const char *buf, int count)
+int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
 {
         int ret;
         struct i2c_adapter *adap = client->adapter;
@@ -1389,7 +1389,7 @@ EXPORT_SYMBOL(i2c_master_send);
  *
  * Returns negative errno, or else the number of bytes read.
  */
-int i2c_master_recv(struct i2c_client *client, char *buf, int count)
+int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
 {
         struct i2c_adapter *adap = client->adapter;
         struct i2c_msg msg;
@@ -1679,7 +1679,7 @@ static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
  * This executes the SMBus "receive byte" protocol, returning negative errno
  * else the byte received from the device.
  */
-s32 i2c_smbus_read_byte(struct i2c_client *client)
+s32 i2c_smbus_read_byte(const struct i2c_client *client)
 {
         union i2c_smbus_data data;
         int status;
@@ -1699,7 +1699,7 @@ EXPORT_SYMBOL(i2c_smbus_read_byte);
  * This executes the SMBus "send byte" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value)
+s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value)
 {
         return i2c_smbus_xfer(client->adapter, client->addr, client->flags,
                               I2C_SMBUS_WRITE, value, I2C_SMBUS_BYTE, NULL);
@@ -1714,7 +1714,7 @@ EXPORT_SYMBOL(i2c_smbus_write_byte);
  * This executes the SMBus "read byte" protocol, returning negative errno
  * else a data byte received from the device.
  */
-s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
+s32 i2c_smbus_read_byte_data(const struct i2c_client *client, u8 command)
 {
         union i2c_smbus_data data;
         int status;
@@ -1735,7 +1735,8 @@ EXPORT_SYMBOL(i2c_smbus_read_byte_data);
  * This executes the SMBus "write byte" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_byte_data(struct i2c_client *client, u8 command, u8 value)
+s32 i2c_smbus_write_byte_data(const struct i2c_client *client, u8 command,
+                              u8 value)
 {
         union i2c_smbus_data data;
         data.byte = value;
@@ -1753,7 +1754,7 @@ EXPORT_SYMBOL(i2c_smbus_write_byte_data);
  * This executes the SMBus "read word" protocol, returning negative errno
  * else a 16-bit unsigned "word" received from the device.
  */
-s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
+s32 i2c_smbus_read_word_data(const struct i2c_client *client, u8 command)
 {
         union i2c_smbus_data data;
         int status;
@@ -1774,7 +1775,8 @@ EXPORT_SYMBOL(i2c_smbus_read_word_data);
  * This executes the SMBus "write word" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_word_data(struct i2c_client *client, u8 command, u16 value)
+s32 i2c_smbus_write_word_data(const struct i2c_client *client, u8 command,
+                              u16 value)
 {
         union i2c_smbus_data data;
         data.word = value;
@@ -1793,7 +1795,8 @@ EXPORT_SYMBOL(i2c_smbus_write_word_data);
  * This executes the SMBus "process call" protocol, returning negative errno
  * else a 16-bit unsigned "word" received from the device.
  */
-s32 i2c_smbus_process_call(struct i2c_client *client, u8 command, u16 value)
+s32 i2c_smbus_process_call(const struct i2c_client *client, u8 command,
+                           u16 value)
 {
         union i2c_smbus_data data;
         int status;
@@ -1821,7 +1824,7 @@ EXPORT_SYMBOL(i2c_smbus_process_call);
  * support this; its emulation through I2C messaging relies on a specific
  * mechanism (I2C_M_RECV_LEN) which may not be implemented.
  */
-s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_read_block_data(const struct i2c_client *client, u8 command,
                               u8 *values)
 {
         union i2c_smbus_data data;
@@ -1848,7 +1851,7 @@ EXPORT_SYMBOL(i2c_smbus_read_block_data);
  * This executes the SMBus "block write" protocol, returning negative errno
  * else zero on success.
  */
-s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_write_block_data(const struct i2c_client *client, u8 command,
                                u8 length, const u8 *values)
 {
         union i2c_smbus_data data;
@@ -1864,7 +1867,7 @@ s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
 EXPORT_SYMBOL(i2c_smbus_write_block_data);
 
 /* Returns the number of read bytes */
-s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client, u8 command,
                                   u8 length, u8 *values)
 {
         union i2c_smbus_data data;
@@ -1884,7 +1887,7 @@ s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
 }
 EXPORT_SYMBOL(i2c_smbus_read_i2c_block_data);
 
-s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client, u8 command,
+s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command,
                                    u8 length, const u8 *values)
 {
         union i2c_smbus_data data;
diff --git a/drivers/i2c/muxes/Kconfig b/drivers/i2c/muxes/Kconfig
index 4d91d80bfd23..90b7a0163899 100644
--- a/drivers/i2c/muxes/Kconfig
+++ b/drivers/i2c/muxes/Kconfig
@@ -5,6 +5,18 @@
 menu "Multiplexer I2C Chip support"
         depends on I2C_MUX
 
+config I2C_MUX_GPIO
+        tristate "GPIO-based I2C multiplexer"
+        depends on GENERIC_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.
+
+          This driver can also be built as a module.  If so, the module
+          will be called gpio-i2cmux.
+
 config I2C_MUX_PCA9541
         tristate "NXP PCA9541 I2C Master Selector"
         depends on EXPERIMENTAL
diff --git a/drivers/i2c/muxes/Makefile b/drivers/i2c/muxes/Makefile
index d743806d9b42..4640436ea61f 100644
--- a/drivers/i2c/muxes/Makefile
+++ b/drivers/i2c/muxes/Makefile
@@ -1,6 +1,7 @@
 #
 # Makefile for multiplexer I2C chip drivers.
 
+obj-$(CONFIG_I2C_MUX_GPIO)      += gpio-i2cmux.o
 obj-$(CONFIG_I2C_MUX_PCA9541)   += pca9541.o
 obj-$(CONFIG_I2C_MUX_PCA954x)   += pca954x.o
 
diff --git a/drivers/i2c/muxes/gpio-i2cmux.c b/drivers/i2c/muxes/gpio-i2cmux.c
new file mode 100644
index 000000000000..7b6ce624cd6e
--- /dev/null
+++ b/drivers/i2c/muxes/gpio-i2cmux.c
@@ -0,0 +1,184 @@
+/*
+ * I2C multiplexer using GPIO API
+ *
+ * Peter Korsgaard <peter.korsgaard@barco.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/i2c.h>
+#include <linux/i2c-mux.h>
+#include <linux/gpio-i2cmux.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+
+struct gpiomux {
+        struct i2c_adapter *parent;
+        struct i2c_adapter **adap; /* child busses */
+        struct gpio_i2cmux_platform_data data;
+};
+
+static void gpiomux_set(const struct gpiomux *mux, unsigned val)
+{
+        int i;
+
+        for (i = 0; i < mux->data.n_gpios; i++)
+                gpio_set_value(mux->data.gpios[i], val & (1 << i));
+}
+
+static int gpiomux_select(struct i2c_adapter *adap, void *data, u32 chan)
+{
+        struct gpiomux *mux = data;
+
+        gpiomux_set(mux, mux->data.values[chan]);
+
+        return 0;
+}
+
+static int gpiomux_deselect(struct i2c_adapter *adap, void *data, u32 chan)
+{
+        struct gpiomux *mux = data;
+
+        gpiomux_set(mux, mux->data.idle);
+
+        return 0;
+}
+
+static int __devinit gpiomux_probe(struct platform_device *pdev)
+{
+        struct gpiomux *mux;
+        struct gpio_i2cmux_platform_data *pdata;
+        struct i2c_adapter *parent;
+        int (*deselect) (struct i2c_adapter *, void *, u32);
+        unsigned initial_state;
+        int i, ret;
+
+        pdata = pdev->dev.platform_data;
+        if (!pdata) {
+                dev_err(&pdev->dev, "Missing platform data\n");
+                return -ENODEV;
+        }
+
+        parent = i2c_get_adapter(pdata->parent);
+        if (!parent) {
+                dev_err(&pdev->dev, "Parent adapter (%d) not found\n",
+                        pdata->parent);
+                return -ENODEV;
+        }
+
+        mux = kzalloc(sizeof(*mux), GFP_KERNEL);
+        if (!mux) {
+                ret = -ENOMEM;
+                goto alloc_failed;
+        }
+
+        mux->parent = parent;
+        mux->data = *pdata;
+        mux->adap = kzalloc(sizeof(struct i2c_adapter *) * pdata->n_values,
+                            GFP_KERNEL);
+        if (!mux->adap) {
+                ret = -ENOMEM;
+                goto alloc_failed2;
+        }
+
+        if (pdata->idle != GPIO_I2CMUX_NO_IDLE) {
+                initial_state = pdata->idle;
+                deselect = gpiomux_deselect;
+        } else {
+                initial_state = pdata->values[0];
+                deselect = NULL;
+        }
+
+        for (i = 0; i < pdata->n_gpios; i++) {
+                ret = gpio_request(pdata->gpios[i], "gpio-i2cmux");
+                if (ret)
+                        goto err_request_gpio;
+                gpio_direction_output(pdata->gpios[i],
+                                      initial_state & (1 << i));
+        }
+
+        for (i = 0; i < pdata->n_values; i++) {
+                u32 nr = pdata->base_nr ? (pdata->base_nr + i) : 0;
+
+                mux->adap[i] = i2c_add_mux_adapter(parent, mux, nr, i,
+                                                   gpiomux_select, deselect);
+                if (!mux->adap[i]) {
+                        ret = -ENODEV;
+                        dev_err(&pdev->dev, "Failed to add adapter %d\n", i);
+                        goto add_adapter_failed;
+                }
+        }
+
+        dev_info(&pdev->dev, "%d port mux on %s adapter\n",
+                 pdata->n_values, parent->name);
+
+        platform_set_drvdata(pdev, mux);
+
+        return 0;
+
+add_adapter_failed:
+        for (; i > 0; i--)
+                i2c_del_mux_adapter(mux->adap[i - 1]);
+        i = pdata->n_gpios;
+err_request_gpio:
+        for (; i > 0; i--)
+                gpio_free(pdata->gpios[i - 1]);
+        kfree(mux->adap);
+alloc_failed2:
+        kfree(mux);
+alloc_failed:
+        i2c_put_adapter(parent);
+
+        return ret;
+}
+
+static int __devexit gpiomux_remove(struct platform_device *pdev)
+{
+        struct gpiomux *mux = platform_get_drvdata(pdev);
+        int i;
+
+        for (i = 0; i < mux->data.n_values; i++)
+                i2c_del_mux_adapter(mux->adap[i]);
+
+        for (i = 0; i < mux->data.n_gpios; i++)
+                gpio_free(mux->data.gpios[i]);
+
+        platform_set_drvdata(pdev, NULL);
+        i2c_put_adapter(mux->parent);
+        kfree(mux->adap);
+        kfree(mux);
+
+        return 0;
+}
+
+static struct platform_driver gpiomux_driver = {
+        .probe  = gpiomux_probe,
+        .remove = __devexit_p(gpiomux_remove),
+        .driver = {
+                .owner  = THIS_MODULE,
+                .name   = "gpio-i2cmux",
+        },
+};
+
+static int __init gpiomux_init(void)
+{
+        return platform_driver_register(&gpiomux_driver);
+}
+
+static void __exit gpiomux_exit(void)
+{
+        platform_driver_unregister(&gpiomux_driver);
+}
+
+module_init(gpiomux_init);
+module_exit(gpiomux_exit);
+
+MODULE_DESCRIPTION("GPIO-based I2C multiplexer driver");
+MODULE_AUTHOR("Peter Korsgaard <peter.korsgaard@barco.com>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:gpio-i2cmux");
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index d827ce570a8c..0d559b6416dd 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -106,9 +106,9 @@ struct ds1307 {
         struct i2c_client       *client;
         struct rtc_device       *rtc;
         struct work_struct      work;
-        s32 (*read_block_data)(struct i2c_client *client, u8 command,
+        s32 (*read_block_data)(const struct i2c_client *client, u8 command,
                                u8 length, u8 *values);
-        s32 (*write_block_data)(struct i2c_client *client, u8 command,
+        s32 (*write_block_data)(const struct i2c_client *client, u8 command,
                                 u8 length, const u8 *values);
 };
 
@@ -158,8 +158,8 @@ MODULE_DEVICE_TABLE(i2c, ds1307_id);
 
 #define BLOCK_DATA_MAX_TRIES 10
 
-static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,
-                                  u8 length, u8 *values)
+static s32 ds1307_read_block_data_once(const struct i2c_client *client,
+                                       u8 command, u8 length, u8 *values)
 {
         s32 i, data;
 
@@ -172,7 +172,7 @@ static s32 ds1307_read_block_data_once(struct i2c_client *client, u8 command,
         return i;
 }
 
-static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,
+static s32 ds1307_read_block_data(const struct i2c_client *client, u8 command,
                                   u8 length, u8 *values)
 {
         u8 oldvalues[I2C_SMBUS_BLOCK_MAX];
@@ -198,7 +198,7 @@ static s32 ds1307_read_block_data(struct i2c_client *client, u8 command,
         return length;
 }
 
-static s32 ds1307_write_block_data(struct i2c_client *client, u8 command,
+static s32 ds1307_write_block_data(const struct i2c_client *client, u8 command,
                                    u8 length, const u8 *values)
 {
         u8 currvalues[I2C_SMBUS_BLOCK_MAX];
diff --git a/include/linux/gpio-i2cmux.h b/include/linux/gpio-i2cmux.h
new file mode 100644
index 000000000000..4a333bb0bd0d
--- /dev/null
+++ b/include/linux/gpio-i2cmux.h
@@ -0,0 +1,38 @@
+/*
+ * gpio-i2cmux interface to platform code
+ *
+ * Peter Korsgaard <peter.korsgaard@barco.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef _LINUX_GPIO_I2CMUX_H
+#define _LINUX_GPIO_I2CMUX_H
+
+/* MUX has no specific idle mode */
+#define GPIO_I2CMUX_NO_IDLE     ((unsigned)-1)
+
+/**
+ * struct gpio_i2cmux_platform_data - Platform-dependent data for gpio-i2cmux
+ * @parent: Parent I2C bus adapter number
+ * @base_nr: Base I2C bus number to number adapters from or zero for dynamic
+ * @values: Array of bitmasks of GPIO settings (low/high) for each
+ *      position
+ * @n_values: Number of multiplexer positions (busses to instantiate)
+ * @gpios: Array of GPIO numbers used to control MUX
+ * @n_gpios: Number of GPIOs used to control MUX
+ * @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used
+ */
+struct gpio_i2cmux_platform_data {
+        int parent;
+        int base_nr;
+        const unsigned *values;
+        int n_values;
+        const unsigned *gpios;
+        int n_gpios;
+        unsigned idle;
+};
+
+#endif /* _LINUX_GPIO_I2CMUX_H */
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 56cfe23ffb39..903576df88dc 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -57,9 +57,10 @@ struct i2c_board_info;
  * transmit an arbitrary number of messages without interruption.
  * @count must be be less than 64k since msg.len is u16.
  */
-extern int i2c_master_send(struct i2c_client *client, const char *buf,
+extern int i2c_master_send(const struct i2c_client *client, const char *buf,
+                           int count);
+extern int i2c_master_recv(const struct i2c_client *client, char *buf,
                            int count);
-extern int i2c_master_recv(struct i2c_client *client, char *buf, int count);
 
 /* Transfer num messages.
  */
@@ -78,23 +79,25 @@ extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
 /* Now follow the 'nice' access routines. These also document the calling
    conventions of i2c_smbus_xfer. */
 
-extern s32 i2c_smbus_read_byte(struct i2c_client *client);
-extern s32 i2c_smbus_write_byte(struct i2c_client *client, u8 value);
-extern s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command);
-extern s32 i2c_smbus_write_byte_data(struct i2c_client *client,
+extern s32 i2c_smbus_read_byte(const struct i2c_client *client);
+extern s32 i2c_smbus_write_byte(const struct i2c_client *client, u8 value);
+extern s32 i2c_smbus_read_byte_data(const struct i2c_client *client,
+                                    u8 command);
+extern s32 i2c_smbus_write_byte_data(const struct i2c_client *client,
                                      u8 command, u8 value);
-extern s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command);
-extern s32 i2c_smbus_write_word_data(struct i2c_client *client,
+extern s32 i2c_smbus_read_word_data(const struct i2c_client *client,
+                                    u8 command);
+extern s32 i2c_smbus_write_word_data(const struct i2c_client *client,
                                      u8 command, u16 value);
 /* Returns the number of read bytes */
-extern s32 i2c_smbus_read_block_data(struct i2c_client *client,
+extern s32 i2c_smbus_read_block_data(const struct i2c_client *client,
                                      u8 command, u8 *values);
-extern s32 i2c_smbus_write_block_data(struct i2c_client *client,
+extern s32 i2c_smbus_write_block_data(const struct i2c_client *client,
                                       u8 command, u8 length, const u8 *values);
 /* Returns the number of read bytes */
-extern s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client,
+extern s32 i2c_smbus_read_i2c_block_data(const struct i2c_client *client,
                                          u8 command, u8 length, u8 *values);
-extern s32 i2c_smbus_write_i2c_block_data(struct i2c_client *client,
+extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
                                           u8 command, u8 length,
                                           const u8 *values);
 #endif /* I2C */