Merge branch 'i2c-for-linus' of git://jdelvare.pck.nerim.net/jdelvare-2.6

  * VIA Technologies, Inc. CX700

    Datasheet: available on request and under NDA from VIA

  * VIA Technologies, Inc. VX800/VX820

    Datasheet: available on http://linux.via.com.tw

Authors:

	Kyösti Mälkki <kmalkki@cc.hut.fi>,

	Mark D. Studebaker <mdsxyz123@yahoo.com>,

 device 1106:3372   (VT8237S)

 device 1106:3287   (VT8251)

 device 1106:8324   (CX700)

 device 1106:8353   (VX800/VX820)

If none of these show up, you should look in the BIOS for settings like

enable ACPI / SMBus or even USB.

VT8231), this driver supports I2C block transactions. Such transactions

are mainly useful to read from and write to EEPROMs.

The CX700 additionally appears to support SMBus PEC, although this driver

doesn't implement it yet.

The CX700/VX800/VX820 additionally appears to support SMBus PEC, although

this driver doesn't implement it yet.

Each registered i2c adapter gets a number, counting from 0. You can

examine /sys/class/i2c-dev/ to see what number corresponds to which adapter.

Alternatively, you can run "i2cdetect -l" to obtain a formated list of all

i2c adapters present on your system at a given time. i2cdetect is part of

the i2c-tools package.

I2C device files are character device files with major device number 89

and a minor device number corresponding to the number assigned as 

explained above. They should be called "i2c-%d" (i2c-0, i2c-1, ..., 

first thing to do is "#include <linux/i2c-dev.h>". Please note that

there are two files named "i2c-dev.h" out there, one is distributed

with the Linux kernel and is meant to be included from kernel

driver code, the other one is distributed with lm_sensors and is

driver code, the other one is distributed with i2c-tools and is

meant to be included from user-space programs. You obviously want

the second one here.

Now, you have to decide which adapter you want to access. You should

inspect /sys/class/i2c-dev/ to decide this. Adapter numbers are assigned

somewhat dynamically, so you can not even assume /dev/i2c-0 is the

first adapter.

inspect /sys/class/i2c-dev/ or run "i2cdetect -l" to decide this.

Adapter numbers are assigned somewhat dynamically, so you can not

assume much about them. They can even change from one boot to the next.

Next thing, open the device file, as follows:

  int file;

  int adapter_nr = 2; /* probably dynamically determined */

  char filename[20];

  sprintf(filename,"/dev/i2c-%d",adapter_nr);

  if ((file = open(filename,O_RDWR)) < 0) {

  snprintf(filename, 19, "/dev/i2c-%d", adapter_nr);

  file = open(filename, O_RDWR);

  if (file < 0) {

    /* ERROR HANDLING; you can check errno to see what went wrong */

    exit(1);

  }

When you have opened the device, you must specify with what device

address you want to communicate:

  int addr = 0x40; /* The I2C address */

  if (ioctl(file, I2C_SLAVE, addr) < 0) {

    /* ERROR HANDLING; you can check errno to see what went wrong */

    exit(1);

Well, you are all set up now. You can now use SMBus commands or plain

I2C to communicate with your device. SMBus commands are preferred if

the device supports them. Both are illustrated below.

  __u8 register = 0x10; /* Device register to access */

  __s32 res;

  char buf[10];

  /* Using SMBus commands */

  res = i2c_smbus_read_word_data(file, register);

  if (res < 0) {

  } else {

    /* res contains the read word */

  }

  /* Using I2C Write, equivalent of 

     i2c_smbus_write_word_data(file, register, 0x6543) */

  buf[0] = register;

  if (write(file, buf, 3) ! =3) {

    /* ERROR HANDLING: i2c transaction failed */

  }

  /* Using I2C Read, equivalent of i2c_smbus_read_byte(file) */

  if (read(file, buf, 1) != 1) {

    /* ERROR HANDLING: i2c transaction failed */

    /* buf[0] contains the read byte */

  }

Note that only a subset of the I2C and SMBus protocols can be achieved by

the means of read() and write() calls. In particular, so-called combined

transactions (mixing read and write messages in the same transaction)

aren't supported. For this reason, this interface is almost never used by

user-space programs.

IMPORTANT: because of the use of inline functions, you *have* to use

'-O' or some variation when you compile your program!

Full interface description

==========================

The following IOCTLs are defined and fully supported 

(see also i2c-dev.h):

The following IOCTLs are defined:

ioctl(file, I2C_SLAVE, long addr)

  Change slave address. The address is passed in the 7 lower bits of the

  Gets the adapter functionality and puts it in *funcs.

ioctl(file, I2C_RDWR, struct i2c_rdwr_ioctl_data *msgset)

  Do combined read/write transaction without stop in between.

  Only valid if the adapter has I2C_FUNC_I2C.  The argument is

  a pointer to a

  The slave address and whether to use ten bit address mode has to be

  set in each message, overriding the values set with the above ioctl's.

Other values are NOT supported at this moment, except for I2C_SMBUS,

which you should never directly call; instead, use the access functions

ioctl(file, I2C_SMBUS, struct i2c_smbus_ioctl_data *args)

  Not meant to be called  directly; instead, use the access functions

  below.

You can do plain i2c transactions by using read(2) and write(2) calls.

returns the number of values read. The block buffers need not be longer

than 32 bytes.

The above functions are all macros, that resolve to calls to the

i2c_smbus_access function, that on its turn calls a specific ioctl

The above functions are all inline functions, that resolve to calls to

the i2c_smbus_access function, that on its turn calls a specific ioctl

with the data in a specific format. Read the source code if you

want to know what happens behind the screens.

Implementation details

======================

For the interested, here's the code flow which happens inside the kernel

when you use the /dev interface to I2C:

1* Your program opens /dev/i2c-N and calls ioctl() on it, as described in

section "C example" above.

2* These open() and ioctl() calls are handled by the i2c-dev kernel

driver: see i2c-dev.c:i2cdev_open() and i2c-dev.c:i2cdev_ioctl(),

respectively. You can think of i2c-dev as a generic I2C chip driver

that can be programmed from user-space.

3* Some ioctl() calls are for administrative tasks and are handled by

i2c-dev directly. Examples include I2C_SLAVE (set the address of the

device you want to access) and I2C_PEC (enable or disable SMBus error

checking on future transactions.)

4* Other ioctl() calls are converted to in-kernel function calls by

i2c-dev. Examples include I2C_FUNCS, which queries the I2C adapter

functionality using i2c.h:i2c_get_functionality(), and I2C_SMBUS, which

performs an SMBus transaction using i2c-core.c:i2c_smbus_xfer().

The i2c-dev driver is responsible for checking all the parameters that

come from user-space for validity. After this point, there is no

difference between these calls that came from user-space through i2c-dev

and calls that would have been performed by kernel I2C chip drivers

directly. This means that I2C bus drivers don't need to implement

anything special to support access from user-space.

5* These i2c-core.c/i2c.h functions are wrappers to the actual

implementation of your I2C bus driver. Each adapter must declare

callback functions implementing these standard calls.

i2c.h:i2c_get_functionality() calls i2c_adapter.algo->functionality(),

while i2c-core.c:i2c_smbus_xfer() calls either

adapter.algo->smbus_xfer() if it is implemented, or if not,

i2c-core.c:i2c_smbus_xfer_emulated() which in turn calls

i2c_adapter.algo->master_xfer().

After your I2C bus driver has processed these requests, execution runs

up the call chain, with almost no processing done, except by i2c-dev to

package the returned data, if any, in suitable format for the ioctl.

S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] P

SMBus Process Call

==================

SMBus Process Call:  i2c_smbus_process_call()

=============================================

This command selects a device register (through the Comm byte), sends

16 bits of data to it, and reads 16 bits of data in return.

  extern s32 i2c_smbus_read_word_data(struct i2c_client * client, u8 command);

  extern s32 i2c_smbus_write_word_data(struct i2c_client * client,

                                       u8 command, u16 value);

  extern s32 i2c_smbus_process_call(struct i2c_client *client,

                                    u8 command, u16 value);

  extern s32 i2c_smbus_read_block_data(struct i2c_client * client,

                                       u8 command, u8 *values);

  extern s32 i2c_smbus_write_block_data(struct i2c_client * client,

be added back later if needed:

  extern s32 i2c_smbus_write_quick(struct i2c_client * client, u8 value);

  extern s32 i2c_smbus_process_call(struct i2c_client * client,

                                    u8 command, u16 value);

  extern s32 i2c_smbus_block_process_call(struct i2c_client *client,

                                          u8 command, u8 length,

                                          u8 *values)

		I2C_BOARD_INFO("tps65013", 0x48),

               /* .irq         = OMAP_GPIO_IRQ(??), */

       },

	{

		I2C_BOARD_INFO("isp1301_omap", 0x2d),

		.irq		= OMAP_GPIO_IRQ(14),

	},

};

static struct omap_gpio_switch h3_gpio_switches[] __initdata = {