i2c: import SMBus stuff from linux

This patch imports i2c_smbus_{read,write}* functions from linux-3.15.

Here is a quote from linux.git/Documentation/i2c/smbus-protocol:

    If you write a driver for some I2C device, please try to use the SMBus
    commands if at all possible (if the device uses only that subset of the
    I2C protocol). This makes it possible to use the device driver on both
    SMBus adapters and I2C adapters (the SMBus command set is automatically
    translated to I2C on I2C adapters, but plain I2C commands can not be
    handled at all on most pure SMBus adapters).

So having i2c_smbus_{read,write}* functions in barebox makes
porting of linux i2c client drivers much easier as many drivers rely on
these smbus functions.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 57 insertions, 0 deletions

diff --git a/include/i2c/i2c.h b/include/i2c/i2c.h
index a107f5edb7..4696f43e31 100644
--- a/include/i2c/i2c.h
+++ b/include/i2c/i2c.h
@@ -85,6 +85,63 @@ struct i2c_client {
 
 #define to_i2c_client(a)	container_of(a, struct i2c_client, dev)
 
+/*flags for the client struct: */
+#define I2C_CLIENT_PEC	0x04		/* Use Packet Error Checking */
+#define I2C_CLIENT_SCCB	0x9000		/* Use Omnivision SCCB protocol */
+					/* Must match I2C_M_STOP|IGNORE_NAK */
+
+/*
+ * Data for SMBus Messages
+ */
+#define I2C_SMBUS_BLOCK_MAX	32	/* As specified in SMBus standard */
+union i2c_smbus_data {
+	__u8 byte;
+	__u16 word;
+	__u8 block[I2C_SMBUS_BLOCK_MAX + 2]; /* block[0] is used for length */
+			       /* and one more for user-space compatibility */
+};
+
+/* i2c_smbus_xfer read or write markers */
+#define I2C_SMBUS_READ	1
+#define I2C_SMBUS_WRITE	0
+
+/* SMBus transaction types (size parameter in the above functions)
+   Note: these no longer correspond to the (arbitrary) PIIX4 internal codes! */
+#define I2C_SMBUS_QUICK		    0
+#define I2C_SMBUS_BYTE		    1
+#define I2C_SMBUS_BYTE_DATA	    2
+#define I2C_SMBUS_WORD_DATA	    3
+#define I2C_SMBUS_I2C_BLOCK_DATA    8
+
+/* This is the very generalized SMBus access routine. You probably do not
+   want to use this, though; one of the functions below may be much easier,
+   and probably just as fast.
+   Note that we use i2c_adapter here, because you do not need a specific
+   smbus adapter to call this function. */
+extern s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
+			  unsigned short flags, char read_write, u8 command,
+			  int size, union i2c_smbus_data *data);
+
+/* Now follow the 'nice' access routines. These also document the calling
+   conventions of i2c_smbus_xfer. */
+
+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(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_i2c_block_data(const struct i2c_client *client,
+					 u8 command, u8 length, u8 *values);
+extern s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client,
+					  u8 command, u8 length,
+					  const u8 *values);
 
 /**
  * struct i2c_board_info - template for device creation