i2c: Rename the PEC functionality bit

Rename I2C_FUNC_SMBUS_HWPEC_CALC as I2C_FUNC_SMBUS_PEC, and list that
functionality as always available through the software implementation.
Update documentation accordingly (and list similar requirements).

The way it's currently packaged doesn't present the capability in a
useful way.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

Documentation/i2c/dev-interface

@@ -90,12 +90,15 @@ ioctl(file,I2C_SLAVE,long addr)
 
 ioctl(file,I2C_TENBIT,long select)
   Selects ten bit addresses if select not equals 0, selects normal 7 bit
-  addresses if select equals 0. Default 0.
+  addresses if select equals 0. Default 0.  This request is only valid
+  if the adapter has I2C_FUNC_10BIT_ADDR.
 
 ioctl(file,I2C_PEC,long select)
   Selects SMBus PEC (packet error checking) generation and verification
   if select not equals 0, disables if select equals 0. Default 0.
-  Used only for SMBus transactions.
+  Used only for SMBus transactions.  This request only has an effect if the
+  the adapter has I2C_FUNC_SMBUS_PEC; it is still safe if not, it just
+  doesn't have any effect.
 
 ioctl(file,I2C_FUNCS,unsigned long *funcs)
   Gets the adapter functionality and puts it in *funcs.
@@ -103,8 +106,10 @@ ioctl(file,I2C_FUNCS,unsigned long *funcs)
 ioctl(file,I2C_RDWR,struct i2c_rdwr_ioctl_data *msgset)
 
   Do combined read/write transaction without stop in between.
-  The argument is a pointer to a struct i2c_rdwr_ioctl_data {
+  Only valid if the adapter has I2C_FUNC_I2C.  The argument is
+  a pointer to a
 
+  struct i2c_rdwr_ioctl_data {
       struct i2c_msg *msgs;  /* ptr to array of simple messages */
       int nmsgs;             /* number of messages to exchange */
   }

drivers/i2c/busses/i2c-amd8111.c

@@ -326,7 +326,7 @@ static u32 amd8111_func(struct i2c_adapter *adapter)
 		I2C_FUNC_SMBUS_BYTE_DATA |
 		I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_BLOCK_DATA |
 		I2C_FUNC_SMBUS_PROC_CALL | I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
-		I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_HWPEC_CALC;
+		I2C_FUNC_SMBUS_I2C_BLOCK | I2C_FUNC_SMBUS_PEC;
 }
 
 static const struct i2c_algorithm smbus_algorithm = {

drivers/i2c/busses/i2c-i801.c

@@ -516,7 +516,7 @@ static u32 i801_func(struct i2c_adapter *adapter)
 	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 	    I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 	    I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK
-	     | (isich4 ? I2C_FUNC_SMBUS_HWPEC_CALC : 0);
+	     | (isich4 ? I2C_FUNC_SMBUS_PEC : 0);
 }
 
 static const struct i2c_algorithm smbus_algorithm = {

include/linux/i2c.h

@@ -491,7 +491,7 @@ struct i2c_msg {
 #define I2C_FUNC_I2C			0x00000001
 #define I2C_FUNC_10BIT_ADDR		0x00000002
 #define I2C_FUNC_PROTOCOL_MANGLING	0x00000004 /* I2C_M_{REV_DIR_ADDR,NOSTART,..} */
-#define I2C_FUNC_SMBUS_HWPEC_CALC	0x00000008 /* SMBus 2.0 */
+#define I2C_FUNC_SMBUS_PEC		0x00000008
 #define I2C_FUNC_SMBUS_BLOCK_PROC_CALL	0x00008000 /* SMBus 2.0 */
 #define I2C_FUNC_SMBUS_QUICK		0x00010000
 #define I2C_FUNC_SMBUS_READ_BYTE	0x00020000
@@ -527,7 +527,8 @@ struct i2c_msg {
                              I2C_FUNC_SMBUS_WORD_DATA | \
                              I2C_FUNC_SMBUS_PROC_CALL | \
                              I2C_FUNC_SMBUS_WRITE_BLOCK_DATA | \
-                             I2C_FUNC_SMBUS_I2C_BLOCK)
+			     I2C_FUNC_SMBUS_I2C_BLOCK | \
+			     I2C_FUNC_SMBUS_PEC)
 
 /*
  * Data for SMBus Messages