i2c-powermac: Refactor i2c_powermac_smbus_xfer

I wanted to add some error logging to the i2c-powermac driver, but
found that it was very difficult due to the way the
i2c_powermac_smbus_xfer function is organized. Refactor the code in
this function so that each low-level function is only called once.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Michel Daenzer <michel@daenzer.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>

diff --git a/drivers/i2c/busses/i2c-powermac.c b/drivers/i2c/busses/i2c-powermac.c
index a74f3ba..dba8e38 100644 (file)
--- a/drivers/i2c/busses/i2c-powermac.c
+++ b/drivers/i2c/busses/i2c-powermac.c
@@ -49,48 +49,38 @@ static s32 i2c_powermac_smbus_xfer( struct i2c_adapter*     adap,
        int                     rc = 0;
        int                     read = (read_write == I2C_SMBUS_READ);
        int                     addrdir = (addr << 1) | read;
+       int                     mode, subsize, len;
+       u32                     subaddr;
+       u8                      *buf;
        u8                      local[2];
 
-       rc = pmac_i2c_open(bus, 0);
-       if (rc)
-               return rc;
+       if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
+               mode = pmac_i2c_mode_std;
+               subsize = 0;
+               subaddr = 0;
+       } else {
+               mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
+               subsize = 1;
+               subaddr = command;
+       }
 
        switch (size) {
         case I2C_SMBUS_QUICK:
-               rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
-               if (rc)
-                       goto bail;
-               rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
+               buf = NULL;
+               len = 0;
                break;
         case I2C_SMBUS_BYTE:
-               rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
-               if (rc)
-                       goto bail;
-               rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
-               break;
         case I2C_SMBUS_BYTE_DATA:
-               rc = pmac_i2c_setmode(bus, read ?
-                                     pmac_i2c_mode_combined :
-                                     pmac_i2c_mode_stdsub);
-               if (rc)
-                       goto bail;
-               rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
+               buf = &data->byte;
+               len = 1;
                break;
         case I2C_SMBUS_WORD_DATA:
-               rc = pmac_i2c_setmode(bus, read ?
-                                     pmac_i2c_mode_combined :
-                                     pmac_i2c_mode_stdsub);
-               if (rc)
-                       goto bail;
                if (!read) {
                        local[0] = data->word & 0xff;
                        local[1] = (data->word >> 8) & 0xff;
                }
-               rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
-               if (rc == 0 && read) {
-                       data->word = ((u16)local[1]) << 8;
-                       data->word |= local[0];
-               }
+               buf = local;
+               len = 2;
                break;
 
        /* Note that these are broken vs. the expected smbus API where
@@ -105,28 +95,35 @@ static s32 i2c_powermac_smbus_xfer(        struct i2c_adapter*     adap,
         * a repeat start/addr phase (but not stop in between)
         */
         case I2C_SMBUS_BLOCK_DATA:
-               rc = pmac_i2c_setmode(bus, read ?
-                                     pmac_i2c_mode_combined :
-                                     pmac_i2c_mode_stdsub);
-               if (rc)
-                       goto bail;
-               rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
-                                  data->block[0] + 1);
-
+               buf = data->block;
+               len = data->block[0] + 1;
                break;
        case I2C_SMBUS_I2C_BLOCK_DATA:
-               rc = pmac_i2c_setmode(bus, read ?
-                                     pmac_i2c_mode_combined :
-                                     pmac_i2c_mode_stdsub);
-               if (rc)
-                       goto bail;
-               rc = pmac_i2c_xfer(bus, addrdir, 1, command,
-                                  &data->block[1], data->block[0]);
+               buf = &data->block[1];
+               len = data->block[0];
                break;
 
         default:
-               rc = -EINVAL;
+               return -EINVAL;
        }
+
+       rc = pmac_i2c_open(bus, 0);
+       if (rc)
+               return rc;
+
+       rc = pmac_i2c_setmode(bus, mode);
+       if (rc)
+               goto bail;
+
+       rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
+       if (rc)
+               goto bail;
+
+       if (size == I2C_SMBUS_WORD_DATA && read) {
+               data->word = ((u16)local[1]) << 8;
+               data->word |= local[0];
+       }
+
  bail:
        pmac_i2c_close(bus);
        return rc;