i2c: Bus drivers return -Errno not -1

Tighten error paths used by various i2c adapters (mostly x86) so
they return real fault/errno codes instead of a "-1" (which is
most often interpreted as "-EPERM").  Build tested, with eyeball
review.

One minor initial goal is to have adapters consistently return
the code "-ENXIO" when addressing a device doesn't get an ACK
response, at least in the probe paths where they are already
good at stifling related logspam.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 11 insertions, 9 deletions

diff --git a/drivers/i2c/busses/i2c-piix4.c b/drivers/i2c/busses/i2c-piix4.c
index ac9165968587..dc76c0e2dc65 100644
--- a/drivers/i2c/busses/i2c-piix4.c
+++ b/drivers/i2c/busses/i2c-piix4.c
@@ -253,7 +253,7 @@ static int piix4_transaction(void)
                 outb_p(temp, SMBHSTSTS);
                 if ((temp = inb_p(SMBHSTSTS)) != 0x00) {
                         dev_err(&piix4_adapter.dev, "Failed! (%02x)\n", temp);
-                        return -1;
+                        return -EBUSY;
                 } else {
                         dev_dbg(&piix4_adapter.dev, "Successful!\n");
                 }
@@ -275,23 +275,23 @@ static int piix4_transaction(void)
         /* If the SMBus is still busy, we give up */
         if (timeout >= MAX_TIMEOUT) {
                 dev_err(&piix4_adapter.dev, "SMBus Timeout!\n");
-                result = -1;
+                result = -ETIMEDOUT;
         }
 
         if (temp & 0x10) {
-                result = -1;
+                result = -EIO;
                 dev_err(&piix4_adapter.dev, "Error: Failed bus transaction\n");
         }
 
         if (temp & 0x08) {
-                result = -1;
+                result = -EIO;
                 dev_dbg(&piix4_adapter.dev, "Bus collision! SMBus may be "
                         "locked until next hard reset. (sorry!)\n");
                 /* Clock stops and slave is stuck in mid-transmission */
         }
 
         if (temp & 0x04) {
-                result = -1;
+                result = -ENXIO;
                 dev_dbg(&piix4_adapter.dev, "Error: no response!\n");
         }
 
@@ -309,17 +309,18 @@ static int piix4_transaction(void)
         return result;
 }
 
-/* Return -1 on error. */
+/* Return negative errno on error. */
 static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
                  unsigned short flags, char read_write,
                  u8 command, int size, union i2c_smbus_data * data)
 {
         int i, len;
+        int status;
 
         switch (size) {
         case I2C_SMBUS_PROC_CALL:
                 dev_err(&adap->dev, "I2C_SMBUS_PROC_CALL not supported!\n");
-                return -1;
+                return -EOPNOTSUPP;
         case I2C_SMBUS_QUICK:
                 outb_p(((addr & 0x7f) << 1) | (read_write & 0x01),
                        SMBHSTADD);
@@ -371,8 +372,9 @@ static s32 piix4_access(struct i2c_adapter * adap, u16 addr,
 
         outb_p((size & 0x1C) + (ENABLE_INT9 & 1), SMBHSTCNT);
 
-        if (piix4_transaction())        /* Error in transaction */
-                return -1;
+        status = piix4_transaction();
+        if (status)
+                return status;
 
         if ((read_write == I2C_SMBUS_WRITE) || (size == PIIX4_QUICK))
                 return 0;