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, 31 insertions, 16 deletions

diff --git a/drivers/i2c/busses/i2c-amd8111.c b/drivers/i2c/busses/i2c-amd8111.c
index 5d1a27ef2504..a4f687915de1 100644
--- a/drivers/i2c/busses/i2c-amd8111.c
+++ b/drivers/i2c/busses/i2c-amd8111.c
@@ -77,7 +77,7 @@ static unsigned int amd_ec_wait_write(struct amd_smbus *smbus)
         if (!timeout) {
                 dev_warn(&smbus->dev->dev,
                          "Timeout while waiting for IBF to clear\n");
-                return -1;
+                return -ETIMEDOUT;
         }
 
         return 0;
@@ -93,7 +93,7 @@ static unsigned int amd_ec_wait_read(struct amd_smbus *smbus)
         if (!timeout) {
                 dev_warn(&smbus->dev->dev,
                          "Timeout while waiting for OBF to set\n");
-                return -1;
+                return -ETIMEDOUT;
         }
 
         return 0;
@@ -102,16 +102,21 @@ static unsigned int amd_ec_wait_read(struct amd_smbus *smbus)
 static unsigned int amd_ec_read(struct amd_smbus *smbus, unsigned char address,
                 unsigned char *data)
 {
-        if (amd_ec_wait_write(smbus))
-                return -1;
+        int status;
+
+        status = amd_ec_wait_write(smbus);
+        if (status)
+                return status;
         outb(AMD_EC_CMD_RD, smbus->base + AMD_EC_CMD);
 
-        if (amd_ec_wait_write(smbus))
-                return -1;
+        status = amd_ec_wait_write(smbus);
+        if (status)
+                return status;
         outb(address, smbus->base + AMD_EC_DATA);
 
-        if (amd_ec_wait_read(smbus))
-                return -1;
+        status = amd_ec_wait_read(smbus);
+        if (status)
+                return status;
         *data = inb(smbus->base + AMD_EC_DATA);
 
         return 0;
@@ -120,16 +125,21 @@ static unsigned int amd_ec_read(struct amd_smbus *smbus, unsigned char address,
 static unsigned int amd_ec_write(struct amd_smbus *smbus, unsigned char address,
                 unsigned char data)
 {
-        if (amd_ec_wait_write(smbus))
-                return -1;
+        int status;
+
+        status = amd_ec_wait_write(smbus);
+        if (status)
+                return status;
         outb(AMD_EC_CMD_WR, smbus->base + AMD_EC_CMD);
 
-        if (amd_ec_wait_write(smbus))
-                return -1;
+        status = amd_ec_wait_write(smbus);
+        if (status)
+                return status;
         outb(address, smbus->base + AMD_EC_DATA);
 
-        if (amd_ec_wait_write(smbus))
-                return -1;
+        status = amd_ec_wait_write(smbus);
+        if (status)
+                return status;
         outb(data, smbus->base + AMD_EC_DATA);
 
         return 0;
@@ -267,12 +277,17 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
 
                 default:
                         dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
-                        return -1;
+                        return -EOPNOTSUPP;
         }
 
         amd_ec_write(smbus, AMD_SMB_ADDR, addr << 1);
         amd_ec_write(smbus, AMD_SMB_PRTCL, protocol);
 
+        /* FIXME this discards status from ec_read(); so temp[0] will
+         * hold stack garbage ... the rest of this routine will act
+         * nonsensically.  Ignored ec_write() status might explain
+         * some such failures...
+         */
         amd_ec_read(smbus, AMD_SMB_STS, temp + 0);
 
         if (~temp[0] & AMD_SMB_STS_DONE) {
@@ -286,7 +301,7 @@ static s32 amd8111_access(struct i2c_adapter * adap, u16 addr,
         }
 
         if ((~temp[0] & AMD_SMB_STS_DONE) || (temp[0] & AMD_SMB_STS_STATUS))
-                return -1;
+                return -EIO;
 
         if (read_write == I2C_SMBUS_WRITE)
                 return 0;