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i2c-core: Return -Errno, not -1
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More updates to the I2C stack's fault reporting:  make the core stop
returning "-1" (usually "-EPERM") for all faults.  Instead, pass lower
level fault code up the stack, or return some appropriate errno.

This patch happens to touch almost exclusively SMBus calls.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
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David Brownell authored and Jean Delvare committed Jul 14, 2008
1 parent 7541549 commit 24a5bb7
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Showing 2 changed files with 57 additions and 48 deletions.
8 changes: 4 additions & 4 deletions Documentation/i2c/writing-clients
View file
Original file line number Diff line number Diff line change
Expand Up @@ -598,10 +598,10 @@ be added back later if needed:
u8 command, u8 length,
u8 *values)

All these transactions return -1 on failure. The 'write' transactions
return 0 on success; the 'read' transactions return the read value, except
for read_block, which returns the number of values read. The block buffers
need not be longer than 32 bytes.
All these transactions return a negative errno value on failure. The 'write'
transactions return 0 on success; the 'read' transactions return the read
value, except for block transactions, which return the number of values
read. The block buffers need not be longer than 32 bytes.

You can read the file `smbus-protocol' for more information about the
actual SMBus protocol.
Expand Down
97 changes: 53 additions & 44 deletions drivers/i2c/i2c-core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -974,7 +974,7 @@ int i2c_transfer(struct i2c_adapter * adap, struct i2c_msg *msgs, int num)
return ret;
} else {
dev_dbg(&adap->dev, "I2C level transfers not supported\n");
return -ENOSYS;
return -EOPNOTSUPP;
}
}
EXPORT_SYMBOL(i2c_transfer);
Expand Down Expand Up @@ -1106,7 +1106,7 @@ int i2c_probe(struct i2c_adapter *adapter,

dev_warn(&adapter->dev, "SMBus Quick command not supported, "
"can't probe for chips\n");
return -1;
return -EOPNOTSUPP;
}

/* Probe entries are done second, and are not affected by ignore
Expand Down Expand Up @@ -1298,7 +1298,7 @@ static int i2c_smbus_check_pec(u8 cpec, struct i2c_msg *msg)
if (rpec != cpec) {
pr_debug("i2c-core: Bad PEC 0x%02x vs. 0x%02x\n",
rpec, cpec);
return -1;
return -EBADMSG;
}
return 0;
}
Expand All @@ -1313,11 +1313,12 @@ EXPORT_SYMBOL(i2c_smbus_write_quick);
s32 i2c_smbus_read_byte(struct i2c_client *client)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,0,I2C_SMBUS_BYTE, &data))
return -1;
else
return data.byte;
int status;

status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, 0,
I2C_SMBUS_BYTE, &data);
return (status < 0) ? status : data.byte;
}
EXPORT_SYMBOL(i2c_smbus_read_byte);

Expand All @@ -1331,11 +1332,12 @@ EXPORT_SYMBOL(i2c_smbus_write_byte);
s32 i2c_smbus_read_byte_data(struct i2c_client *client, u8 command)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command, I2C_SMBUS_BYTE_DATA,&data))
return -1;
else
return data.byte;
int status;

status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, command,
I2C_SMBUS_BYTE_DATA, &data);
return (status < 0) ? status : data.byte;
}
EXPORT_SYMBOL(i2c_smbus_read_byte_data);

Expand All @@ -1352,11 +1354,12 @@ EXPORT_SYMBOL(i2c_smbus_write_byte_data);
s32 i2c_smbus_read_word_data(struct i2c_client *client, u8 command)
{
union i2c_smbus_data data;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command, I2C_SMBUS_WORD_DATA, &data))
return -1;
else
return data.word;
int status;

status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, command,
I2C_SMBUS_WORD_DATA, &data);
return (status < 0) ? status : data.word;
}
EXPORT_SYMBOL(i2c_smbus_read_word_data);

Expand Down Expand Up @@ -1390,11 +1393,13 @@ s32 i2c_smbus_read_block_data(struct i2c_client *client, u8 command,
u8 *values)
{
union i2c_smbus_data data;
int status;

if (i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, command,
I2C_SMBUS_BLOCK_DATA, &data))
return -1;
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, command,
I2C_SMBUS_BLOCK_DATA, &data);
if (status)
return status;

memcpy(values, &data.block[1], data.block[0]);
return data.block[0];
Expand All @@ -1421,14 +1426,16 @@ s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
u8 length, u8 *values)
{
union i2c_smbus_data data;
int status;

if (length > I2C_SMBUS_BLOCK_MAX)
length = I2C_SMBUS_BLOCK_MAX;
data.block[0] = length;
if (i2c_smbus_xfer(client->adapter,client->addr,client->flags,
I2C_SMBUS_READ,command,
I2C_SMBUS_I2C_BLOCK_DATA,&data))
return -1;
status = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
I2C_SMBUS_READ, command,
I2C_SMBUS_I2C_BLOCK_DATA, &data);
if (status < 0)
return status;

memcpy(values, &data.block[1], data.block[0]);
return data.block[0];
Expand Down Expand Up @@ -1469,6 +1476,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
};
int i;
u8 partial_pec = 0;
int status;

msgbuf0[0] = command;
switch(size) {
Expand Down Expand Up @@ -1518,10 +1526,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
} else {
msg[0].len = data->block[0] + 2;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) {
dev_err(&adapter->dev, "smbus_access called with "
"invalid block write size (%d)\n",
data->block[0]);
return -1;
dev_err(&adapter->dev,
"Invalid block write size %d\n",
data->block[0]);
return -EINVAL;
}
for (i = 1; i < msg[0].len; i++)
msgbuf0[i] = data->block[i-1];
Expand All @@ -1531,10 +1539,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
num = 2; /* Another special case */
read_write = I2C_SMBUS_READ;
if (data->block[0] > I2C_SMBUS_BLOCK_MAX) {
dev_err(&adapter->dev, "%s called with invalid "
"block proc call size (%d)\n", __func__,
dev_err(&adapter->dev,
"Invalid block write size %d\n",
data->block[0]);
return -1;
return -EINVAL;
}
msg[0].len = data->block[0] + 2;
for (i = 1; i < msg[0].len; i++)
Expand All @@ -1549,19 +1557,18 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
} else {
msg[0].len = data->block[0] + 1;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
dev_err(&adapter->dev, "i2c_smbus_xfer_emulated called with "
"invalid block write size (%d)\n",
data->block[0]);
return -1;
dev_err(&adapter->dev,
"Invalid block write size %d\n",
data->block[0]);
return -EINVAL;
}
for (i = 1; i <= data->block[0]; i++)
msgbuf0[i] = data->block[i];
}
break;
default:
dev_err(&adapter->dev, "smbus_access called with invalid size (%d)\n",
size);
return -1;
dev_err(&adapter->dev, "Unsupported transaction %d\n", size);
return -EOPNOTSUPP;
}

i = ((flags & I2C_CLIENT_PEC) && size != I2C_SMBUS_QUICK
Expand All @@ -1579,13 +1586,15 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
msg[num-1].len++;
}

if (i2c_transfer(adapter, msg, num) < 0)
return -1;
status = i2c_transfer(adapter, msg, num);
if (status < 0)
return status;

/* Check PEC if last message is a read */
if (i && (msg[num-1].flags & I2C_M_RD)) {
if (i2c_smbus_check_pec(partial_pec, &msg[num-1]) < 0)
return -1;
status = i2c_smbus_check_pec(partial_pec, &msg[num-1]);
if (status < 0)
return status;
}

if (read_write == I2C_SMBUS_READ)
Expand Down

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