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authorJean Delvare <khali@linux-fr.org>2007-07-12 14:12:29 +0200
committerJean Delvare <khali@hyperion.delvare>2007-07-12 14:12:29 +0200
commit4b2643d7d9bdcd776749e17f73c168ddf02e93cb (patch)
tree1642900ea1c196cc27d120f0af4de44fff30633e /drivers/i2c
parentba7fbb723f50ab2607989a282af655fb0fab0492 (diff)
i2c: Fix the i2c_smbus_read_i2c_block_data() prototype
Let the drivers specify how many bytes they want to read with i2c_smbus_read_i2c_block_data(). So far, the block count was hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense. Many driver authors complained about this before, and I believe it's about time to fix it. Right now, authors have to do technically stupid things, such as individual byte reads or full-fledged I2C messaging, to work around the problem. We do not want to encourage that. I even found that some bus drivers (e.g. i2c-amd8111) already implemented I2C block read the "right" way, that is, they didn't follow the old, broken standard. The fact that it was never noticed before just shows how little i2c_smbus_read_i2c_block_data() was used, which isn't that surprising given how broken its prototype was so far. There are some obvious compatiblity considerations: * This changes the i2c_smbus_read_i2c_block_data() prototype. Users outside the kernel tree will notice at compilation time, and will have to update their code. * User-space has access to i2c_smbus_xfer() directly using i2c-dev, so the changed expectations would affect tools such as i2cdump. In order to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the old numeric value. When i2c-dev receives a transaction with the old value, it can convert it to the new format on the fly. Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'drivers/i2c')
-rw-r--r--drivers/i2c/busses/i2c-powermac.c3
-rw-r--r--drivers/i2c/busses/i2c-viapro.c2
-rw-r--r--drivers/i2c/busses/scx200_acb.c2
-rw-r--r--drivers/i2c/chips/eeprom.c6
-rw-r--r--drivers/i2c/chips/max6875.c1
-rw-r--r--drivers/i2c/i2c-core.c12
-rw-r--r--drivers/i2c/i2c-dev.c9
7 files changed, 23 insertions, 12 deletions
diff --git a/drivers/i2c/busses/i2c-powermac.c b/drivers/i2c/busses/i2c-powermac.c
index 1425d2245c82..0ab4f2627c26 100644
--- a/drivers/i2c/busses/i2c-powermac.c
+++ b/drivers/i2c/busses/i2c-powermac.c
@@ -121,8 +121,7 @@ static s32 i2c_powermac_smbus_xfer( struct i2c_adapter* adap,
if (rc)
goto bail;
rc = pmac_i2c_xfer(bus, addrdir, 1, command,
- read ? data->block : &data->block[1],
- data->block[0]);
+ &data->block[1], data->block[0]);
break;
default:
diff --git a/drivers/i2c/busses/i2c-viapro.c b/drivers/i2c/busses/i2c-viapro.c
index 7a2bc06304fc..a0f7e4a303b5 100644
--- a/drivers/i2c/busses/i2c-viapro.c
+++ b/drivers/i2c/busses/i2c-viapro.c
@@ -235,7 +235,7 @@ static s32 vt596_access(struct i2c_adapter *adap, u16 addr,
if (!(vt596_features & FEATURE_I2CBLOCK))
goto exit_unsupported;
if (read_write == I2C_SMBUS_READ)
- outb_p(I2C_SMBUS_BLOCK_MAX, SMBHSTDAT0);
+ outb_p(data->block[0], SMBHSTDAT0);
/* Fall through */
case I2C_SMBUS_BLOCK_DATA:
outb_p(command, SMBHSTCMD);
diff --git a/drivers/i2c/busses/scx200_acb.c b/drivers/i2c/busses/scx200_acb.c
index dc64f8b6b24a..e6c4a2b762ec 100644
--- a/drivers/i2c/busses/scx200_acb.c
+++ b/drivers/i2c/busses/scx200_acb.c
@@ -310,8 +310,6 @@ static s32 scx200_acb_smbus_xfer(struct i2c_adapter *adapter,
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
- if (rw == I2C_SMBUS_READ)
- data->block[0] = I2C_SMBUS_BLOCK_MAX; /* For now */
len = data->block[0];
if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
return -EINVAL;
diff --git a/drivers/i2c/chips/eeprom.c b/drivers/i2c/chips/eeprom.c
index bfce13c8f1ff..48f857ae8748 100644
--- a/drivers/i2c/chips/eeprom.c
+++ b/drivers/i2c/chips/eeprom.c
@@ -88,8 +88,10 @@ static void eeprom_update_client(struct i2c_client *client, u8 slice)
dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice);
if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
- for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX)
- if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX)
+ for (i = slice << 5; i < (slice + 1) << 5; i += 32)
+ if (i2c_smbus_read_i2c_block_data(client, i,
+ 32, data->data + i)
+ != 32)
goto exit;
} else {
if (i2c_smbus_write_byte(client, slice << 5)) {
diff --git a/drivers/i2c/chips/max6875.c b/drivers/i2c/chips/max6875.c
index 76645c142977..e9e9e5171b53 100644
--- a/drivers/i2c/chips/max6875.c
+++ b/drivers/i2c/chips/max6875.c
@@ -106,6 +106,7 @@ static void max6875_update_slice(struct i2c_client *client, int slice)
I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
if (i2c_smbus_read_i2c_block_data(client,
MAX6875_CMD_BLK_READ,
+ SLICE_SIZE,
buf) != SLICE_SIZE) {
goto exit_up;
}
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index cccfa8678245..6971a62397db 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1344,10 +1344,14 @@ s32 i2c_smbus_write_block_data(struct i2c_client *client, u8 command,
EXPORT_SYMBOL(i2c_smbus_write_block_data);
/* Returns the number of read bytes */
-s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command, u8 *values)
+s32 i2c_smbus_read_i2c_block_data(struct i2c_client *client, u8 command,
+ u8 length, u8 *values)
{
union i2c_smbus_data data;
+ 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))
@@ -1468,7 +1472,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
if (read_write == I2C_SMBUS_READ) {
- msg[1].len = I2C_SMBUS_BLOCK_MAX;
+ msg[1].len = data->block[0];
} else {
msg[0].len = data->block[0] + 1;
if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) {
@@ -1524,9 +1528,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter * adapter, u16 addr,
data->word = msgbuf1[0] | (msgbuf1[1] << 8);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
- /* fixed at 32 for now */
- data->block[0] = I2C_SMBUS_BLOCK_MAX;
- for (i = 0; i < I2C_SMBUS_BLOCK_MAX; i++)
+ for (i = 0; i < data->block[0]; i++)
data->block[i+1] = msgbuf1[i];
break;
case I2C_SMBUS_BLOCK_DATA:
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c
index e7a709710592..64eee9551b22 100644
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -283,6 +283,7 @@ static int i2cdev_ioctl(struct inode *inode, struct file *file,
(data_arg.size != I2C_SMBUS_WORD_DATA) &&
(data_arg.size != I2C_SMBUS_PROC_CALL) &&
(data_arg.size != I2C_SMBUS_BLOCK_DATA) &&
+ (data_arg.size != I2C_SMBUS_I2C_BLOCK_BROKEN) &&
(data_arg.size != I2C_SMBUS_I2C_BLOCK_DATA) &&
(data_arg.size != I2C_SMBUS_BLOCK_PROC_CALL)) {
dev_dbg(&client->adapter->dev,
@@ -329,10 +330,18 @@ static int i2cdev_ioctl(struct inode *inode, struct file *file,
if ((data_arg.size == I2C_SMBUS_PROC_CALL) ||
(data_arg.size == I2C_SMBUS_BLOCK_PROC_CALL) ||
+ (data_arg.size == I2C_SMBUS_I2C_BLOCK_DATA) ||
(data_arg.read_write == I2C_SMBUS_WRITE)) {
if (copy_from_user(&temp, data_arg.data, datasize))
return -EFAULT;
}
+ if (data_arg.size == I2C_SMBUS_I2C_BLOCK_BROKEN) {
+ /* Convert old I2C block commands to the new
+ convention. This preserves binary compatibility. */
+ data_arg.size = I2C_SMBUS_I2C_BLOCK_DATA;
+ if (data_arg.read_write == I2C_SMBUS_READ)
+ temp.block[0] = I2C_SMBUS_BLOCK_MAX;
+ }
res = i2c_smbus_xfer(client->adapter,client->addr,client->flags,
data_arg.read_write,
data_arg.command,data_arg.size,&temp);