diff options
author | Jean Delvare <khali@linux-fr.org> | 2007-07-12 08:12:29 -0400 |
---|---|---|
committer | Jean Delvare <khali@hyperion.delvare> | 2007-07-12 08:12:29 -0400 |
commit | 4b2643d7d9bdcd776749e17f73c168ddf02e93cb (patch) | |
tree | 1642900ea1c196cc27d120f0af4de44fff30633e /drivers/i2c/chips/eeprom.c | |
parent | ba7fbb723f50ab2607989a282af655fb0fab0492 (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/chips/eeprom.c')
-rw-r--r-- | drivers/i2c/chips/eeprom.c | 6 |
1 files changed, 4 insertions, 2 deletions
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) | |||
88 | dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice); | 88 | dev_dbg(&client->dev, "Starting eeprom update, slice %u\n", slice); |
89 | 89 | ||
90 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { | 90 | if (i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_READ_I2C_BLOCK)) { |
91 | for (i = slice << 5; i < (slice + 1) << 5; i += I2C_SMBUS_BLOCK_MAX) | 91 | for (i = slice << 5; i < (slice + 1) << 5; i += 32) |
92 | if (i2c_smbus_read_i2c_block_data(client, i, data->data + i) != I2C_SMBUS_BLOCK_MAX) | 92 | if (i2c_smbus_read_i2c_block_data(client, i, |
93 | 32, data->data + i) | ||
94 | != 32) | ||
93 | goto exit; | 95 | goto exit; |
94 | } else { | 96 | } else { |
95 | if (i2c_smbus_write_byte(client, slice << 5)) { | 97 | if (i2c_smbus_write_byte(client, slice << 5)) { |