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>
diff --git a/drivers/macintosh/windfarm_smu_sat.c b/drivers/macintosh/windfarm_smu_sat.c
index 1043b39..351982b 100644
--- a/drivers/macintosh/windfarm_smu_sat.c
+++ b/drivers/macintosh/windfarm_smu_sat.c
@@ -67,26 +67,6 @@
.detach_client = wf_sat_detach,
};
-/*
- * XXX i2c_smbus_read_i2c_block_data doesn't pass the requested
- * length down to the low-level driver, so we use this, which
- * works well enough with the SMU i2c driver code...
- */
-static int sat_read_block(struct i2c_client *client, u8 command,
- u8 *values, int len)
-{
- union i2c_smbus_data data;
- int err;
-
- data.block[0] = len;
- err = i2c_smbus_xfer(client->adapter, client->addr, client->flags,
- I2C_SMBUS_READ, command, I2C_SMBUS_I2C_BLOCK_DATA,
- &data);
- if (!err)
- memcpy(values, data.block, len);
- return err;
-}
-
struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id,
unsigned int *size)
{
@@ -124,8 +104,8 @@
return NULL;
for (i = 0; i < len; i += 4) {
- err = sat_read_block(&sat->i2c, 0xa, data, 4);
- if (err) {
+ err = i2c_smbus_read_i2c_block_data(&sat->i2c, 0xa, 4, data);
+ if (err < 0) {
printk(KERN_ERR "smu_sat_get_sdb_part rd err %d\n",
err);
goto fail;
@@ -157,8 +137,8 @@
{
int err;
- err = sat_read_block(&sat->i2c, 0x3f, sat->cache, 16);
- if (err)
+ err = i2c_smbus_read_i2c_block_data(&sat->i2c, 0x3f, 16, sat->cache);
+ if (err < 0)
return err;
sat->last_read = jiffies;
#ifdef LOTSA_DEBUG