From 4b2643d7d9bdcd776749e17f73c168ddf02e93cb Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Thu, 12 Jul 2007 14:12:29 +0200 Subject: 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 --- drivers/macintosh/windfarm_smu_sat.c | 28 ++++------------------------ 1 file changed, 4 insertions(+), 24 deletions(-) (limited to 'drivers/macintosh') diff --git a/drivers/macintosh/windfarm_smu_sat.c b/drivers/macintosh/windfarm_smu_sat.c index 1043b39aa123..351982bcec1b 100644 --- a/drivers/macintosh/windfarm_smu_sat.c +++ b/drivers/macintosh/windfarm_smu_sat.c @@ -67,26 +67,6 @@ static struct i2c_driver wf_sat_driver = { .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 @@ struct smu_sdbp_header *smu_sat_get_sdb_partition(unsigned int sat_id, int id, 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 @@ static int wf_sat_read_cache(struct wf_sat *sat) { 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 -- cgit v1.2.3-58-ga151