Hi, On 04/04/2014 02:26 PM, Wolfram Sang wrote: > >> So what we really have is a single slave i2c host sort of. At least >> we could model it like that. The host could be told which address to >> listen to (and which single i2c write to do to init the pmic) through >> devicetree and then all the differences would be hidden in the host >> driver, ie we would check the slave-address and if it is not the single >> one we support, we just return the appropriate error for a device not >> acking, and everything should work as a regular i2c host which >> only supports i2c_smbus_read_byte and i2c_smbus_write_byte. > > I'd think we need a new message flag like I2C_M_PUSHPULL which says that > this message has only the direction bit instead of the address and needs > a parity bit afterwards. In addition to that, we need a new > functionality flag I2C_FUNC_PUSHPULL which means the host driver can > handle those messages. So, the PMIC driver could query support for > I2C_FUNC_SMBUS_BYTE | I2C_FUNC_PUSHPULL and if successful send messages > using smbus functions with the new flag set. Thanks for the input this sounds good, I guess we'll give this a shot when we get around to coding up support for the p2wi block in the A31. > Not sure about the I2C-to-PushPull switch: Is it 100% host configuration > or does it also depend on the one slave attached? The datasheet we've suggests that it actually influences the one slave attached. Note that u-boot on this machines will likely already have made the switch, but I guess we don't want to count on that. > Are there some datasheets available? The AXP221 is documented here: http://linux-sunxi.org/AXP221 This is translated by one of our community members from a Chinese datasheet. The P2WI interface is (somewhat) documented in the A31 datasheet, but we cannot share that in public. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
