i2c: rcar: document HW incapabilities

Add recent findings (IGNORE_NAK) and document in a bit more detail why
the feature is not possible.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Wolfram Sang 2017-06-19 23:41:46 +02:00 committed by Wolfram Sang
parent f64622167f
commit b395ba2169

View File

@ -783,7 +783,12 @@ static int rcar_unreg_slave(struct i2c_client *slave)
static u32 rcar_i2c_func(struct i2c_adapter *adap)
{
/* This HW can't do SMBUS_QUICK and NOSTART */
/*
* This HW can't do:
* I2C_SMBUS_QUICK (setting FSB during START didn't work)
* I2C_M_NOSTART (automatically sends address after START)
* I2C_M_IGNORE_NAK (automatically sends STOP after NAK)
*/
return I2C_FUNC_I2C | I2C_FUNC_SLAVE |
(I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
}