| Message ID | 20250225113939.49811-10-demonsingur@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | i2c: atr: allow usage of nested ATRs | expand |
On mardi 25 février 2025 12:39:37 heure normale d’Europe centrale Cosmin Tanislav wrote: > Some I2C ATRs can have other I2C ATRs as children. The I2C messages of > the child ATRs need to be forwarded as-is if the parent I2C ATR can > only do static mapping. > > In the case of GMSL, the deserializer I2C ATR actually doesn't have I2C > address remapping hardware capabilities, but it is able to select which > GMSL link to talk to, allowing it to change the address of the > serializer. > > The child ATRs need to have their alias pools defined in such a way to > prevent overlapping addresses between them, but there's no way around > this without orchestration between multiple ATR instances. > > To allow for this use-case, add a flag that allows unmapped addresses > to be passed through, since they are already remapped by the child ATRs. > > There's no case where an address that has not been remapped by the child > ATR will hit the parent ATR. > > Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com> > --- > drivers/i2c/i2c-atr.c | 3 +++ > include/linux/i2c-atr.h | 2 ++ > 2 files changed, 5 insertions(+) > > diff --git a/drivers/i2c/i2c-atr.c b/drivers/i2c/i2c-atr.c > index f7b853f55630..1986fa055f20 100644 > --- a/drivers/i2c/i2c-atr.c > +++ b/drivers/i2c/i2c-atr.c > @@ -394,6 +394,9 @@ static int i2c_atr_map_msgs(struct i2c_atr_chan *chan, > struct i2c_msg *msgs, c2a = i2c_atr_get_mapping_by_addr(chan, > msgs[i].addr); > > if (!c2a) { > + if (atr->flags & I2C_ATR_PASSTHROUGH) > + continue; Shouldn't this check also be added to i2c_atr_smbus_xfer? > + > dev_err(atr->dev, "client 0x%02x not mapped!\n", > msgs[i].addr); > > diff --git a/include/linux/i2c-atr.h b/include/linux/i2c-atr.h > index 2f79d0d9140f..b3797a930a7a 100644 > --- a/include/linux/i2c-atr.h > +++ b/include/linux/i2c-atr.h > @@ -22,9 +22,11 @@ struct i2c_atr; > * enum i2c_atr_flags - Flags for an I2C ATR driver > * > * @I2C_ATR_STATIC: ATR does not support dynamic mapping, use static > mapping + * @I2C_ATR_PASSTHROUGH: Allow unmapped incoming addresses to pass > through */ > enum i2c_atr_flags { > I2C_ATR_STATIC = BIT(0), > + I2C_ATR_PASSTHROUGH = BIT(1), As stated for the previous patch, I'd prefer the "I2C_ATR_F_*" naming convention. Thanks,
diff --git a/drivers/i2c/i2c-atr.c b/drivers/i2c/i2c-atr.c index f7b853f55630..1986fa055f20 100644 --- a/drivers/i2c/i2c-atr.c +++ b/drivers/i2c/i2c-atr.c @@ -394,6 +394,9 @@ static int i2c_atr_map_msgs(struct i2c_atr_chan *chan, struct i2c_msg *msgs, c2a = i2c_atr_get_mapping_by_addr(chan, msgs[i].addr); if (!c2a) { + if (atr->flags & I2C_ATR_PASSTHROUGH) + continue; + dev_err(atr->dev, "client 0x%02x not mapped!\n", msgs[i].addr); diff --git a/include/linux/i2c-atr.h b/include/linux/i2c-atr.h index 2f79d0d9140f..b3797a930a7a 100644 --- a/include/linux/i2c-atr.h +++ b/include/linux/i2c-atr.h @@ -22,9 +22,11 @@ struct i2c_atr; * enum i2c_atr_flags - Flags for an I2C ATR driver * * @I2C_ATR_STATIC: ATR does not support dynamic mapping, use static mapping + * @I2C_ATR_PASSTHROUGH: Allow unmapped incoming addresses to pass through */ enum i2c_atr_flags { I2C_ATR_STATIC = BIT(0), + I2C_ATR_PASSTHROUGH = BIT(1), }; /**
Some I2C ATRs can have other I2C ATRs as children. The I2C messages of the child ATRs need to be forwarded as-is if the parent I2C ATR can only do static mapping. In the case of GMSL, the deserializer I2C ATR actually doesn't have I2C address remapping hardware capabilities, but it is able to select which GMSL link to talk to, allowing it to change the address of the serializer. The child ATRs need to have their alias pools defined in such a way to prevent overlapping addresses between them, but there's no way around this without orchestration between multiple ATR instances. To allow for this use-case, add a flag that allows unmapped addresses to be passed through, since they are already remapped by the child ATRs. There's no case where an address that has not been remapped by the child ATR will hit the parent ATR. Signed-off-by: Cosmin Tanislav <demonsingur@gmail.com> --- drivers/i2c/i2c-atr.c | 3 +++ include/linux/i2c-atr.h | 2 ++ 2 files changed, 5 insertions(+)