Hi Luca, Jacopo, Wolfram, Peter, On 09/08/2019 11:45 PM, Vladimir Zapolskiy wrote: > Hi Luca, Jacopo, Wolfram, Peter, > > On 09/01/2019 05:31 PM, jacopo mondi wrote: >> Hi Luca, >> thanks for keep pushing this series! I hope we can use part of this >> for the (long time) on-going GMSL work... >> >> I hope you will be patient enough to provide (another :) overview >> of this work during the BoF Wolfram has organized at LPC for the next >> week. >> >> In the meantime I would have some comments after having a read at the >> series and trying to apply its concept to GMSL >> > > I won't attend the LPC, however I would appreciate if you book some > time to review my original / alternative implementation of the TI > DS90Ux9xx I2C bridge device driver. > > For your convenience the links to the driver are given below: > * dt bindings: https://lore.kernel.org/lkml/20181012060314.GU4939@dell/T/#mead5ea226550b > * driver code: https://lore.kernel.org/lkml/20181012060314.GU4939@dell/T/#m2fe3664c5f884 > * usage example: https://lore.kernel.org/lkml/20181012060314.GU4939@dell/T/#m56c146f5decdc > > The reasons why my driver is better/more flexible/more functional are > discussed earlier, please let me know, if you expect anything else > from me to add, also I would be happy to get a summary of your offline > discussion. I forgot to repeat my main objection against Luca's approach, the TI DS90Ux9xx I2C bridge driver does not require to call i2c_add_adapter() or register a new mux/bus and then do run select/deselect in runtime to overcome the created handicap. > The undeniable fact is that the device tree bindings in my I2C bridge > implementation can be improved further, thanks to Luca for the comments. > >> On Tue, Jul 23, 2019 at 10:37:19PM +0200, Luca Ceresoli wrote: >>> An ATR is a device that looks similar to an i2c-mux: it has an I2C >>> slave "upstream" port and N master "downstream" ports, and forwards >>> transactions from upstream to the appropriate downstream port. But is >>> is different in that the forwarded transaction has a different slave >>> address. The address used on the upstream bus is called the "alias" >>> and is (potentially) different from the physical slave address of the >>> downstream chip. >>> >>> Add a helper file (just like i2c-mux.c for a mux or switch) to allow >>> implementing ATR features in a device driver. The helper takes care or >>> adapter creation/destruction and translates addresses at each transaction. >>> >>> Signed-off-by: Luca Ceresoli <luca@xxxxxxxxxxxxxxxx> >>> > -- Best wishes, Vladimir
