Again, please don't top post. And your line wrapping is messed up. IOW, you can't use Outlook. On Tue, Dec 13, 2016 at 4:50 AM, Luis de Oliveira <Luis.Oliveira@xxxxxxxxxxxx> wrote: > The controller for i2c-designware cannot be slave/master at the same time and it has to be enabled knowing beforehand if we want it to be slave or master by something outside of the controller itself. > > I as looking and I see the use of this I2C_OWN_SLAVE_ADDRESS with the "linux,slave-24c02" slave interface but I am not seeing how it will help me identify a selected i2c-designware block as a "slave" device before instantiation. I'm sorry if I'm not understanding properly. > I use the "linux,slave-24c02" to instantiate the i2c-designware as a slave with an address so I can do write/read operations, it is how I tested it. Something like this: of_for_each_child_node(child) { of_property_read_u32(child, "reg", ®); if (reg & I2C_OWN_SLAVE_ADDRESS)) im_a_slave = true; } ...rather than testing "mode" is equal to "slave". Rob > > Luis > > -----Original Message----- > From: Rob Herring [mailto:robh@xxxxxxxxxx] > Sent: Monday, December 12, 2016 23:16 > To: Luis de Oliveira <Luis.Oliveira@xxxxxxxxxxxx> > Cc: wsa@xxxxxxxxxxxxx; mark.rutland@xxxxxxx; jarkko.nikula@xxxxxxxxxxxxxxx; andriy.shevchenko@xxxxxxxxxxxxxxx; mika.westerberg@xxxxxxxxxxxxxxx; linux-i2c@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Ramiro.Oliveira@xxxxxxxxxxxx; Joao.Pinto@xxxxxxxxxxxx; CARLOS.PALMINHA@xxxxxxxxxxxx > Subject: Re: [PATCH v4 3/5] i2c: designware: Add slave definitions > > On Mon, Dec 12, 2016 at 12:35 PM, Luis de Oliveira <Luis.Oliveira@xxxxxxxxxxxx> wrote: >> Hi all, > > Please don't top post. > >> >> The slave address could be set by the I2C slave backend so I can't use it to setup the controller. >> A boolean property was my initial approach then Andy and Wolfram Sang suggested the use of compatible strings and later It was suggested to use a property to select mode but I can do it again if it's the best way. >> Can you please tell me where should it be documented? > > bindings/i2c/i2c.txt. > > Actually, looking at this some more, we already have a way to describe the controller being a slave device with the I2C_OWN_SLAVE_ADDRESS flag in the reg property. We should just need a helper to read reg property of each child and check for the bit set. > > Rob -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html