Hi Miquel, On lun., oct. 09 2017, Miquel RAYNAL <miquel.raynal@xxxxxxxxxxxxxxxxxx> wrote: > Hi Thomas, Gregory, > > On Fri, 6 Oct 2017 15:15:21 +0200 > Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx> wrote: > >> Hello, >> >> On Fri, 06 Oct 2017 15:01:18 +0200, Gregory CLEMENT wrote: >> >> > /* >> > * To enable the second UART on J17 (pins 24,26) refer to the uart1 >> > * node from armada-3720-db.dts. >> > * Note that TX and RX signal are the ones coming directly from >> > the SoC: >> > * 1.8V TTL. >> > */ >> >> One issue with this comment (and Miquèl's version as well) is that it >> does not explain why you don't enable this UART by default. >> >> The real reason is in the commit log from Miquèl, and should probably >> be part of the comment. Perhaps something like: >> >> /* >> >> * Connector J17 (pins X, Y, Z) exposes a number of different >> * features: >> * - UART1 (pins 24 = RX, pins 26 = TX), see armada-3720-db.dts for >> an >> * example on how to enable UART1. Beware that the signals are 1.8V >> * TTL. >> * - SPIxyz >> * - I2Cxyz >> */ > > Thanks for both your comments, there is my version, inspired from both > comments: > > /* > * Connector J17 exposes a number of different features. Some pins are > * multiplexed. This is the case for the UART1 feature (pins 24 = RX, > * pins 26 = TX). See armada-3720-db.dts for an example of how to enable it. > * Beware that the signals are 1.8V TTL. > */ Seems good for me however I prefer Thomas version, easier to read and to extend latter with the description of other pins if needed. Gregory > > Thanks, > Miquèl > >> >> Otherwise, it's not clear at all why you don't just enable UART1. Or >> perhaps I misunderstood Miquèl's commit log ? >> >> Best regards, >> >> Thomas > > > > -- > Miquel Raynal, Free Electrons > Embedded Linux and Kernel engineering > http://free-electrons.com -- Gregory Clement, Free Electrons Kernel, drivers, real-time and embedded Linux development, consulting, training and support. http://free-electrons.com -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
