> -----Original Message----- > From: Wood Scott-B07421 > Sent: Friday, July 24, 2015 8:58 PM > To: Jain Priyanka-B32167 > Cc: linuxppc-dev@lists.ozlabs.org > Subject: Re: [PATCH][v2] powerpc/fsl-booke: Add T1040D4RDB/T1042D4RDB > board support > > On Wed, 2015-07-22 at 05:49 -0500, Jain Priyanka-B32167 wrote: > > > > > -----Original Message----- > > > From: Wood Scott-B07421 > > > Sent: Friday, July 17, 2015 10:37 PM > > > To: Jain Priyanka-B32167 > > > Cc: linuxppc-dev@lists.ozlabs.org > > > Subject: Re: [PATCH][v2] powerpc/fsl-booke: Add > > > T1040D4RDB/T1042D4RDB board support > > > > > > On Fri, 2015-07-17 at 01:17 -0500, Jain Priyanka-B32167 wrote: > > > > > > > > > -----Original Message----- > > > > > From: Wood Scott-B07421 > > > > > Sent: Friday, July 17, 2015 1:06 AM > > > > > To: Jain Priyanka-B32167 > > > > > Cc: linuxppc-dev@lists.ozlabs.org > > > > > Subject: Re: [PATCH][v2] powerpc/fsl-booke: Add > > > > > T1040D4RDB/T1042D4RDB board support > > > > > > > > > > > > + i2c@118100{ > > > > > > > + mux@77{ > > > > > > > + compatible = "nxp,pca9546"; > > > > > > > + reg = <0x77>; > > > > > > > + #address-cells = <1>; > > > > > > > + #size-cells = <0>; > > > > > > > + }; > > > > > > > + }; > > > > > > > > > > > > A mux with no nodes under it (and yet it has > > > > > > #address-cells/#size- cells)? > > > > > > What is it multiplexing? > > > > > > [Priyanka]: PCA9546 is i2c mux device , to which other i2c > > > > > > devices (up-to 8 > > > > > > ) can be further connected on output channels On T104xD4RDB, > > > > > > channel 0, 1, 3 line are connected to PEX device, Channel 2 to > > > > > > hdmi interface (initialization is done in u-boot only), other > > > > > > channels are > > > grounded. > > > > > > So, as such Linux is not using the second level I2C devices > > > > > > connected on this MUX device. So, I have not shown next level > > > hierarchy. > > > > > > Should I replace 'mux' with some other name? . Please suggest. > > > > > > > > > > The device tree describes the hardware, not just what Linux uses... > > > > > but what I don't understand is why you describe the mux at all > > > > > if you're not going to describe what goes underneath it. > > > > > > > > > [Jain Priyanka-B32167] : Is below looks OK? > > > > i2c@118100{ > > > > + i2c@77{ > > > > + compatible = "nxp,pca9546"; > > > > + reg = <0x77>; > > > > + #address-cells = <1>; > > > > + #size-cells = <0>; > > > > + }; > > > > + }; > > > > > > Where in my above comment did it appear that I was complaining about > > > the node name? > > > > > [Jain Priyanka-B32167] > > From what I understand: > > PCA9546 is a mux device and it would be good if we were able to > > present the I2C devices on output lines as subnodes like in case of > > B4qds board and then 'mux' name would have make more sense. > > The name "mux" makes more sense regardless. > > > But in case of T1040D4RDB board, output i2c lines are going to PEX > > slots, PCI connector. I am not aware of how to represents them as sub- > nodes in dts. > > OK, so you're saying the i2c devices are pluggable (and I'm assuming by "PEX > slots" you just mean that the physical slot is repurposed, not that the PCI > express protocol is involved)? Making a non-runtime-enumerable bus be > pluggable seems like a bad idea, but if that's really what has been done, > there needs to be a device tree that represents the entire system, not just > the motherboard. This could be done either via a dts file that /include/s the > motherboard dts, or via firmware dtb edits. The dts for the motherboard > should include the mux node with a comment explaining what the situation > is. > [Jain Priyanka-B32167] Is the below comment looks OK? "Output I2C data, clock lines (SDO/SC0,SD1/SC1 , SD2/SC2, SD3/SC3) are going mini PCI connector slot1, mini PCI connector slot2, HDMI connector, PEX slot respectively The sub-nodes will depend upon the device that will be connected on these slots"
> -Scott _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev