On Thu, 2015-07-16 at 04:34 -0500, Jain Priyanka-B32167 wrote:
>
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, July 15, 2015 11:17 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, 2015-07-15 at 15:00 +0530, Priyanka Jain wrote:
> > T1040D4RDB/T1042D4RDB are Freescale Reference Design Board which can
> > support T1040/T1042 QorIQ Power Architecture™ processor respectively
> >
> > T1040D4RDB/T1042D4RDB board Overview
> > -------------------------------------
> > - SERDES Connections, 8 lanes supporting:
> > - PCI
> > - SGMII
> > - SATA 2.0
> > - QSGMII(only for T1040D4RDB)
> > - DDR Controller
> > - Supports rates of up to 1600 MHz data-rate
> > - Supports one DDR4 UDIMM
> > -IFC/Local Bus
> > - NAND flash: 1GB 8-bit NAND flash
> > - NOR: 128MB 16-bit NOR Flash
> > - Ethernet
> > - Two on-board RGMII 10/100/1G ethernet ports.
> > - PHY #0 remains powered up during deep-sleep
> > - CPLD
> > - Clocks
> > - System and DDR clock (SYSCLK, “DDRCLK”)
> > - SERDES clocks
> > - Power Supplies
> > - USB
> > - Supports two USB 2.0 ports with integrated PHYs
> > - Two type A ports with 5V@1.5Aperport.
> > - SDHC
> > - SDHC/SDXC connector
> > - SPI
> > - On-board 64MB SPI flash
> > - I2C
> > - Devices connected: EEPROM, thermal monitor, VID controller
> > - Other IO
> > - Two Serial ports
> > - ProfiBus port
> >
> > Add support for T1040/T1042D4RDB board:
> > -add device tree
> > -Add entry in corenet_generic.c
> >
> > Signed-off-by: Priyanka Jain <priyanka.j...@freescale.com>
> > ---
> > Changes for v2:
> > Incorporated Scott's comments on device tree
>
> You didn't respond to the comments on the CPLD node.
> [Priyanka]
> T1042D4RDB, T1040D4RDB are derivatives of same board , CPLD is same for
> both.
> So, I have moved below node having compatible and reg field together in
> t104xd4rdb.dtsi.
> Is this fine?
> cpld@3,0 {
> compatible = "fsl,t1040d4rdb-cpld";
> reg = <3 0 0x300>;
> };
If the CPLD image is exactly the same on both, this is fine.
> > + 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.
-Scott
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