[PATCH v2 2/2] ARM: dts: aspeed: Add Facebook Backpack-CMM BMC

[Andrew Jeffery]

On Thu, 8 Nov 2018, at 11:16, Tao Ren wrote:
> On 11/7/18 4:24 PM, Andrew Jeffery wrote:
> 
> >> +&uart1 {
> >> +	status = "okay";
> >> +};
> >> +
> >> +&uart3 {
> >> +	status = "okay";
> >> +};
> >> +
> >> +&uart4 {
> >> +	status = "okay";
> >> +};
> > 
> > UARTs 1-4 should be explicitly pinmuxed. It's a bit fiddly as each of the UART lines has its own mux configuration, but it at least allows some flexibility (i.e. whether you just want Rx/Tx, or something more). See e.g. the uart1 node in arch/arm/boot/dts/aspeed-bmc-opp-romulus.dts.
> 
> Thank you for pointing it out and I will fix it.
> 
> > Speaking of pinctrl, as it's an AST2500 system you'll probably want to add the following to ensure you have full control of the pinmux configuration:
> > 
> > &pinctrl {
> > 	aspeed,external-nodes = <&gfx &lhc>;
> > };
> > 
> >> +
> >> +&uart5 {
> >> +	status = "okay";
> >> +};
> > 
> > UART5 has fixed pins, so no pinctrl necessary here.
> 
> Got it. Thank you.
> 
> 
> > You said this in the commit message:
> > 
> >> Note: I2C devices on Backpack Line Cards and Fabric Cards are not
> >> listed in the device tree file because Line/Fabric Cards may be
> >> unplugged.
> > 
> > It's not clear to me what this actually means, and I'm trying to reconcile it with enabling all of the i2c buses as I'm curious as to whether that's necessary.
> 
> Sorry for the confusion. In general, all the i2c buses are initialized 
> in device tree, but i2c leaf devices are created from user space because 
> these i2c devices may be unplugged at boot time (which causes 
> driver_probe failures).

This is what I was thinking, was just after some clarification.

> Let me refine the commit message and will send 
> out updated patch soon.

Thanks.

Andrew

> 
> Thanks,
> Tao Ren